Table of Contents
Format for Geography paper one ————-6
Introduction to Geography——————–7
Weather and Climate ————————44
Map and Map work —————————117
Field Work ———————————–188
Mineral and salts —————————-206
Internal land forming processes————241
External land forming processes ———–307
Soils ——————– ———————458
Vegetation ———————————–480
Format for Geography paper two ———-517
Statistics one and two ———————-518
Mining —————————————562
Forestry————————————-583
Photography ——————————–604
Agriculture———————————-620
Land reclamation and rehabilitation ——-692
Fishing ————————————–706
Wildlife and tourism ———————–737
Energy ————————————- 767
Industry ————————————787
Trade —————————————815
GEOGRAPHY (312)
PAPER ONE
INTRODUCTION
Questions in this paper will mainly test topics on physical Geography, map interpretation and field work.
Topics on physical geography topics include:
The earth and solar system.
The internal land forming processes.
The external land forming process.
Weather and climate.
Soils and Vegetation.
The time allocated for this paper is 2 ½ hours
The paper consist of a total of 100 marks
The paper shall consist of two section: : Section A and B
Section A
This section will have 25 marks compulsory short answer questions sampled from topics on Physical Geography.
Section B S
This section will have 75 marks
One compulsory question on topographical map, (25marks).
A choice of four (4) essay questions on physical Geography and Field work, candidates to answer any two (2).
Specific Objectives
By the end of the topic the learner should be able to:
Define the terms Geography and Environment;
Describe the branches of Geography;
Explain the importance of studying Geography;
Explain the relationship between geography and other disciplines.
Content
a.)Definition of:
Geography.
Environment.
b.)Branches of Geography:
Physical geography. Human Geography.
c.)Importance of studying Geography.
d.)Relationship between geography and other disciplines.
Introduction
Geography is the scientific study of the earth as the home of human kind. The term Geography is derived from the Greek words: Geo and Graphein. Geo means Earth and graphien means to write, draw or describe. These two words are combined to form Geographein, which means to describe, write about or draw the earth.
Definition of environment
Environment refers to external conditions that surround living things. These conditions influence the behavior or activities of living things.
Environment can be divided into two parts:
i.) Physical Environment
External surrounding which is made up of the features that are not created by human beings a though their presence may have been influenced by human activities.
ii.) Human Environment
Comprises of activities of people on the earths surface.
Branches of Geography
There are two main branches:
i.) Physical Geography
It is concerned mainly with the land forming processes that shape the surface of the earth and the resulting features.
Areas of study under physical geography.
The external land forming processes.
Weather and climate.
Soil and vegetation.
The earth and the solar system.
ii.) Human Geography
It involves the study of human activities on the earth’s surface.
Areas of study under human geography.
Forestry
Wildlife, tourism and fishing.
Mining, energy and industries.
Population and urbanization.
Trade, transport and communication.
Agriculture.
Management and conservation of environment.
iii.) Physical Geography
This aspect gives learners an opportunity to develop practical skills.
Areas of study under practical geography.
Map work
Photography.
Field study and statistics
Importance of studying Geography
It is a career subject.
Creates awareness in the people on the significance of management and conservation of environment. iii.One is able to acquire basic skills and knowledge which contribute to local, regional and national development.
Through the study of field work, geography teaches one how to manage time properly by drawing a time schedule and adhering to it.
Encourages international awareness, interaction and cooperation.
It enables the learner to understand and appreciate different environmental influences at work on different societies.
We are able to learn and explain the origin of the earth, the solar system and the internal structure of the earth.
Geography and other subjects
Geography relate widely with other subjects as follows.
Chemistry
Geography applies Chemistry concepts in studying the chemical composition of rocks and soils.
Chemistry concepts are used in Geography to explain chemical changes that occur in rocks/soils.
Physics
Physics deal with matter, energy, light, heat, sound, gravity and magnetism while studying the atmosphere;
Geography focuses on heat from the sun as it’s responsible for movement of air, evaporation or water and distribution of moisture in the atmosphere.
Physics is a branch of Science concerned with study of matter and its properties; Physics is important in Geography as it is used to explain how important process such as faulting, folding and vulcanicity happen.
Agriculture
Agriculture deals with farming and involves the growing of crops and the rearing of livestock.
Geography studies the distribution of agricultural activities and how factors like relief, climate and soils affect them.
Also looks at both the positive and negative impact of agriculture on the environment.
Biology
This is the study of living things. A branch of biology called ecology dals with how living things relate to each other and the environment.
Biogeography which is a branch of geography is quite similar to ecology as it deals with the distribution of plants and animal life on the earth and their relationships to climate,soil,relief and other factors.
Meteorology and climatology
Meteorology is the study of atmospheric conditions of a given place at a specific time while climatology is the study of weather.
Geography as a discipline deals with all the elements of weather and the distribution of different climatic zones of the world.
Civil engineering
This is the branch of science that deals with the buildings and maintenance of structures like roads, bridges, railways, airports, dams and drainage systems.
Geographical knowledge on landforms, rocks and soils are important before these structures are constructed.
Mathematics
This is the branch of science that deals with numbers, quantity and space. Mathematics helps geographers to simplify and interpret numerical data.
Mathematical techniques in arithmetic and statistics are used by geographers to calculate averages, distances population densities and sizes and reading charts and graphs.
Through mathematics a geographers is able to identify the relationship between different geographical phenomena of the world.
Geology
Geology is the study of materials (rocks, soils, etc.), which make up the earth and their changes during the history of the world.
All these aspects are also dealt with in physical geography.
Economics
Economics deals with the production, distribution and consumption of goods and service.
Economics is related to geography in that economic development is based on natural resources like land, vegetation, minerals and animal life.
Geographers are interested in providing a description of the type , location and distribution of natural resources while Economists provide details on how the resources should be used to generate income.
History
History is the study of past events on a time basis thus it deals with past and current events and the people’s way of life.
Geographers requires historical knowledge to know how the earth was formed, the distribution of people and their past economic activities.
Demography
This is the statistical study of human population. It deals with the general characteristics of a given population which includes, the number of people living in an area, their ages, composition by gender, birth and death rates.
All this aspect is also covered in population geography which deals with the study of population distribution and changes in population structure.
Medicine
This is the science of treating and understanding diseases. It deals with diseases, their causes and possible cures.
Medical geography explores the factors that influence the distribution of pest and diseases, how these factors affect human activities on earth.
Past KCSE Questions on the topic
What is practical geography? (2mks)
Name two branches of geography
(2mks)
Name any three study areas in human geography
(3mks)
Define the term environment (2mks)
Explain three reasons for importance of studying geography
(3mks)
Name five human features
(3mks)
What is habitat (2mks)
List six disciplines related to geography
(6mks)
Differentiate between each of the following:
Democracy and population geography
Economics and economic geography
(4mks)
Name two Greek words from which term geography originate
(2mks)
By the end of the topic the learner should be able to:
Define the solar system;
Explain the origin of the earth;
Explain the effects of rotation and revolution of the earth;
Describe the structure of the earth.
Content.
a.)Definition and composition of the solar system.
b.)Origin, shape, size, and position of the earth in the solar system
c.)Rotation and revolution of the earth and their effects.
d.)Structure of the earth:
The atmosphere
The hydrosphere
The lithosphere/crust
The asthenosphere/mantle
The barysphere/centrosphere
Definition of the solar system
The solar system is made up of the sun with the nine planets orbiting around it. The solar system includes the sun, its planets and satellites, billions of meteoroids and thousands of comets.
Members of the solar system
The planets.
Heavily bodies – asteroids
Comets
Meteors
Meteorites
Satellites such as the moon
Note:
The solar system does not include other stars.
Origin of the solar System
The two theories that are commonly used to explain the evolution of the solar sytem are:
a.)Passing start theory.
b.)Nebular cloud theory.
Passing star theory
The theory was advanced by Jeans and jeffreys.
They suggested that a star that a star with greater gravitational pull than the sun passed close by the sun drawing off a stream of material in form of a gas.
This material spit cooled and condensed to form the planets set in orbit by the passing star.
The moons and other heavenly bodies moving around the sun were formed to have been formed in the same way.
Weakness of the theory
Chances of another star approaching the sun are minimal.
High temperature material drawn from the sun or from the star would disperse rather than condense.
It does not explain where the sun and the passing star came from.
Nebula Cloud Theory
It starts that the solar system could have been formed from a cloud or nebular of gas and dust.
As the nebula rotated, it flattened into the disc with a high concentration of material at its centre. The flattening out was due to the centrifugal force.
In the outer sections of this disc, some substances such as methane and ammonia condensed while some like hydrogen and helium remained as gas.
This outer rings formed the planets like Jupiter, Saturn, Uranus and Neptune.
Near the centre of the nebula, temperatures were much higher and the planets were formed by the accumulation of the particles bumping into each other and growing into sizes large enough to exert gravitational attraction to each other.
Continued accumulation and the condensation of these gases led to the formation of other planets.
At the same time, the sun continued to shed off most of its gases hence reducing its rate of rotation to about once in 25 days.
Due to the high temperatures, most volatile gases were probably swept outward.
Weakness of the theory
The origin and causes of the nebula are not explained.
Composition of the solar systems
The study of the heavily bodies is known as Astronomy. The solar system is made up of the following:
The sun
The planets
Asteroids
Comets
Meteors
The moon
The sun
The sun is actually, a star.
It is a yellow colored star of moderate size among the billions of stars in the Milky Way.
It rotates on its own axis in an anti – close wise direction.
Formed of very hot gases mainly hydrogen 70%.
The sun is a heated star. The temperature at the centre of the sun is about 150,000,000° Celsius and at the surface it is about 6,000° Celsius.
It is the source of light and heat of the earth but also of other planets and satellites. The earth would have been eternally dark without sun light.
The planets
Planet is a Greek word for wanderer or one who is constantly moving.
There are nine planets in the universe moving around the sun in the same direction.
The sun maintains a strong pull of gravity that keeps all the planets in their orbits.
The nine planets starting from the one nearest to the sun are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.
Facts about the planets
Mercury is the smallest while Jupiter is the largest.
All the planets have moons moving around them except for Mercury and Venus.
Asteroids are small bodies moving around the sun and occupy the spaces between the orbi
Mars
Referred to as the red planet because when observed from the earth using a telescope it always appears to be red in color.
It has two moons revolving around it.
Jupiter
It is the fifth planet and the largest planet in the universe.
Rotates on its own axis at a very faster speed.
Keep on charging in color from time to time.
Has thirteen rings.
Saturn
It is the sixth planet and second largest.
It has three rings around it, the middle ring being the largest and brightest.
It has eight moons/planets.
Neptune
It is the eighth planet and very similar in size ,color and character to Uranus.
Asteroid
These are small planet – like objects also known as the planetoids.
Comets
These are heavenly bodies revolving around the sun in their own orbits with a head and a tail.
Meteors
Meteors are small heavily bodies that enter the earth’s atmosphere from the universe at very fast speeds.
Meteorites
These are meteors that pass through the atmosphere, fail to burn up and land on the surface of the earth as large rocks.
Moon
The moon is a natural satellite meaning it has no light of its own.
The origin of the earth.
Many scientist believes that the earth could have been formed approximately 4600 million years ago.
A hot mass of gases was thrown off the sun.
These gases cooled to form a liquid.
The heavier materials collected at the centre to form a core of heavy liquid metal.
Around this core collected less and less heavy materials to form the mantle and the crust.
As the cooling continued, the outer part of the earth hardened faster to form the crust.
The size of the Earth
The circumference of the earth is about 40,000 km.
The circumference reduces from the equator to the poles because the earth is not shaped like a perfect sphere.
The diameter of the earth at the equator is longer than the polar diameter.
The shape of the Earth
The earth is a sphere which is slightly flattened at the poles and such a sphere is called geoid/oblate spheroid.
The slightly flattened poles are as a result of the rotation of the earth on its axis.
This movement as also caused the bulge at the equator.
Forces involved in the formation of the earth’s shape
Centripetal force
It pulls the North Pole and the South Pole towards each other thus flattening areas at the poles. Centrifugal force
It results in the bulging of the earth at the equator due to variation in rotation towards the equator
Force of gravity
It attracts objects on the earth’s surface and materials within the earth towards its centre hence making the earth to have a spherical shape.
Proofs that the earth is spherical
i.) Circum-navigation of the earth surface shows that you always end up at the point you started.
ii.) Approaching ship from the shore always start with the smoke, the gradually the body. If the earth was flat the whole ship could be seen at once.
iii.) The earth rotates from west to east. The sun appears earlier in the east than in the west and if the earth was flat the whole of it could receive light at the same time.
iv.) During the eclipse of the moon, the shadow of the earth appears spherical.
v.) The earth’s surface is always circular when standing on a very high tower
or when in an airplane.
vi.)Since all other planets, the moon and the sun are round when viewed through a telescope, the earth must also be round since it’s also a planet.
vii.)Photographs taken by satellite at great distance away from the earth shows that the earth is round.
Rotation of the earth and its effects
Rotation of the earth is the movement of the earth on its own axis in an anticlockwise direction from west to east once in every 24 hours.
Effects of rotation
Causes day and night.
It causes difference of one hour between meridians 150 apart.
It causes deflection of wind and ocean currents.
It causes variation in the speed of air masses.
It causes the rising and falling of ocean tides.
Revolution of the Earth and its effects
Revolution of the earth is the movement of the Earth around the sun on its own orbit and it takes 362 ¼ days.
It can also take 366 days to make one complete revolution around the sun in every leap year. A leap year occurs after every four years.
Effects of movement of the earth round the sun
Causes the four seasons.
Causes lunar eclipse.
Causes the Varying lengths of day and night.
Changes in the position of the midday sun at different times of the year
This causes the following, Summer solstice, winter solstice and equinoxes.
Characteristics of summer solstice
Day time is longer than night time at latitudes beyond the equator
The hours of day time increase from the tropics towards the poles
Occurs on 21st June when the sun is overhead at mid – day along the tropic of Cancer.
Characteristics of winter solstice
Occurs 22nd December when the sun is midday along the Tropic of Capricorn.
The sun is visible for only a few minutes when it appears above the southern horizon.
Characteristics of equinox’s solstice
Occurs on 21st March and 23rd September.
The sun rises in the east and sets in the west.
Equal hours of days and nights.
The four seasons
There are four main seasons namely:
The spring
Summer
Autumn
Winter
(b) The diagram below shows the internal structure of the earth.
Causes lunar Eclipse
An eclipse is a shadow that results when the sun’s rays are blocked from reaching the earth or moon’s surface.
The lunar eclipse occurs when during the revolution of the earth, the earth lies in between the sun and the moon.
This casts the shadow of the earth onto the moon.
Note:
Since the moon’s orbit is inclined, partial lunar eclipses are experienced more often than total eclipses.
Sometimes lunar eclipse pass unnoticed because they happen at night when many people are asleep.
The solar eclipse
Occurs as a result of the revolution of the moon around the earth whereby the moon lies between the sun and the earth.
This casts the moon’s shadow unto the earth.
The shadow has two parts:
Umbra
Penumbra
Umbra
This is the darkest part.
Penumbra
This is the lightest part.
The structure of the Earth
It consist of a series of layers both internal and external that vary in composition and thickness.
The internal layers are:
Lithosphere
Asthenosphere
Barysphere
The external layers are:
The atmosphere
The hydrosphere
The structure of the earth
External structure of the Earth
Atmosphere
It is an envelope of transparent and odorless gases held to the earth by gravitational attraction.
It consist of four main layers.
The layers of the atmosphere from the earth’s surface upwards are :
Troposphere
Stratosphere
Mesosphere
Thermosphere
Hydrosphere
The part of the earth’s surface covered by water mases. E.g. the oceans, rivers, lakes and swamps.
Internal structure of the earth
Lithosphere or crust.
This is the outer shell of the solid earth made up of variety of rocks.
Composed of series of plates which are in constant motion.
It also consist of the continental and oceanic crust.
Note:
The continental crust is also called SIAL.
This is because it consist of mainly silica SI and aluminum AL.
State three characteristics of sial.
Forms the continental crust/upper crust.
Consists mainly of silica and aluminum
Sial is made up of light rocks/2.7g/cc / floats on sima.
Sial is made up of granitic/ sedimentary/ metamorphic rock
Contains 75% of the total gaseous mass of the atmosphere
90% of water vapor found in this layer.
Sial is made up of rigid/brittle rocks.
The oceanic crust consist mainly of basaltic rocks averaging between 6 – 10 km.
The layer is also known as SIMA because it consist mainly of Silicon and Magnesium.
It forms the oceanic basins and is therefore referred as the oceanic layer.
The crust is separated from the mantle by a discontinuity known as Mohorovicic discontinuity.
Composition of the mantle.
It is made up of two parts / upper mantle and lower mantle.
Lower mantle is viscous fluid.
Upper mantle is elastic solid. Semi-molten.
Dominant mineral is olivine / ferromagnesian silicate.
The mantle has an average density of 3.0 – 4.0 gms/cc.
The mantle and the core are separated by a layer of discontinuity called Gutenberg discontinuity.
The Barysphere/Core/Centrosphere
Composed of very dense rocks made up of nickel and iron.
It is divided into two zones:
The outer core.
The inner core.
Characteristics of the outer core
The outer core is composed of molten rock material.
It is made up of iron and nickel.
It is about 2100 km to 2890 km thick.
It has temperatures ranging from 37000C to 5,0000C.
It has an average density of 10.0gm / cc to 12.3gm/cc.
Characteristics of the inner core.
It is solid.
Composed of hard rocks.
Reasons why the interior of the earth is still hot.
The overlying rocks generate a lot of pressure that create heat on the rocks beneath.
During the formation of the earth, the outer part cooled faster than the interior thus trapping the heat beneath.
Through radio activity, materials beneath collide creating friction that generates heat.
Past KCSE Questions on the topic
(a) State two effects of the rotation of the earth
(2mks)
Which movement of the earth is represented by the diagram?
(1mk)
Give two effects of the movement represented by the diagram (2mks)
The diagram below represents the structure of the earth. Use it to answer question
Name
The parts marked P and Q
The discontinuity marked R
State three characteristics of the mantle
3.The diagram below shows the composition of the solar system
Name the planets marked F and G
(2mks)
State three effects of the rotation of the earth on its axis
(3mks)
a) What is the solar system?
b) Use the diagram below to answer the questions that follow.
What type of eclipse is represented by the diagram?
Name the features marked L and M
(a) (i) Give the two dates in a year during which the number of hours
of darkness is equal in both the north and south poles.
Why do the lengths of days and nights vary from one part of the earth to another?
Apart from the sun name other heavenly bodies.
(b)The diagram below shows the revolution of the earth around the sun. Use it to answer the questions that follow
If the earth takes 366 days to make a complete revolution during a leap year, how long will it take to move from position 1 to position 4?
What season is experienced in the southern hemisphere when the earth is in Position 1?
Define the following,
Solar system
Galaxy
Star
Asteroids (6mks)
Differentiate between the following
Dateline and international dateline
Meteors and Meteorite.
(6mks)
State three differences between solar eclipse and lunar eclipse.
(2mks)
State four factors that support life on planet earth.
(4mks)
(a) List four effects of earth rotation.
(4mks)
At Nairobi on longitude 37°E local time is 1 p.m. What time would it be
at Sarissa on longitude 41 °E?
(4mks)
(a) Define equinox. 2mks
(b)State characteristics of summer solstice.4mks
12. The earth is inclined to the ecliptic plane at an angle of….. and the axis is also inclined at an angle ….. to perpendicular line.
(4mks)
Fill in the table from (a) – (f)
(10mks)
Property s/Layer Major constituent Thickness Density Temperatur
e
Outer crust (a) iii. 16-24
kms (b)
Inner crust ii. Magnesium S (c) 2.8-30 gms/cc
Asthensophere i. Iron 2900 kms (d) 5000 C
Centrosphere ii. Nickle (e) (f)
State three weaknesses of the passing star theory.
(6mks)
Differentiate between hydrosphere and atmosphere.
(4mks)
Planet … 1… is seventh planet from the sun and is greenish in colour. Planet
…2… takes shortest time to revolve round the sun about 88 earth day. Planet …3… and …4… are referred to as twin planets. Planet …5… takes about 11.86 earth years to revolve round the sun. All the planets have satellite orbiting
round them except planet …6… and …7…
(7mks)
Explain reasons for flattening and bulging of earth.
(4mks)
State characteristics of winter solstice
(4mks)
Differentiate between summer solstice and winter solstice.
(4mks)
(a) What is an eclipse?
(2mks)
Apart from planets name other heavenly bodies.
Specific Objectives
By the end of the topic the learner should be able to:
Distinguish between weather and climate;
State the elements of weather;
Explain the conditions necessary for siting a weather station,
Use instruments to measure elements of weather;
Analyze and interpret data on weather conditions,
Describe the structure and composition of the atmosphere;
Explain the factors that influence weather and climate;
Describe the characteristics of climatic regions of Kenya;
Describe the characteristics of major climatic regions of the world;
Account for the causes of aridity and desertification;
Explain the effects and possible solutions to aridity and desertification, discuss the causes and impact of climate change on the physical and human environment;
(1) Carry out field study on a weather station.
Content
a.)Distinction between weather and climate.
b.)Elements of weather.
c.)Factors to consider in siting a weather station.
d.)Instruments for measuring weather elements.
e.)Recording and calculating weather data.
f.)Structure and composition of the atmosphere.
g.)Weather forecasting.
h.)Factors influencing weather.
i.)Factors that influence climate.
j.)Distribution and characteristics of climatic regions of Kenya and the world.
k.)Causes, effects and possible solutions to aridity and desertification.
l.)Causes and impact of climate change on physical and human environment.
m.)Field w o r k – a study based on a weather station.
Meaning of weather
Weather is the condition of the atmosphere for a short period of time usually a day.
Elements of weather
These are a number of factors or conditions of the atmosphere. They include the following:
Temperature
Humidity
Precipitation
Air pressure
Winds
Sunshine
Cloud cover.
Temperature
This is the degree of sensible heat within the atmosphere. The temperature is caused by radiant heat received from the sun.
The process of transmission of sun’s energy in the form of short wave is called insolation/solar radiation.
Radiation is the process by which energy is propagated or transferred through a medium by means of wave motion.
The amount of solar radiation reaching the earth is determined by the following factors:
The intensity of the sun’s radiation in the space and the earth’s average distance from the sun.
The area and nature of the surface on which the rays falls.
The inclination/angle of the surface on which the sun’s rays fall.
The position of the earth on its orbit which produces different seasons.
The transparency of the atmosphere.
Note;
Lines drawn on a map showing places with the same temperatures are called Isotherms.
The atmosphere is heated through three main process:
Radiation
Conduction
Convection
Radiation
All bodies emit/radiate energy in the form of waves called electromagnetic waves.
This energy travels outward from its source, spreading equally in all directions.
The intensity of radiation depends on:
Size of the body emitting it
Temperature of the body emitting it
Radiation does not require a medium hence it can travel through a vacuum.
The earth emits heat by long-wave radiation called terrestrial radiation which is invisible.
Note:
The main difference between solar and terrestrial radiation is that solar radiation is by short wave and is partly visible as the sunlight we see.
Conduction
This is the transfer of heat through matter without moving it.
It is the transfer of heat energy through motion, from one molecule to another.
Air in the atmosphere is heated by direct contact with the earth.
Convection
This is the transfer of heat by mass movement of fluid.
Convection in the atmosphere takes place when air is heated by the earth and becomes less dense.
The colder dense air above the surface descends down to replace the warm rising air.
The colder air on reaching the surface in turn becomes heated and rises.
This movement of lighter air upwards and dense air downward creates cycles called convectional currents.
Humidity
This is the amount of water vapor in the atmosphere
Significance of variations in humidity
i.)The amount of water vapor in a given volume of air is an indication of the atmosphere’s potential capacity to hold moisture.
ii.) Water vapour regulates the heat loss from the earth.
iii.)The amount of water vapour determines the amount of energy stored in the atmosphere for the development of storms.
Note:
When the atmosphere contains maximum amount it can hold, it is said to be saturated.
The temperature at which air becomes saturated is known as dew point.
Absolute Humidity
This is the actual amount of water vapour in given volume of air at a particular temperature expressed in gm/𝑚2.
Relative humidity
This is the ratio between absolute humidity of a given mass of air and the maximum amount of water vapour that it can hold at the same temperature.
Precipitation
Precipitation is the forms of moisture, which fall from the atmosphere to the earth’s surface.
The amount of water in the atmosphere comes from evaporation of water from:
The grounds
Open water bodies
Plants through Evapo-transpiration
Major forms of precipitate
Dew
Frost
Snow
Mist and fog
Rainfall
Dew
Forms at night when the air in the lower parts of the atmosphere gets cooled and the water vapour in it condenses into droplets which are then deposited on objects.
Conditions necessary for the formation of Dew
The air should be calm so that it can remain in contact with the ground long enough to be cooled below its dew point.Unless that temperature has been reached,dew cannot be form.
Day time should be warm to accelerate evaporation and thus provide a lot of water vapour in the air.
A cloudless night accelerates the rate at which the earth losses the heat gained during the day.
Frost
It refers to tiny ice crystals deposited on objects on the ground.
Snow
This is the precipitation that falls in the form of flakes of numerous tiny ice crystals.
Mist and Fog
Mist is a mass of tiny water droplets suspended immediately above the ground.
It forms when air is called below dew point but the resultant water droplets remain suspended.
This causes obscurity or cloudiness which reduces visibility to between one and two kilometers.
Fog
Fog is denser and visibility is less than one kilometer but formed in the same way is dew.
Main types of fog
i.)Radiation fog – This forms when air in contact with the ground is cooled as a result of terrestrial radiation.
ii.) Advection fog – This form a result of warm moist air passing over a cooler land or water surface.
iii.) Hill fog – Forms on a low sheet of cloud on hills as a result of moist air stream advancing inland from the sea.
iv.) Frontal fog – This forms at points where cold air masses meet with warm air masses. The cold air causes moisture in the warm air to condense and form fog.
v.) Steam fog – A fog associated with cold air passing over the surface of
Warm air.
Rainfall
A form of precipitation from the clouds in the form of drops of water. Lines drawn on a map to show areas receiving the same amount of rainfall are called isohytes.
Air that condenses to form rainfall may be made to rise in three different ways:
When winds blow over a mountainous region.
When hot air rises by convectional currents.
When warm air rises over cold air.
Types of rainfall
Relief/orographic rain
Relief rain occurs in areas where onshore winds rise over hilly or mountainous regions lying parallel to the coast. It also occurs in areas where moist air is forced to ascend relief features far from water bodies. The rainfall is experienced in Kenyan highlands and the rift valley.
Formation
A water body/ sea lake is heated causing evaporation.
Moist air from the sea is forced to ascend up a hill/ mountain size.
Forced ascent leads to cooling of air.
The moisture in the air condenses forming clouds.
Rain falls mainly on the windward side of the hill/ mountain
Convectional Rainfall
Experienced in areas around the equator which get intense heating from the sun.
E.g. Lake Victoria and coastal regions
Formation
When warm air is heated, it rises in the form of convectional currents.
When this air reaches higher in the atmosphere, the moisture in it condenses to form clouds which later fall as rain.
It falls mainly in the late afternoons usually accompanied by thunder and lightning.
It falls in large drops thus its torrential.
It last for a short time.
Sometimes accompanied by ice pellets known as hailstones.
Cyclonic Rain/frontal
When warm moist air is forced to rise over cold air.
The moisture in it is cooled and condenses to fall as cyclonic rainfall.
The point where the two air masses meet is called a frontal zone.
It is usually very heavy and is accompanied by thunder and lightning.
B Cold air sinks
Warm moist lighter air rises above cold air below warm air
A – This line represent the plane separating warm air from cold air.
Air pressure /atmospheric pressure
Air pressure is the weight exerted by the atmosphere on the surface of the earth. Pressure decreases with increase in altitude. Lines on a map connecting places with the same air pressure are called isobars.
Factors influencing atmospheric pressure on the earth’s surface. – The altitude of a place on the earth’s surface.
The amount of temperature
The rotation of the earth
Winds
Wind is a moving air over the earth’s surface.
Air moves from areas of high pressure to those of low pressure.
Types of winds
Land and sea breeze
Katabatic and anabatic
Chinook
Sea breeze
This is the movement of cool air from the sea to the land during the day.
Formation of sea breeze.
During the day the land heats faster than the sea.
The air over the land rises.
Cooler air from the sea blows towards the land to replace the rising air
The cool air from the sea is called sea breeze
What causes sea breeze.
Differences in atmospheric pressure between the land and the sea, the land has a lower pressure.
Differences in temperature between the land and the sea, land is warmer.
Effects of sea breeze,
It lowers the high temperature on land (cooling effect).
It might lead to convectional rainfall,
Land breeze
This is the movement of cold air from the land to the sea at night.
Formation of Land breeze
During the night the sea is relatively warmer than the land since the land losses heat faster.
The air over the water being warmer rises while the cooler dense air from the land flows in to replace the rising air.
This causes land breeze.
Sunshine
This is the direct rays of sunlight received on the surface of the earth. Places of same sunshine intensity on a map are joined by lines referred to as isohels.
Factors affecting sunshine intensity and duration
Latitude
Aspect
Cloud cover.
Cloud Cover
A cloud is a mass of tiny visible particles of water or ice which is formed by condensation.
Ways in which clouds are classified
According to the altitude of their bases.
Their appearance/structure.
Their formation
Types of clouds
Cirrus clouds
Thin, feather-like.
Ice crystals.
High altitudes.
Patches or bands
Stratus
Gray, low bases.
Sheet-like.
Usually associated with low.
pressure systems
Cumulus
Convective currents.
Flat bases Dome-shaped tops.
Rain not likely
Cumulo -nimbus
They are big, dense, heavy masses of cloud.
Causes heavy rains or thunderstorm.
Darker at the base and sometimes white at the sides.
Other types of clouds.
Cirro – stratus
Thin sheets covering the whole of the sky.
Have a milky appearance.
Give rise to haloes when the sun or moon shines through them.
Cirro – cumulus
White clouds consisting of white ice crystals.
Have a thin base.
Globular in appearance or arranged in ripples.
Alto – stratus
Uniform in layers and contain water droplets.
Forms sheet of grey – white color.
They are transparent.
Alto – cumulus
Uniform sheets of thin flakes or flattened globular masses arranged in lines/waves.
Vary considerably in thickness and shape.
Strato – cumulus
Loose in structure with large globular masses frequently arranged in groups, lines or undulated formations.
They are big but vary greatly in sizes and shape. They are grey or grey – white in color.
Nimbo – stratus
A rain cloud.
Shapeless, dark –grey and dense.
Spreads all over the sky in low uniform layers.
A weather Station
This is a place where the elements of weather are observed, measured, and recorded.
Factors for siting a Weather station
These factors are to be considered when siting a weather station:
i.) It should be in an open place with free flow of air.
ii.) Away from barrier e.g. trees.
iii.) Should be on a fairly level ground..
iv.) The site should be free from flooding.
v.) The site should provide a wide view of the surrounding landscape and the sky.
vi.) The area should be secure.
Instruments for Measuring Elements of Weather
Instruments that they are likely to be found in a weather station:
Thermometer – temperature
Rain gauge – rainfall
Hygrometer – humidity
Barometer – air pressure
Anemometer – wind
Sunshine recorder – duration and intensity of sunshine.
Wind vane – wind direction
Some of these instruments are placed in a wooden weather box known as Stevenson screen. Which provides the thermometers with free flow of air and shade.
Instruments found in Stevenson Screen are:
Maximum thermometer.
Minimum thermometer.
Six‘s thermometer.
Hygrometer.
Note:
Why Stevenson screen is painted white
So that it can reflect direct heat from the sun.
Has Louvers
To allow free flow of air in and out of it. In order to obtain room temperature
It is raised about 121 centimeters above the ground
To prevent contact with direct radiation from the earth’s surface.
Measurement of temperature.
Temperature is measured using various thermometers.
Maximum thermometer
Minimum thermometer
Six’s thermometer – combined maximum and minimum thermometer.
Maximum and minimum thermometer to measure the maximum and minimum temperatures
When temperature rises, the mercury expands, pushing the metal index along the tube. When temperature falls, the alcohol contracts and pulls the metal index along the tube
How a maximum thermometer works 3mks
When temperature rises the mercury in the bulb is heated and expands. √ ½
The mercury flows towards the bulb, as it moves forward; it pushes themetallic index in the capillary tube. √ ½
When the highest temperature of the day is reached and it begins to cool, the mercury contracts and withdraws towards√ 1/2 the bulb. The metallic index is left at the position it was pushed to.
The point of the index which was in√ ½ contact with the mercury indicatesthe highest temperature reached during the day.
After the reading is taken, the index is set by placing a magnet on the glass√ ½ and gently moves it towards the bulb. The index is dragged until it touches the mercury.
The Six’s Thermometer
For the Six’s thermometer (U-shape maximum and minimum thermometer), the temperatures are obtained by reading the values indicated at the bottom of the metal index (indicators).
After taking the readings, the thermometer is reset using a magnet.
The readings of the minimum and maximum temperatures are useful for the calculation of the following:
Mean daily temperature/ Diurnal temperature range – It is obtained by finding the average between the maximum and minimum temperatures recorded during the day/24 hours.
The Diurnal Range of temperature – The difference between the maximum and minimum temperatures recorded in a day (24hours).
Diurnal range of temperature = Daily maximum temperature minus daily minimum temperature
Mean monthly temperature – This is the average temperatures of the month.
Mean monthly temperature =
Mean annual temperature – sum of mean monthly temperatures in the year divided by 12.
Mean annual temperature =
Annual temperature range – This maximum temperature minus minimum temperature recorded in a year.
Measurement of humidity/psychromotor
Humidity is measurement by a wet and dry bulb thermometer known as thermo – hygrometer.
The difference between the two thermometer readings is used to calculate relative humidity using a humidity table.
If the temperature is saturated there is no evaporation hence the temperature readings on both thermometers remain the same.
This means that the relative humidity is 100%.
Note:
When the difference is small, it means that the relative humidity is high but when the difference is large, it means that the relative humidity is low.
Relative humidity
Relative humidity refers to the ratio between water vapour actually present in the air and its capacity to hold water vapour at a given temperature.
It is called using the following formula:
Example
If the air at 200𝑐contains 8.26/𝑚2 and the given air can hold a maximum of 17.117 gm/𝑚2at 200𝑐 then the relative humidity would be
Relative humidity depends on both the absolute humidity and temperature. If the moisture remains constant then the relative humidity will decrease as temperature rises and will increase as temperature falls.
Hygrometer is also used to measure relative humidity.
Measurement of rainfall
A rain gauge is used to measure the amount of rainfall.
The rain gauge is sunk into the ground and its top being 30cm above the ground level.
To avoid surface run off and splashing of water during rainfall.
The funnel at the top will direct rain water into the cylindrical container containing a glass jar which will collect the rain water.
The collected rain water will be emptied into a measuring cylinder which will give the amount of rainfall in millimeters for the clay.
From rainfall figures it is possible to calculate the following:
Daily rainfall – the amount of rain that falls over 24 hours.
Mean monthly rainfall – obtained by adding all the total monthly rainfall figures for a year and dividing them by 12.
The mean annual rainfall – Obtained by adding total annual rainfall usually for a period of 35 years and dividing by 35.
Measuring of Air pressure
Atmospheric pressure is measured in millibars using an instrument known as barometer. There are two types of barometers:
Mercury barometer
Aneroid barometer
Mercury Barometer
The height of the mercury column is a measure of the air pressure.
Aneroid barometer
The aneroid barometer consist of an air tight metal box which is a partial vacuum.
The box responds to changes in pressure by expanding when the pressure falls.
Collapse slightly when pressure increases.
These movements are conveyed by a series of levers to a pointer.
Advantage of aneroid barometer
It can record changes in atmospheric pressure as they occur during the day.
Measurement of wind
The instrument used to determine wind direction is wind vane.
When the wind blows, the arm swings until the pointer faces the direction of the wind.
The arrow points the direction in which the wind is coming from.
Wind sock
A windsock is also used to determine wind direction.
It points to the direction the wind is blowing to.
It is commonly found in air strips
Anemometer
It measures the speed of wind in kilometers per hour or in nautical miles.
Measurement of Sunshine.
Sunshine is measured using an instrument called sunshine recorder
It records the duration and intensity of sunshine.
The atmosphere
The atmosphere is a thin layer of gases surrounding the earth and held by the earth’s gravitational pull.
The structure of the atmosphere
The atmosphere consist of four main zones namely:
a.)Troposphere
b.)Stratosphere
c.)Mesosphere
d.)Thermosphere/ionosphere.
Characteristics of the troposphere.
Most weather phenomena occur in this layer.
Contains the weather making constituent/life supporting layer.
Temperature decreases with increase in altitude (positive lapse rate)/ rate of 6.50C per 1000m.
Pressure falls with increase in height.
Rises to about 15km above the surface of the earth.
Contains most of the atmospheric water vapour, cloud, dust/pollutants
There is a layer of discontinuity between the atmosphere and the stratosphere called the tropopause.
In this zone there is no change in temperature with increase in height. Hence it experiences zero lapse.
Characteristics of Stratosphere
Layer above the tropopause.
Contains very little dust and water vapor, hence no clouds are found in this layer.
Temperature increases with increase in altitude a process known as negative lapse rate.
There is steady increase in temperature caused by the over concentration of Ozone gas.
Winds are light in the lower part but increases with height.
Pressure falls as the air is dry.
Stratosphere is a protective shield against meteorites that usually burn out as they enter the earth’s gravitational field.
The upper limit of the stratosphere is marked by the stratopause .A layer of discontinuity between the stratosphere and mesosphere.
Mesosphere
Lies above the stratosphere.
Experience temperature decrease with increase in height hence it has a positive lapse rate.
Temperature fall quickly as there is no water vapor, cloud dust or ozone to absorb incoming radiation.
The area experiences the atmospheric lowest temperature and strongest winds.
The layer of discontinuity between the mesosphere and the upper most layer of the atmosphere is called mesopause.
Thermosphere /ionosphere
Contains electrons and ions that influence radio waves.
Temperature rises rapidly with height perhaps reaching 15000 c.
This is due to an increasing proportion of atomic oxygen in the thermosphere.
The structure of the atmosphere
The composition of the atmosphere
The atmosphere is a mixture of oxygen with inert gases such as argon
Gas %
Nitrogen 78
Oxygen 20
Water vapour 1
Argon 0.94
Carbon dioxide 0.03
Note:
Inert gases such as neon, helium, krypton and xenon are found in negligible percentages
Ozone layer absorbs the shorter ultra – violet rays from the sun. This is important to human life as exposure to such radiation may cause skin cancer and other forms of ailments.
Apart from water vapor name two other substances that are suspended in the atmosphere.
Gases such as – carbon dioxide and oxygen.
Air (wind) –
Clouds
Pollen grains and smoke/dust particles
Weather forecasting
Weather forecasting is the prediction of weather situation for a given place within a short period of time like an hour, a day, a week, a month or a year.
Methods of weather forecasting
Methods of weather forecasting are grouped into three:
Ancient
Weather lore methods
Modern methods
Problems of weather forecasting
Inaccurate data
Defective instruments
Personnel with limited skills
Vagaries of nature such as earthquakes
Significance of Weather Forecasting
Determines times for sea and air travel.
Determine time when sporting activities take place.
Determines the fishing activities and habits in the area.
Help determine suitable clothing for the day.
Help plan farmers calendar of activities.
Help plan suitable housing.
Factors influencing weather
a.)Cloud cover and humidity
Clouds determine the amount of solar radiation reaching the earth’s surface and the amount leaving the earth’s surface. This determines temperature conditions.
Day temperatures are moderated by clouds.
Areas of thick rain clouds have high rainfall.
b.)Altitude
This is the height above the sea level.
Temperature vary with height above the sea level of a place above sea level.
This means that highlands experience cooler temperatures than low-lands.
Pressure decreases with rise in altitude.
c.)Humidity
Very humid air absorbs heat during the day and retains it during the night.
d.)Aspect
This is the direction a slope faces in relation to incoming solar radiation.
Because of direct sunshine the sun facing slopes are warmer than the opposite slopes which face away from the sun.
e.)Inter-tropical convergence zone
This is a zone of low pressure lying within the tropics, that is, between north and south.
Since it is a convergence zone for southeast and northeast trade winds, it causes heavy rainfall wherever it passes.
It is associated with convectional rainfall and thunder- storms.
f.)Latitude
Areas around the equator re hotter than areas in temperate lands which are warmer than the poles.
This is because at lower altitudes the sun’s rays cover a shorter distance and pass through reflection, absorption and scattering by the lower latitudes.
Equally the sun’s rays strike the lower latitudes at right angles hence cover a smaller area leading to greater heat concentration.
g.)Nearness to water bodies
They facilitate the development of land/sea breezes through creation of pressure difference.
The air currents from such water bodies also lowers the temperature of the surrounding areas and may increase precipitation by supplying extra moisture content through evaporation.
Climate
Climate is the average weather conditions of a place which have been observe and recorded over a long period of time, usually 30 -35 years.
Distinction between weather and climate
Weather is the atmospheric conditions of a place over a short period of time, usually 24 hours while climate is the average weather conditions of a given place which have been observed and recorded over a long period of time, usually 30-35 years.
Factors influencing Climate
They are known as climatic factors and they include the following:
a.)Warm ocean currents
When on-shore winds cross over a warm ocean current, the winds are warmed and carry the warming effect of the sea onto the land causing an increase in temperature on the adjacent coastal land.
On-shore winds crossing over a warm ocean current are warmed up and pick moisture causing an increase in humidity on the adjacent coastal land.
On-shore winds crossing over a warm ocean current are warmed up, pick moisture causing rainfall on the adjacent coastal land.
b.)Latitude
Latitude influences temperature over the surface of the earth. Areas near the equator are warmer since the sun’s rays are more intense within the tropics because the sun is almost overhead throughout the year/high latitudes experience lower temperatures because the sun’s rays strike the ground at a narrow angle and spread over a wide area.
Latitude influences seasonal variation of rainfall. Some areas receive maximum rainfall when the position of the sun is overhead.
Latitude influences the intensity of sunshine. Places near the equator receive more intense sunshine than those far away since the sun’s rays are concentrated over a smaller area/the sun strikes the earth’s surface at right angles/the sun’s rays travel over a shorter distance thus less heat loss.
c.)Altitude
Lowlands are usually warmer than highlands because the atmosphere becomes thinner as you go down hence the higher you go the cooler it becomes.
This is because the sun’s rays do not heat the air directly but heat the earth which in turn heat the atmosphere.
d.)Distance from the sea
During hot seasons coastal lowlands are relatively colder than inland areas on the same latitude due to effect of sea breezes which bring cold air to the land.
In winter land loses heat gained in summer faster than the sea. Sea breezes carry warmer air to the land making areas closer to the sea warmer than inland areas.
Coastal lands receive more rainfall than the interior of continents .This is because the coasts receive moist winds from the sea and by the time the winds reach inland areas they are usually dry.
e.)Configuration of the Coastline
This is the alignment, appearance or nature of the coastline.
Irregular coastlines tend to receive more rainfall because the prevailing winds blow on-shore carrying moisture inland.
The shape of the coastline/alignment of the coast also affects the size of the land area that comes into contact with the water. Areas with more water bodies’ experiences sea and land breezes which leads to lowering of temperature during the day and raising of temperature at night.
f.)Air Masses
An air mass is a widespread body of air with uniform properties such as temperature and moisture content and moves in one direction.
When an air mass moves out of its region of origin /source, it affects all areas it transverses over in terms of temperature and moisture conditions.
g.)Aspect
This is the general alignment of the slope to the sun’s isolation.
The slopes of high areas which do not receive direct sunrays have lower temperatures.
The influence of aspect on temperature is more significant in the mid and high latitude areas than in the tropics where the sun is always overhead.
h.)Human Activities
The human activities influencing climate include the following:
Settlement and agricultural activities
Development of urban centers
Construction of Dams
Settlement and agricultural activities
Before people settle in a given area, they clear natural vegetation to make room for settlement.
They also clear vegetation to be able to grow crops.
When large areas of vegetation is cleared the effect on climate can be very significant.
Development of Urban Centres
Smoke from factories and vehicles can lead to formation of fog which reduces visibility and also likely to cause an increase in temperature.
The presence of buildings and planned roads within an urban set- up can also change the direction of wind by making it blow along the streets.
Construction of dams
When dams create large human made lakes, they tend to have a modifying effect on the temperatures of the surrounding land.
They also lead to an increase in the amount of moisture in the atmosphere through evaporation leading to an increase in the amount of rainfall received.
Classification of Climate
Climatic zones may be classified based on the following:
Temperatures
Physical components using measurable quantities such: net ,radiation, temperature, precipitation.
Soil types.
Using these physical components three major climatic classifications have been advanced. These are:
The thornwaite classification
The koppen climatic classification
The miller’s classification
Distribution and characteristics of Climatic Regions of Kenya
seven climatic types have been identified in Kenya as shown in the figure below.
Key
Modified Equatorial climate of the Coast.
Modified Tropical climate of the Highlands.
Modified equatorial climate of the lake basin.
Modified equatorial climate of the north western margin.
Tropical climate —Narok and Kwale.
Tropical semi desert climate – central and northern areas.
Desert climate of the central northern areas
Modified Equatorial climate of the Coast
It covers the coastal belt of Kenya extending from Vanga in the south – east to Lamu in the north coast. It is due to the presence of the Indian Ocean.
Characteristics
No real dry month but rainfall is low than Equatorial.
Rainfall is heavy 1600 mm/year.
Temperature ranges between 20°C to 27°C.
It has double maxima rainfall, mostly afternoon.
Relative humidity is high between 1500 and 2000mm all the year round. Has a double maxima rainfall regime i.e. two rainy seasons
Modified Tropical climate of the Highlands
It is found mainly in the highlands east and west of rift valley. Modification is due to the relief. It is also referred to as highland sub-tropical climate.
Characteristics
Temperatures are much cooler than expected of tropical climate because of the high altitude.
Receives rainfall through the year.
It has double maxima rainfall regime.
Relief/orographic rainfall is common.
Annual rainfall totals ranges from 1000 – 1500 mm.
The average temperatures ranges between 17°C to 24°C.
Experiences moderate humidity.
Mean annual range of temperature is 3°C to 5° C.
Modified Equatorial climate of Lake Victoria basin
It is located within the lake region of Kenya and mainly covers Nyanza and Western Provinces. Modification results mainly from the varied relief and the influence of the Lake Victoria.
Characteristics
Rainfalls throughout the year / no dry month.
Rainfall ranges between 1,000 – 1600 mm.
Rainfall is mainly conventional in nature.
Double maximum of rainfall regime.
High humidity.
High temperature(s) throughout the year.
Small annual range of temperature.
Modified Equatorial climate of the North Western Borders
It is best seen in the Kara Suk areas and is mainly considered to be a continuation of the climate of western and Northern Uganda.
Characteristics
Rainfall totals are lower than in typical equatorial climate averaging 850 mm per year.
Most of the months are dry.
It receives convectional rainfall between June and September.
Temperatures are generally high throughout the year.
Tropical climate of the Narok and southern Taita/kwale Areas
It is located in areas around the Loita hills, Taita hills and shimba hills.
Characteristics
Rainfall comes in March to May and October to December with maxima in April and November.
High relief of hills such as loita exerts a cooling influence on the climate making it more tolerable than the semi-desert climate of Eastern Kenya.
Tropical continental/Semi –Desert Climate of Eastern Kenya
It is found mainly in Eastern Kenya in areas such as Isiolo, Garissa, and Tana River and in Southern Kenya in areas such as Kitui Machckos, Kajiado and parts of Northern Kenya in areas includeing Mandera, Moyale and parts of Turkana.
Characteristics
It is generally dry with less than 500m of rainfall which is unreliable.
It has large diurnal and annual ranges of temperatures.
The skies are generally clear.
Temperature are high with mean between 22°C and 27° C.
Desert Climate of Central Northern Area
Covers the northern Kenya. Wajir and Lodwar are in this climate region
Characteristics
Has low rainfall — less than 250mm p.a.
High temperatures throughout the year.
Night temperatures are extremely low.
Low humidity.
High temperature range.
Sandstorms are common.
Occasional floods covere4 by sporadic rain
Distribution and characteristics of Climatic Regions of the world
According the miller’s classification, the world climatic regions can be classified into four broad climatic belts. These are:
Hot climates
Warm temperate climates
Cool temperature climates
Arctic/tundra climates ( very cold climates)
Mountain climates.
Key
Tropical monsoon climate.
Mediterranean climate
Equatorial climate.
Tundra climate
Hot climates
These are found approximately 200 N and S of the equator. The zones are most extensive in Africa and South America.
It can be subdivided into the following climatic sub –types:
a.)Equatorial climate
b.)Tropical monsoon and tropical maritime
c.)Savannah ( continental interior)/Sudan type
d.)Tropical desert
Equatorial Climate
It is mainly found in the following regions:
South America – Amazon Basin, the West Coastlands of Ecuador and Colombia.
Along the coast of West Africa from Guinea to Cote de Ivoire and the Western parts of the Ghanaian coast.
In Equatorial Africa from the southern part of Nigeria through Cameroon, Gabon ,Central African Republic of Congo.
Southern East Asia – Malaysia and Indonesia and also the stretch between Burma and Vietnam.
Characteristics of Equatorial climate
Experience high temperatures (24 – 27 0 C).
Experience the small annual range of temperatures of 30 C.
Mean annual rainfall exceeds 1500 mm and is evenly distributed throughout the year.
It receives double maxima rainfall regime after the equinox.
Low diurnal range of temps of approximately 60C.
High humidity due to high rainfall and high evaporation rates.
Major winds due are trade winds.
Rainfall mainly conventional but orographic is common in Mt areas.
Thick cloud cover throughout the year.
Tropical monsoon
This climate is experienced in the tropical and temperate latitudes that are heavily affected by seasonal land and sea winds. The countries that experience tropical monsoon type of climate outside Africa are Mexico, India, Bangladesh, Burma, Vietnam, Indonesia and North of Australia. In Africa they are Guinea and parts of Sierra Leon.
Characteristics
Temperature range from 15°C in the cool season to 32° C in the hot seasons.
It experiences moderate temperature ranges between 9°C and 18° C.
High rainfall during the summer.
It has a marked dry season during winter.
Low pressure during summer hence winds blow onshore bringing heavy rains.
High pressure on the land during winter hence blow offshore
Cloudy skies in summer and clear skies in winter.
Seasonal reverse of winds.
Note:
A typical monsoon climate has three seasons which include:
Cool, dry season (November to February) when the offshore North – East monsoon winds blow.
Hot dry season (March to May) when temperatures are very high because of the overhead midday sun and when winds are almost absent.
Hot wet season (June to October) when the onshore south- west monsoon winds blow and when the rainfall is very heavy in onshore winds.
Tropical desert climate
It lies between 15° and 35° and of the equator on western margins of continents that are washed by cold ocean currents. Examples include: the Sahara, the Kalahari, Namib, Iranian Desert, Mexican Desert, the Great Austrian Deserts, Arabic Deserts, Atacama Desert and Thar Desert in Asia.
Characteristics
Low rainfall approximately 250 mm per annum.
The rainfall is unreliable.
The solar radiation is intense.
The winds are warm and dry, hence bring no rain.
Skies are always cloudless hence temperature often go over to 32° C No real defined season.
Flash floods and thunderstorms are common when it rains.
Humidity is low and the evapotranspiration rate is low.
Large diurnal ranges that go up to 20° C in some areas.
Warm temperate climate
They lie in regions that are affected by the divergence of winds. There are three types of climate based on rainfall distribution namely:
a.)Warm temperate western margin/Mediterranean climate.
b.)Warm temperate interior /warm temperate continental climate.
c.)Warm temperate eastern margin/humid sub –tropical/china climate.
Warm temperate western margin/Mediterranean climate.
The main areas experiencing this type of climate are:
Central coast of California – North America
Southern tip of Africa – Cape town
Around Mediterranean sea
Central Chile – South Africa
South West and Southern Austria
Characteristics
Hot summers with temperatures of approximately 210c and mild winters of temperatures approximately 100c.
Moderate annual range of temperatures approximately 100c.
Mean annual rainfall of between 500-900-mm.
Cyclonic rainfall caused by depressions falls in showers in winter.
Offshore trade winds in summer causes a dry season.
Hot and cold local winds are common
Has distinct seasons – spring, autumn , summer and winter
Warm temperate interior/warm Temperature Continental
Climate
It is also known as the steppe type climate. It is found in the interior of continents between 30°N and 50°S of the equator.
Main areas where it is found include:
Prairies of Canada and USA.
Pampas of Argentina in South America.
The veld of South Africa.
The towns of New South Wales and Victoria in Austria.
Characteristics
Temperatures range from 2°C to 6° C in winter.
Long and cool winters.
The summers are warm and short with temperatures ranging between 18°C and 21° C.
It experiences extreme temperatures due to it’s continentally.
Summer rainfall is caused by convection and depression.
There is moderate rainfall with an annual mean of about 500 mm.
Humidity is high.
Warm temperate Eastern Margin Climate
It is also known as China type or humid subtropical climate. It lies between 23° and 35° N and S of Equator on the eastern margins of continents.
The main areas where it is found are:
South Eastern states of U.S.A
Southern Brazil, Paraguay and Uruguay.
The coastal belt around Durban in South Africa.
Central China.
Coastal regions of Australia.
Characteristics
The area has a moderate annual range temperature of about 13°c.
Presence of warm Ocean currents has a moderating influence in winter in coastal areas.
Winter temperature are low due to the influence of the local winds.
Typhoons or hurricanes or tornadoes are common and they lead to heavy rainfall.
In winter the trade winds are offshore resulting in very little rain.
Convectional rainfall is common in summer.
Trade winds are onshore causing heavy rainfall in the coastal lands and highlands.
Summers are hot at 26° C whereas winters are mild at 13° C.
Rainfall is moderate between 760 and 1500 mm in some areas and is well distributed all year round.
Cool Temperate Climates
Found between latitudes 35° and 60° north and south of equator. Cool temperate climates can be divided into the following three types:
a.)Cool temperate Western margin.
b.)Cool temperate continental
c.)Cool temperate Eastern margin
Cool temperate Western margin
It is also referred to as cool temperate west coast, European type or British type. It is found on Western sides of continent s between latitudes 45° and 60° North and South of the Equator.
Main areas where this type of climate is found are:
North West Europe, covering northern Spain through France, the Benelux countries, West Germany, British Isles, Denmark and Norway.
North West U.S.A and British Columbia in Canada.
Tasmania in Austria and South Islands of New Zealand.
Southern Chile.
Characteristics
Warm summer between 13°c and 15°c and cool winters between 2°c and 7°.
Small annual range of temperature (3° to 11°c) due to maritime influence.
Rainfall is well distributed throughout the year ranging from 760 mm to 2000 mm.
In the lowlands at the coasts,cyclonic rainfall occurs while in the mountainous areas,relief rainfall is dominant.
Humidity is high in winter
Summer days are long and generally warm with irregular thunderstorms.
Winds blows onshore during winter hence heavy rainfall in winter.
Winters are mild.
Cool temperate Continental
It is sometimes referred to as Siberian type or cool temperate interior type. It extends between latitudes 35°North and 60° North.
Main areas where it is found include:
Alaska and most of Canada.
Eurasia covering Sweden, Finland, Poland, Germany and across former U.S.S.R up to Kamchatka peninsula in the East.
Characteristics
The winter temperatures are extremely cold.
Winters are long with longer nights.
Summers are generally short and warm with maximum temperature of about 19° C in July.
The annual temperature range is very high especially in the interior.
Precipitation is mainly in the form of snow, which falls during winter.
Convectional rainfall accompanied by thunder is experienced.
The annual precipitation ranges from 400mm to 500 mm and varies from place to place.
Relatively high humidity.
Cool temperate Eastern Margin
This type of climate is also known as laurentian type or cool temperate east coast or humid continental warm summer type. It is found on the eastern margin of continents of North America and Asia between latitudes 35° N and 50° N.
Main areas where it is found
The north Eastern parts of U.S.A and Southern Canada.
North Korea, Northern China and Eastern part of Siberia.
Characteristics
Winters are very cold with temperature ranging from – 40° C and 0° C.
Long summers.
Annual range of temperature is large.
Humidity is high during summer.
There is precipitation all year round.
In winter precipitation is in the form of snow.
Annual precipitation varies from 600 to 1000mm.
In summer winds are on shore.
Rainfall is both conventional and cyclonic.
Destructive typhoons are frequent in September.
Polar climates /Tundra and Ice Cap (very Cold Climates)
These climates are found above 66 ½ ° North and South (arctic and Antarctic Circles).
The main areas where it is found include:
Northern parts of America from Alaska through Northern Canada to Greenland.
Eurasian from Northern Norway, Finland Greenland and Northern former U.S.S.R Antarctica.
Characteristics
Winters are very cold and last for 8 months in a year with temperatures ranging from -58 ° C to 0 °C.
Summers are cool but short.
The annual temperatures range is very large sometimes going up to 73 ° C.
Permanent cover of snow and ice.
The area is generally dry with low annual precipitation ranging from 100mm to 250 mm.
Precipitation occurs mainly during summer.
During the long cold winters,polar winds are dominant.
Snow storms known as blizzards are common.
Mountains Climate
This type of climate is best developed in great mountain ranges of the world such as the Alpine Ranges of Europe, the Himalayas and Tibet Plateau of Asia, the Ethiopian Highlands, the east African Highlands, Drakensberg Mountains, The Adamawa and Cameroon Ranges of Africa.
Examples of Mountains with well-developed mountain Climate are:
Mt Everest ( 8,848 m)
Mt Kilimanjaro ( 5,895 m)
Mt Kenya ( 5199 m)
Mt Ruwenzori ( 5,109 m)
Characteristics
Temperature decreases with increase in altitude.
Temperatures range from cool to very cold.
Some mountains peaks are ice capped.
Diurnal range of temperature is small.
Pressure on the mountain top is low due to rarefaction of air.
Rainfall is predominant in these zones.
Rainfall is mainly relief/orographic.
Rainfall intensity depends on aspect.
Identify any three types of cold climates.
Tundra climate
Cold temperature eastern margin.
Cold temperature continental
Polar climate
Micro-climate. (Local Climates)
Micro climate is a climate which is experienced within a small or localized area and slightly modified or different from the general climate of a region. It mainly arises from the differences in slopes, aspect, and nature of the surface, color and texture of the soil and vegetation cover.
Human activities such as building of cities, dams and industrial plants produce micro – climates. In large cities micro – climate is also referred to as urban climate.
Examples of areas experiencing micro- climates include:
Dammed areas – Aswan High Dam, Kariba Dam, Masinga Dam.
Heavily built up areas- Nairobi, New York and Johannesburg.
Forested areas such as Kakamega and the Aberdares forest.
Activity !
Using an atlas locate all the climatic zones of the world in the following figure.
Aridity and Desertification
Aridity is a state of land being deficient in moisture leading to scanty or lack of vegetation and deficiency in soil fertility.
Desertification is the encroachment of large areas of barren land which are covered with sands.
Causes of aridity and Desertification
The causes are divided into:
Natural factors
Human factors
Natural factors
a.)Rainfall
Insufficient Rainfall of less than 250mm which makes it difficult for natural vegetation to grow or thrive
b.)Temperature
High temperatures which heads to high rates of evaporation.
c.)Ocean currents and winds
Cold Ocean currents being a chilling effect on areas that they wash on shore hence cold desert conditions. Dry winds transfer dry conditions to the areas where they blow.
d.) Location on leeward sides
On leeward sides of mountains, rain shadow effects causes aridity. Onshore wind, on crossing mountain barriers, deposits moisture on the windward side hence crosses such barriers as warm dry winds which absorbs moisture rather than causes rain.
e.)Continentally/distance from the sea
Places that are located in the interior of continents are not influenced by the effects of wet winds compared to places located on the shores.
f.)Pressure systems
Areas of the world where high pressure system exist with low humidity have no rainfall because there is no moist air to rise before condensation takes place.
Human activities
Poor farming methods for example: Overgrazing, Monoculture, Ploughing on slopes Deforestation. Poor irrigation practice.
Industrialization leading to emission of various gases in the atmosphere which causes pollution and Global warming.
Population pressure leading to replacement of rangeland with cultivation.
Where nomadic pastoralism is practiced, large parts of the land have been overgrazed.
Destruction of vegetation so as to increase land under cultivation, build industries, acquire building materials and fuel.
Effects of aridity and desertification
Desertification lowers the fertility of the soils, hence lowering the productivity of the land.
Reduced food production leading to famine.
Desertification leads to the destruction of the water catchment areas.
Causes destruction of vegetation which consequently exposes land to erosion.
People from the affected areas migrate to the unaffected areas thus causing population pressure.
It can result in the extinction of plants and animal species and therefore contribute to the loss of biodiversity.
Possible solutions to Aridity and Desertification
Controlled grazing of animals.
Afforestation and deforestation programs.
Irrigation of dry land.
Introduction of suitable farming method.
Controlling soil erosion.
Use of alternative source of energy other than wood fuel.
Public education on environmental management and conservation
Climate Change
Climate change is the establishment of a new climatic state or continuous changes in climatic state such as temperature and precipitation over time.
Causes of climatic change
Causes can be classified as either external or internal
External causes
These are causes which operate from outside the particular climatic system for example from outer limit of the atmosphere.
Internal causes
These are causes which operate from within the particular climatic system for example factors operating from within the earth’s atmosphere. It is mainly concerned with the accumulation of specific gases, which absorb infrared radiation leading to rising temperatures on the earth’s surface and vulcanicity which also lead to emission of gases.
Global warming/Greenhouse Effect
This is an increase in Carbon IV Oxide levels in the atmosphere leading to an increase in surface temperatures.
Causes of Global warming.
Depletion of ozone layer exposing the earth to short energy radiation rays e.g. ultra violet.
Deforestation
Greenhouses gases.
The green houses gases in the atmosphere are transparent to light but absorb infrared radiation.
They allow sunlight to penetrate the atmosphere and be absorbed by the Earth’s surface.
This energy is reradiated as infrared radiation which is absorbed by the greenhouse gases.
The gases include:
Carbon dioxide into the atmosphere.
Chloro-fluorocarbon in the atmosphere.
Methane
Consequences of climate change
Global warming / increased temperature may led to increase evaporation of ocean water which may cause heavy rainfall in some areas.
Increased temperature may lead to the melting of ice caps / ice sheets and glaciers leading to rising sea level. Increased temperature may also lead to high evaporation causing drought.
Climate change may cause changes in rainfall pattern in different parts of the world.
In temperate regions, winters are likely to be wetter and summers drier.
Wetter and warmer conditions may increase pests and diseases which will affect humans, crops and livestock.
Disruption of the natural ecosystems, through adaptation and extinction of various plants and animals species.
vii.Flooding from rising sea level due to melting of ice.
Evidence of the effects of climatic change in the recent Past
The heat waves in Greece due to increased temperature which led to the death of many people.
The receding of the ice –cap on Mt.Kilimanjaro and the disappearing of glaciers on Mt Ruwenzori.
The melting of polar glaciers have resulted into rise in the sea level.
The increase I rainfall causing flooding in some parts of South East Asia and Central Europe.
End of topic
Did you understand everything?
If not ask a teacher, friends or anybody and make sure you understand before going to sleep!
Past KCSE Questions on the topic
a.) How does a sea breeze occur? (2 mks)
a.) Name two theories of the origin of the earth (2 mks)
(b) Name four layers of the earth’s atmosphere (4 mks)
a.) State two conditions that are necessary for the formation of fog.
(b) The diagram below shows some types of clouds. Use it to answer the questions that follow.
Name the clouds marked R
Give two weather conditions associated with cumulonimbus clouds
a) the tables below represent rainfall and temperature of stations X and
Y.
Use them to answer questions (a) and (b)
MONTHS J F M A M J J A S O N D
TEMPERATURE
IN 0c 30 31 31 31 30 29 29 28 28 29 29 30
RAINFALL IN
MM 250 250 325 300 213 25 25 25 100 275 380 200
MONTHS J F M A M J J A S O N O
TEMPERATURE
IN 0C 21 20 20 17 15 13 12 13 15 16 18 20
RAINFALL IN
MM 12 12 15 50 90 110 87 87 50 35 20 15
a) (i) For each of the two stations calculate the mean annual temperature.
–
–
Calculate the annual rainfall for station Y
On the graph paper provided, draw a bar graph to represent rainfall for station x. Use vertical scale of 1cm to represent 50mm
b) Describe the climatic characteristics of station Y.
a) The table below shows climatic data of a station in Kenya.
Use it to answer question (a)
Month Jan Feb Mar Apri
l May Jun
e Jul Aug Sep Oct Nov Dec
Temp
in oC 28.
9 29.
7 30.
3 29.9 29.
7 29.2 28.
4 28.
7 29.
6 30.
1 29.
2 28.
7
Rainfal l in mm 9.0 8.0 21.0 49.0 25.
0 9.0 20.
0 10.0 4.0 10.
0 17.0 11.0
What is the annual range of temperature at the station?
Calculate the total rainfall for the station.
b) State three factors that influence climate.
(a) Name two elements of weather that can be recorded at a school weather station (b) Give three reasons why the recording of data at a school weather station may be inaccurate
7(a) Describe a suitable site where you would locate a weather station in your School (2 mks)
(b) Give reasons why a Stevenson’s screen is:
Painted White (2 mks)
Has louvers (2 mks)
Define relative humidity. (2 mks)
(a) Identify four characteristics of convectional rainfall. (4mks)
(b) State the difference between radiation fog and advection fog. (4mks)
(a) Briefly describe how the six thermometers operate. (5mks)
(b) Three ways in which clouds are classified. (3mks)
(a) Give three precautions to be taken when citing a weather station. (3mks)
(b) State three factors determining the amount of solar radiation reaching the earth’s surface.
(3mks)
Define the following terms:
Climate
Relative humidity
Weather forecasting
Absolute humidity
Weather lore
(5mks)
State the advantages of studying weather through field work.
(5mks)
(a) Describe how you would use the following apparatus during a field study.
Rainfall, maximum and minimum thermometers.
(3mks)
Identify and explain the formation of the type of rainfall found in the
Lake Region or Kenya.
(8mks)
Briefly write down two problems associated with the type rainfallabove.
(4mks)
(a) What is weather forecasting?
(2mks)
List four problems of weather forecasting.
(4mks)
State four ways in which weather forecasting is important to the human activities. (4mks)
(a) Explain three ways in which clouds influence weather.
(3mks)
(b) Use the data below to answer questions that follow.
Month of the year J
F
M
A
M
J
J
A
S
O
N
D
Temp in °C
25
26
26
24
23
22
21
21
22
22
22
22
Rainfall in mm
42
40
73
171
90
89
163
160
71
68
64
42
Calculate mean annual temperature
Calculate annual rainfall
Calculate annual range of temperature.
Calculate the mean annual rainfall
Which is the wettest month? (10 mks)
(a) Define 3 air mass. (2mks)
Name types of air masses.
(3mks)
A mass of air at 15°C can hold 20gm/cm3 of moisture. The same air at the same temperature has 6gm/cm3 of moisture. What is its relative humidity?
(4mks)
Name two instruments placed in the Stevenson Screen.
(2mks)
Why does sea breeze flow at night time?
(3mks)
Specific Objectives
By the end of the topic the learner should be able to:
Define pictures, plans and maps;
Explain the relationships between pictures plans, and maps;
Identify types of maps and state their uses;
Identify and use marginal information on maps;
Identify types and uses of scales;
Determine distances and areas using scales;
Distinguish between direction and bearing;
Identify traditional and modern methods of locating places and features;
Locate places and features on maps using various methods,
Describe the different methods of representing relief on topographical maps;
Identify and describe physical features and human activities on topographical maps;
(1) Enlarge and reduce parts of topographical maps;
(1) Draw cross-sections from topographical maps;
Calculate and interpret vertical exaggeration and gradient
Determine points of indivisibility.
Content
a.)Definition of pictures, plans and maps.
b.)Relationship between pictures, plans and maps.
c.)Types of maps e.g. Atlas maps, topographical maps, and sketch maps. d.)Uses of maps.
e.)Marginal information.
f.)Map scales: Types of scales, conversion of scales, sizes of scales.
g.)Uses of scales: Estimation and measurement of distance and calculation of areas of regular and irregular shapes.
h.)Distinction between direction and bearing.
i.)Traditional and modern methods of showing direction.
j.)Calculation of bearing.
k.)Location of places and features using compass direction, bearing, distance, place names, latitudes and longitudes, grid reference.
l.)Methods of representing relief on topographical maps.
m.)Identification and description of the following in topographical maps:Landforms, vegetation, drainage, economic activities and settlement.
n.)Enlargement and reduction of maps.
o.)Drawing of cross-sections.
p.)Calculation and interpretation of vertical exaggeration and gradient.
q.)Determining indivisibility.
Introduction
Map work involves drawing pictures, Maps and plans.
A picture
A picture is an image of an actual object represented either as a drawing, painting or photograph. A picture has three dimension that is length, breadth and height.
A map
A map is a representation of a part of the earth or the whole earth on a flat surface like a sheet of paper or chalkboard usually drawn to scale.
A plan
A plan is a map of a place or a picture drawn to scale for a specific use. It is drawn to give specific information.
Distinction between Pictures Plans and Maps
A picture gives details in their visible shapes and sizes while a map will show details which a map maker would like to depict. A plan is a chart drawn and meant to give very minute details about very small areas like towns or villages.
Note:
A map and a plan are always drawn as if the drawer was above the ground.
Types of maps
The most common types of maps are:
Topographical
Atlas maps
Sketch maps
Topographical maps
The word topographical is derived from the word topography. Topography refers to the description of surface features such as human made or natural.
Diagram of topographical maps
Natural features shown on topographical maps include:
Rivers
Lakes
Mountains
Shapes
Sizes of countries.
Human made features include:
Railways
Buildings
Roads
Dams
Airports
Atlas Maps
An atlas map is an allocation of maps in one volume. Atlas maps are dawn to scale and the scale may vary from map to map within the atlas.
Sketch maps
These are maps drawn to give specific information which the learner wants to know. They are usually not drawn to scale.
Characteristics of a good sketch map
Be neat and clear.
Have title.
Have a key to explain the meaning of different symbols and signs used.
Be enclosed in a frame
Have compass direction.
Uses of maps
To show direction of places and phenomena on the surface of the earth.
To show human and economic activities such as settlement patterns, land – use, communication network, mining areas, forestry and fishing.
To indicate physical features such as relief, drainage patterns, etc.
To show weather trends e.g. rainfall distribution, temperature and climatic regions.
To show political and administrative boundaries and so is adjudicated land for ownership.
Have become important in military strategies as enemy positions are clearly pin pointed through the use of maps.
Marginal information
This is the information that is given on the margin of a map sheet.
This information tells everything about the map.
Common types of marginal information include.
Map series
This refers to the number in the margin of the sheet which identifies the map sheet with other map sheet in the same groups, which have in common the size of sheets or same specification in the margin scale.
The edition
The edition of the map gives the year it was published or republished and helps to explain some omissions of features which could have developed after the time of publications.
The sheet index number
This is the number given to each sheet to identify it in relation to the adjoining ones.
Copyright
Copyright, symbolized by © is a law that protects the owners of published works from having others using their literature without permission.
The scale
The scale is usually shown on the map as a representative fraction for example 1: 4,000,000
Or as a linear scale and units given in kilometers or miles.
Compass direction and magnetic variation
This is given in the form of a diagram as shown below.
The key
The key contains convectional signs and symbols used on maps to represent both natural and human – made features in a given area.
Various colors and shades are used to represent different geographical phenomena.
The blue/black – represents water features such as seas, coastlines, lakes, rivers and streams.
The green color –represents vegetation this includes forests, woodlands and grass lands.
Vegetation that grows in water is usually represented by blue color.
Relief is always represented by the use of form lines, sport heights and trigonometrical points.
The impression of relief can be emphasized by the use of layer coloring and rock drawing.
The common colors used include various shades of green, orange and brown.
The colors are usually arranged in a sequence. Lighter colors represent higher altitudes.
Scales
This is the ratio between the length on a map and the corresponding length on the ground. This means that the scale indicates the relationship between the two distances measured that is the one on the map and one on the actual ground surface.
Types of scales
There are three types of scales:
Statement scale
Representative Fraction (RF) or ratio scale.
Linear scale
Statement Scale
This is when the scale is expressed in words, for example, 1 centimeter to 1 kilometer, or 1 centimeters represents 1 kilometer or 1 kilometer is represented by 1 centimeter.
Note
It is wrong to say equals to.
Representative Fraction (R.F)
This is a scale where distance on the map are expressed as a fraction of the actual distances on the ground.
For example ,the scale 1 centimeter represents 1 kilometer can be expressed as a representative fraction this way:
In this scale, the numerator represents the distance on the map while the denominator represents the actual distance on the ground.
Note
Units for the numerator and denominator should be the same.
The representative functions can also be expressed in the ratio form as 1:100,000.
The numerator of the RF scale must always be 1 (one).
Linear scale
The linear scale is a line sub – divided into small equal units. Each unit marked the line represents a distance on the actual ground.
For example 1 centimeter on the line represents 1 kilometer on the ground.
The 0 (zero) is usually placed one unit away from the left end of the linear scale.
This unit to the left of the zero is divided into smaller sub – divisions and stands for the secondary scale on which fraction distances are measured .
Advantage
Ground distances obtained directly without calculations.
Note
When measuring distances from a linear scale, read from the right towards the left.
Full units are read to zero mark and any fraction distances will overlap the secondary scale and can be read.
Conversion of scales
There is a relationship among the three types of scales as shown below:
1.)To Convert RF to statement Scale
Convert the denominator of the representative fraction into kilometers so that it represents the distance on the ground.
For example ,to covert the into statement scale, first divide by 100,000
100,000 is the number of centimeres in a kilometre.This gives you 1 km.
Therefore ,the R.F
When expressed as a statement is 1 cm on the map represents 1 kilometre on the ground or 1 cm to 1 km.
2.)To convert statement Scale to Representative Fractions
To convert the statement scale 1 cm to 2 km into representative fractions, the following steps should be followed:
Express the ground distance in the same units as maps distance ( 2 x 100,000 = 200,000)
Convert the scale into R.F by expressing the map distance as the numerator and the ground distance as the denominator
This can also be expressed as a representative fraction 1:200,000
Activity!
Find the relationships in the following scales.
3.)To convert Linear Scale into Representative Fraction
4.)To convert R.F into Linear Scale
Sizes of scales
Map scales sizes fall into three groups namely:
Small
Medium
Large scales
Small Scale Maps
The area represented on a small scale map is large and shows a few details.
An example of a small scale is 1:1,000,000,000.
Any Scale from 1:250,000 and above is a small scale.
The ratio or denominator in such a scale is a large number indicating that the actual lengths have been substantially reduced.
Median Scales Maps
These falls between small scale and large scale maps.
They range from 1:25,000 to 1:50,000.
Large Scale Maps
The area represented on a large scale map is small and shows many details.
The lengths on such a map are less reduced therefore the ratio or denominator is small numbers e.g 1:10,000.
Large scale maps are from 1:25,000 and below.
Uses of scales
Scales are used to:
i. Measure distances on maps ii.Calculate areas on maps
Measure of distance on maps
The distance measured on a map is either straight or curved for example, a road, a river or a railway line.
The methods used in measuring distance include the use of rulers, edges of paper, strings and pair of dividers.
The choice of methods used is mainly determined by the nature of the line, that is, weather it is long or short, straight or curved.
a.)Measuring distance along a straight line.
The use of sheet of paper
Mark the two points XY on the map and draw a pencil line joining them as shown below.
Place the edge of a sheet of paper along the ruled line and on it mark the length of the distance XY as shown below.
Read the distance by placing the edge of sheet of paper against the linear scale as shown below.
The distance of line XY is 8.2 km.
The use of a pair of dividers This involves the following steps:
Spanning the distance to be measured with a pair of dividers.
Transferring the dividers onto the linear scale and then reading the distance.
For distances which are longer than the span of the dividers, the following procedure should be followed.
Mark the two points on the map and draw a pencil line joining them.
Open your dividers to span a convenient number of whole units on the linear.
Rotate the dividers along the line to be measured and carefully note the number of rotations made.
Multiplying the distance of the span by the number of rotations to get the distance of the line between two points.
The line above is sub-divided into a convenient number of whole units on the linear scale.
Number of Rotations = 5 each rotation covers a distance of 2 km. Therefore the total distance of the line is 5 x 2 km = 10 km.
Note:
Make sure your pair of dividers does not readjust as this will give you wrong results.
b.)Measuring Distance along a curved line.
A part from straight lines, you may be required to measure distance between two points along winding route like along a road, river or railway line. The following methods can be used:
i. Use of a piece of string
Take a length of string – it’s best to take one longer than you think you’ll need – and place one end on your starting point.
Now carefully lay the string along to road or path you know you’re going to use, following the curves as closely as you can.
When you reach your finishing point, mark it on you string with a pen.
Now that you have your distance from the map, you can straighten out your string and place it against the scale bar to find out how far you will actually be travelling
ii. Use of a paper edge
Another method of measuring distance is to take a sheet of paper and place the corner of a straight edge on your starting point. Now pivot the paper until the edge follows the route that you want to take.
Every time the route disappears or moves away from the straight edge of your paper, make a small mark on the edge and pivot the paper so the edge is back on course.
Repeat this process until you reach your destination.
You should be left with a series of marks along the edge of your paper. You can now place the sheet against the scale bar on your map.
The last mark you made will tell you the real distance you need to travel.
Finding areas of Regular and irregular shapes
Scales are used to calculate areas of regular and irregular shapes of various features shown on a map.
Areas of regular shapes can be calculated by using standardized mathematical formulae after measuring the respective distances on the map.
Examples
Square and rectangles
Area = length x width
Triangles
Area = ½ base x height
Circles
Area = 𝜋𝑟2
To find areas of irregular Shapes
The entire shape should be covered with a grid of squares. On a map of 1:
50,000 each grid squares should be 2𝑐𝑚2𝑟𝑒𝑝𝑒𝑠𝑒𝑛𝑡𝑖𝑛1 𝐾𝑚2 on the ground.
Count all the complete squares and number them.
Count all incomplete squares. Each incomplete square squares should be considered as half square.
Divide the number of incomplete squares by two to convert them into full squares.
Add the complete squares and the number of halves divided by two.
The total should give you the number of full squares covering the shape.
Examples
Number of full squares = 99.
The number of halves squares = 33
Divide half squares by 2 to make 16.5 complete squares.
The total is therefore 99 16.5 = 111.5 sq.km
Direction and bearing
Direction and bearing are used to indicate a line along which something or an object is moving or facing.
Direction or bearing may also denote a point of reference on which a particular object or place on a map or the earth is situated.
We use compass to show direction or bearing.
In indicating direction, reference to any of the points of the compass can be made. e.g. south of, East of e.t.c.
While when stating bearing, only one point of the compass is referred to that is North. Bearing is read from north in clockwise direction.
Showing direction on maps
There are two ways of indicating direction on maps: a.)Traditional methods
i.) Use of land marks ii.) The heavenly body
b.)Modern methods
i.) The use of points of compass
ii.) The use of bearing.
Traditional Methods
i.) Use of landmarks
Landmarks are familiar features on the surface of the earth that can guide the traveler in finding the way from one place to another.
Examples are rivers, hills, roads and buildings
ii.)The use of heavenly bodies
Where there are no land marks such as deserts and large water bodies. It is possible to use:
The North Star.
The Southern Cross and the South Pole.
Modern Methods
i.) The use of the compass
A compass is a scientific instrument whose needle always points to the north.
A compass has a total of 32 points as shown below.
North, East, South and West are the four main points referred to as cardinal points.
Modern maps do indicate three expressions of the north as follows:
True or Geographical North.
Magnetic North.
Grid North.
True or Geographic north
This is the position of the North Pole as shown on the globe (the point where longitudes meet.)
Magnetic North
This is the earth’s Magnetic North Pole as determined by the earth’s magnetic field.
This is the direction to which the needle of a compass points when it comes to rest.
The angular difference is known as magnetic variation.
Grid North
It is in the same alignment as the north –south map grid lines on topographical maps.
It is based on the national grid system. However each map-maker can draw a map and set his own grid north.
It is usually as close to the true north as possible and coincides with it.
ii.) The use of bearing
The starting point that is the North-South line is always taken as Oº.
Bearings are always read in a clockwise direction from the North line through a full circle of 36Oº.
Bearings are stated in three figures. For example, North is stated as 36Oº or of 000º and East as 090º.
Calculation of Bearing
Bearing helps to determine the position of one place from another.
The figure below illustrate how the position of A from B can be determined by means of bearing.
To measure the bearing of A from B accurately, the following procedure should be followed:
Draw a light pencil link to A from B.
Draw a North- south line through point B parallel to the North-South line given in the margin of the map. If the North- South line is not given, draw the line parallel to the grid lines or parallel to the sides of the map running North-South.
Intersect this North- South line with another perpendicular line East- West through Point B.The East –West line should be parallel to the horizontal grid lines or sides of the map due east – West.
Measure angle NBA using a protractor reading degrees in a clockwise direction from the North line. The bearing of A from B in the diagram above is 225º.Now find the bearing of B from A.
Locating places on a map
The position of a place on a map or on the earth’s surface can be expressed in any of the following ways:
By use of direction, bearing and distance.
By use of a place name.
By use of latitude and longitudes.
By use of grid reference system.
Use of latitudes and longitudes.
Latitude
Imaginary lines drawn on the globe or on a map to show how far north or south a place is from equator.
All latitudes are parallel to each other hence they are also called parallel.
The main lines of latitudes include:
1.)The equator which is the longest also called green Circle.
2.)Tropic of Cancer 23 10 N of the equator.
3.)Tropic of Capricorn 23 S of the equator.
4.)The Arctic Circle 66 .
10
5.)Antarctic Circles 66 S.
Latitudes are measured from the centre of the earth towards north and south to a point of 90 as shown below.
The distance between two lines of latitude 10apart is approximately 111 km.
Longitudes
These are imaginary lines drawn on the globe or on a map showing how far east or west a place is from the center of the earth.
It is the shortest North- south line that joins any two places on the earth.
The 00longitude is the one that is conventionally known as the prime Meridian or The Green which Meridian.
All longitudes to the east of the prime Meridian are numbered from 00 westward to 1800.
Note
In either direction, the longitude 180 is the same line.
All longitudes meet at the poles.
They are all of the same length and the distance between them is widest at the equator and narrowest towards the poles.
The distance between one longitude and the next one 10 apart at the equator is 111km.
Since the distance between longitudes decreases polewards,the distance along any longitude away from the equatorial would be less than 111km.
To give the position of a place on a map using latitude and longitude’s,the following steps are used.
i. Identify the place whose location you want to give. ii. Identify the nearest numbered latitude and longitude.
iii.Estimate the latitude and longitude to the nearest 10.For example 7 Nairobi is about 1 S and 37 E
Note
Because latitude and longitudes are angular measurements, they are made in degrees which are further sub-divided into minutes and seconds.
This helps in locating a place accurately 10 I equivalent to 60 seconds
Example
When the local time is 2.00pm at longitude 450E, what is the longitude of a place whose local time is 8.00pm?
Solution
450E X
2 pm 8pm
Time difference = 6 hrs
150 = 1h
= 6h 𝑥 150 = 900
= 90 + 45 = 1350E
Example
Differentiate between a latitude and a longitude.
(2mks)
Find the time at town X on Longitude 200W, if the local time t town W on longitude 270 E is 10.00am. (2mks)
Solution
Differentiate between a latitude and a longitude.
A latitude is a line based on the angular distance North or South of the equator/it is an imaginary line drawn on the maps/globes from west to East measured in degrees North to South of the equator while a longitude is a line based on the angular distance of a place East or West of the prime meridian/Greenwich meridian (00)/ an imaginary line drawn on maps/globes from north pole to south pole measured in degrees East or West of the prime meridian/Greenwich meridian(00).
Find the time at town X on Longitude 200W, if the local time t town W on longitude
270 E is 10.00am.
-Longitudinal difference
200 +270 E =470
-Time difference.
470 x 4min =188 minutes/ 3hrs 8mins.
-X is 3hrs 8mins behind W
Time will be.
10.00
3.08
6.52 a.m1
T = 2mks.
Grid References
A grid is network of imaginary horizontal and vertical lines drawn on a map forming equal squares.
The vertical lines are called Eastings because they are numbered eastwards while the horizontal lines are called Northings because they are numbered northwards.
East grid line is given a number starting from the southwestern corner. This corner is called grid origin.
All readings start from the south western corner.
How to Give a Grid Reference
Read and give the figure for the Eastings /vertical grid line first and following this figure with the northings/horizontal grid line.
Each eastings or Nothings on a map represent a given number of metres from the point of origin.
When giving a grid reference, both decimal points and commas are eliminated in the co-ordinates and a single continuousfigures is given.
All grid values are plain figure that is unit of length are not expressed.
Note
Grid can be given in four Figure Grid Reference or six figure grid reference.
Giving the six figure Grid Reference
Write down the easting.
Subdivide the eastings into 10 equal parts.
Repeat the same for the northings.
Method of Representing Relief on Topographical Maps.
The term relief means the actual appearance of the earth’s surface.
Relief features include valleys,gullies,rolling or undulating plains and dissected landscape.
Vegetation,seas,lakes and ponds and human – made features like buildings roads and runways do not form part of relief features of the earth’s surface.
Relief features may be represented by the use of the following ways:
Contours/isohypses
They are lines drawn on maps to join all points with the same height above the sea-level.
Contours are drawn at fixed interval known as the vertical Interval (VI)the vertical interval is always kept constant.
Where contours come too close this suggest that the land is steep and where the contours are far apart, it suggest that the land has a gentle slope.
Contours have one advantage in that they are easy to understand and consequently can be used to interpret the features on the map effectively.
However the effectiveness of the use of contours depends largely on the vertical intervals used.
Formlines
These are lines drawn on a map which are not sufficiently mapped to estimate where actual contours would pass.
This unlike contours form lines are not accurately surveyed.
Formlines are indicated by a broken line.
Pictorial Representation
This method shows land appearance in pictures.
Based on the artist impression of the land scale.
The features are drawn on small convectional pictorial symbols.
Hill shading
This is an attempt to show reliefs accurately by shading areas which would be in shadow when light is shining from a given direction.
The rays of the light are either oblique or vertical depending on the source.
The shading of the slope depends on its gradient. The steeper the slop, the darker the shade will be on the map.
Plateus,valley bottoms and plains are light shaded.
In oblique lighting, the eastern and south-eastern slopes will be shaded. While north – western and western slopes are unshaded.
Disadvantages
Does not give the heights of places unless spot heights are used.
Does not distinguish uphill from downhill or spurs from valleys.
Neither does it distinguish plateaus from plain land.
Colouring/Layer tinting
In this method different colors are used to show different aspects of relief.
For example light green can be used to represent low lying areas while brown maybe used to show high altitudes.
In this method, the shades become darker with increased heights.
One major advantage in colouring is that it is useful in representing landscapes of varied relief.
Disadvantages
Dark colours tend to obscure details.
The monotone of colours may not give a good visual impression of plains or plateaus.
Cliff and Rock Drawing
On topographical maps, areas with steep cliffs and rock faces are shown by the use of wedge – shaped black lines.
The thin ends of these black lines point downslope.
This method of representing relief is referred to as cliff and rock drawing.
On maps clifs or rock drawing may take one or more of the shapes shown.
Hashures
A method used to represent relief on mountains or hilly areas.
It involves the drawing of lines down slope in the direction of the steepness gradient.
The length and steepness of the hachures indicate the direction of the steepness of slope.
Advantages
Effective in representing relief in mountainous or hilly areas.
Gives a visual impression of the hilly landscape by showing ridges and valleys clearly.
Disadvantages
Difficult to draw
Do not show the exact height of the land scape.
Cannot be used to show flat ground on maps.
Spot heights and Trigonometrical stations
On topographical maps, a spot height is shown as a dot with its height indicated next to it.
The dot indicates the exact height of a particular point on the map.
A trigonometrical station/a triangulationpoint is a survey point represented on a map by the use of a triangle with a dot at the centre.
It may also be represented by a small circle with a dot at the centre.
Trigonometrical stations may be shown as pillars or ground stations or others.This are distinguished by thickness of lines of the sides of the triangle.
The position on which the apex of the triangle is placed will indicate whether the stations are either primary or secondary.
The circular Trigonometrical symbols are referred to as others. The spot heights and trigonometrical stations are easier to locate on maps because they are bodly printed.
Spot heights and trigonometrical stations on maps must be used with care for if crowded they give little or no visual impression on the general relief pattern.
They also need to be used with other methods especially contours if their use on maps is to be more meaniful.
Map work II
Interpretation of physical Features and Human Activities on Topographical Maps
Physical features and human activities include:
Landforms
Drainage
Vegetation
Economic activities
Settlement on topographical maps.
Interpretation of physical features and human activities depends on clues available on a particular map.
Precautions taken when describing physical features and human activities on a map.They include:
Avoid definite words but use words like “suggest that”, “possibly”, “likely indication of’’.
One clue should not come out with a conclusive description.
Avoid the following phrases when reading a map:
The top right corner of the map – but the south eastern area.
Top of the map – instead the northern part of the area.
Left corner of the map – instead the north-western part of the area.
Steep contours – instead use the area is steep as revealed by close contours shown on the map.
Bottom of the map –instead the southern part of the area.
The river flows towards left, upwards, downwards, or to the right- the river flows westwards, northwards, southwards, east wards.
Study the map when looking at the key. Use the key to interpret the information you have got from the map.
Interpretation of physical features
Physical features on a map include natural landforms natural vegetation and drainage.
Landforms
Landforms constitute what is referred to on the surface of the earth and on maps as relief.
Relief refers to the way the land surface looks like: whether dissected, rolling, hilly or mountainous.
Landforms can be predicted by the use of contours, conventional signs and names of depicted features.
Types of landforms
Dissected landform
This refers to part of the earth’s surface that has been deeply cut by many rivers/streams.
On topographical maps, such a landscape is shown by curved or irregular contours.
The more crooked the contours, the more the earth’s surface.
Rolling landform
Rolling landforms /undulating relief.
It is a type of relief with gentle slope represented by spaced contours.
Characterized with absence of high peaks and rivers flowing in pronounced valleys.
Hilly or Mountainous Landform
A hill is a higher ground or an upland that rises up above relatively lower areas or grounds.
They may be regular or irregular.
On topographical maps, they are represented by circular or near circular/concentric contours whose values increase towards the top of the hill.
Valley
This is a low lying part of land bound by two facing slopes.
They are represented on topographical maps with contours that are U/V shaped with their apex pointing towards the higher grounds.
Spurs
This is a piece of raised land jutting into a valley or a projection of land from a mountain or ridge.
Types
Interlocking spurs are those which project into a younger river valley, where the river tends to follow a winding course round obstacles.
Truncated spurs are found in glaciated highlands areas. As glaciers moves down a V-shaped valley, they gradually trim off the tips of interlocking spurs forming truncated spurs.
The valley is transformed into a U – shape with near vertical slope and a broad floor as shown below.
Interlocking spurs
Truncated spurs
Pass
A pass is a narrow deep gap that lies between high hills/mountain areas.
Examples of passes in kenya
Marich Pass in West Pokot
Kiti pass
They are shown on a map by the absence of contours between high areas but with a transport route passing through them.
Saddle/col
A col (saddle) is a small depression on a hilly area that is located between hills on a ridge.
It is represented on topographical map by a gap between two hills without contours shown on them.
Ridge
A ridge is a roughly narrow and elongated hill with steep slopes on all the sides.
The top of the ridge may either be level or rugged with several hills forming in a range.
Ridges are shown on topographical maps by closely packed contours descending on both sides.
Escarpment
This is a relatively continuous line of steep slopes dipping to/facing the same direction.
It exhibits a gentle slope on one side and a short steep slope on the other/opposite side.
On topographical map, an escarpment is shown by closely spaced contours on the steep (scarp) slope but the contours become more widely spaced further down the slope on the gentle slope.
Bays and straits
A bay is a piece of water jutting into land. Big bay is called a gulf and a small one a cove.Winam Gulf is made up of many bays like Asembo Bay,Kidimu Bay,Kendu Bay and Homa Bay.
A strait is a narrow stretch of water linking two areas of sea, forexample ,the strait of Gibralta links the Mediterranean Sea to the Atlantic Ocean.
Channel is a stretch of water joint two seas or two large parts of a water body for example,Rusinga Channel joins lake Victoria to Winam Gulf,Siyu Channel joins the two large bodies of Indian Ocean separated by Pate and Faza islands North of Malindi.
A sound is a stretch of water connecting two large water bodies.It is wider than a strait.
A bight is a wider-gentle curve or indentation of the coast, commonly between two headlands but a head of a gulf.
Watershed
This is a high point which separate head-waters of two or more drainage basins. It can be on a ridge, plateau, hill or escarpment.
It is sometimes referred to as a divide, interfluve or water –parting.
It is shown on a map by sources of rivers flowing from a high area downhill to different directions as shown below.
Slopes
This is an inclination/slant/gradient of the land.
A slope is determined by the following
Contour patterns: – these can be fairly straight to represent level surface or curved to show rugged surface.
Contour Spacing: – contours can be widely spaced to represent gentle slopes or closely spaced for steep slopes.
Contour heights: – these can be high or low and are used to determine the general direction of slope.
Slopes can therefore be classified into the following types:
Type of slope Description
Steep These are shown on topographical maps by contours drawn very close together
Gentle These are shown on topographical maps by contours drawn far apart from each other
Even These are also referred to as regular or constant slopes.
They can be gentle or steep
They are shown by contour spaced at regular intervals
They are found in fairly level areas e.g. plateaus and peneplanes.
Type of slope Description
Uneven These are also referred to as irregular slopes.
Shown by unevenly spaced contours i.e. widely spaced in one area and closely spaced in another area.
Convex These are slopes that are steep in the lower sections but become gentler in the upper ends.
Are indicated by contours that are closely packed together at the lower sections and widely spaced upslope.
Are common in escarpments and along plateau edges
Concave Are slopes that are gentler in the lower sections and steeper upslope
Are indicated by contours that are widely spaced at the lower sections and closely packed upslope.
Note
Land generally slopes from high to low grounds. The direction of slope from high to low is determined by studying the values and patterns of contours.
The direction of slope is determined using the cardinal points of the compass e.g. the land slopes from to the southern, eastern, western or northern parts of the mapped area.
Steps to take when describing the relief on topographical map
Give or state the general relief of the area covered by the map i.e. the area can be a highland, hilly, lowland or plain.
A highland is depicted by contour/trigonometrical station values that exceed 1000metres above the sea level.
A hilly area will comprise of several conical hills; shown by concentric contours with values increasing towards the summit of the hill or named hills.
Lowland areas will have contour values of below 1000metres above the sea level
A plain will be shown by very widely spaced contours whose values range between 0 – 600 metres above the sea level.
Give the range of the altitude of the mapped area i.e. the heights of the highest and lowest points covered by the map. Trigonometrical stations, spot heights and contours are used to determine these.
Candidates are advised to give the exact location of these heights on the map by use of directions of the compass or grid squares.
State the general direction of the slope of the area covered by the map. Use the contour heights; studying their pattern and behaviour. Direction of flow of rivers can also be used to give the general direction of slope.
Identify and name the relief features present in the area and their distribution e.g. many hills/escarpments and give examples.
Vegetation
This refers to the collection of plant cover on the earth surface. In strict geographical sense, it entails the entire plant cover except cultivated crops/plantations.
Different areas on the topographical maps are covered by different vegetation types that include forests, scrub vegetation, scattered trees, woodland, riverine trees, palm trees, thickets, mangrove trees, etc.
All these have symbols that represent them in the key of the topographical map.
Some major vegetation areas covered by the map may be named e.g. Kiptaberr Forest, Tingwa Hill Forest, etc.
When describing vegetation, consider;
Identify the vegetation types in the mapped area.
Use the compass direction to give their distribution.
Do not include plantations as part of the vegetation.
Drainage
These are physical/natural water features that are found on the earth’s surface/mapped area.
They include rivers, lakes, seas, oceans and springs amongst others.
Drainage features on topographical maps are mainly shown by blue colour.
The following points should be put into consideration when describing drainage of a mapped area.
Identify the drainage features that are present in the mapped area and state their locations.
State the number of the features i.e. the mapped area has many rivers; giving examples in each case.
Give the type and state of the identified feature i.e. whether seasonal or permanent
Rivers are the most common features of drainage likely to be found in areas covered by topographical maps.
When describing rivers;
State whether the rivers are permanent, seasonal or intermittent.
(a) Permanent rivers are shown by continuous blue lines (scan). They are likely indication of heavy rainfall and impermeable rock. Season
(b) Seasonal rivers are shown by broken blue lines. (Scan). They are likely indication of low/unreliable and seasonal relief.
(c) Intermittent/disappearing/vanishing rivers are shown by blue lines that end abruptly (scan). They are likely indication of porous rocks, underground drainage and low rainfall
Name the main river in the mapped area. It is shown by wide/thick and continuous blue lines (scan).
Give the general direction of flow of the river from the source to the mouth but most preferably; to the mouth.
Name the drainage patterns exhibited by the rivers and their tributaries in the mapped area.
The major drainage patterns are
(a) Dendritic: – tributaries join the main river at acute angles
(b) Trellis: – tributaries join the main rivers at right angles
(c) Parallel: – rivers and streams run nearly parallel to each other
(d) Radial: – rivers flow outwards in all directions from a mountain summit
(e) Centripetal: – formed when many rivers flow into an inland depression
Another drainage feature likely to be found in an area covered by a topographical map is swamps.
When describing swamps; consider the following:
Identify the type of swamp i.e. whether seasonal, papyrus or mangrove using symbols shown in the key.
State their location/distribution in the mapped area. Use compass direction or grid references
Dendritic drainage
Radial Drainage
Centripetal Drainage
Rectangular Drainage
Settlement
This refers to a place where people live or dwell/or housing units.
They can be both rural and urban settlements.
On topographical maps rural settlements or huts are shown by black dots while urban settlements shown by block shadings that are black in colour.
Settlements patterns refer to the arrangements of housing units on an area covered by a topographical map.
They may be nucleated, linear or dispersed.
Nucleated settlement pattern refers to many housing units clustered together round a particular feature e.g. a water point or a market centre.
On topographical maps, they are shown by clustered dots or block shadings
Linear settlement pattern form along a communication line e.g. road, railway, coastal belt or river.
On topographical maps, such patterns are indicated by block shadings or dots along the communication line
Dispersed settlement pattern is also referred to as scattered settlement pattern. The housing units are considerable distances away from each other.
On topographical maps, such patterns are indicated by scattered dots or scattered block shading.
When describing settlement on topographical map; take into the account the following
Identify the type of settlement and state its distribution on various parts of the topographical map e.g. the eastern sections of the map are characterised by nucleated settlements/the mapped area majorly comprises of rural settlements
When describing settlement on a topographical map, the following terminologies should be used; DENSE, FEW, NO, SCATTERED/SPARSE.
Examples
There is dense settlement in the northern parts of the map extract.
There are few settlements around the swamps.
The areas around the forest reserves have no settlements.
Scattered/dispersed settlements are evident on the western parts of the map.
Note
Avoid mentioning the terms population, populated or people. This is because the settlement units do not depict the population/people of the area.
Sometimes candidates may be required to explain the factors that influence distribution of settlement in the mapped area or account for the distribution of settlement in the map extract. This will require evidence from the map to support the explanations.
Such factors are majorly physical and include relief features, altitude, and drainage, presence of water source, and presence of a trading centre or centre with basic facilities such as security, health care provision and education. Others include crop growing for plantation, etc.
Most likely questions on settlement
Study the map of Nkubu provided and answer the questions that follow.
Identify two settlements patterns in the area covered by the Nkubu map.
Describe the settlement of the area covered by the map.
Citing evidence form the map, explain three factors influencing settlement in the mapped area.
Students from a school in the mapped area conducted a field study on settlement in the mapped area.
State two ways in which the map may be useful to them.
Name two methods of data collection they might have used during the study.
State three problems they may encounter during study.
Functions of an urban/rural settlement as seen in the map extract
These refer to the services that are offered in the mapped area. They may be income generating and social (bring people together).
They must be stated ending or having the caption “ion” or the word “centre” at the end.
They include
Function Evidence
Industrial Centre Presence of a processing plants e.g. creameries, cement processing, named industry or a factory.
Agricultural Centre Grain silos and posho mills for crop farming, named plantations/crops, cattle dips and dairies for livestock farming
Sports/Recreation Sports centre, golf course or a stadium
Forestry Centre Forest Guard Post, sawmills, forests, etc.
Administration Chief’s camp, District Officer, District Commissioner offices.
Education Schools, libraries and colleges
Transport & Communication Centre Roads, railway lines, airports, airfields, airstrips, post office.
Tourist Centre/Tourism Museums, game parks & national reserves, historical monuments, high class hotels.
Commercial/Trading Centre Markets, shops and roads converging at a given centre.
Religion Churches, mosques and chapels.
Medical/health care centre Health centres, dispensaries, hospitals
Security centre Police stations/police patrol bases
Note
Utmost care should be taken by the candidates when naming the economic activities within the mapped area or stating the functions of the mapped area/section of the mapped area.
The two are almost similar especially their evidences but the manner in which they are stated brings the difference clearly.
Most likely questions on Human Activities
Study the map of Homa Bay provided and answer the questions that follow.
Citing evidence from the map, name four economic activities in the area covered by the Homa Bay sheet.
Students from Homa Bay High school conducted a field study on functions of Homa Bay township.
Citing evidence from the map, name three functions of Homa Bay Township they are likely to observe.
State two ways in which they would prepare for the study.
State two physical problems they may encounter during the study, citing evidence in each case.
Climate
This can be concluded from a topographical map using the following evidence:
(a) The type of crops grown in the mapped area e.g. tea and coffee would depict a cool and wet climate, wattle and sugar cane a warm and wet climate.
(b) The type of vegetation i.e. forest vegetation for a cool and wet climate, scrub vegetation and woodlands for a hot and wet climate
(c) The type of rivers flowing in the mapped area e.g. permanent rivers depict a wet climate (rain falls all year round), while seasonal rivers would show a hot and dry climate.
Soils
Soils on topographical maps are depicted by:
(a) The types of rivers e.g. intermittent rivers will depict porous soils
(b) Seasonal swamps/swamps in general would depict waterlogged/impermeable soils
(c) Type of crops grown e.g. coffee, tea would depict fertile volcanic soils
Enlargement and Reduction of Maps/Sections of Maps
This involves increasing or decreasing sections of the topographical map.
This is done using grid squares and scale.
When sections of the map are enlarged, the scale is reduced while if reduced the scale is increased.
Drawing sections and profiles
A section is a vertical cut through soil, rock or landscape or the representation of the actual appearance of the landscape in diagrammatic form.
Longitudinal sections are called profiles.
Importance of sections in interpretation of maps
They enable ne to determine the type of lope,whether even,concave or convex.
They provide a comprehensive appearance of the landscape which can be of great assistance in construction.
They enable us to determine intrvisibility.
They give a general impression of the physical appearance of the landscape.
Types of sections
Transect Sections
These are sections drawn to show different types of natural and artificial features.
They can be longitudinal,traverse or radial.
They can show geographical zones like vegetation and changes in landscapes.
A traverse section
It is more accurate and is drawn between two identified points on a given contour map.
It shows the general landscape and other geographical phenomena like vegetation, settlement and communication routes.
Sketch Sections
These are sections which are not drawn to scale.
They also represent the appearance of the landscape of a given area between two points.
Sketch sections are drawn by simply estimating the general trend of the landscape.
They show roughly the uphills and depressions.
River Profile
This is a section along the river valley from the source to the mouth.
The ideal river profile is made up of youthful,mature and old stages.
Youthful stage
Has torrential course and velocity is high.
The gradient is steep or broken and irregualar.
Vertical erosion dominates, leading to formation of steep sided V- Shaped valleys.
The mature Stage/Valley Course
Made up of gentler gradient with broader valleys separated by rounded ridges.
The old stage/flood plain course/Senile
Has levelled gradient with broader river valleys made up of flood plains
Cross Sections
A cross section is a diagrammatic representation of the variation between identified points along a straight line.
Steps taken when drawing cross- Sections:
Identify the two end points to be covered by the cross- section.
Draw a light Pencil line to join the two points.
Then fold a paper on the map by placing its straight edge along the line.
Apply the strip of paper on the map by placing its straight edge along the line.
While holding the paper very firmly, on it mark the two end points, then identify the heights of these two points and mark them on the paper.
Mark on the paper the contours crossed by the line. Where there is a river mark with a depression sign, for example ‘U’ and where there is a hill mark with a special sign for example “n”.This downwards and upward symbol will help you draw curves appropriately.
Name any conspicuous features where they appear on the the paper.
Note the highest and lowest points crossed because these will determine your scale.Then calculate the amplitude of relief .The difference between the highest and lowest contour)This is important in ddeterming the vertical scale.
Then determine your vertical scale.When determining the vertical scale a suitable range is necessary.
Draw equal lines on a fresh paper, preferably a graph paper and mark it A and B at both ends. Then draw the vertical lines at both ends.On them mark the heights accordingly. Then remove the strip of paper from the map and place it on the line A and B on your graph paper.Hold the paper firmly and then transfer the information from it to the graph.Plot the heights on the graph.Finally draw a smooth curve to connect the points in form of a line graph.
Annotate or Label the cross- section. Whennaming, usearrows. Do not draw anything on the section, whether it is a river show by arrows only. Note that the arrows must come from the top and not the bottom because the elevation is viewed from the ground and not underground.
Calculation and Interpretation
Vertical Exaggeration ( VE)
Vertical exaggeration is the ratio of the horizontal scale to the vertical scale.
It is normally calculated after drawing the cross-section.
The verical scale is always larger than larger than the horizontal scale and therefore it is always exaggerated.
Calculating the vertical Exaggeration
V.E=(vertical scale)/( horizontal scale)
Gradient
This is the steepness of a slope between two given points.
It is either expressed either as a proportion between the vertical interval VI and its Horizontal Equivalent H.E.
It involves expressing the gradient as fraction, reducing to a decimal and then looking up the angle corresponding to this calculated tangent in a logarithm table.
Intervisibility
Intervisiblity is the ability to see or view two points from either sides.
Ways of determining intervisbility
Draw across- section. Then draw a line of sight from the point of observation to other point. If there is any rise any rise which intervene,then the points are not intervisible but if there is no rise which intervenes,then the places are intervisible.The part which is not seen is the dead ground.
By calculating the overall gradient of the line of sight from the observer to the second point or gradients from any possible point of intervention of view to the second point.If the gradient from the line of sight to the far point is gentler than gradients to any interfering points,the two stations are not intervisible as shown below.
Example
Study the map of MIGWANI (1:50,000) and answer the following question.
(a) (i) Convert the sale of the map into a statement scale. (2 marks)
(ii) What is the magnetic variation of the map? (2 marks)
(iii) Give the six- figure grid reference for the junction of the roads C94 and D502. (2 marks)
(b) Using a vertical scale of 1 cm to represent 100 m, draw a cross section from grid reference 060640 to 130640. (4 marks)
(i) On it, mark and label the following parts
Steep slope
Water pipeline
Road
Footpath (4 marks)
(ii) Calculate the vertical exaggeration of the cross-section (2 marks)
(c) Describe the drainage of the area covered by the map. (5 marks)
(d) Citing evidence from the map, give two economic activities carried out in the area. (4marks)
Solution
(i) 1km = 100000cm
50000/(100000 ) cm x 1 km=0.5km
Vertical Scale
Horizontal Scale
V,E =1:10000 =I/l00005000011 1:50000
Thus V.E =5
Drainage of the area covered by the map
The main drainage features are rivers.
The main permanent rivers are Ngoo and MuiThere are dams in the area covercd by the map i.e in grid square 0062
To the North-East of the area covered by the map is well drained due to presence of permanent rivers e.g Ngoo.
The river around Mutito forest forms fadial drainage pattern.
Vinda and its tributaries form trellis drainage pattern.
Economic activities Evidences
Trading Indicated by the presences of shopping centres.
Mining Presence ofthe rock.
Transports Indicated by the presence ofdense road networks
Example
Study the map of Karatina 1 : 50,000( sheet 121/3) provided and answer the following questions.
(a) (i) What is the longitudinal extent of the map ? (2mks)
(ii) Name two physical features in grid square 8959. (2mks)
(iii) Measure the distance of the dry weather road (D451) from grid reference 905622 to grid reference 952578. Give your answer in Kilometers. (2mks)
(b) (i) Calculate the bearing of the church at Kirimara grid square 9255 from the trigonometrical station at grid square 9456. (2mks)
(ii) Name two types of natural vegetation in the area covered by the map. (2mks)
(c) Draw a rectangle measuring 15cm by 10 cm to represent the area enclosed by Eastings 80 to 90 and Northing 50 t0 60 . (1mk)
On the rectangle mark and name the following
(i) River Sagana.
(ii) Forest
(iii) All weather road(bound surface).
(iv) Hirigafactory. (4mks)
(d) Describe the relief of the area covered by the map. (5mks)
(e) Citing evidence from the map , identify five social services that are offered in Karatina Municipality.
Solution
The map of Karatina
(a) (i) The longitudinal extent of the map
-37000’E – 370 15’E /15’ (2mks)
(ii) Physical features
–Hill
-Spur
-River valley.
(Any 2 x 1 = 2mks)
(iii) Distance of the dry weather road
= 8.1kms + 0.1km ( 2mks)
(b) (i) The bearing of the church at Kirimara
– 2590+ 10 (2mks)
(ii) Types of natural vegetation in the area covered by the map
-Forest
-Bamboo
-Woodland
-Scattered trees
-Scrub
-Papyrus swamp (Any 2 x1 = 2mks)
(c) Draw a rectangle measuring 15cm by 10cm to represent the area enclosed by Easting 800
900 and nothing 50 – 60 (graph paper) (1mk)
(d) About the relief of the area covered by the map:
-There are numerous steep slopes to the North, North East and South East / gentle slopes to the west, North West and South West.
-There are many, narrow river valleys.
-The land scape is dissected by many river valleys.
-They are many interlocking spurs along the river valleys.
-The landscape is generally hilly / has many hills.
-The land rises from the South to North.
-The lowest altitude is 5,100ft / highest altitude is 9050 ft A.M.S.L.
(e) Citing evidence from the map, identify five social services that are offered in Karatina Municipality.
Services Evidence
Health/ medical
Religious
Administration/ security
Housing
Education
Water supply Hospital
Church,mosque
D.C /Police post
Built up areas / houses
Schools
Water supply works
Example
Study the map of karatina 1:50,000 (sheet 121/3 provided and answer the following questions.
a) i) What type of map is Karatina map?
– A topographical map (1mk)
ii) What was the magnetic variation as at the time the map was taken.
– 010091 (2mks)
b) i) Identify the human made feature found at grid square 824503.
– Bridge
– All weather road (2mks)
ii) Calculate the area of part of mount Kenya forest found in Kirinyaga District.
– Complete square = 9km2
– Incomplete square = 42/2 = 21km2
Total area = (9 + 21)
= 30km2 (2mks)
c) i) State the longitudial extent of the are covered by the map extract.
-37º 00’ to 37º15’ (2mks)
ii) Identify any two methods used to represent relief on the map extract.
-By contours
-By use of trogometrical stations
– By use of spot heights (2mks)
iii) Calculate the gradient between the point 010450 and the water reservoir at grid square 9648.
Horizontal equivalent = 1900ft
Vertual equivalent = 650ft
Gradient =
= 1: 2.923076 (3mks)
d) Reduce the area bounded by Easting 93 and Easting 05 and Northing 50 and 57 by half. On it mark and name the following. (2mks)
i) District boundary.
ii) Forest
iii) All weather road D451
RECTANGLE SHOWING BOUNDED BY EASISTING 93 &05 NORTHING 50 & 57 ON KARATINA MAP
KEY
e) Descibe the drainage of the area covered by the map.
There are numerous rivers in the area covered by the map.
Most of the rivers flow from north to south western part of the area covered by the map.
Most rivers are permanent e.g River sagala.
There is a papyrus swamp in south eastern part of the area covered by the map.
Most rivers form dendritic pattern.
There is radial drainage pattern on mouth Kenya forest.
End of topic
Did you understand everything?
If not ask a teacher, friends or anybody and make sure you understand before going to sleep!
Past KCSE Questions on the topic
1. Study the map of Taita Hills (1:50,000) sheet 189/4 provided and answer the following questions
(a) (i) What is the bearing of the peak of Mwatunga hill in grid square 3214 from the water tank in grid square 2619? (2mks)
(ii) What is the length in kilometers of the section of the Mwatate – Voi railway line in the south – eastern part of the map? (2mks)
(b) Draw a rectangle measuring 16cm by 12 cm to represents the area enclosed by the Eastings 24 and 40 and Northings 20 and 30 ( 1 mk)
On the rectangle, mark and name the following features:
Mgange hills ( 1 mk)
A rock out crop ( 1 mk)
All weather road, bound surface ( 1 mk)
River Ruhia ( 1 mk)
Ronge forest ( 1 mk)
(c) Using evidence from the map, explain three factors that have favoured the establishment of the Teita sisal Estates in the Southern part of the area covered by the map ( 6 mks)
2. Study the map of Nyahururu, 1: 50,000 (sheet 105/4) provided and answer the following questions
(a) (i) Give the six figure grid of the junction where the road to Ndaragwa (D 388) meets with the road to Nyeri & Nanyuki (B5) (2mks)
(ii) Calculate the bearing of point X from point Y (2mks)
(iii) Name three physical features found along the line XY (3mks)
(b) (i) Draw a square 12 cm by 12 cm to represent the area enclosed by the Easting 10 and northing 10 to the North- eastern part of the map (1mk)
(ii) On the square, mark and label
The main river (1mk)
All weather loose surface road (1mk)
A forest (1mk)
Citing evidence from the map,
explain two Physical factors that may have influenced the location of Nyahururu town (4mks)
Factors that favour saw milling in the area covered by the map (4mks)
3. Study the map of Taita Hills (150: 50,000 sheet 189\4) to answer the following questions.
a) What is the approximate height of the hill at the grid square 3926. (2mks)
b) Measure the length of all-weather 6 to roads (bound surface) from Wundanyi to southern edge of the area covered by the map. (2mks)
c) Citing evidence from the map describe the relief of the area shown. (5mks)
d) State differences between a map and a plan. (2mks)
e) Explain two importance of scale in maps. (2mks)
4. Study the map of Kisumu East (1:50,000) and answer the following questions.
(a) (i) What is the bearing of the trigonometrical station at gridreference
081980 from the rock antelop at grid reference 071992. (2mks)
(ii) Measure the length of the all-weather road (bound surface) 1321, from, the junction at grid reference 974911 to the edge of the map, grid reference 947967. (2mks)
(b) (i) Describe the relief of the area covered by the map.
(ii) Explain how relief has influenced the settlement in the area
Covered by the map. (8mks)
(c) Citing evidence give three economic activities carried out in the area
Covered by the map.
(d) Students from the school at Masago (grid square 0681) carried out field
study of the course of river Ombeyi.
State three findings they are likely to have come up with. (3mks)
Give three advantages of studying rivers through field work
Specific Objectives
By the end of the topic the learner should be able to:
Define the term field work;
State different types of field work;
Explain the importance of field work;
Explain the procedure to be followed during field work; •
Identify possible problems during field work;
Carry out field work within the local environment.
Content
a.)Definition of field work.
b.)Types of field work.
c.)Importance of field work.
d.)Field work procedure.
e.)Problems likely to be encountered during fieldwork.
f.)Field work within the local environment
Definition
Fieldwork may be defined as an activity that involves the seeing and using of the environment around us as a laboratory for the teaching and Learning of Geography.
It is a scientific method of study that enables geographers and other researchers to use the available natural and human- made phenomena to understand the environment better.
Fieldwork allows the learners to interpret for themselves what they see and to
Confirm the facts and ideas that they acquire in the classroom.
It is one of the activities that make geography a practical subject. The activities may be conducted within the school environment, around the school and sometimes far from the school.
Types of fieldwork
Field study or field teaching.
Excursions. iii.Fieldwork research.
Field study
A field study is aimed at collecting data in order to achieve specific objectives.
These objectives are formulated and clearly outlined by the researcher before the study.
They are expressions of what the researcher intends to find out during the field study.
The study is conducted by an individual or a group of people.
It is based on a specific theme, such as: A visit to a farm. The data collected in such a study is recorded, analyzed, interpreted and conclusions drawn from it.
An excursion
An excursion is a sight-seeing outing, mainly aimed at relaxing the people involved.
It does not require the formulation of objectives or the collection of data.
It is however, possible to conduct a field study within an excursion.
Fieldwork research
The fieldwork research is a problem solving activity.
It is a study conducted by experts in their respective fields of specialization.
For example, when there is a disease outbreak affecting livestock in a certain area, the veterinary officers, who are the experts in that field go to the area affected by the disease.
Their main aim is to identify the cause of the disease and come up with possible solutions to the problems.
Note:
These three types of fieldwork may be carried out together or separately.
Importance of fieldwork
It helps the geographer to be able to:
Apply the skills learned in the classroom to the real life situation.
Identify specific problems that may require geographical investigation.
Study geographical phenomena and processes such as faulting, mass wasting, so as to understand them better.
Identify and categorize factors and features of given geographical phenomena so as to be able to record them for use now and in the future.
Think and use observation skills to reason logically and make objective judgment.
Use the geographical techniques of gathering, analyzing and presenting data so as to perfect the following skills: An accurate oral description of what they observe, Coherent expression of ideas, High level reasoning and making of independent and objective judgment and Good maintenance of human relations.
Be familiar with the environment in which they live by training them to acquire the appropriate attitudes, skills and knowledge with which to interpret and improve the environment.
Draw local examples from their own interpretation and observations.
Break the monotony of classroom teaching and learning so that both become more vivid and realistic.
Fieldwork procedure
A procedure is an established way of doing things.
The fieldwork procedure is straight forward and involves a series of activities to be completed in order to achieve certain objectives.
The normal pattern that the fieldwork procedure takes is summarized in the below.
Identify the topic of study
Statement of objectives
Formulation of the hypotheses
Prepare for the fieldwork
Conduct the actual study
Identifying the Topic of Study
The topic of study refers to the title of the field study that is to be carried out.
The title can be drawn from a topic that has already been studied in the classroom.
It should be started in a short, clear and precise statement.
For example:
A study of weather station.
A study of Ol’Kalou market.
A study of Nyadorerea fish fillet factory.
Statement of Objectives
An objective describes the actual detail that the researcher intends to look for during the study.
Every topic of study may have several objectives.
The objectives must be relevant to the topic of study.
They should be stated in short clear sentences.
Example
For a topic ‘A study of Kisumu fish fillet factory, the following are possible objectives:
To find out when the factory was established.
To find out who owns the factory.
To find out the number of workers employed in the factory.
To identify the market outlet for the fillet processed in the factory.
For the topic ‘A study of landforms near the school, ‘ the following are possible objectives:
To find out the types of landforms near the school.
To find out the highest and the lowest points of the study area.
To identify the possible processes involved in the formation of the main landforms.
To investigate the relationship between landforms and soil depth in the area.
To identify the economic importance of the landforms around the school.
Every objective must have a stem. Other than’ to find out’ other suitable stems could be: To investigate……………’ To identify………………’
A good objective therefore should be specific, measurable, achievable, and realistic and time bound (SMART).
Formulation of the Hypotheses
A hypothesis is the researcher’s own speculation about the problem in question.
It is a tentative answer to the problem in question.
It is therefore a theory that has not yet been proved.
The researchers make guesses on the basis of any knowledge they have in the area of study.
The fieldwork exercise revolves around the testing of the hypotheses to establish whether or not they can be accepted as statement of fact.
Two main types of hypotheses:
Null hypothesis
This is stated negatively, for example, there is no relationship between landforms and soil depth in the area.
Alternative or substantive hypothesis
This is stated positively, for example, there is a relationship between landforms and soil depth in the area.
Students may use either of the two whenever they formulate hypotheses for a study.
Characteristics of a good hypothesis
It has an element of comparison, whereby two or three items are compared.
The quantitative words used are easily measurable, for example, more, most majority, all. Avoid the use of words like a lot, many or few.
The hypothesis leaves room for ‘yes’ or ‘no’.
It must be related to one or more of the objectives in question. This means that a hypothesis at times is in question form or negative form.
A hypothesis should not be obvious. Below are examples of hypotheses used on the study of landforms used above.
Most of the landforms in the area has resulted from internal earth movements.
The highest point in the area is at the top of Mt Longonot.
Is lowest point in the area occupied by a lake?
Preparation for the fieldwork
Students and researchers should prepare adequately before going out for a field Study.
The more thorough the preparation, the more successful the field study.
The sequence of activities involved in preparation is outlined in the below
Seek permission
Conduct a reconnaissance
Adjust objectives and hypotheses
Choose methods of data collection
Assemble necessary tools
Prepare a working schedule
Divide the students into groups
Seek Permission
Preparation for fieldwork begins with the seeking of permission from the relevant authorities, and/or the acquisition of a research permit.
Where the fieldwork is conducted by the students and their teacher, the first authority to approach is the principal of the School.
Within his/her permission, other details concerning transport, packed lunch, entry fees to national parks, etc., can be taken care of easily.
Once the principal’s permission is acquired, the teacher and /or the students decide on the suitable data of study.
If the study is to be conducted in an industry, the letter is addressed to the manager of the industry.
It should be written well in advance to give the manager ample time to reply.
The letter should also contain a list of areas that students are interested in.
Reconnaissance
Once permission is acquired, the teacher will select a small group of students.
Together, they will conduct a reconnaissance or a pre-visit to the intended place of study.
A reconnaissance is a short visit to the place of study prior to the actual day of study.
Importance of reconnaissance
It familiarizes the researcher with an area of study.
It introduces the researcher to the authorities and respondents in the area of study. This makes it easier to extract information from people already known.
It helps the researcher to identify and decide on the methods and tools to use in collecting information during the study.
It helps to determine the suitability of the area for the study. If it is found unsuitable, then an alternative area of study is sought.
It helps to identify any problems the researcher is likely to encounter during the study. This gives him an opportunity to prepare on how to cope with the situation.
It enables the researcher to estimate the cost of study and plan accordingly. vii.It is useful in designing a working schedule.
Revision of objectives
After the reconnaissance, the researcher will revisit the objectives and hypotheses and make any necessary adjustments in accordance with the findings of the reconnaissance.
Methods of Data collection
Suitable methods of data collection are then chosen some of which may require prior arrangements.
For example, the production of enough questionnaire and acquisitions of relevant materials for the study should be done before visiting the field.
Assembling of Research Equipment
The researcher then decides on the methods of data collection suited to the area of study.
The tools needed for the study should be assembled early to eliminate the last minute rush and forgetfulness.
Such tools may include maps, writing materials, a loaded camera, tape recorder, compass, tape measure, plastic bags, geological hammer, binoculars, masking tape etc.
The choice of tools is determined by the topic of study and the methods the researcher intends to use to collect data.
Working Schedule
It includes a plan of activities for each day of study.
It shows specific times during which particular activities should be conducted.
Importance of a working schedule.
It gives ample time to each activity so that no activity is forgotten.
It reduces the tendency to waste time and forces the researcher team to work within the allocated time in order to complete the project within the stipulated time.
It provides a basis for evaluating the fieldwork while it is still in progress.
It provides a framework that guides the researcher to remain within the scope of the topic.
It provides an estimate of the time required for the study.
The Actual Field Study
The actual field study takes place on the day chosen for the study.
On this day, the students should rise up early.
The schedule should be observed from step one.
The main activity taking place is the collection of data.
The data to be collected is aimed at satisfying the objectives and testing the hypotheses outlined earlier.
Main methods of data collection
a.)primary or direct methods
questionnaire
Interview
Taking photographs
Experimenting
Counting
Measuring
b.) Secondary or indirect methods mainly content analysis
Methods of data recording
Field sketching
Taking photographs
Tallying
Tape recording
Note taking
Labeling samples
Filling – in questionnaires
Data presentation may be done in the following ways:
Drawing graphs and charts
Drawing sketch maps and diagrams
Displaying the completed questionnaires
Playing the tapes
Writing a report
Giving a lecture
Displaying the labeled samples
Problems likely to be encountered during Fieldwork
The main problems include:
The researcher may fall sick during study.
The respondents may become uncooperative or may fail to keep time.
A language barrier between the researcher and the respondents may call for an interpreter thereby slowing down the progress of the study.
Transport problem e.g. the vehicle in which the researcher is travelling may break down.
Environmental constraints e.g. rainfall may cut short the field work.
The researcher may face the danger of wild animals.
Steep slopes may be difficult to climb.
Thick vegetation may be difficult to penetrate.
Dishonest respondents may lead to collection of inaccurate data.
Financial constraints may bring the fieldwork to a standstill.
Follow up Activities
These are activities that the students will be involved in immediately after the study.
The activities involves
Discussions.
Comparing notes.
Write reports.
Taking advise on how to present
End of topic
Did you understand everything?
If not ask a teacher, friends or anybody and make sure you understand before going to sleep!
Past KCSE Questions on the topic
State two ways in which information collected during the field study would be useful to the local community. 2mks
Your class is required to carry out a field study of a river. What would be the advantage of dividing the class into groups according to the stages of the long profile 3 of a river?
What would be the disadvantages of c using secondary data in this kind of a field study?
You intend to carry out field study on population in the local open air market,
State three reasons why it would be necessary for you to visit the market
Before actual field study.
Give two methods you would use to collect information on pollution. ,
State three follow up activities necessary for the study. -51
You are supposed to carry out a field study on the uses of vegetation in the area around your school.
State three reasons why it would be necessary to visit the area before the day of the study.
Givefour uses of vegetation you are likely to identify during the study.
(3mks)
Why is it necessary to sample part of the forest for the study?
List three types of fieldwork.
(3mks)
Explain the importance of field work. (5mks)
Outline the procedure for carrying out field study.
(5mks)
List some topics in physical geography on which you can carry out a field study.
(4mks)
State five ways in which you would prepare for field study to a weather.
(5mks)
What is the importance of carrying samples from the field to the school?
(4mks)
Formulate five suitable objectives for field study on a visit to a forest.
(5mks)
Discuss types of hypothesis.
(2mks)
List five methods of data presentation.
(5mks)
Explain five problems one would encounter on field study in a forest?
(5mks)
Why is reconnaissance important?
Specific Objectives
By the end of the topic the learner should be able to:
Define minerals and rocks;
State the characteristics of minerals;
Classify rocks according to mode of formation;
State the characteristics of rocks;
Account for the distribution of major types of rocks in Kenya;
Explain the significance of rocks;
Identify major types of rocks and their use within the local environment.
Content
a.)Definition of (a) minerals and (b) rocks.
b.)Characteristics of minerals.
c.)Classification of rocks according to mode of formation.
d.)Characteristics of rocks.
e.)Distribution of major types of rocks in Kenya.
f.)Significance of rocks.
g.) Field work – Identification of major types of rocks and their uses within the local
Introduction
What is a mineral
Inorganic substances which occur naturally at or beneath the earth surface/A naturally occurring, crystalline, inorganic substances with a definite chemical composition and physical properties.
Characteristics of Minerals
Tenacity
This is the ability of a mineral to resist/to withstand tearing, crushing or breaking differs. It is different from one mineral to another and it can be brittle, ductile, elastic, malleable or flexible.
Lustre
Refers to surface appearance of minerals as it reflects light. The two main types of lustre are metallic and non-metallic. Some minerals are shiny while others are dull.
Colour
Minerals have specific colours for example gold is yellow and Copper is brown.
Hardness
The measure of degree of resistance of a mineral to disintegration. Some minerals such as diamond have a high resistance while others such as Talc are soft.
Shapes
Some minerals aggregate into distinct crystal shapes, for example, a crystal of quartz is a six- sided prism.
Composition
Some minerals are composed of one element such as gold, copper, diamond and silver while others such as bauxite and feldspar have two or more elements.
Specific gravity
This is the measure of the relative weight of a substance. Different minerals have different specific gravity.
Tastes and solubility
Different minerals have different tastes and solubility.
Definition of Rocks
A rock is an aggregate of mineral particles forming solid part of the earth’s crust
Different between a rock and a mineral
A rock is a natural occurring aggregate of mineral particles forming the earth’s crust while a mineral is a naturally occurring crystalline inorganic substance with a definite chemical composition and physical properties.
Rock is a solid substance made up of an aggregate of minerals while a mineral is an inorganic substance found in the crust or on the surface made up of one or more elements.
Ways in which rocks can be classified.
a.)By mode of formation
b.)By physical and chemical characteristics.
c.)By age
Classification of Rocks According to the Mode of Formation or Origin
According to mode of formation we get three types of rocks.
Igneous rocks
Sedimentary
Metamorphic rocks
Igneous rocks
The word igneous means fire in Latin.
Igneous rocks are formed the cooling and solidification of magma which is a combination of silicate minerals.
Formation of extrusive igneous rocks
During volcanic eruptions, lava and other volcanic materials are thrown on to the earth’s surface.
The lava cools and solidify to form extrusive/volcanic igneous rocks.
The rate of cooling and solidification is very rapid due to presence of low temperature such that the rocks formed will have minerals with fine textured and small crystals.
General characteristics
Crystalline in structure
Glassy in appearance
Igneous rocks can be divided further into:
a.)Intrusive/plutonic rocks
Plutonic rocks are intrusive igneous rocks which are formed deep on the earth’s crust.
Types of plutonic rocks
Granite
Diorite
Peridotite
Gabro
Syenite
How intrusive igneous rocks are formed
Heat and pressure beneath causes rocks to melt.
This lead to formation of lines weakness cooling into the earth coast cooling into the earth coast.
Magma cools and solidifies inside the coast to form intrusive igneous rocks
b.)Hypabyssal rocks
They result from magma being intruded into other rocks, often overlying layers of strata at shallow depths beneath surface level.
Since the molten rock undergoes relatively rapid cooling in dykes (vertical fissures) and sills ( horizontal sheets),
Crystallization is speeded up and the rocks are therefore finer in texture than the coarsely, crystalline plutonic rocks.
Examples
Porphyry
Dolerite
Lamprophyre
Volcanic or Extrusive Igneous Rocks
Volcanic rocks are rocks which are formed on the surface of the earth when lava cools and solidifies.
The cooling and solidification is very rapid because of lower pressure and temperatures on the surface of the earth.
Characteristics
Small crystals
Fine grained/fine texture
Classification of Extrusive rocks
Those that are formed as a result of larva flow.
Those that formed as a result of ejection of volcanic materials.
Those formed as a result of Lava Flows
Formed from lava that flows on the surface before cooling and solidifying.
Some of the resultant rocks may have the same composition as intrusive types for examples rhyolite – granite, andesite- diorite while basalt is the extrusive equivalent to gabbro.
Those formed as a result of Ejection of Volcanic materials
Solid or nearly solid materials throughout during volcanic eruption on cooling forms various types of rocks.
An example is pumice which is spongy and can float on water.
Sedimentary rocks
Sedimentary Rocks are formed from pre-existing igneous or metamorphic rocks, through the process of weathering/ erosion.
The sediments are deposited in layers / strata and over a period of time they are consolidated into hard rock.
Characteristics
Made up of layers known as strata / bedding planes.
Are either mechanically / organically chemically formed.
Have joints that meet the bedding planes at right angles.
Some have fossils.
Are non-crystalline.
They are formed in layers/stratified.
They easily bend/fold when subjected to pressure.
They consist of different rock particles/sediments.
Classification of sedimentary rocks
Mechanically derived sedimentary rocks
Organically derived sedimentary rocks
Chemically derived sedimentary rocks.
Mechanically formed sedimentary rocks
These are Rocks which are formed when eroded rock materials are transported by agents of erosion and deposited in layers.
Formation of mechanically formed sedimentary rocks
Formed from pre-existing rock material
Weathered rock particles pre-existing rock are particles transported and deposited by wind, water, ice or waves in layers.
The materials are laid down/deposited in thick layers/strata.
The sediments are compressed over time and become compacted and hard due to pressure.
This forms mechanically formed sedimentary rocks e.g. sandstone
Types of mechanically formed sedimentary rocks
Arenaceous rocks e.g. sandstone.
Argillaceous rocks e.g. shell.
Rudaceous e.g. brecia
Organically Formed Sedimentary Rocks
These rocks are formed when remains of previously existing plant or animal organisms are accumulated over period of time forming layers.
Formation of organically formed sedimentary Rocks
Dead plant or animal remains/fossils are deposited in layers in lakes/oceans or on land.
Over time they are compressed by other sediments piling on them.
They are compacted and harden to form organically formed sedimentary rocks e.g. limestone.
Classification according to composition
Calcareous
Rocks are rich in calcium carbonate.
Formed from skeleton/ shells of dead organism.
They include limestone rich calcite and dolomite.
Limestone rich in fossils is called coral or shelly.
The ones derived from skeletons of calcareous algae is called chalk.
Oolite is rich in ooliths.
Ferruginous
Rocks are formed in lakes and marshes by precipitation of hydrated iron oxide from water.
This process is assisted by minute bacterial organism released by decomposing vegetative matter.
Example is ferruginous rocks.
Siliceous
Rocks formed by the accumulation of remains of organisms like radiolarians, diatoms and sponges whose skeleton are rich in silica.
They are formed in places which were once under water but are now dry.
Diatomite is an example of a siliceous rock.
Carbonaceous
Rocks are formed from the accumulation of remains of plants which have been buried.
Once buried these remains change gradually, under pressure.
At each stage the amount of carbon content increases.
Coral is the main rock of carbonaceous type.
Chemically Formed Sedimentary Rocks
These are formed when rocks are precipitated or when solutions of salt are evaporated and particles accumulate in layers.
Formation of Chemically formed sedimentary rocks
Minerals of the preexisting rocks are dissolved when it rains and carried away in solution.
Mixture of this solution carried by rivers and the lake/sea water react and cause precipitation of the sediments.
The sediments are laid down in layers on the bed of oceans/lakes, where they are compacted and harden to form chemically formed sedimentary rocks
Or
Dissolved minerals in Lake Basin may evaporate due to high temperatures.
This causes the minerals to re-crystallize and settle/deposit on the lake bed.
They accumulate over time in layers where they are compressed, compacted and harden to form chemically formed sedimentary rocks e.g Travertine, Trona, etc.
Classification of chemically formed sedimentary Rocks
a.)Carbonates
b.)Sulphates
c.)Chlorides
d.)Silicates
e.)Iron stones
Carbonates
Contains mainly carbonate compounds
Examples are Travertine, Dolomite, Trona
Sulphate
These are mainly made of sulphate compunds
They are formed as a result of desiccation/drying or evaporation from waters of shallow desert lakes or constricted shallow bays of seas where evaporation is rapid.
Examples are gypsum
Chlorides
These are mainly salt made up of the mineral halite sodium chloride
Silicates
These are formed from deposition of silica,originally in solution in sea water.
This leads to accumulation and compression into rock. Examples are flint.
Ironstones
Examples are limonite and haematite
Metamorphic Rocks and their characteristics
The word metamorphic is derived from two Greek words meta meaning change and morphee meaning form hence change of form.
These are rocks formed within the earth crust by transformation in the solid state of pre-existing rocks as a result of high temperature, high pressure or both.
Factors determining the degree of change of rocks during metamorphosis
The resistance of the rock to crushing.
The grain size of the rock being changed.
The porosity of the rocks.
iv. The solubility of the constituents of the rocks.
The chemical action of the minerals.
The stability of the minerals that are produced.
The metamorphosis or change from the original state may result from:
a.)Heat which causes the minerals to re –crystalize; such action is called thermal metamorphism.
b.)Stress which causes alteration in the rock structure; this kind of metamorphism is referred to as cataclastic metamorphism.
c.)The action of heat and stress working together: a process referred to as regional metamorphism.
The above gives three kinds of metamorphism.
Dynamic / Kinetic metamorphism
Occurs when pre-existing rocks are subjected to intense pressure
When the weight of the overlying rock layers creates pressure on the lower layers, it leads to change in structure / gain alignment of the rocks
Contact / Thermal
Occurs when pre-existing rocks are subjected to intense heat.
During volcanic eruptions, hot magma / gas / liquids may intrude into sedimentary rock. The rock grains will recrystallize due to heat to form new minerals.
Thermal – dynamic metamorphism
It occurs when pre- existing rocks are subjected to both heat and pressure.
In the mountain building process, sedimentary rocks are compressed and due to this, pressure, heat is generated. This heat modifies the structure of the original rocks.
Changes that occur in rocks during metamorphism
-New minerals are formed.
The rocks are hardened / become more resistant.
The rock may recrystallize.
The chemical composition of the rocks change
Physical characteristics / appearance of the rock changes is altered.
Distribution of major Types of Rocks in Kenya.
Distribution of Rocks in the Coastal Region
The Coastal region of Kenya is generally an uplifted area. As a result of this uplifting, a platform of sedimentary limestone rocks was exposed.
This platform that was once part of the ocean floor is termed as the continental shelf.
The coastal region of Kenya consist of three types of geological formations. These are:
a.)Sedimentary Rocks
The sedimentary rocks of the coastal areas are and the ocean fringe are largely lime stones of coral origin.
Coral limestone deposits are mainly produced by coral polyps.
Polyps are minute marine organisms that live in colonies in warm tropical waters.
Why coral rocks are widespread at the coast
Salty water favors growth of coral polyps
Warm water with temperatures between 200c and 290c for the growth of coral polyps
Clear water which is free from silt or mud favor coral growth by receiving sunlight
Shallow water of less them 60 meters deep to which sunlight can penetrate for coral growth
Well oxygenated water for coral growth
Importance of coral rocks
Used as building materials and blocks.
Fascinating rock features attract tourists.
Coral limestone is a raw material for cement manufacture.
Limestones sedimentary rocks extents from the north coast in kilifi through Mombasa island to the south coast Kwale.
Sandstones are common in kilifi and kwale Districts.
A small section of Malindi with gypsum rocks.
Reasons why sedimentary rocks are dominant along he Kenyan coasts
Some parts of the coastal plain emerged from the sea where sedimentation occurred.
The coastal plain is lowland which has facilitated deposition of weathered rock materials.
iii.The shallow continental shelf provides favorable environment for the coral polyps whose skeletons are deposited and accumulate to form rocks.
b.)Basement rocks
Basement complex rocks are found to the west of the sedimentary rock areas.
They occur in many areas of Taita and Tana River Districts.
Quartzite rock is found in some parts of Tana River,Kilifi and kwale Districts.
Distribution of rocks in the Nyika Plateau and the Dry Lowlands
The rocks include:
a.)The metamorphic rocks of the basement complex system.
b.)Sedimentary rocks.
c.)Volcanic rocks.
Distribution of rocks in the Rift Valley and its Associated HighLands
The region contains three distinct types of rocks. They include:
a.)Basement complex rocks – they are sedimentary rocks usually compounds of grits, sandstones, shales and lime stones.
b.)Tertiary Volcanic rocks – these were erupted during the tertiary geological times and they are the most widespread rocks in the rift valley and its associated highlands.
c.)Quaternary volcanic rocks – they are the youngest rocks in the region.
Distribution of rocks in western Kenya
These region has some of the oldest rocks and one of the most complicated geological history in kenya.
Granite and gneiss are common in most parts of kisii districts,Maragoli and Bunyore areas.
Volcanic rocks are common near the shores of kavirondo and winam Gulfs and in the area around Gwasi hills volcanic rocks are found.
Winam gulf and Kano Plains the zones are covered by sedimentary rocks.
The southern shores of winam gulf are covered by quartenary sedimentary rocks which are also found in Rusinga and Mfangano islands.
Significance of rocks and minerals to the economy
Some rocks such as granite, volcanic peaks may form unique sceneries which attract tourists promoting tourism industry.
Rocks provide the parent materials through weathered rocks especially volcanic rocks forming fertile volcanic soils for agricultural production.
Rocks such as sandstone, marble and limestone are strong and resistant to weathering are used in the building and construction industry. iv.Minerals and other valuables substances are extracted/mined. Some rocks are used as raw materials for the manufacturing industry.
Impermeable rocks may act as storage of underground water which can be tapped to supply water for domestic and industrial use.
Through weathering rocks provide soils which are useful for agricultural production
Some rocks have valuable mineral ores which are exploited and sold to generate revenue. Some rocks are e.g kisii soapstone is used for making carvings.
Some provide salts used for both domestic and industrial purposes e.g soda ash in lake magadi.
Fuels of great economic value are derived from rocks e.g coal and petroleum.
Sedimentary rocks contain nitrates ad potash used in making of fertilizer, medicine and dyes.
Field work on Rocks and Minerals
1.) You carried out a field study on rocks within the school vicinity.
a.)State three objectives of your study.
To find out the type of rocks within the school vicinity.
To find out the physical characteristics of the rocks within the school vicinity.
To find out the uses of the rocks within the school vicinity.
To find out the distribution of the rocks within the school vicinity.
b.)State three equipment/tools you used during data collection.
i. Geological map/route map ii. Geological hammer iii. Magnifying lens iv. Paper bags
v. Camera
c.)Give three reasons why you used field work in studying rocks.
To get first-hand information on different types of rocks.
Application of theoretical knowledge learnt in class to real life situation.
Developed various skills such as observation, sketching and analysis during the collection of data.
To break the classroom monotony.
To enhance visual memory/comprehension of the content on rocks.
d.)What three recommendations would you give to the local community from your findings?
To advertise the various features formed by the different rocks as tourist attractions.
To drill wells since some of the rocks are water reservoirs. iii. To exploit the rock for construction. iv. The rocks disintegrate to form soils which they can use for pottery. v. To quarry the rocks for sale as a source of livelihood.
vi. Ways of protecting the soil due to quarrying/adopt environmental protection measures.
e.)Preparation of field study
Read extensively on different types of rocks.
Prepare a working schedule.
Obtain permit from the relevant authorities.
Select suitable methods of data collection/recording
Conducting previsit.
Holding discussion in class.
Obtain necessary materials and equipment. viii. Obtain the map of the area.
Distribution of rocks in Kenya
Pictures of common rocks and minerals
Silver.
Copper.
Graphite.
Pyrite.
Galena
Halite or rock salt.
Corundum
Hematite
Calcite.
Dolomite
Gypsum.
Albite.
Biotite.
Hornblende.
Olivine.
Orthoclase.
Quartz
Past KCSE Questions on the topic
(a) Describe the following characteristics of minerals
Colour (2mks)
Cleavage (2mks)
Hardness (2mks)
(i) Give two types of igneous rocks (2mks)
(ii) Explain three conditions necessary fro the growth of coral
polyps
(6mks)
State four uses of rocks (4mks)
You are planning to carry out a field study on the rocks within your school environment
Give two secondary sources of information you would use to
prepare for the field study
(2mks)
State why you would need the following items during the field study:
A fork jembe (1mk)
A polythene bag (1mk)
Suppose during the field study you collected marble, sandstone and granite, classify each of these samples according to its mode of formation (3mks)
(a) State two characteristics of sedimentary rocks
(2mks)
Give two examples of chemically formed sedimentary rocks
(2mks)
a) Name the type of rocks which results from the metamorphism of:
Granite
Clay (2mks)
Give two reasons why sedimentary rocks are widespread in the coastal plain of Kenya.
(2mks)
(a) (i) What is a rock? (2mks)
(ii) Describe three ways through which sedimentary rocks are formed
Mechanically formed
Organically formed
Chemically formed (6mks)
Describe two process through which sedimentary rocks changer into metamorphic rocks
Give an example of each of the following types of igneous rocks
Plutonic rocks (1mks)
Hypabyssal rocks (1mks)
Volcanic rocks (1mks)
Suppose you were to carry out a field study of rocks within the vicinity of your school
Name three secondary sources of information you would use to
prepare for the field study
(3mks)
State four activities you would carry during the filed study
(3mks)
State three problems you are likely to experience during the
field study
(3mks)
(a) Differentiate between plutonic rocks and volcanic rocks
Describe how lava plateau is formed
(i) Name three volcanic features found in the rift valley of Kenya
(ii) Explain four negative effects of vulcanicity in Kenya
You intend to carry out a field study of a volcanic landscape
State four reasons why it is necessary to conduct a
reconnaissance of the area of study.
(a) State two main conditions that influencethe characteristics of igneous rocks. (2mks)
Write down three characteristics of sedimentary rocks.
(3mks)
Name two examples of organic sedimentary rocks and where found in
Kenya.
(2mks)
Name four examples of metamorphic rocks and state the original rock from which each was formed.
(4mks)
Describe the importance of rocks to human activities.
(5mks)
(a) State with examples three classes of mechanically formed sedimentary rocks. (6mks)
Differentiate between regional metamorphism and contact metamorphism.(4mks)
(a) List two examples of extrusive igneous rocks.
(2mks)
Differentiate between extrusive and intrusive rocks giving an example
in each case. (2mks)
What is a rock? (2mks)
What is a mineral? (2mks)
Describe changes that occur in sedimentary rocks when they are subjected to high heat and pressure. (4mks)
Describe calcareous rocks.
(2mks)
Describe carbonaceous rocks.
(2mks)
Give examples of chemically formed sedimentary rocks.
(2mks)
How are coral rock formed? (3mks)
How do rocks become metamorphic? (3mks)
INTERNAL LAND FORMING PROCESSES
Specific Objectives
By the end of the topic the learner should be able to:
Define earth movements;
Explain the causes of horizontal and vertical earth movements;
Explain the theories of Continental Drift and Plate Tectonics;
Define folding, faulting, vulcanicity and earthquakes;
Explain the processes of folding, faulting, and vulcanicity;
Describe types of folds, faults and forms of vulcanicity;
Explain features that result from folding, faulting and vulcanicity;
Explain the causes of earthquakes;
Describe how earthquakes are measured;
Account for the world distribution of earthquake zones, fold mountain systems and features due to faulting and vulcanicity;
Explain the significance of the resultant features of folding, faulting, vulcanicity and Effects of earthquakes.
Content
Earth Movements
Definition
Types of earth movements – horizontal and vertical movements.
Causes of earth movements
Theories of
Continental drift
Plate tectonics
Folding
Definition, and processes of folding.
Types of folds
Features resulting from folding.
World distribution of fold mountain systems.
Significance of folding to human activities.
Faulting
Definition, and processes of faulting.
Types of faults.
Features resulting from faulting.
A study of the Great Rift Valley.
World distribution of features formed through faulting.
Significance of faulting to human activities.
Vulcanicity
Definition of vulcanicity.
Types of vucanicity and the resultant features.
World distribution of features formed through vulcanicity.
Significance of vulcanicity to human activities.
Earthquakes
Definition of earthquakes.
Measurement of earthquakes.
Distribution of the major earthquake zones of the world.
Effects of earthquakes.
Earth movements
It’s the Displacement or Movement of Crustal rock caused by Tectonic forces which originate and operate in the interior of the earth.
These forces are responsible for the formation of various landforms that can either be external or internal. The formation of these landforms is determined by:
The nature and age of the earth’s materials for example the degree of their elasticity.
The type of movement involved.
The intensity and scale of the forces involved.
Types of Earths Movements
There are two types:
Horizontal earth movement.
Vertical Earth Movements
Horizontal Earth Movements (orogenic/lateral)
These are movements which act along a plane but since the earth is curved, these forces act along a targent.
They occur when the earth’s materials are forced to stretch, shorten and shear (divided into many layers).
Horizontal earth movements are caused by the forces which pull crustal rocks apart, or push them towards earth other but with equal forces on the Earth’s crust.
These forces cause tension, compression or shearing in the rocks.
This movements causes formation of various features such as:
Faults
Rift valley
Basin
fault scarps
-Block mountains
-Cleavages
-fault blocks
-Tilt blocks
Vertical Earth Movement (Epeirogenic)
These movements occurs along the Earth’s radius either towards the earth’s surface or towards it centre.
Vertical earth movements are caused by strong forces pushing crustal rocks upwards or pull them downwards leading to up warping, down warping or tilting of the crustal rocks.
These vertical movements of crustal rocks may cause isostatic adjustments, emergence and submergence of coast, faulting, rifting and crustal displacement.
The process may also lead to the formation of various surface features such as basins,plateaus,faultscarps,fault blocks,tilt blocks and rift valleys.
Causes of earth movements
Magma movement
Gravitational force
Conventional current
Isostatic adjustment
Magma Movement
When the rocks within the crust and mantle get so hot that thy melt, the liquid rock (magma) may flow forcefully into the earths.
As the crustal rocks move, theirplaces is taken over by the intruding magma causing earth movements.
Gravitational force
This force tends to pull the rocks towards the earths centre.
This leads to down movement of crustal rocks due to the gravitational pull.
Convectional Currents
The convention currents within the molten rock in the mantle are in circular motions from the mantle towards the crustal rocks.
These currents exert a frictional drag with the sima rock causing crustal rocks to move horizontally.
Isostatic Adjustment
Isostasy is the state of balance existing between the lighter upper crust (SIAL) and the denser inner region (SIMA) of the earth. This balance must be maintained at all times.
If disturbance caused by other movements disrupt this balance, then an isostatic adjustments occurs.
The continental Drift Theory
The Theory States that the earth was initially one liquid mass called Pangea.
It was surrounded by a great ocean called Panthalassa whose floor was mainly dima layer.
During the late Precambrian period, Pangaea broke up into two blocks Laurasia and Gondwanaland.
They were separated by a narrow ocean called Tethys.
During Mesozoic era, Laurasia broke up into two; Laurentaian shield and Fennoscandia.
Gondwanaland broke up into blocks forming seven Continents.
Africa and India drifted northwards while Australia drafted eastwards. The Americas drafted westwards.
Evidences that support the continental drift theory
i.Jig saw fit of continental margins e.g., eastern coastline of South America and western coastline of Africa. ii.Similar geological structures between rocks in Brazil (South America) and Republic of South Africa (Africa).
The Distribution of ancient glacial deposits.
Sea floor spreading i.e. younger rocks in the middle of oceans while older rocks found near the coasts.
Paleontological evidence i.e. similarities of fossils in southern continents and between North America and Europe.
Palaeomagnetic evidence shows similarities in magnetic alignment in minerals.
Paleozoic glacial deposits found widely dispersed in continents of India, Australia and South America.
Climatological evidence points to coal today found in temperate latitudes but are believed to have formed in tropical climates.
The Mid-Atlantic Ridge shows that there are continuos mountain ranges extending the whole length of the Atlantic Ocean bed.
Plate Tectonic Theory
This is a modern improvement of the continental drift theory.
Plate tectonics is the study of the movement of plates and various landforms resulting from such movement.
The theory state that:
Earth crust is made –rigid blocks called tectonic plates
Each plate is separated from another by distinct boundaries.
The plates are sitting on the semi-molten layer of the upper mantle.
The plates move relative to each other/towards or away.
The seven plates include: -The Eurasian plate
The Austrian plate
The African Plate
The Antarctic plate
The North American Plate
The South American Plate
The Pacific Plate
Due to convectional currents that are being generated by the heat from the centre of the earth, plates may move in three different ways. These include:
Away from each other.
Towards each other.
Parallel past one another along transformed faults.
There are three types of boundaries associated with plate tectonic movements.These are:
Extension boundaries/constructive margins.
Compressional boundaries/destructive margins
Transform faults/conservative margins
Reasons why geographers study the plate tectonics theory.
To understand the origin of continents.
To understand the formation of physical features. iii. To understand the significance associated with the movements of plate.
Extension /Tensional/constructive boundaries
Extension boundaries is one where the tectonic plates are moving away from each other.
Compressional/destructive boundaries
Compressional boundary is one where plates move towards each other
Transform faults/conservative boundaries
Transform faults is one in which there are no new materials that are added or lost because it does not destroy the crust and it is also does not not creat any feature.
Folding
This is the bending of the rocks of the earth’s crust due to earth movements.
It occurs in sedimentary rocks when they are still in a semi-elastic state.
During folding rocks are bend upwards or downwards.
The upfolds are called anticlines while the downfolds are called synclines.
The top part of fold mountains is called the crest while the bottom most- part is called is called the trough.
The axis is the central line in a fold from which the rock layers dip/slope away as in the anticline or from which the rock layers rise in opposing directions as in the syncline.
The limb of a fold is the layer of rock on either side of the axis/
Processes involved in folding
When the rocks are subjected to the forces of compression.
The rocks bends upwards forming upfolds/anticlines and downwards forming downfolds .
An extensive depression called a geosynclines is formed on the surface of the earth.
The surrounding land masses are eroded and resultant materials deposited in the geosyncline in layers.
Accumulation and weight of sediments causes the floor of the geosycline to subside further.
Further subsidence of the geosynclines triggers off compressional forces drawing higher grounds close.
The layers of sediment in the geosynclines are the folded bending upwards form mountain
Types of folds and Resultant Features
Fold mountains can be classified into the following:
a.)Simple/symmetrical folds
-Formed when compressional forces of equal magnitude and of moderate strength act on crustal rocks
− − − − −→ 𝐶𝑜𝑚𝑝𝑟𝑒𝑠𝑠𝑖𝑜𝑛𝑎𝑙𝑓𝑜𝑟𝑐𝑒 ← − − − − −
A – Syncline B – Limb C- Anticline
b.)Asymmetrical folds
Results from unequal compressional forces acting on crustal rocks
One of the forces is slightly stronger than the other resulting to limbs that are asymmetrical about the axis.
c.)Overfold
It is an asymmetrical anticline which has been completely pushed over or overturned by compressional forces.
d.)Isoclinal folds
These are series of close parallel overfolds with all limbs dipping at approximately the same angle and in the same direction.
e.)Overthrust fold
Crustal rock layers are subjected to compressional forces.
Intense folding results into formation of an overfold.
With increased pressure the over fold is compressed further to form a recumbent fold
When pressure if very great, a fracture occurs along the axis producing a thrust plane to form an overthrust fold
f.)Recumbent folds
These are Fold Mountains which have been forced over into near horizontal positions with their axial surfaces nearly horizontal.
g.)Anticlinorium- synclinorium
These are anticlines and synclines on which minor up folds and down folds have been formed.
The anticlinal complex is the anticlinorium while the synclinal complex is the synclinorium
Features resulting from Folding
The process of folding is responsible for the formation of various external landforms such as:
a.)Fold Mountains
Some of the world’s largest mountains were formed through folding.
Various theories have been put in place to explain how these mountains were formed and they include the following:
The contraction Theory
After berth formation surface rocks cooled faster and contracted faster than those of the interior.
As the interior continued to cool the surface rocks wrinkled to fit on the contracting interior leading to Fold Mountains.
The Convection Theory
Conventional currents within the molten rock in the mantle move in circular motions towards the crust.
These currents exerts a friction drag with the sima rock causing crustal rocks to move horizontally resulting into the formation of Fold Mountains.
Plate Tectonic Theory
When an oceanic plate meets a continental plate, the dense oceanic plate sinks beneath the higher continental one.
The higher continental plate due to compression crumbles to form Fold Mountains.
b.)Escarpments
When folding takes place on a rock mass the extended steep limb from the anticline forms an escarpment.
c.)Synclinal valleys
These are valleys formed as a result of folding.
d.)Depressions
These are deformation or depressions of the crust that have occurred over a large area.
World distribution of fold Mountains
The processes of fold mountain building are known as Orogenesis while the period in which they were build is known as orogeny.
Classification of Fold Mountains according to the period or
Orogeny
a.)Charnian Orogeny/pre-Cambrian period
Precambrian mountains belong to the geological time prior to the Cambrian period.
A period that extended for more than 4000 million years.
The rocks have been subjected to upheaval and metamorphosis.
Traces of fossils are found in some un metamorphosed rocks of Precambrian origin.
Some of the examples are Laurentian Mountains, Algoman Mountains, Kilarnean mountains of Feno-Scandinavia, North-west highlands and Angleysey of Europe.
b.)Caledonian Orogeny
Caledonian mountains originated due to the great mountain-building movements and associated tectonic movements of the late Silurian and early Devonian periods.
The mountains have a northeast-southwest alignment in the north-western part of Europe.
Caledonian mountains came into existence between approximately 430 million years and 380 million years ago.
Examples are the mountains of Scotland, Ireland and Taconic mountains of the Appalachians, Aravallis, Mahadeo etc.
c.)Hercynian Orogeny
Hercynian Mountains originated during the Upper Carboniferous to Permian Period in Europe.
Some authors use the term Hercynian for the whole mountain systems belonging to central Europe.
Whereas others use the terms Altaides, Variscan to identify the same mountains system.
Hercynian mountains came into existence between approximately 340 million years and 225 million years ago.
Some examples are the mountains of Iberian peninsula, Ireland, Spanish Messeta, Vosges and Black Forest, Variscan mountains of Europe and Altai, Sayan, Baikal Arcs, Khingan and Tien Shan mountains of Asia.
d.)Alpine Orogeny
Alpine system had its origin in the Tertiary Period which consists of the Palaeocene, Eocene, Oligocene, Miocene and Pliocene epochs.
The mountains were formed from about 65 million years to 7 million years ago.
Examples are the Rockies of North America, the Alpine mountains of Europe, the Atlas mountains of north-western Africa, the Himalayas of the Indian sub-continent, mountains radiating from Pamir knot like Pauntic, Taurus, Elburz, Zagros and Kunlun etc.
Effects of Fold Mountains to human activities.
windward side of fold mountains receive heavy precipitation which
Enhance agricultural activities / forestry.
Rivers which originate from fold mountains provide water which is used iv.For generation of HEP/irrigation/domestic and industrial purposes.
Some fold mountains have exposed minerals deposits which are exploited.
Fold Mountains are important tourist attractions/snow capped mountains encourage sporting activities.
Fold Mountains may act as barriers to transport and communication.
Topographic nature of the landscape may
encourage/discourage agriculture/settlement
Ways in which Fold Mountains influence climate.
The slopes of mountains which face the sun receive direct sunshine and are warmer.
Mountain slopes cause the development of local winds due to variation in pressure between the mountain top and the valley bottom.
The windward slopes of mountains receive high rainfall due to orographic effect.
Atmospheric pressure reduces with increasing attitude along a mountain slope.
Temperature decreases with increasing /altitude along a mountain slope.
Name the countries in which the following fold mountains are found.
Atlas – Western Sahara/ Morocco/ Algeria
Alps – Austria/ Switzerland/ Italy/ France/ Leichstein.
Himalayas – India/Pakistan/Afghanistan/ Bhutan/ Nepal/ China.
Andes -Chile/ Peru/ Bolivia/ Argentina/ Venezuela/ Ecuador/ Colombia.
Faulting
Faulting is the cracking or fracturing of rocks of the Earth crust/) process by which brittle crustal rocks fracture or break due to tectonic forces.
Processes of faulting
Faulting processes is related to three main forces. They are:
Tension
Compression.
Shear
Where these forces becomesintense, a line of weakness called a fault developes on the rock mass.
Eventually the forces will result in the displacement of the two block masses from their original position either vertically or horizontally.
Tensional forces
Causes the movement of land masses away from one another.
They pull the landmasses apart, resulting in there, tearing as shown below.
Compressional forces
Cause the movement of landmases towards one another.
Shear forces
Cause the movement of landmases alongside one another, usually along a crack or a line of weakness.
The mases of land move in opposite directions as shown below.
Types of Faults and Resulting Features
Types of faults depend on the nature and direction of Movement of Rocks along the fault plane.
There are five main types of faults that include:
a.)Normal faults
b.)Reverse fault
c.)A tear ,shear or slip fault
d.)A thrust fault
e.)An anticlinal faults
Normal Fault
Result from tension force in a vertical or an inclined fault planes.
The inclination of the fault plane and the direction of the downthrown are both to the left or both to the right.
Heave is the lateral displacement
Hade is the inclination of the fault to the vertical
A Reverse fault
-A reverse fault is caused by compression where the rockbends on one side of the fault plane are thrust over those on the side.
Downthrow
Upthrow
A tear/shear or Slip Fault
Caused by two opposing parallel forces which result in slipping.
The rock strata remain at the same level on the surface but their structural position is altered as two adjacent positions slide past each other.
Sometimes actual crushing and shattering may take place on the line of tear,shear or slip.
Examples are great Glen Fault of Scotland.
A Thrust Fault
Caused by strong crustal compression forces.
A block of land is forced to ride on top of another along a fault which is in a near horizontal position.
An anticline Fault
Further compression causes gaping cracks to form at the crest of the anticlie due to localized maximum tension there.
Features Resulting From Faulting
Direct effets of faulting causes formation of physical features as follows: a.Fault scarp
Block/horst Mountain.
Tilt block
Rift valley
Fault scarp
A fault scarp is a steep slope formed by the vertical movement of the earth along a fault.
It is the face of a fault plane facing the downthrow.
It is also called an escarpment though not all escarpments are fault scarps. Formation
Formed when two parallel faults occur on a land mass forming a central block as shown below.
The two landmasses on either side of the central block are pulled away from the central block by tensional forces.
Leaving room for the central block to subside /sink into Sima/molten rock.
Examples of fault scarps are Mau,Nyandarua,Nyando<Kikuyu and Elgeyo Marakwet escarpments in kenya. -Manyara and Chunya scarps in Tanzania -Butiaba scarp in Uganda.
Block Mountain
A block mountain is an elongated upland bordered by fault scarps on both sides.
It may be formed in two ways:
i.) When block of land between two faults is uplifted due to compressional forces. ii.) When land on either side of the central block sinks as a result of tensional forces.
Formation of Horst Mountains by tensional forces
Tensional forces act on layers of crustal rocks leading to the formation of parallel normal faults
Continued tensional forces make the side blocks to subside .The subsidence of the side blocks leaves the middle blocks standing as a horst mountain
(diagram =2mks=text=3mks)
(ii)Examples of horst mountains in E.A
Ruwenzori mountaisn – Uganda
Usambara mountains – Tanzania
Pare mountains – Tanzania
Mathew Range ,Nyiru and Ndoto hills of Kenya.
Vosges of France and the Black Forest Ranges of Germany.
Tilt Block
If the middle block has greater uplift on one side, then the fault block is not flat at the top but tilted.
It then becomes a tilt block.
Examples ,the west Kenya tilt block, the Ruwenzori tilt
Rift valley
This is a long narrow trough between more or less parallel faults with steep fault scarps on either side.
Examples of major rift V alley in the world are the Great Rift Valley in Eastern Africa, The Rhine Rift Valley in central Europe and the Baikal Rift Valley System of Siberia.
Formation of Rift Valleys
Theories put in place to explain the formation of rift valleys.
Tension
ii.)Compression iii.)Anticlinal arching
Formation by Tension
Crustal rock layers are subjected to tensional forces due to instability within the earth’s crust.
Further tension leads to development of parallel normal faults /lines of weakness develop
The middle block gradually subsides or sinks.
The depression so created by the sunken middle part forms the Rift valley
e.g. ; The Great East African Rift valley and the Rhine Valley in Europe.
Formation by Compression
When the Rock layer are subjected to compressional force.
Cf
Lines of weaknes occurs leading to Formation of adjacent Reverse faults
Cf Cf Outer block of land area thrust above the middle block along their fault plane
Cf Cf
Protruding parts area removed by erosion or may collapse to form escarpments.
Formation by Anticline Arching
A rift valley may also be formed as a result of upwarping.
This is caused by forces pushing sedimentary strata upwards.
This leads to the bending of rock layers into a big arch/an
A gaping crack develops at the crest of the arch due to tension at the top.
This because a valley.
Features associated with Gregory rift valley.
Fault blocks
Fault-steps
Fault scarps (escarpment)
Tilt block
Basins
Effects of faulting on the physical environment
Faulting across a river valley can cause it to change direction and start flowing along the fault or disappear into the fault
Subsidence of land result into formation of depressions which are filled with water to form lakes.
Weak lines within rocks allows magmatic water to reach the surface as geysers and hot springs
Fault scarps expose the water table which forms springs that are sources of rivers
Block mountains formed result in orographic rainfall that support the growth of forests on the windward side
State three effects of faulting on drainage of an area.
Down warping due to faulting may lead to formation of depressions which may be filled by water to form lakes.
Fault lines due to fracturing of crustal rocks may change the course of river making the river to start flowing a long the fault line forming faulting guided drainage pattern.
Fault scarps forming across rivers course may lead to formation of waterfalls.
Faulting may lead to formation of lines of weakness in earth’s crust which becomes passages for hot water from the underground to the earth’s surface to form hot springs and geysers.
State three positive effects of faulting.
Faulting leads to formation of features that are tourist attraction.
Depression in the rift valley contain water that form lakes – for fishing / mining / water for domestic use.
Faulting exposes minerals which can be exploited by man.
Step faulting makes rivers have waterfalls for H.E.P generation. v. Faulting leads to formation of rainfall which attract rainfall. vi. Springs occur at the foot of the fault scarps creating settlement
Vulcanicity
Vulcanicity is the process of eruption/escaping of magma/through which gaseous, liquid/molten and solid materials are intruded in to the earth’s crust or are extruded onto the surface.
Types of Vulcanicity
There are two types of vulcanicity:
Extrusive vulcanicity
This is the process where the material actually breaks through the surface of the earth in a volcanic eruption.
Intrusive vulcanicity
This type happens when the material does not have enough strength to break thrugh the surface of the earth.
The material forms rock bodies of various shapes and sizes, which may later be exposed at the surface because of the wearing down of the overlying rocks. -The features formed are referred to as intrusive landforms.
The materials involved in volcanic activity originate from deep in the earth where temperatures are extremely high.
Due to this temperatures the rocks deep below the earth crust exist in semi – solid state called Magma.
Ones the molten rock is ejected onto the surface, it loses it gases and its reffered to as Lava.
Both Magma and Lava are acidic,basic or intermediate.
Features Resulting From Vulcanicity
Extrusive Landforms
Two ways in which volcanic materials reach the earth’s surface.
Through a vent(pipe)
Through a fissure(crack)
Vent Eruptions and Types of Features Formed
1.)Volcano
Eruption through a vent results in the material piling up to build a cone- shaped hill called a volcano.
Volcanoes built around one vent be called central volcanoes.
They are built of lava or pryroclasts or a mixture of the two kinds of rocks.
They vary greatly in size, shape and steepness of their slopes depending on whether the ejected material is acidic or basaltic ( basic).
Basalt is a basic lava with low silica content. It is therefore of low viscosity.
Intermediate lava such as trachyte and phonolite has high viscousity meaning it is thicker and sticker when molten hence it does not flow far before it cools and hardens. As result the cones it builds up generally have steeper slopes than basaltic shield volcanoes.
Most central volcanoes have an approximately circular depression known as crater at the summit.
This depression represents the upper end of the vent through which eruptions have occurred.
It is filled with rock that cooled from the last magma to move up the vent.
Many volcanoes are extinct meaning that they have not shown any signs of volcanic activity in historic times.
Examples of extinct volcanoes are Mts Kenya and Elgon.
Active volcanoes show current volcanic activity.These volcanoes are said to have erupted in the recent past.Examples are Ol donyo Lengsi in Tanzania,Mt Cameroon ,Erte Ale in Ethiopia and Nyamalagira in Zaire.
Dormant volcanoes are those which are not active but show signs of volcanic activity.
Such volcanoes are not known to have had full activity in the recent past but likely to erupt again.Examples are mount Kilimanjaro,Longonot and Menengai.
2.)Basic (Basaltic) Lava/Shield Domes
This is a central volcano with a very wide gently sloping cone. Basic lava (basalt) due to its low viscosity, spreads and flows for a long distance before it cools and hardens.
When it finally solidifies, it builds up a broad, gently sloping volcanic dome.
This dome is very wide in proportion to its height and the angle of its slopes are quite low hence the name shield volcanoes.
Examples of such volcanoes include Mt marsabit in Kenya, Mts.Malle and Simien in Ethiopia, Nyamlagira on Zaire- Rwanda border and Tukuyu in Tanzania. Mt Mauna Loa in Hawaii ,USA provides one of the best world examples.
3.)Acidic Lava Cones
Acid lava is viscous.It builds high volcanic cones since it does not spread over a wide area but cools close to the vent.
Resultantly it has steep sided slopes.Examples include the East African Volcanoes such as Mt Kenya,Kilimanjaro,Elgon, Longonot,Suswa ,Menengai and OlDonyo Lengai.
4.)Complex Cones(stratified and Parasitic)
Vent type eruptions can build simple cones or complex ones in the sense that repeated eruptions can cause stratified cones with successive layers of ash,cinder and magma.
Sometimes,however,the vent branches and results in the formation of parasitic cones.
For examples,Mt Longonot.
5.)Ash and Cinder Cones
These occurs in vent type eruptions where the emitted materials consist of ash and pryroclastic materials which is very light and can be blown by the wind.
Depending on the direction of the prevailing wind at the time of eruption,more volcanic material settles on the leeward side of the mountain than on the wind ward side.
Examples are Mt.Teleki and Likaiyu near Lake Turkana.
6.)Plug-Dome Volcano,Spine Volcano plug Volcano
When the viscouse magma solidifies soon after extrusion and does not flow far.
It may form a cumuloform plug dome.
This means that it accumulates into a heap- like dome.
Examples of these are the Hyrax and Fischer’s Hills near Lake Naivasha.
7.)Volcanic plug
This is a larva that solidifies within the vent and is later exposed through denudation.
Viscous lava may solidify in the vent.
If the surrounding rocks are softer, they may be denuded (eroded) leaving a hard feature standing above the earth surface.
This feature is called a volcanic plug or neck. Examples are Lenana and Batian Peaks on Mt Kenya and the Tororo rocks in Uganda.
8.)Composite Cone/strato Volcanoes
A composite cone is built up of a mixture of lava and pyroclasts.
The lava and the pyroclasts are arranged in layers or are stratified.
The volcano begins each eruption with great violence forming a layer of ash.
As the eruption proceeds,the violence ceases and lava pours out forming a layer ontop of the ash.
Examples include Mt.Kilimanjaro in Tanzania ,Mt Cameroon,Ol Donyo Lengai and Mt Meru.
9.)Volcanic Depressions
There are two types of volcanic depressions.
Crater
Caldera
Crater
It is rounded funnel shaped hollow at the mouth of a volcanic vent.
It represents the upper end of a vent through which eruptions have occurred.
Examples
Ol Donyo lengai and Nyorongoro in Tanzania .Ol Donyo Nyokie near Magadi in Kenya.
Note
The openings through which hot springs,geysers and gas springs are emitted are also called Craters.
Caldera
Large basin type hollow bounded by steep cliffs.
It is formed due to subsequent volcanic eruptions in the crater when it blow off its top and enlarge the hollow/crater.
Through subsidence where the weight of the cone collapseso into the underlying magma.
Examples
Longonot ,Manengai,Suswa,Pakka and Silai calderas.
Craters may be filled with water to form lakes.Examples of such lakes include Lake paradise and Simbi in Kenya.
The largest caldera lake in the world is Asosa in Kyushu ,Japan.
Example
The diagrams below shows formation of a caldera through volcanic explosion.
Study it and answer the questions that following
Describe the processes shown by the diagrams E, F and G
E – After volcanic eruption and a volcano formed, magma in the vent settles cools and solidifies firmly sealing the vent/forming a volcanic plug. This suppresses subsequent eruption creating a buildup of pressure in the interior.
F – Eventually, the pressure overcomes the resistance of the overlying rocks resulting in an explosive eruption. This eruption blows off the head of the volcano destroying the plug to open the vent.
G – Broken rock debris falling back in the vent are melted in the magma chamber to leave a large basin shaped depression at the top of the old volcano called an explosion caldera.
10.) Hot springs ,Steam Jets and Geysers
Hot spring
Spring with water that is warmer than the normal water temperature in a certain area.
Geyser
It is a type of hot spring in which water bibles gently in a pool and is often violently expelled from the surface into the air as a column of boiling water and steam.
A steam jet
A mixture of steam and other gases (fumaroles) escaping from a small crack or hole in the ground.
Water vapor is the the most common gas,but small amounts of other gases are often mixed with it e.g Sulphur.
Examples of places with hot springs in Kenya include Lake Turkana Basin,Lake Bongoria ,Eburu Volcano between Nakuru and Naivasha,Lake Magadi,Homa Hills and Mai Mahiu near kijabe.
The major volcanic peaks where steam jets are prominent are Kilimanjaro,Ol Donyo Lengai and Longonot.
Fissure Eruptions and Types of Features Formed.
Fissures eruptions occurs through fissures or cracks.As a result of the large vents through which magma reaches the surface,Lavs spreads over large areas forming plateaus.
In Kenya,Examples include Yatta ,Laikipia and Uasin Gishuu.
There are two features resulting from eruption.
These are:
1.)lava plateau
2.)Tuff plateau
Lava Plateaux
Forms when lava escapes from different fissures and spreads over a wide area.
The lava has low viscosity which makes it very fluid and hence flows for a long distance on gentle slopes before cooling and solidifying.
The rocks build up evenly instead of piling around a single vent.
The resultant landform is a relatively even surface with very gentle slopes.
The lavas fills former valleys and covers most of the landscape with the exception of high hills.
Lava plateaux are often quite fertile areas. Where there is adequate rainfall,basalt lava weathers down to form rich volcanic soils.
Tuff Plateaux
These are wide areas of flat land similar to lava plateau that forms from the eruption of a volcanic rock called tuff.
Tuff does not flow quietly out of the ground like lava.
It is produced in a violent explosion which throws shattered fragments high in the air.
These fragments cool and harden as they fly in the air.
They eventually fall back on the ground further way from their point of eruption depending on their weight.
On falling on the ground, they form volcanic rock particles called pyroclasts or Tephra.
The various kinds of tephra are:
Volcanic ash – The finest (smallest and lightest)particles, less than 4 mm in diameter.
Lapili -The small stones, the size of peas or beans.
Blocks – large lumps of rocks as big as motor vehicle.
Bombs – Usually large with a curved shape and twisted at the end.
Pumice – This is a rock with a frothy spongy and cellular appearance .it is light and floats easily on water. It is derived from acidic lava
Explain two ways in which the geysers and hot springs at Ol Karia are of significance to the economy of Kenya.
The geysers are used to generate geothermal power for domestic and industrial uses.
The hot springs and geysers and the Ol Karia geothermal project attract tourists thus earning the country foreign exchange.
Geothermal power project at Ol Karia has created employment opportunities/source of income thus improving living standards. iv.Through establishment of the geothermal power plant at Ol Karia, there has been an improvement in infrastructure through road construction, provision of water and electricity, etc.
Intrusive land forms
When magma is unable to force its way out of the surface, it cools and solidifies in the crust.
Depending on the viscosity of the magma and the nature of rocks through which the magma pushes, avariety of features occurs as follows:
Batholith
This is a large-scale intrusion of magma so deeply seated that the root is often of unknown depth.
It is dome-shaped when exposed to the surface by denudation.
They are mainly made up of granite.
Laccolith
This is an intrusive mass of magma which has forced up or domed overlying strata as shown below.
The cooling is usually near the surface.
Dyke
This is a mass of intrusive rock which cuts across the bedding plane of the existing rock.
It can be vertical or inclined.
When the rock around it is softer, it will be eroded and the dyke will stand as a ridge.
An example of such dykes are found in North West Scotland.
When the dyke is softer than the surrounding rocks, it will be eroded to form along narrow depression.
An example of such a dyke is the Kaap Valley of South Africa.
A sill
This is a horizontal intrusion of magma between the strata the bedding plane.
When exposed to the surface they form ridges or low escarpments.
Example of sills are the Three Sisters of Cape Province and Sill cappings in parts of Morocco.
The Kinkon Falls near Pita in Futa Jalon in Guinea are examples of Sill outcrops across river beds.
A Lopolith
This is a larger scale saucer – shaped intrusion of igneous rocks lying concordant with the strata and forming a shallow basin.
For example the Bushveld Lopolith in the Transvaal.
Other intrusive volcanic forms include phacoliths and bismaliths.
Diagrams of intrusive landforms
The diagram below represents features of vulcanicity. Use it to answer the questions that follow.
Name the features labeled K, L and M.
K – Batholith.
L – Lopolith.
M – Laccolith.
N- volocanic mountain
Give two examples of the feature labeled N in East Africa.
N – Volcano/Volcanic Mountain
Mount Elgon.
Mount Meru.
Mhavura.
Mgahinga.
Marsabit.
Jukuyu.
World Distribution of Features due to Faulting
The volcanic belts of the world are closely associated with the earthquake belts of the world.
Three main types of volcanic belts occur:
i.) Along the extension boundaries for example, the mid ocean ridges.
ii.) Along the transform faults, for example, the ocean deeps and volcanic islands.
iii.) Along compression boundaries, for example, ocean trenches.
Significance of vulcanicity to Human Activities.
Constructive Consequences
i.) Volcanic activities has resulted in large central volcanoes such as Mt.Kenya, Mt.kilimanjaro and Mt.Elgon.The lower slopes of these mountains are amoung the cool,well watered highland areas of high agricultural productivity.
ii.) Volcanic activity has also contributed greatly to the scenic beuty of the landscape which attract tourists.
iii.) Volcanic activity sometimes results in the formation of rich metallic minerals.
iv.) Geothermal steam and power is resource that result from volcanic activity.
v.) Production of Carbon dioxide which is used as a cooling agent or as dry ice.
vi.) Volcanic rocks are valuable as building stone and road material.
vii.) Volcanic mountains are catchment areas, sources of rivers and springs and are thickly forested.
viii.) Pumice , a volcanic rock is used by human beings domestically as a scrubbing
stone.
Destructive Consequences
i.) Sometimes a volcanic eruption can be so violent that it can cause great loss of life and damage to property.
ii.) Volcanic eruption results in the pollution of the environment and the emission of dust and pungent gases into the atmosphere.
iii.) Volcanic eruption can cause great damage to infrastructure, buildings and livestock.
iv.) The leeward slopes of volcanic mountains receives very little rainfall and prone to aridity which hinders agriculture.
v.) The steep slopes produced through vulcanicity discourage settlement and
are barriers to construction of communication lines.
Earthquakes
Definition of earthquakes
This is the sudden earth movement causing trembling vibrations with and below the earth crust.
Causes of Earthquakes
Natural causes
Tectonic activities/movements/convergence & collision of plates/shifting of tectonic plates.
Isostatic adjustments i.e. relative movements between the continental and oceanic crusts during isostatic recovery may trigger off earthquakes as a state of balance is restored.
Vulcanicity/magma movement within the crust can cause tremors since the overlying crustal rocks are being displaced suddenly by the strong convectional currents/magma.
Gravitative pressure i.e. crustal rocks overlying the voids left behind by erupting magma are pushed inwards by force of gravity causing them to shake in the process hence earthquakes.
Human activities
Construction of large reservoirs.
Explosives used in mines and road construction.
Movement of underground trains.
Explosions from underground nuclear tests
NOTE
All these may send shock waves to the crustal rocks and cause earthquakes.
Measurements of Earthquakes
The instrument used for measuring earthquakes is called a seismograph or a seismometer.
Three types of seismic waves are recorded on a seismograph.These are:
Primary seismic waves/p-waves
They travel faster and therefore their vibrations reach the seismograph first.
P- waves cause any rock in their path to compress and then expand in the same direction the waves are travelling.
Secondary seismic waves
These are known as S-waves.
They are called secondary waves because their vibrations reach the seismograph later than the p- waves.
Long waves/L- waves
These are seismic waves with large amplitude wiggles.
They are also known as L-waves.
Their broadness makes them be referred to at times as large waves.
NOTE
Earthquakes are measured by their intensity and magnitude.The intensity of an earthquake refers to how had or strong the earthquake shakes the ground.The Mercalli Scale is used to express the intensity of earthquakes with a scale running from roman I –XII.
Mercalli Scale
Imperceptible –Recorded by instruments only.
Very feeble – Only felt by people at rest or at the tops of buildings.
Feeble -Sounds like a passing motor car, slight disturbances of loose objects.
Moderate- Rattling and roaring noises heard by people indoors, movement of seats and shaking of beds, considerable disturbance of those objects, some sleepers awakened.
Rather strong-Most sleepers awakened, swinging of suspended objects, vibration generally felt in the open,slight movement of heavy.
Strong – overthrow or considerable movement of large and heavy objects,cracks in ceiling and crumbling of paster.
Very strong – breakage of objects, slight damage to buildings.
Destructive – Gaping crucks in walls and some walls brought down.
Highly destructive – Sever damage to structures ,some buildigs completely wrecked.
Devastating – Destruction of numerous buildings and their foundations.
Catastrophic – Hardly a stone structure remains standing.
Majar catastrophe – Every building destroyed, a major geographic effect.
Note
Magnitude is theamount of energy off or produced by anearthquake. This is measured on a Richter scale, which ranges from 0 to 8.9.
The higher the scale, the more sever the earthquake. It is important to note that the intensity varies from place to place depending on how far a place is from the epicenter.
However the magnitude does not vary but remains constant.
Major earthquake zones of the world.
Mid Atlantic Belt/Mid Indian Ocean Ridge.
The Great Rift Valley Region.
The Circum – Pacific Belt/Ring of Fire.
The Mediterranean Belt/Mid – South East Asian Region.
In areas of volcanic activity.
Effects of Earthquakes
It leads to loss of lives and destruction of properties.
Earthquakes in the oceans gives rise to waves, which are known as tsunamis which are very destructive when they get to the shores.
Earthquakes tends to trigger fires hence the occurrence of fire after an earthquake is a common feature.
The shaking of the earth’s crust triggers landslides. This is detrimental to both plants and animals.
They can either lower or raise the sea floor. A sudden subsidence of land near the sea can cause flooding.
They restrict the development of towns.
Aftershocks, which are the small/minor tremors that follow major earthquakes tend to further weaken structures already weakened by major earthquakes.
Field work.
a.)Students from Maranda School intend to conduct a field study on volcanic features in the Rift Valley of Kenya.
Other than Ol Karia, name two other places they are likely to visit for the study.
Lake Bogoria.
Eburru – between Lakes Naivasha and Nakuru.
Menengai Crater.
Longonot Crater.
Marsabit.
Around Lake Turkana.
Around Mt. Elgon.
Hell’s Gate – Hyrax and Fischer’s Hills.
Mulot area in Bomet.
State two methods of data recording they are likely to use during the study.
Note taking.
Photographing/taking photographs/video recording.
Tape recording.
Filling in questionnaires.
What problems are they likely to encounter during the study?
Steep/rugged terrain difficult to climb thus delaying the study.
Accidents in the terrain would delay/end the study abruptly.
Sudden rainfall would stop the data collection temporarily or even end it prematurely.
High temperatures from scorching sun would make data collection difficult.
Lack of adequate data may bring the study to a premature end.
End of topic
Did you understand everything?
If not ask a teacher, friends or anybody and make sure you understand before going to sleep!
Past KCSE Questions on the topic
Earth movements.
(a) Name the two types of earth movements that occur within the earth’s
crust (2mks)
(b) Describe the origin of the continents according to the Theory of
continental Drift (3mks)
Explain what you understand by each of the following:
Earth movements.
Internal land forming processes.
External land forming processes. (6mks)
Explain four evidences put forward to proof continental drift theory.
(8mks)
Explain plate tectonic theory.
(4mks)
Folding
(a) In your answer booklet, draw a diagram to show a simple fold and on it
mark and name,
An anticline. 1 mk
A limb. 1 mk
A syncline 1 mk
Name two fold mountains in Africa. 2 mks
(a) Name one fold mountain in;
Asia
North America
South America
(i) Apart from Fold Mountains, name three other features resulting from folding.
With the aid of a labelled diagram, describe the formation of an overthrust fold.
Explain four effects of Fold Mountains on human activities.
(i) How would students in your school prepare themselves for study of landforms in your district,
State two advantages of studying landforms through field work.
Define orogenesis. 2 mks
What is folding? 2 mks
Explain the meaning of compressional boundaries. 2 mks
Differentiate between limb and axis in relation to folding.
4 mks
Differentiate between foreland and back land. 4 mks
Fill in the table provided details on age, period and features formed in each named orogenies.
Orogeny Years (age) Period Mountains/features
built
Charnian
1
Precambrian period 2
Caledonian
Old 440 million years ago
-Akwapim Hills of Ghana – Scottish highlands
Hercynian
3
Upper Carbon ferrous period
Cape ranges –
Appalachian mountains
Ural mountains
Alpine Youngest 70 million years ago 4
6 mks 9. Explain formation of Fold Mountains by contraction theory.
Faulting
a) A part from the Rift Valley name two other relief features that were
formed as result of faulting. (2mks)
With the aid of a well labeled diagram, describe how a Rift Valley is
Formed by tensional forces. (8mks)
The diagram below represents features produced by faulting.
Use it to answer questions that follow.
Name the features marked P, Q, and R
Differentiate between a normal faulty and a reverse fault.
State ways in which faulting influences drainage. (3mks)
Name two examples of Horst Mountains in East Africa. (2mks)
Explain two ways in which features resulting from faulting are of economic
importance (4mks)
(a) (i) With aid of diagrams outline formation of rift valley by tension
theory. (5mks)
Students are planning to carry out field study of an area affected by
faulting.
State four importance of having a pre-visit of the area.
Give three disadvantages of using observation to study such an
area.
Name three types of fault. (3mks)
Explain how compressional forces lead to formation of rift valley. (5mks)
Give two of escarpments in East Africa. (2mks)
Explain ways in which features resulting from faulting are of importance.
(8mks)
Describe formation of fault steps with aid of diagrams. (6mks)
Vulcanity
The diagram below shows some intrusive features formed by vulcanicity.
i) Name features marked X,Y, and Z (3mks)
Explain how a sill is formed (4mks)
Describe the characteristics of a composite volcano(4mks)
Explain four ways in which volcanic mountains positively influence
human activities. (8mks)
Students carried a field study on volcanic rocks
Give four reasons why it is necessary to collect rock samples
during such a field study. (4mks)
State two problems they are likely to have experienced during
the field study
(4mks)
(a) Differentiate between plutonic rocks and volcanic rocks
Describe how lava plateau is formed
(i) Name three volcanic features found in the rift valley of Kenya
Explain four negative effects of vulcanicity in Kenya
(d) You intend to carry out a field study of a volcanic landscape
State four reasons why it is necessary to conduct a reconnaissance of the area of study.
During your field work, you intend to study volcanic rocks, state
why you would need the following items
Name three volcanic features found in the Rift Valley of Kenya. (3mks)
Explain four negative effects of vulcanicity in Kenya. (8mks)
Describe how lava plateau is formed. (5mks)
Differentiate between sill and dyke. (4mks)
What is vulcanicity. (2mks)
Describe how Crater Lake is formed. (5mks)
Describe how Mt. Kenya was formed.
Earthquakes
1. (a) Name two scales used to measure the intensity of an earthquake
(2mks)
(b) Give three causes of earthquakes (3mks)
2.(i) What are earthquakes
Name two types of earthquakes.
State the five ways in which the earths’ crust is affected by earthquakes. (a) You intend to carry out a field study of an area recently affected by intense earthquake.
Give two sources of information that you would use in preparation for the study.
Explain two factors that would make it difficult for you to collect accurate data during the field study.
(a) State three causes of earthquakes
(b) Give two effects of earthquakes in built up areas
State the major causes of earthquakes (2mks)
Explain how intensity of earthquake is measured. (2mks)
List major effects of earthquakes where they occur. (4mks)
Distinguish between seismograph and seismogram (4mks)
Differentiate between intensity and magnitude of earthquake (4mks)
Students from your school intend to carry out a field study of an area recently affected by intense earthquake.
Give two sources of information that you would use in preparation for the study.
Explain two factors that would make it difficult for you to collect accurate data during the field study.
CHAPTER EIGHT
Specific objectives
By the end of the topic the learner should be able to:
(a) Define weathering, mass wasting, hydrological cycle, river systems, lakes and glaciation;
(b) Distinguish between oceans and seas;
(c) Describe water movement in oceans and seas;
(d) Explain the factors that contribute to the sculpturing of the earth;
(e) Explain external land-forming processes and the resultant features;
(f) Identify the sources of underground water;
(g) Discuss the significance of the resultant physical features to the environment;
(h) Carry out field-work of the landforms within the local environment.
Content
Weathering
(a) Definition of weathering.
(b) Agents of weathering.
(c) Types and processes of weathering.
(d) Significance of weathering to physical and human environments.
Mass Wasting
(a) Definition of mass wasting.
(b) Factors influencing mass wasting.
(c) Types and processes of mass wasting.
(d) Effects of mass wasting on the physical and human environments.
Hydrological cycle
(a) Definition of hydrological cycle.
(b) Process of the cycle.
(c) Significance of the cycle
Action of rivers
(a) Definition of rivers
(b) River erosion, transportation and deposition and the resultant features.
(c) Development of cross and long river profiles.
(d) River capture and rejuvenation.
(e) Drainage patterns.
(f) Significance of rivers and river formed features.
Lakes
(a) Definition of the term lake.
(b) Formation and classification of lakes.
(c) Significance of lakes.
Oceans, seas and their of coasts
(a) Distinction between oceans and seas.
(b) Nature of ocean water.
(c) Water movement: meaning, causes and significance of vertical movements and horizontal movements
– Ocean currents
– Tides and waves.
(d) Wave erosion, transportation and deposition, and resultant features.
(e) Types of Coasts.
(f) Significance of oceans, seas, coasts and coastal features.
Action of wind and water in arid areas.
(a) Processes of wind erosion and transportation in arid areas.
(b) Features formed by wind erosion and deposition.
(c) Features formed by water in arid areas.
(d) Significance of features found in arid areas.
Action of water in limestone areas
(a) Sources of underground water.
(b) Formation of features by surface and underground water in limestone areas.
(c) Significance of the features.
Glaciation
(a) Definition of the term glaciation, glaciers, ice sheets, ice caps and icebergs.
(b) Processes of glacial erosion, transportation and deposition in highland and lowland areas and the resultant features and Significance of glaciation.
Field work
Study of significant land-forming processes within the local environment.
Weathering and Mass wasting
Definition of Terms
Denudation: – refers to all the processes of destruction, wastage and removal of parts of the earth’s surface. It includes weathering, mass wasting, erosion, deposition and transportation of materials by wind, water or ice
Weathering is the breaking, disintegration and decay of solid rock at or near the earth’s surface without movement (in situ). The waste materials produced after weathering are called regoliths
Agents of Weathering
– Heat leads to differences in temperatures that exert stress upon the rocks and influence chemical reactions within the rocks
– Water: carbon (IV) oxide is dissolved in water from the atmosphere reacts to produce carbonic acid that dissolves rock mineral hence weathering
– Plants and animals: activities of burrowing animals e.g. rodents/termites encourage weathering. Also plants’ roots penetrates through cracks and joints on the rocks causing stress ; facilitating weathering
Factors influencing weathering
(i) Climate
– The main elements of climate that influence weathering are temperature, frost, rain, humidity and sunshine.
– Chemical weathering is very pronounced in equatorial regions due to the hot, humid conditions
– Physical weathering is pronounced in desert areas due to extreme diurnal range of temperature low precipitation and high evaporation rates.
(ii) Living organisms
– Bacteria facilitate the decay of other organisms which produces organic acid. These acids react with certain mineral sin a rock causing them to decay
– Roots of plants may cause rocks to crack as they penetrate, thereby seepage of water into the rock
– Burrowing animals provide passage through which air and moisture can reach the rocks beneath the surface.
– Lichen and mosses keep the surface of rock moist thus facilitate chemical decay.
– Human activities such as mining, digging, blasting and construction also lead to rock break-up
– Hoofed animals trample on rocks.
(iii) Nature of the rock
– Differences in the mineral composition of rocks create differences in the physical and chemical stability of the rocks as the minerals expand and contract at different rates due to temperature variations.
– Well jointed rocks easily break upon exposure to agents of weathering.
– The joints within a rock also allow passage of air and moisture into the rock.
– Colour determines rate of heat absorption, dark rocks absorb more heat than shiny ones.
– Texture: fine grained rocks are affected more by chemical weathering as compared to coarse-grained rocks.
(iv) Topography
– On steep slopes, the weathering materials are quickly removed by agents of denudation (wind, ice, water) thereby exposing the rock surface to further weathering.
– Gentle slopes allow accumulation of rock materials in one place covering the rock beneath.
Types and processes of weathering
(a) Physical weathering/mechanical wethering
– This involves rock disintegration without any chemical change. It makes the rocks to break into smaller fragments and it is common in ASALs and high altitude areas that experience marked variations in temperature
– It occurs through the following processes: –
Block disintegration
– This is a process in which blocks of large rocks break away from the original rock mass along joints and bedding planes
– It occurs in areas with large diurnal temperature ranges i.e. ASALs
– The high temperatures during the day
Exfoliation
– In arid areas rock surfaces heat up rapidly and expand when exposed to high day temperatures.
– During the day the outer layer of the rock is more heated than the interior, hence expand more than the interior.
– At night, when temperature fall, the outer layers of a rock cool and contracts while the inner core is still warm.
– The differential expansion and contraction of the rock creates stress between the outer layer ands the inner core.
– The rock cracks, splits and peels off like an onion a process known as exfoliation.
Exfoliation domes are rock hills whose surface has peeled off and an accumulation of rock shells at the foot of the rock hill.
Block disintegration
– A process in which blocks of rock break away from the original rock mass along the numerous joints and bedding planes which are lines of weakness.
– May be caused by large diurnal temperature ranges in deserts which cause differential expansion and contraction of the rock mass.
Granular disintegration
– Is the break up of rocks into small particles/grains.
– Common mainly in coarse grained intrusive igneous rock.
– It caused by the alternate healing and cooling of heterogeneous rocks. Different minerals expand and contract at different rates. This causes stress and strain within the rock thus individual rock grains break off from the rock mass.
Frost Action
– Water enters the cracks/joints and pore spaces in high mountain regions.
– Low temperatures make the water to freeze into ice crystals which grow in the cracks.
– As the crystals grow, pressure is exerted on the joints thus widening the cracks that will allow more water to get in and freeze.
– Freeze and thaw action is repeated over time, making the outer part of the rock to break away and fall off.
Pressure release/unloading
– Deep seated igneous rocks are under great pressure from the overlying rock layers.
– Continuous denudation removes the overlying layers exposing the underlying rocks at/near the earth’s surface.
– The upper part of the exposed rock expands slightly due to reduced pressure.
– This leads to big shells of rock breaking away from the parent rock mass.
Crystal Growth
– During the long dry seasons, the water in the rocks is drawn to the surface by capillary action.
– High temperatures make the water to evaporate depositing tiny particles of salt in rock cracks and pores.
– The salt crystals accumulate and grow in side exerting pressure hence widening it.
– Eventually the rock piece falls off.
Slaking
– Common in areas with alternate dry and wet seasons.
– In the wet season, rocks with high clay content absorb moisture and swell.
– In the dry season, the particles lose much of this water causing them to shrink.
– This alternate wetting and drying is repeated causing individual mineral particles to become loosely attached and break off.
(b) Biological weathering.
Human activities
– Rocks are broken up when they are blasted with explosives in quarries.
– Rocks are also scooped and carried away during open cast mining.
– Air pollution leads to the formation of acid rain which causes chemical weathering when it falls on rocks.
– Bush fires caused by human’s heat rocks and cause exfoliation.
– Rocks are affected by chemicals released into the environment by industrial activities.
Animals
– Hoofed animals creates pressure on rocks as they directly walk on the rock surface.
– Rabbits and moles have burrowing habits which assist in the breakdown of rocks.
– Termites and worms brings to the surface large quantities of fine materials which promote Weathering as lower layers of rocks becomes aerated.
Plants
– The roots of trees can force joints in rocks to widen.
(c)Chemical weathering
This is a process in which mineral elements of a rock undergo chemical changes or decay. As a result of chemical weathering;
– New minerals are formed
– Some minerals undergo chemical changes
– Mineral dissolve in water
Causes of chemical weathering
– Presence of moisture
– Gases
– High temperature
Chemical weathering process
Hydrolysis
– Water breaks down into hydrogen ions which then combine with the minerals e.g. potash feldspar (orthoclase) turns into clay (Kaolin) which swells when it absorbs water.
Oxidation
– Common in rocks rich in iron compounds.
– When ferrous compounds (grey, blue in colour) are exposed to oxygen in the presence of water, they become oxidized forming a new mineral (reddish brown) – ferric oxide.
– The ferric compounds readily crumble and the rock disintegrates.
Carbonation
– Common in limestone/chalk areas.
– As rainwater falls, it dissolves small quantities of carbon dioxide from the atmosphere forming weak carbonic acid which reacts with limestone rocks to form calcium bicarbonate which is soluble in water, hence the rock disintegrates.
Solution
– Minerals in the rock directly dissolve in water without their chemical composition being altered i.e. minerals change from solid to solution state.
– Common especially in rock salt, gypsum.
Hydration
– Some hygroscopic minerals in a rock absorb water from the atmosphere; they swell and expand creating internal stress within the rock.
– This leads to disintegration of the rock
Mass wasting
– Refers to the movement of weathered rock materials down a slope under the influence of gravity
Factors that influence mass wasting
a) Nature and weight of the materials
– Heavy /large materials like rocks move down slope rapidly than fine weathered materials.
– Large rocks overlying weak rocks such as clay can slide more easily than if they were overlying sand.
b) Amount of water
– Saturated soils easily slide down slope than dry masses of soil.
c) Angle of slope
– The steeper the slope the faster the movement of weathered materials
d) Amount and nature of rainfall received
– Areas with heavy rainfall have saturated soils which easily move down slope causing landslide.
e) Vegetation
– Absence of plant cover encourages movement while presence of dense vegetation cover holds the soil particles together reducing movement.
f) Tectonic movements
– Such as earthquakes may trigger off widespread movement of materials. Also volcanic eruptions may set off landslide.
g) Human activities
– Such as mining quarrying, road construction, clearing vegetation affect the stability of surface materials thus encourage movement of materials.
Types of mass wasting
(a) Slow mass wasting-
– This is the slow but steady movement of soil or loose rock debris down a slope.
– Main processes are; soil creep; talus creep, rock creep and solifluction.
(i) Soil Creep
– The materials involved is mainly fine soil particles on a gentle slope
– It is the slowest kind of mass movement and quite hard to notice where the vegetation is dense
– It can be noticed by
Mounds of soils behind walls
Tilting of walls/electricity poles
Bending of tree trunks
Cracked roads
Soil creep is triggered by
Alternate heating and cooling – soil particles expand and contract hence shift position down slope.
Freezing of soil water/Frost heaving – This causes the water to expand; the soil particles on the surface are lifted at right angles to the slope then fall back perpendicularly to the horizontal plane due to gravity. In this way soil particles shift their positions down slope.
Rainwater – percolating into the soil may drag individual grains of soil along with it causing them to change their positions
Removal of the soil downhill/ploughing across the slope causes the soil to be turned towards the lower side of the slope hence particles shift down slope
External forces- (earthquakes, animals) have a trigger effect on soil particles causing a down slope movement.
Effects of Soil creep
It causes accumulation of soil particles at the base of a slope causing deep soils suitable for agriculture.
Displacement of fine soil particles down slope leaves the steep upper slopes bare and exposed.
It pushes posts and fences from their original position and become inclined/ breaking of stone walls.
It interferes with road, railways making maintenance expensive.
Terracettes (stepped pattern) develop across the slope.
May lead to slope retreat i.e. the slope becoming gentler.
(ii) Talus/Scree Creep
– Talus creep is the gentle and slow downhill movement of a mass of broken rock particles at the base of a cliff or scarp slope.
– It involves angular waste rock materials of various sizes (talus or scree) creeping down a mountain side
(iii) Solifluction
– This is the movement of saturated soils and gravel down a moderate slope over a permanently frozen sub soil.
– Occurs on cold mountain slopes where the soils are frozen in winter and during spring, thawing saturates the soils to slide down slope
(b) Rapid mass wasting
– This refers to sudden and fast movement of materials down slope
– They are at times dangerous and destructive
– Include earth flows, mudflows, avalanches and landslides.
(i) Earthflows
– In humid regions, the materials on the surface get saturated with water causing them to flow downhill under gravity.
– This leaves behind a shallow scar at the original position of the materials while forming bench-like terraces at their destination.
(ii) Mudflows
– Occurs on moderate to steep slopes especially where the soil is bare or covered by scanty vegetation/ASALs.
– Heavy rainstorms produce more rainwater than the soil can absorb and as the water flows downhill, it turns the soil into mud which then flows in large quantities.
– May also occur when heavy rain accompanies a volcanic eruption in which water turns volcanic ash and dust into mud which then flows downhill.
Factors that influence mudflows
Presence of loose/unconsolidated material at the surface which becomes slippery when wet.
Scarcity/absence of vegetation – lack of obstacles.
Abundant and intermittent water supply.
Occurrence of steep slopes
(C) Avalanches
– This is a sudden sliding and falling of a large mass of snow, ice and loose rock down a mountain side.
– Accumulated quantities of snow usually break away and slide over older, more hardened snow surfaces.
– Snow may fall as a result of thawing or from the margins of snow in a hanging valley
(d) Landslides/Landslips
– A landslide is a rapid movement of a large mass of earth and rocks down a hill.
– The water content of the material is small
Landslides may be caused by the following conditions;
Steepening of the slope during mining or rail construction
Undercutting of a steep slope by rivers or sea waves
Loosening of rocks by earthquakes and volcanic activities
Clearing of vegetation from steep slopes by man
Thawing of frozen soils on steep slopes and movement of melt water down the slope that triggers off landslides.
It occurs in the forms such as slumping, rock fall, rock slide, debris slide and debris fall.
Slumping/slump
– This involves tearing away of rock materials along a concave plane.
– It is common on very steep slopes (cliffs, scarps) where large masses of rock, loose material and vegetation rapidly move down a concave slope.
– It takes place when the underlying soils/rock is saturated making the surface rock to slide down slope.
– The overlying rocks break off and the rock mass slides downhill while rotating around a curved plane.
Debris slide/earth slide/soil slip
– Accumulated rock debris and other loose materials which are products of weathering may suddenly move downhill as a whole mass without breaking up and without back-tilting i.e. the movement is horizontal.
Debris fall
– Loose materials on top of a cliff/steep slope (almost vertical) suddenly fall freely to the base of the slope.
– The movement of the materials/debris is along a vertical or overhanging cliff
– It is a sudden movement common in undercut banks of streams or undercut cliffs
Rock fall
– This is the most rapid of all the mass wasting processes
– Individual rocks/boulders fall freely from a steep slope or a cliff.
– The falling materials may be as small as sand grains or as large as huge rock blocks
Rock slide
– A mass of rock slides down a slope especially over a lubricated surface.
Effects of mass wasting
Encourages soil erosion on the landscape especially on highland areas.
Deposited materials may form mounds that may block rivers and change their courses
Can cause damage to property – telephone lines, buildings, railway.
Can cause death of human beings (landslides may burry settlements, rock falls are dangerous to human life)
Hinders transportation by blocking roads, railways
Materials washed down slope form fertile soils where they are deposited.
Mounds of debris have dammed river courses thereby creating temporary lakes.
Leave permanent scars upslope resulting into land dereliction.
Hydrological cycle
– Hydrological cycle is the endless/continuous circulation/interchange of water between the sea, atmosphere and land
– It involves the following processes
(a) Evaporation: – This is the physical process through which moisture is directly lost from various water surfaces and the soil. The loss is due to sun’s heat and the effect of air movement. It involves changing of water from oceans, seas, lakes and rivers into water vapour by the sun’s heat then it rises into the atmosphere. It depends on
Availability of moisture on the land surface
Increase in temperature
Wind
Sunshine duration
Characteristics of water
(b) Cooling: – as the water vapour rises into the atmosphere, it expands and cools due to reduced atmospheric pressure in the upper layers of the atmosphere
(c) Condensation: – this is the cooling of water vapour below the dew point. It turns the water vapour into tiny water droplets that join together in large quantities to form clouds
(d) Precipitation: – occurs when clouds become too heavy and drop the moisture they are holding. The dropped moisture then return to the soil inform of rain, snow or hail.
(e) Surface runoff: – when precipitation reaches the ground in form of rain, some water flows on the surface into valleys, ponds, lakes, swamps and even to the sea
(f) Infiltration: – this is the water that seeps through cracks, crevices/fissures, joints and pores found within the rock and soil over which the surface runoff flows
(g) Percolation: – is the process by which infiltrated water moves downwards and sideways by force of gravity through the pores and cracks.
Significance of hydrological cycle
(a) It provides water that supports life for other human activities e.g. domestic and industrial uses
(b) It maintains the atmospheric energy stored in the atmosphere for the development of storms
(c) Moisture in the atmosphere is important in absorbing the terrestrial radiation thus keeping the lower atmosphere warm
(d) Leads to the formation of clouds and rainfall that assist in agriculture and vegetational growth
(e) Leads to distribution of water on the earth’s surface
Action of Rivers
Definition of terms associated with rivers
River: – is a large natural stream of water flowing in a valley from an upland area towards the lowland
Source: – is the origin of the river. It can be a forested area, a mountain or a spring
Mouth: – is the terminal/end point of a river/the point where a river drains its water e.g. lake, sea or ocean
Catchment area: – This refers to the source of most rivers e.g. forested, mountainous area where a river draws its waters
Tributaries: – small streams/rivers that flow into larger/bigger rivers; feeding the main river with water
River system: – combination of a river together with its tributaries
Watershed/divide: – the boundary of a drainage basin marked by a ridge of higher land. It separates one drainage basin from other adjacent ones.
Drainage basin: – area of land drained/served by a river and its tributaries.
River discharge: – amount of water passing down a stream expressed in m3/second
River regime: – is the seasonal fluctuation or variation in the volume of river water or discharge
Interfluves: – high areas in between tributaries
The Action of Rivers and Development of River Profile
– This involves erosion, transportation and deposition
River Erosion
– Involves the wearing away of the earth’s surface through the action of naturally flowing water/rivers
– Occurs through the processes of hydraulic action, attrition, corrosion and solution
(i) Hydraulic action
The force of the moving water and the eddying effect sweep away loose materials in the river channel or water is forced into cracks on the river banks
When water is hurled against the riverbanks; air in the cracks is compressed, creating pressure, which widens the cracks.
As water retreats; pressure in the cracks is suddenly released. The compression and widening of cracks repeatedly shatter the rocks, which are then carried away by the retreating water
(ii) Attrition
Boulders being transported downstream are in constant collision with each other thereby reducing them into smaller particles forming smooth, rounded pebbles
(iii) Corrosion/Abrasion
The river uses its load (gravel, boulders) as erosive tool i.e. the load is used as a tool for scouring. The load is hurled by the river water against the banks and dragged along the bed thereby chipping off the rocks on the bank and bed
As the river load is hauled by the river against the river bank/bed, it scours/sculptures/abrades the sides and bed of the river channel
(iv) Solution
Running River may dissolve minerals found in the rocks in which they flow. The material is carried down the river channel in solution
Factors that influence the rate of river erosion
Volume of the stream/river i.e. the larger the volume the greater the force of moving water and hence the greater the erosion.
Nature and amount of load: – large and hard objects e.g. boulders and rock pebbles cause more erosion compared to smaller and finer objects
River gradient and velocity: – steep slopes experience higher velocity of river water due to greater influence of gravitational force. The rivers flow very fast and exhibit higher rates of erosion
Nature of the river bedrock: – river beds with less resistant rocks are easily eroded especially if the rocks are well jointed or soluble in water.
Types of River Erosion
1. Head-ward Erosion
– Involves the river extending its length by cutting back upstream above its original source
– It may be caused by spring sapping (shifting of the position of a spring uphill thus shifting the source point of the river), rain wash, gullying and soil creep
– It increases the length of the river
2. Vertical Erosion
– Occurs on the river bed through abrasion and solution processes
– It leads to the deepening of the river channel
3. Lateral Erosion
– Occurs on the sides/banks of the river
– Leads to widening of the river channel
Resultant features of river erosion
1. Stream cut/V shaped valleys
– As river water moves down slope over the earth’s surface it cuts a depression/channel that starts as a gulley. With time the gulley widens through lateral erosion and deepens through vertical erosion forming a V shaped valley
– Common in the upper courses of the rivers near the source
2. Gorges
– A gorge is a deep, narrow and steep sided river valley. It forms in the following ways: –
Where a river flows across a plateau composed of horizontal and alternate layers of hard and soft rocks. Examples include Chebloch gorge on R. Kerio.
Where a river flows along a line of weakness, e.g. fault line/line of less resistant rocks. Examples are gorges found on the floor of Rift Valley e.g. gorges along Rivers Malewa and Shiroro gorge on River Kaduna – Nigeria.
Where a river maintains its course across a landscape which is being slowly uplifted (antecedent gorge).
Where a waterfall retreats upstream, leaving a deep valley on the downstream side due to vigorous erosive activity of the river water e.g. Batoka Gorge below Victoria falls on River Zambezi, gorges below Tissisat falls on Blue Nile (Ethiopia)
3. Waterfalls
– A waterfall is a steep fall of river water where a river bed has sudden vertical/near vertical drop
– They may be formed in the following ways
Formation Examples
When a layer of more resistant rock lies across a river bed horizontally, vertically or inclined, the less resistant rock on the downstream is eroded faster than the more resistant rock upstream leading to a steeper gradient that develops into a waterfall
Gura/Tana/Grand/Adamson – all on river Tana
14 falls – R. Athi
Thomsons – Ewaso Ngiro
Where a river descends/flows over a fault scarp; the river enters the rift valley through a fault scarp
Turkwell – R. Turkwell
Torok – R. Torok
Webuye – R. Nzoia
Kabalega – R. Nile
Kalambo – R. Kalambo
Where a river descends a sharp edge of a plateau
Chandler’s – R. Ewaso Ngiro
Lugard’s – R. Galana
Pangani – R. Pangani
Formed as a result of river rejuvenation (i.e. at knick point)
Winjo
Gogo – all in R. Kuja
Where a river descends a hanging valley into a glacial trough
Vivienne – R. Nithi
Where a river descends a cliff coast into the ocean; some rivers may not be able to erode through the rocks forming a cliff because they may be very resistant, the river then drops into the ocean forming a waterfall
Lobe fall – R. Sanaga – Cameroon
Where a dyke blocks a river/a river descends a lava barrier or from a landslide; this leads to accumulation of water on the upstream side to form a lake/dam, a waterfall may form at the point of overflow
Chania
Thika – all on R. Tana
Tissisat – R. Nile
4. Rapids
-This is a section of the river with accelerated current; where the stream descends at high speed without a break in the slope of the river bed sufficient enough to form a waterfall
– Occurs where a layer of resistant rock lies across the river bed and dips downstream
– Example Kora rapids on R. Tana
5. Interlocking spurs
– These are projections of land in the upper course of a river that overlaps with each other.
– They form when a river comes across an obstacle/ resistant rock, hence will tend to curve round these rocks, following areas of least resistance, making the river to have a winding course
– With time the bends are extended and become more pronounced.
6. Potholes
– When water in a river is flowing rapidly over shallow depressions on the river bed, it develops strong currents called whirlpools that flow in circular manner.
– This also keeps the river load in circular manner too causing the rock fragments to erode the river bed leading to formation of circular depressions called potholes
River Transportation
– Eroded material in a river are transported through solution, suspension, traction and saltation.
(a) Solution: – This involves transportation of materials that are dissolved in water
(b) Suspension: – This is the transportation of light and insoluble materials in the form of a mixture. The lighter material float on the water surface or are partially submerged in the river water flowing downstream.
(c) Traction: – Larger particles (boulders) are pushed and rolled along the streambed by the force of water i.e. hydraulic action and action of gravitational force.
(d) Saltation/hydraulic lift: – medium sized load are moved in a series of short jumps/hops along the riverbed. The force of water lifts the particles but they land again by the force of gravity.
Factors that influence river transport
Nature/amount of the load: – small and lighter particles can be transported over longer distances/larger and heavier particles e.g. boulders are transported over shorter distances.
Gradient and velocity of the river: – if a river flows over steep land, it flows faster/at a higher velocity and this enables it to transport more material/load.
Amount of river discharge/volume of river: – a river with a larger amount/volume of river water transports a greater quantity of load.
Presence/absence of obstacles along the river channel e.g. rock outcrops, swamps etc that check the river velocity thus reducing its ability to transport
River Deposition
– This occurs when the competence and capacity of a river to transport its load is reduced/decreases
– It is caused when a river’s energy to transport is reduced. This can be due to the following factors:
(a) Emptying into a calm water body e.g. a swamp/lake
(b) Reduction of river velocity due to reduction in the river’s gradient
(c) Freezing of river water especially in very cold areas e.g. high latitude/altitude areas
(d) Fluctuation of river volume due to underground seepage/flooding
(e) Obstacles within the river channel reducing the river competence
(f) Wider and larger load causes more friction with the river channel leading to reduction in stream velocity thus deposition
(g) Widening of the stream bed due to lateral erosion
Resultant features of river deposition
– These include alluvial fans, meanders, ox bow lakes, braided river channels/river braids, natural levees, flood plains and deltas
1. Alluvial fans
– This is a fan shaped deposit of fairly coarse material laid down by a stream with a large load as it emerges from a steep narrow valley onto a wide gentle plain.
– Deposition takes place when a fast flowing river in a constricted valley/channel losses its velocity on entering a plain.
– Examples include Ombei Fan – Kano plains (Kenya)
2. Meanders
– These are loop-like bends in the river course that develop from the sluggishness of a river due to a decrease in gradient.
– The river therefore flows slowly and tends to flow round an obstacle instead of cutting through it
– Once a bend develops around the obstacle, the water current pushes hard on the outer banks causing maximum lateral erosion
– The river water comes to a temporary stand still on the inner bank causing the river to deposit alluvium while at the same time eroding the outer bank
– The meander grows bigger and more pronounced due to alternate deposition and erosion on the inner and outer banks respectively
– Meanders are common on the lower courses/stages of rivers Yala, Miriu, Nzoia, Nyando, Tana and Sabaki – all in Kenya.
3. Ox bow lakes
– This is a horse shoe/crescent shaped lake formed on the flood plain of a river
– Active lateral erosion takes on the outside of the bends narrowing the meander neck. The meander neck is eventually cut through
– The cut ends of the meander are sealed by deposition and the meander now becomes an ox-bow lake.
– Examples includes lakes Kanyaboli (R. Yala) , Shalu, Bilisa, Gambi and Shakababo – all on R. Tana.
4. Braided river channels/river braids
– This is an extremely wide, shallow channel in which the river divides and subdivides in a series of interconnecting minor channels separated by sand banks and islands of alluvium.
River braids occur under the following conditions: –
i. Heavily loaded streams flowing between banks of easily eroded material.
ii. Areas of reduced gradient of the stream.
iii. Arid areas where evaporation is high.
iv. Dry season, when the river volume is reduced.
v. Presence of obstacles like rock outcrops, which may cause the river to be subdivided
– Examples are common in the lower courses of rivers Nzoia, Yala, Sondu and Nyando.
5. Natural levees
These are raised river banks between which a river flows during its old stage.
They start forming when a river floods, spilling over its banks and deposition occurs.
Coarse materials are deposited first followed by finer alluvium that are carried further into the flood plain.
These accumulation of course materials raise the river banks to form natural levees.
Examples of rivers with natural levees include Hwang Ho (China), Yang Tse Kiang (China), Mississippi(North America), and Omo (Ethiopia)
6. Deferred tributaries
– This is a river that is forced to flow alongside the main river for long distance before being able to join the main river
– The tributary then starts flowing parallel to the main river across the flood plain until it finds a break in the bank further downstream where it can join the mainstream.
7. Flood plains
– This is a wide flat plain of alluvium on the floor of a river valley over which the river may spread in time of flood
– It is produced through erosion and deposition by a meandering river. As the river meanders, it widens the river valley through lateral erosion; removing the interlocking spurs/reducing them into low bluffs/cliffs 16
– In the process, the meanders migrate downstream hence widening the river channel
– The initial deposits at the end of the slip off slope merge to form continuous alluvial deposit on both sides of the channel
– During floods, alluvium is deposited on the entire valley floor resulting into a flood plain
– Examples of rivers with flood plains include Nzoia, Yala, Tana, Sabaki and Nyando
8. Deltas
– This is a wide and low lying flat tract of alluvial deposits formed at the mouth of a river.
– It forms when a river deposits some of its load on entering into as sea; as a marine delta or on entering into a lake; as a lacustrine delta
– The velocity of the river is checked by the relatively stagnant sea or lake water as the river enters into a sea/lake from the flood plain
– The heavier load is deposited immediately at the mouth whereas lighter materials are carried further into the sea/lake
– As the deposited materials accumulate, this part of the sea/lake becomes shallower, the river builds levees on the sides of the channel making it narrower
– In some cases, the river may burst its banks and divide into smaller channels called distributaries that spread the river deposits and increasing the area covered by the delta.
Conditions ideal for the formation of deltas
River must have a large load of sediments to be deposited at the mouth.
River should be slow flowing on entering the mouth/low velocity at the mouth to facilitate deposition.
Rivers load should be deposited faster than it can be removed by currents and tides.
Absence of obstacles (lakes, swamps) in the river’s course which would filter sediments.
Calm sea/absence of strong waves.
Shallow continental shelf/shore.
Types of Deltas
(a) Arcuate delta
– This consists of coarse sediments of sand and gravel
– Forms where the offshore currents are very strong
– Examples are deltas on rivers Yala, Tana, Sondu and Rufiji. Others include Nile Delta (Egypt), NigerDelta (Nigeria) 18
(b) Bird’s Foot Delta
– Forms on rivers, which carry large quantities of fine alluvium into waters where there is low wave energy
– The river flows into the sea/lake through distributaries that form the shape of a bird’s foot
– It forms at the river mouths with few tides, currents and waves to disturb the silt
– Examples include deltas of rivers with the mouths at Lake Victoria e.g. Nyando, Miriu, Kuja, and Nzoia. Others are deltas found on the mouths of rivers Malewa, Gilgil, Omo and Turkwell.
(c) Estuarine Delta
– An estuary is a submerged river mouth at the coast
– An estuarine delta forms in the estuary as the river deposits its load forming sandbanks and islands until the whole estuary is filled up with the sediments and the river cuts across it in a single channel that may be bordered by levees.
– Examples are deltas on River Zambezi (Mozambique), Volta (Ghana), Betsiboka (Madagascar) .
(d) Inland Deltas
– Forms along the course of a river before it reaches the mouth; lake/sea
-Develop when the velocity of the river is reduced on entering a relatively flat land, especially a swampy one.
– During floods, the river builds up levees, which cause distributaries to develop.
– Alluvial deposits are spread over vast area when the river floods.
– Examples include Niger Delta (Mali), Okavango Delta (Botswana)
Development of a river profile
– River profile is the longitudinal section of a river from the source to the mouth
-It focuses on the appearance of the rivers course laying emphasis on gradient and characteristic features on the long profile.
The river profile is divided into: –
(a) Youth/youthful/torrential stage/upper course
(b) Mature/middle/valley stage/course
(c) Old/plain/lower stage/course
Youthful Stage
– The river flows very fast/at high velocity
– The most dominant river action here is erosion with vertical erosion being more dominant compared to head ward erosion
– Characteristic features here include gorges, waterfalls, rapids, interlocking spurs, potholes and V shaped valleys
Mature stage
– The river channel is wider because it is joined by many tributaries from upstream
– Lateral erosion is more dominant than vertical erosion
– The river slopes become gentle
– Deposition takes place along some sections
– Characteristic features include U shaped river valleys, meanders, river bluffs, slip off slopes.
Old stage
– Large river load
– Deposition is dominant
– River gradient is very gentle/almost level.
– River flows very slowly
– The river valley is shallow, broad and flat.
– Seasonal flooding
– The river is very sluggish, forming pronounced meanders 21
– Deposition along the banks forms levees
– Characteristic features include deltas, distributaries, natural levees, raised river beds, flood plains, alluvial fans, river braids, pronounced meanders, and ox bow lakes
River Capture/river piracy
– This is the diversion of the headwaters of one river into the system of an adjacent but more powerful river due to erosion
– Initially these two rivers flow adjacent to each other and share a common watershed
– The pirate river has a more erosive power due to high water volume. If it is flowing over less resistant/softer rock, it erodes these softer rocks faster compared to the weaker river
– The valley of the pirate river becomes deeper and wider making it to flow at a lower level compared to the weaker river
– The pirate river also extends its valley backwards by headword erosion. Eventually it joins the weaker river and the weaker river’s headwaters start flowing into the valley of the pirate river
– The remaining section of the river where the upper waters have been captured is called the misfit/beheaded stream
– The sharp bend at the point of capture is called an elbow of capture
-The dry river valley between the elbow of capture and the new course of the misfit stream forms a wind gap.
River before capture
River after capture
Conditions necessary for a river capture to occur
– The pirate river ought to be flowing at a lower level compared to the less powerful river
-Powerful and misfit rivers must be flowing in adjacent valley, sharing a watershed
– The pirate river should have a wider valley compared to Misfit Rivers
– The pirate river must have a more active head ward erosion compared to the misfit stream
Examples of river capture in Africa
R. Miriu captured to form R. Sondu.
R. Mwine captured R Mizmui – Tanzania.
R. Tano captured by Black Volta River – Ghana.
R. Gongola captured by R. Benice – Chad.
R. Eyong captured by R. Imo – Nigeria
River Rejuvenation
– This is the renewal or revival of a river’s erosive activity/ability
– It can occur at any stage/course of the river
Causes of river rejuvenation
(a) Change in base level
– Base level is the lowest level to which a river can erode its bed and over which land can be eroded by running water
– This change can be caused by a fall/drop in sea level, regional or local uplift of land, unequal regional subsidence of the land and creates a sharp knick point along the river course.
– Rejuvenation caused by changes in the base level is referred to as dynamic rejuvenation
(b) Increase in a river’s discharge
– This can be due to increase in precipitation and river capture leading to greater erosive power
– This is called static rejuvenation
(c) Change in rock resistance
– From resistant rock to less resistant rocks
– When the river passes over relatively softer rock, it starts to erode vigorously once again.
Features resulting from river rejuvenation
(a) Knick points
– This is a point with a sudden break of slope in the long profile of a river
– They occur following a fall in base level
(b) River Terraces
– These are step-like benches cut out on old river valleys and abandoned by rejuvenated rivers as they renew their erosion to cut new channels
– Expose – can be paired and unpaired
(c) Incised meanders
– These are meanders formed when a rejuvenated river cuts deeper into the original meander
– The river cuts deeply into its bed creating a new valley with the same meandering shape within the old valley
– Can be ingrown (asymmetrical) or intrenched (symmetrical)
(d) Rejuvenation gorges
– Increased down cutting of the river channel as a result of river rejuvenation may create gorges along the river course
– This can be due to antecedence (a river maintaining its course while the surrounding area is being uplifted) or due to change in climate
– This is the plan or layout made by a river and its tributaries on the landscape/earth’s surface
Factors influencing the development of a drainage pattern:
Slope of the land guides the direction of a river flow
Difference in rock resistance/hardness – determines how deep and wide a river channel will become.
The rock structure along a river’s profile.
The Features include
(a) Dendritic: – the tributaries join the main river at acute angles. It develops on rocks with uniform resistance and structure. Examples of rivers with dendritic drainage patterns are Sondu, Nzoia, Yala, Ewaso Ngiro, Athi and Tana
(b) Radial: – develops on a volcanic dome/a cone shaped upland. The river flows outwards/radiates from the peak/top of the volcano downslope around the dome/mountain that forms the source of the rivers. Examples include rivers Ewaso Ngiro and Tana on Mt. Kenya.
(c) Trellis/Rectilinear: -tributaries join the main river at right angles as well as the minor tributaries to the major tributaries. It develops in areas of heterogeneous rocks that dip/slope in the same direction. It is mainly found in scarpland regions/regions of folded rock. Examples are rivers Lak Galole and Kakoni that join R. Tana at right angles
(d) Centripetal: – this comprises of rivers flowing into a common inland basin or depression e.g. a lake, sea or swamp. It occurs in both homogeneous and heterogeneous rocks. The river is guided by the slope dipping towards the depression. Examples are rivers flowing into the rift valley lakes.
(e) Parallel: -the rivers run parallel to each other in areas with well jointed rocks. Examples include rivers Tana and Athi
(f) Fault guided: – this develops in faulted areas. The rivers flow along the fault line because they are relatively weak hence easily eroded. The drainage pattern formed depends on the pattern of the fault line. Example include river Kerio and Ewaso Ngiro
Drainage System
– This refers to the flow of river water in valleys with respect to the nature of underlying rock
Types of drainage systems
(a) Accordant
(b) Discordant
(c) Back tilted
(a) Accordant: – the river flows according to the rock structure and slope by following weaker rocks
(b) Discordant: -the river flows against the slope, nature of rock and land forming process. It is further divided into antecedent and superimposed drainage systems
(i) Antecedent drainage system: – here, the river maintains its course and direction of flow while the surrounding rock is uplifted. The position of the river is maintained through continuous vertical erosion of the rising landscape. The uplift leads to rejuvenation and formation of an antecedent gorge. Examples of rivers with antecedent drainage system are Rivers Malewa and Gilgil, the Great Ruaha River and R. Niger
(ii) Superimposed drainage system: – develops where a river flows over the rocks it is down cutting. Once these rocks are removed through erosion, the river begins to flow over a new set of rocks of a different structure that are older. If the river maintains its original direction of flow without being influenced by the newly exposed rock structure, it is said to be superimposed on the new set of rocks. Examples include River Nile, R. Zambezi and R. Vaal (RSA)
(c) Back tilted: – occurs due to major river capture or large scale diversion of the river direction due to uplift or down warping
Significance of Rivers and the resultant features
Rivers provide water used for domestic, industrial and irrigation purposes e.g. rivers Yala, Nairobi, etc.
Some rivers especially in their older stage form natural waterways that can be used for transport e.g. Yang Tse Kiang, Rhine and Mississippi.
Drowned or submerged river mouths form rias/fiords that are deep and well sheltered thus facilitate the development of ports e.g. Rotterdam on Rhine Delta – Netherlands
Some rivers are rich fishing around (St. Louis Mississippi)
Gravel and sand harvested from river banks are used for building and construction purposes.
Some river deposits contain alluvial soils with valuable mineral e.g. gold, diamond e.g. R. Orange diamond.
Features formed by rivers (waterfalls, gorges, meanders) are tourist attraction hence earning foreign revenue.
Some rivers provide sites for development of HEP stations and projects e.g. Seven Forks (Tana), Owen Falls (Nile – Uganda).
Rivers deposit fertile alluvial soils good for cultivation.
LAKES
– A lake is a hollow depression/basin on the earth’s surface in which water has accumulated
– The water in these basins comes from many sources such as rainfall, rivers, underground water and melting ice.
Factors that determine the permanence of a lake
1. Availability of water drained into the basin from the sources.
2. Nature of the underlying rocks – non-porous rocks limit water loss through seepage.
3. Rate of evaporation: – In areas experiencing high temperatures, much water is lost through evaporation and lakes may become seasonal.
4. Human activities such as diversion of water for irrigation influence a lake’s permanence.
– Lakes may contain salts/saline/salty or fresh water. Fresh water lakes include Naivasha, Baringo, Victoria, etc. saline lakes include Magadi (Kenya) and Katwe (Uganda).
Reasons why some lakes are saline
Absence/lack of out-flowing rivers/outlets to drain out excess salts. This leads to accumulation of salts in the water in the lake
Some lakes lack enough fresh water rivers that drain into/emptying into the lakes or are fed by underground water that may contain high concentration of salt.
Some lakes are located in arid areas with very high rate of evaporation which leads to increased concentration and accumulation of dissolved mineral salts in the lake.
The bed of the lake may comprise of soluble rock with mineral salts which dissolve in the lake water
Surface run-off and rivers may dissolve a lot of salt from the rocks on which they flow. They eventually deposit this salt solution in the lakes into which they drain
Formation and classification of lakes
– Lakes are classified according to their mode of formation into
1. Lakes formed due to tectonic movements
2. Lakes formed as a result of volcanic activity
3. Lakes formed by glaciation
4. Lakes formed by deposition
5. Lakes formed by erosion
6. Human made lakes
Lakes formed due to tectonic movements
– These are Faulted (Rift Valley) lakes and lakes formed by down warping
(a) Faulted/rift valley lakes: – during faulting and the subsequent formation of a rift valley, some parts of the valley are deeply faulted to form long narrow depressions/hollows. If water from direct rain, rivers/surface run offs or underground water accumulate into such depressions, a faulted or a rift valley lake is formed. Examples include lakes Turkana, Baringo, Bogoria, Nakuru, Elementaita, Naivasha and Magadi
(b) Lakes formed by crustal warping/down warping: – internal land forming processes due to forces of compression and tension may cause some parts of the crust to warp upwards or downwards. Down warping can result in the formation of a shallow depression that is eventually filled up with water from rivers or underground to form a lake. Examples include lakes Victoria, Kyoga, Koki & Wamala (All in Uganda), Bangweulu (Zambia), Mweru (Zambia – DRC border)
Lakes formed as a result of volcanic activity
– Include crater/caldera lakes and lava dammed lakes
(a) Crater/caldera lakes: -form when water accumulates into a crater/caldera of a volcanic summit/volcano. Such lakes are always saline as they lack outlets. Examples include lakes Paradise (Mt. Marsabit), Simbi (Rachuonyo), Central Island Crater lake (Central Island Volcano), Nkunga (Meru), Shala (Ethiopia) and Nyos (Cameroun)
(b) Lava dammed lakes: – These form when flowing lava block sections of river valleys creating areas where water can accumulate. Lava from an erupting volcano may flow downhill into a river valley. As the lava flows, it may cool and solidify and block the river; forming a dam on its course. Water accumulates behind this dam/barrier and eventually forms a lake. Examples include lakes Mutanda and Kayumba (Uganda), Ruhondo, Bulera and Kivu in Rwanda, Tana (Ethiopia) and Itasy (Madagascar)
Lakes formed by glaciation
– These are cirque/corrie lakes, moraine dammed, ribbon and kettle lakes
(a) Cirque/corrie lakes: – these are formed from glacial erosion. When a glacier erodes, it forms a hollow/depression called a cirque/corrie. When rain or melt water accumulate in the cirque, it forms a lake known as a tarn/corrie/cirque lake. Examples on Mt. Kenya include Hidden, Teleki and Nanyuki tarns.
(b) Moraine dammed lakes: -moraine refers to the materials/debris carried down by glacial erosion. When carried downhill and finally deposited by a glacier, it may form a dam in front of the eroded hollow. When ice within the glacier melts, the water accumulates in this blocked/dammed hollow to form a lake. Examples are lakes Ellice, Tydall and Alice on Mt. Kenya
(c) Ribbon lakes: – are found in hollows that have been removed by glacial erosion. They are formed due to depression caused by load of glacier. Examples include Lake Sacred (Mt. Kenya – Meru)
(d) Kettle lakes: – these are circular hollows/depression filled with water in glaciated areas due to previous presence of large masses of detached ice that have progressively melted. Example is Lake Mahoma in Ruwenzori Mountains – Uganda
Lakes formed by deposition
– Include ox bow lakes and lagoons
(a) Ox bow Lakes: – these develop at the mature/old stage of a river. The river develops pronounced meanders and the deposited materials may block the course of the old river channel to form an ox bow lake. Examples include lakes Shakababo, Bilisa and Gambi on Lower Tana, Kanyaboli in R. Yala
(b) Lagoon: – formed by ocean waves that result into the formation of sand bars. These materials carried in a wave may enclose lagoons that are periodically submerged by water from sea or lake. Example is Lake Sare on the mouth of R. Yala
Lakes formed by solution
– These are found in areas characterized by limestone/chalk rocks. The earth’s crust is dissolved leading to formation of sink holes that may be covered with water when it rains. Example is the Etosha Pan (Namibia)
Lakes formed by erosion
– Are found in ASALs through deflation and abrasion processes. This leads to formation of a deflation hollow. If a deflation hollow is deepened by eddy currents up to the point where it reaches water bearing rocks/table, water may seep into the depression from below to form in to a lake. Example Qattara Depression between Libya and Egypt
Human made lakes
– Are formed as a result of construction of a dam upstream along a river channel.
– Water accumulates behind such dams to form a lake e.g. 7 forks dams on R. Tana, Volta (Ghana), Caborra Bassa (Mozambique), Kainji (R. Niger).
Significance of Lakes
Lakes provide water for domestic and industrial use.
Fresh water lakes provide water for irrigation farming e.g. L. Naivasha supports the horticultural farming in the area.
Some lakes are sources of valuable minerals which are exploited to generate income e.g. Trona mining in Lake Magadi.
Human made lakes are harnessed to generate hydro-electric power.
Lakes provide natural water ways thus facilitating water transport e.g. lake Victoria
Sand harvested from the shores is used in construction industry.
Lakes attract tourists and encourage water sports hence source of foreign revenue e.g. hot springs of Lake Bogoria.
Source of fish, thus providing food/alternative source of protein
Modify the climatic conditions of their immediate surrounding through land and sea breezes, increased rainfall etc
Lakes may harbor diseases causing pests and micro-organisms.
Seasonal flooding of the low lying lake basin displace people
Lakes are barriers to road and railway transport.
Oceans, Seas and their Coasts
Definitions
Ocean: – vast bodies of saline/salty water on the earth’s surface that surrounds the land or continent
– Examples are Pacific, Atlantic, Indian and Arctic oceans
Definitions of Seas
Large salty water bodies surrounded by land/saline but lack connection with the oceans e.g. Caspian Sea, Aral Sea, Dead Sea. They lack an outlet to the ocean
Large salty water bodies joined to/separated from the oceans through a submerged rock sill/strait e.g. Mediterranean Sea (connected to the Atlantic Ocean through a strait – Gilbatar). Others are Red, Black and Baltic seas
Smaller divisions of oceans aka marginal seas i.e. are at the margins of the four oceans e.g. Caribbean Sea, Arabian Sea, North China Sea, etc.
Distinctions between seas and oceans
Similarities
Both contain saline water
Their waters are in constant motion due to waves
Differences
Oceans are affected by tides whereas seas are not affected by tides other than marginal seas.
Oceans have strong ocean currents whereas seas have well developed land and sea breezes
Oceans surround continents/vast lands while seas are surrounded by vast lands/continents other than marginal seas
Sunlit eastern coasts of oceans lead to corals formation whereas seas experience/lack coral formation whether sunlit or not
Nature of Ocean Water
– The nature of ocean water has the following aspects: –
Saline Water
Temperature of Ocean water
Ocean topography
Ocean life
Ocean pollution
a.) Saline water
– Source of ocean water mineral salts are mainly;
The ocean water dissolves soluble mineral salts from the rocks forming the ocean bed.
A lot of salt is added to the oceans from rivers, springs which flow over soluble rocks
Volcanic eruptions in the ocean bed also generate huge amounts of soluble minerals salts.
Note
Isohalines – are lines drawn on a map to show places with the same salinity in the ocean.
Factors influencing salinity of oceans water
Latitude
– This affects the salinity of the surface water. The salinity is lower at the Equator than at the poles. The greatest salinity is around 300N because of higher temperature causing evaporation.
– Salinity is low in temperate oceans due to low evaporation rates and melting ice being added.
– It decreases towards the equator because of heavier rainfall and less evaporation due to high humidity and more cloud cover.
Depth
The surface water is generally more saline compared to the bottom water.
Amount of fresh water
The amount of fresh water added into the ocean
The position of the inland water
Seas located in regions of high temperatures have higher evaporation rates hence the water is more saline.
Mixing of surface water and water below the surface makes the level of salt in the water to be fairly constant.
b.) Ocean Temperature
– Ocean water temperature is not uniform i.e. it varies depending on the following factors;
Latitudinal position of the oceans.(oceans found in higher latitudes experience lower temperature) Depth – temperature decreases from surface to bottom.
Mixing/ upwelling of surface and deep waters.
Generally ocean water temperature increases with depth except in the poles
c.) Ocean Topography
– Ocean topography is composed of various features such as continental shelf, continental slope, abyssal/deep sea plain, oceanic island, mid ocean ridges and sea scarps
Continental Shelf
– This is the relatively flat part of the continent which is covered by ocean water.
– It’s characterized by the following;
It is shallow (about 180m deep) and gently sloping.
Width varies between 120 – 160 km between places.
Some have islands formed by marine erosion and coral reefs.
Contains depositional materials brought in by rivers and spread out by currents
Continental Slope
– This is the steeply dipping surface between the outer edge of the continental shelf and the ocean basin
Abyssal/deep Sea plain
– This is the flat and almost level area of the ocean where mud/sediments from the continental shelf and continental slope are deposited
– These plains, which generally extend from the continental slope rise to the mid-oceanic ridges.
– They are the deepest parts of the ocean, with the exception of deep-sea trenches
Mid Ocean ridges and Sea scarps
– These are found within the ocean waters where they are submerged with various heights formed through volcanic and seismic activities.
– Those formed through faulting are called sea scarps
The islands
– Island, any comparatively small body of land completely surrounded by water
– There are three types of oceanic islands.
(i) Continental island: – these rise from the continental shelf and are structurally similar to the neighboring continental land mass. They form as a result of submergence of upland coasts due to isostatic or climatic changes. Examples; Pemba, Lamu, Zanzibar, Malagasy, Sri Lanka, Indonesian and Philippine islands, Newfoundland and British Isles
(ii) Volcanic islands: – These rise from the deep sea floor. Volcanic eruption within the sea builds up islands where the materials pile up above sea level e.g. the Canary Islands, Cape Verde, Seychelles.
(iii) Coral islands: May be found both on the continental shelf and in the deep seas. Accumulation of coral into reefs becomes coral islands e.g. Bermudas (Atlantic), Aldabra and Maldives (Indian Ocean)
N/B
Islands may also from in the following.
(i) As the coastline retreats due to marine erosion resistant rocks are isolated as islands
(ii) Deposition of materials across bays, river mouths and lagoons build up barriers/ islands which project above the water level.
Deep Sea Trenches
– These are narrow deep sided sub marine valleys on the ocean floor.
– They occur when the ocean crust is destroyed and where the ocean plate melts by sliding under the adjacent mantle
– They are associated with guyots and seamounts
– Guyots are submerged atolls forming an underwater mountain with a flat top within the ocean water
– Seamounts are volcanoes that do not rise above the sea level.
Movement of Water in the Oceans
– Ocean water is not static i.e. moves vertically and horizontally covering many kilometres and great depths
– Only a portion of ocean water is involved in these movements (not the whole mass)
Vertical movements
– This is the rising of water from the ocean bottom to replace the sinking water from the ocean surface.
– It’s caused by,
Difference in the density of ocean water.
Density of ocean water depends mainly on temperature and salinity. Density is lower within the tropics where water is heated and is denser in the temperate and polar lands.
In the poles the cold denser surface water tends to sink after which it moves horizontally towards the equator at low depths. While the less dense water of the tropics tends to move to the poles through the action of winds. The cooler water below rises to take its place.
When a mass of ocean water with a high salinity meets another mass of low salinity, the more saline water sinks below the less saline water because it is denser.
ii. Convergence of oceans currents.
– Upwelling water can also form at a meeting point of two converging masses of surface water. Upon converging sinking occurs. At the lower depths the sinking water diverges after which it moves horizontally.
Horizontal movements
These are movements of water across the ocean waters. It occurs in three ways namely Ocean currents, Waves and Tides.
Ocean Currents
– An ocean current is a mass of surface ocean water which covers a considerable distance and depth and which is moving in a distinct direction.
– Ocean currents are caused by: –
(a) Winds: – as the prevailing winds blow, they encounter friction with the surface ocean water causing the water to move in the direction of the wind. Ocean currents resulting from movement of winds are called drift currents e.g. the North Atlantic drift current caused by the westerlies
(b) Rotation of the earth: – affects the direction of winds and that of ocean currents. In the northern and southern hemispheres, winds and ocean currents are deflected to the right and left respectively. This phenomenon is called coriolis effectwhich causes a body in motion to be deflected from its initial path due to earth’s rotation
(c) Shape of the landmass: – When an ocean current flows from the ocean towards a land mass, it changes its direction and follows the outline of the coastline. In some cases a current may be split into two when it meets a land mass e.g. South equatorial current split by Madagascar Island. Where an ocean current flows through a constriction between land masses, its velocity increases on leaving the area of constriction. Such a current is referred to as a stream current e.g. the Gulf stream
(d) Differences in water temperature and density: – the warm less dense water in the tropics tends to move pole wards while the polar cold and denser water sinks and moves equator wards where it rises to replace the tropical water.
Characteristics of major ocean currents
Generally the ocean currents flowing from the equator/low latitude areas towards the poles are warmer.
Ocean currents which flow from the poles/high latitude areas towards the equator are cooler/cold.
Ocean currents which flow in the Northern hemisphere generally move in a clockwise direction while the ones flowing in the Southern hemisphere move anticlockwise.
The warm ocean currents are found on the eastern coasts of continents, while the cold ocean currents are found on the western coasts of continents.
Convergence of ocean currents tends to occur on the eastern coasts while divergence tends to occur on the western coasts of continents.
Ocean currents are less developed in the northern part of Indian Ocean because the monsoon winds interfere with the smooth flow.
Distribution of ocean currents in the world
Tides
– Tides are the periodic rise and fall in the level of the sea and other large water bodies.
– All water bodies are held onto the earth by the force of gravity.
– The moon and to some extent the sun, also exert their gravitational pull on the earth including its water bodies. This results in the bulging of water.
Causes of tides
a.) Rotation of the earth
– Rotation of the earth brings any point on the earth’s water surface under the influence of two high and two low tides during the lunar day i.e. time taken by the earth in revolve once in respect to the moon.
– At high tide the level of water rises and covers most of the beach while at low tide the level of water falls and waves can be seen breaking a distance away on the sea ward end.
– The difference in height between the high water level and the low water level is called tidal range.
b.) The influence of the moon and the sun
– The moon has a strong gravitational pull on the earth. As it does so, the water on the earth’s surface which faces the moon bulges resulting in a high tide on that side of the earth.
– At the same time the earth is also pulled towards the moon, the water on the opposite of the earth also piles to form a high tide.
– While this is happening the water on the sides around the earth is drawn away resulting in low tides
Types of tides
(a) Spring tides
– Occur when the sun, moon and the earth are in a straight line- a position called syzygy.
– The tide producing forces are very strong resulting in the highest high tide and the lowest low tides
– This happens twice a month when the moon lies between the earth of the sun and at full moon when the earth is lying between the moon and the sun.
– The forces causing the tides to occur are strongest when the moon and the sun are pulling in the same direction.
(b) Neap tides
– Occur when the moon, sun and earth are at quadrature i.e. such that they form a right angle with the earth at the right angle apex.
– This position is reached twice in a lunar month (the time between one new moon and the next, a period of about 29.5days/the time the moon takes to make one complete orbit of the earth) and at half moon.
– At this position, the moon and the sun exert their gravitational pull on the earth in opposition to each other.
– This results in the high tide being lower than normal and the low tide not as low as expected
(c) Perigean tides
– Occur when the moon is at its nearest point to the earth, a point known as perigee.
– At this position the moon’s tide producing effect is greatest and results in high tide which are 20% higher than normal of so is the tidal range
(d) Apogean tides
– Occur when the moon is at its farthest point from the earth, a point known as apogee.
– Its influence is weakest resulting in high tides which are lower than normal and so is the tidal range.
Waves
– A wave is a ridge of moving water which is caused by oscillation of water particles.
– As the wind blows over the water, there is frictional drag between the bottom layer of wind and the surface water.
– The frictional drag is transmitted into layers above and surface water begins to oscillate as waves.
– Waves form over open water bodies
– The distance of open water over which the wind blows is called a fetch
– The size of a wave is determined by: –
The strength/speed of wind
Wind regularity and duration
The fetch over which the wind blows
Breaking of a wave
– As the wave nears the shore, the depth of water decreases causing the wave to break
– After a wave has broken some water moves forward to the beach, this movement is termed as the swash.
– The water then moves backwards to the sea due to gravity. This movement is known as the backwash.
– Some of the water may be pushed back to the shore by the next breaking wave while the rest flow at the bottom back into the sea in water current called the undertow
Types of waves
(a) Constructive waves: -have a stronger swash than the backwash hence responsible for building features such as beaches, sandbars through deposition.
(b) Destructive waves: -these have a weaker swash and a stronger backwash hence responsible for destruction or modification of the existing coastal features through erosion
Wave action and resultant features
– Involves erosion, transportation and deposition
Wave Erosion
– Erosion by waves occurs through the processes of hydraulic action, solution, corrasion and attrition
(a) Hydraulic action
This is the action caused by the force of moving water. The force causes the water to remove loose materials from the coastline
It takes place through the following ways
Compressed air action: – The force of breaking waves compress air in the cracks/joints on the cliff face thus increases its pressure. Due to the increased pressure the cracks widen. As the wave retreats, the pressure is suddenly released causing the trapped air to suddenly expand. This causes the rocks to fracture further and the cracks to enlarge. The process of alternate compression and expansion of air is repeated over a period of time causing the cliff face to shatter. The backwash then carries away the broken rock particles towards to sea.
Direct wave action: – In a breaking wave, large amounts of water crush against the rock face shattering the rocks
(b) Solution
This occurs when the rocks that make the cliff-face and the bed of the shore is soluble in sea/ocean water e.g. limestone, it is dissolved by the chemical reaction of water.
(c) Corrasion
The rock fragments carried by the waves are used as erosive tools as the waves break against the cliff face. These materials are hurled against the foot and face of a cliff causing the rock to break up/undercut.
As the waves retreat, the fragments are dragged back into the water by the back wash. The materials scratch the ocean floor.
(d) Attrition
As the pebbles, boulders and rock fragments are dragged up and down the shore by the swash, they continuously hit against each other and against the cliff.
In this way they gradually break up and become smaller in size.
This process does not contribute to the wearing away of the coast but provides erosive tools to be used to abrade the cliff and sea floor
Factors influencing wave erosion
– Availability and nature of marine load.
– Nature of the rock bordering the sea: – if resistant, less wave erosion
– The strength of the wave: – stronger waves lead to more erosion
– The gradient of the shore: – erosion is more dominant on steeply sloping shores
Features resulting from wave erosion
– These include cliffs, wave cut platforms, caves, blowholes, geos, arches, stumps, and stack.
Cliff
– This is a steep rock face which borders the sea. It may be vertical or nearly vertical
– The breaking waves attack the steep coast through hydraulic action and abrasion creating a notch at the position where they break at high tide.
– Continued wave attack makes the notch to be more pronounced and wider. Meanwhile the upper part of the rock face where waves do not reach is attacked by agents of weathering forming an overhanging cliff.
– Continued undercutting by breaking waves may cause the overhanging cliff to collapse leaving a steep rock face bordering the sea called a cliff.
Wave Cut Platform
– This is a flat part of the shore which is formed by wave erosion as the cliff line retreats inland.
– The process of cliff formation may continue and the cliff line retreated inland forming a fairly flat part of the shore
– The initial stage is a smooth sloping land surface. Undercutting begins at the base of the cliff at about high tide level forming a notch.
– The notch is enlarged by wave erosion which produces undercutting. The overhanging cliff is formed and eventually collapses due to gravity. A new cliff face results and provides a fresh starting point for undercutting.
– The process is repeated over a period of time, the cliff line retreats leaving behind a rock surface floor known as a wave cut plat form.
Cave
– This is a natural cylindrical tunnel-like chamber extending inland into a cliff or into the side of a headland.
– It mainly forms at the base of a cliff. Abrasion and hydraulic force enlarge initial hollow/ line of weakness in the coastal rock especially along joints and bedding planes
– Corrosion/direct dissolving act on the base of the cliff enlarges the hollow which extends inwards into the cliff. This process continues until the hollow is transformed into a cylindrical chamber called a cave
– They are common along the Kenyan coast at Watamu, Shimoni and Funzi Bay
Blowhole
– On the leeward side of a cliff, a near vertical hole may form with its bottom open to the roof of the cave
– Wave erosion acts on a line of weakness at the back part of the roof of a sea cave. At the same time weathering especially by solution acts on the line of weakness from the surface downwards
– Eventually a vertical shaft/hole which connects the surface to the cave below is formed called a blowhole
Geo
– During the high tide as the breaking wave splash against cliff face, a spray of water emerges through the blowhole
– When the roof of the cave collapses, a narrow inlet is formed called a geo
Arch
– Caves may develop on both sides of a head land or a single case may extend right through the headland to the other side forming an opening called an arch
Stack
– Continued erosion may enlarge the arch until its roof collapses leaving a pillar of rock standing on the seaward side of the cliff line called a stack.
Stump
– Continued erosion of the stack gradually reduces its height to a point where it becomes submerged during high tide and becomes visible as a remnant of a stack only during low tide such a feature is called a stump.
Wave Transportation
– The load transported by waves is acquired from the following sources,
Materials brought in by rivers and wind.
Materials that are products of mass wasting along the coast
Products of erosion and weathering along the coast
Volcanic debris resulting from volcanic eruption in the sea or on the coast
The Long shore Drift
– If waves break obliquely to the shore, the swash will push the materials up the shore obliquely while the backwash will drag them back at right angle to the shore.
– These two actions are responsible for the progressive dragging of materials along the shore.
– Some of the materials are moved into the deeper waters by the undertow
Factors influencing transport of materials along the coast.
Strength of a wave – Strong waves can carry large quantities and varieties of load over a long distance. Weak waves can only move materials over short distances along the shore.
Tides – When a tide occurs it extends the area under the influence of waves further up the beach.
As the tide rises, the tidal current brings materials from the water to the land. These materials are also deposited further up on the beach.
Ocean currents – the movement of ocean currents is responsible for the movement of materials from one part of the ocean to another and eventually onto the beach.
Gradient of the shore – On gentle coasts, transportation of materials by longshore drift is favored especially where waves approach the coast at an oblique angle. When the waves break, the swash and the backwash drag materials along the beach. Conversely, as waves break on the cliffs along steep coasts, the materials they carry bounce off the cliff and remain floating in the water.
Orientation of the coastline.Where the coastline is aligned obliquely to the direction of breaking waves, transportation of materials by long shore drift is favored. Where the coastline lies transversely to the path of the waves, the waves move the materials back and forth on the beach along the same line.
Nature of the load.Very heavy materials boulders are not transported by waves. After breaking from the cliff, they drop directly below on to the seabed while lighter load such as sand are carried over long distances.
Wave Deposition
– Waves sort out their load during deposition i.e. boulders are deposited at the furthest end on the land side followed by pebbles then sand and finally mud which is dropped nearest to the water.
– Boulders are swept towards the land by powerful swash during high tide. The weak back wash brings back the lighter load towards the sea.
Factors influencing wave deposition.
The nature of the waves – for deposition to take place, the breaking waves must have a strong swash and a weak backwash. Waves should also break at a low frequency to allow materials to settle.
Gradient of the shore- a shore with a gentle gradient reduces the velocity of the backwash thus causing the waves to start depositing their load.
Configuration of the coastline: – this is in relation to the path of prevailing winds and the direction of advancing waves. Where the coastline changes direction abruptly, the longshore drift is halted and the transported material is deposited there
Depth of the water- deposition is great where the water is shallow since cyclic motion of waves is broken as the waves come into contact with the floor of the sea.
Features resulting from wave deposition
(i) Beach
– A beach is a gently sloping mass of accumulated materials such as sand, shingle, pebbles and boulders along the coast
– They are formed by constructive waves especially during calm weather when the backwash is at its weakest
– This results in the accumulation of materials at the shore
Conditions for formation of beaches include:
They form where the land slopes gently into the sea at the head of bays.
The waves must be constructive
Requires relatively calm weather
The waves should carry large quantities of load ( sand, shingle)
Occurrence of low and high tides
vi.) Presence of boulders, sand and coral fragments
– Examples of beaches along the Kenyan coast are Diani, Nyali, Bamburi, Shanzu, Silver Sands, Watamu and Malindi
– Several smaller features may develop on the beaches. These include beach ridges, berms, beach cusps and beach rock shells
(a) Beach Ridges: – are low ridges of coarse sand, boulders and shingle deposited along a regular coast and are roughly parallel to the shore line. They are constructed by breaking waves. They develop on the foreshore of a beach and are only visible during the low tide
(b) Berms: – is a ridge or bench/terrace of shingle that has been thrown up to the beach by storm waves. They appear like a platform with a steep front facing the sea
(c) Beach Cusps: – are projections of sand and shingle alternating with rounded depressions along the beach
Beach Rock Shells: – comprises of sand, shells and pebbles that have been cemented together by calcium carbonate forming projections above the sand on the beach.
(ii) Spit
– This is a low lying ridge of sand, shingles and pebbles with one end attached to the coast and the other end projecting into the sea
– It forms at a point where the coastline changes its direction towards the land e.g. across a river estuary or at the entrance to a bay
– They develop when the movement of materials by the long shore drift is halted and the material piled up/deposited in the sea/ocean water.
– This continues until they bulge out with the accumulation growing towards the sea
Conditions necessary for formation of a sand spit.
Presence of ample materials to be deposited.
A weak longshore drift.
An indented coastline/presence of a headland.
A shallow continental shelf
A relatively weak backwash.
(iii) Tombolo
– This is a bar that links the mainland to an offshore island
– It starts as a spit then grows out into the sea until it joins and island into the sea
– An e.g. in Kenya is at Ngomeni (north of Malindi)
(iv)Bars
– A ridge of sand, mud, shingle or a mixture of these materials deposited by waves in the shallow water at the coast
– There are two types of bars namely bay bars and offshore bars
(a) Bay Bars: – forms when a spit grows completely across a bay or sea inlet. It encloses a section of water on the landward side to form a lagoon
(b) Offshore Bars: – Along very shallow coastline, waves are forced to break off-shore hence deposit its load at the point of breaking. The materials accumulate and form a ridge of sand running parallel to the shore. The bar may enclose a shallow lagoon with the main land.
(v) Cuspate Foreland
– This is a broad triangular shaped deposit of sand or shingle projecting from the main land into the sea
– It is formed by two spits converging towards each other at an angle. This is due seasonal changes in the direction of winds that cause a change in the way the waves approach the shore
– Continued deposition makes it wider as more materials are added to form beach ridges.
– Eventually the lows are filled with water to form shallow lagoons
(vi) Mudflats & Salt marshes
– Mudflats are formed when fine silt is deposited on the sheltered part of the foreland.
– Their development is assisted by alluvium carried seawards by rivers.
– When vegetation grows and spreads on the mudflats, a salt marsh is formed
(iv)Dune belts
– These comprises of fine sand that is carried further and deposited above the high tide level forming coastal sand dunes
Types of Coasts
Definitions
Coast: – this is the zone of contact between the land and the sea or ocean
Shore: – The land along the edge of the sea. Such land lies between the lowest point and the highest point reached by the waves.
Coastline: – This is the line where the highest wave reaches the land. On rocky/highland coasts it’s called the cliff-line.
Shore line: – This is the line where the shore and the water meet.
– The various types of coasts form as a result of certain factors responsible for coastal evolution. These factors influence the shape and character of coastlines as well as coastal land forms.
– Coasts can be concordant or discordant.
– Concordant (regular/longitudinal) coasts lie parallel to the great trend line of the land e.g. the coast of Kenya between Malindi and Lamu. They lie parallel to the prevailing winds hence are dry.
– Discordant (irregular/traverse) coasts lie at right angle to the prevailing winds e.g. the coast of Mombasa.
Factors influencing the type of coast existing in a given area
Action of waves and tidal currents.
– Waves are agents of erosion, transportation and deposition by the sea. Where erosion is dominant the coast is characterized by features of wave erosion. On the other hand, where deposition takes place, the coast will have accumulation of deposited materials.
– Tides influence the area of the shore exposed to wave action. Coasts with large tidal ranges haves more surface area over which waves can operate.
Nature of the coastal rocks.
– Along a coast made of resistant rocks, wave erosion is minimal forming a highland coast characterized by steep resistant cliffs.
– If the coastal rocks offer little resistance to erosion then wave erosion will be intense resulting in the formation of sea inlets such as bays.
– Where rocks are soluble (e.g. limestone) they are easily eroded through solution process forming caves.
Orientation of the coastline to the path of prevailing winds.
– When the coast lies across the path of prevailing winds, the waves will be breaking transversely as well. Marine erosion is therefore very intense on such a coast.
– Where waves break almost parallel to the coastline, transportation and eventual deposition of materials will be more pronounced than erosion.
Climate
– Coral coasts develop in the tropical regions along the warm seas.
– Fiord coasts exist in coastal uplands that experienced glacial erosion.
– Climate also influences the weathering of coastal rocks; weakening them hence wave erosion is more effective.
Changes in sea level
– A rise in the level of the sea results in coast submergence forming features such as fiords, rias, and straits. Submergence of lowland coasts may result in estuaries and broader continental shelf.
– Alternatively a fall in sea level exposes the coastal feature such as coral reefs.
Human activities
– For example as construction of canals and harbours influence the shape and character of a coastline.
– Coasts are divided into submerged, emerged and coral coasts
Submerged Coasts
– Form when part of the coastal land is drowned by sea water due to changes in base level or relative rise in the sea level.
– Submergence can be due to
Subsidence of the coastal region as a result of local faulting or folding along the coast
Subsidence of the coastal land could also be due to the ocean bed rising due to isostatic movements
A positive change in the sea level due to increased rainfall or melting of ice sheets and glaciers may cause a rise in the sea level which eventually drowns the adjacent coastal land.
– They are further divided into submerged lowland and submerged upland coasts
(a) Submerged lowland coasts
– These are characterized by gentle slopes. Upon submergence water covers extensive areas of land. River mouths and sizeable section of their upstream valleys are drowned to form estuaries which are much wider and shallower
– Submergence of lowlands results in the broadening of the continental shelf.
– Along glaciated rocky lowland coasts, fjards form. These are sea inlets resulting from the submergence of glaciated coasts. They are deeper then rias but have lower shores and broader profiles than fiords.
Submerged upland coasts
– These are places where land slopes steeply into the sea. When such an upland area is submerged a number of features are formed
– They are classified into rias, fiords and dalmatian coasts
(i) Rias: – form from the submergence of a river mouth in the upland coast. It’s funnel shaped and deeper on the sea ward end but becomes shallower and narrower further inland. The drowned river mouth is called an estuary while the interlocking spurs project into the sea as headlands/promontories e.g. Kilindini. They are suitable sites for harbours because they are deep and well sheltered
(ii) Fiords/fjords: – are submerged glacial troughs found in the upland areas lying adjacent to the coastline. They form inlets which are shallower at the sea ward end but deeper inland. The shallowness is caused by the deposition of terminal moraine. They are common on the coasts of Scandinavian countries
(iii) Dalmatian/Longitudinal coasts: – form when mountains lie parallel to the coast. They form during submergence of these mountains to form long sounds (a passage, channel of water in between an island and mainland) with parallel islands. They are straight and regular
b.) Emerged Coasts
– A coast may emerge from the sea when part of the land which was formerly under water becomes permanently exposed.
– Emergence could also be due a change in the level of the sea in relation to the land caused by;
Negative change in the sea level due to a reduction in sea water as a result of incomplete hydrological cycle when glaciers hold up water instead of releasing it to the sea.
Uplift in the coastal land due to upward displacement by faulting. Tectonic movements may cause up warping.
Isostatic adjustment can also cause the coastal land to rise
– Emerged coasts can either be upland or lowland coasts
Emerged upland Coast– result from high lands adjacent to coasts. They are characterized by;
Raised beaches – found on land that is far away from the present edge of the water and standing above the present shoreline.
Raised wave cut platforms.
Exposed notches on the raised cliffs: – these are V shaped cuts formed due to undercutting of a cliff during high tides on an emerged coast
Emerged lowland coast– These are constructed from emergence of gently sloping/low lying coasts. They are characterized by;
Fall line is a point where rivers flowing into the ocean descend through waterfalls and rapids from the edge of the plateau into the emerged lowland coast.
Gentle coastal plains: – the original coast is raised to form a gentle or almost flat plain
c.) Coral Coasts
– Coral is a limestone rock called coralline limestone. It comprises of remains of tiny marine organisms called polyps
– Coral polyps (tiny marine organisms) extract calcium from the sea water to form exoskeleton. These organisms live in colonies and attach themselves onto rocks and to one another. When they die, their shells are cemented by algae to form a ridge – like rock which is parallel to the shore.
– Coral coasts are majorly found in the tropical lands and can extend as far as 300 north and south of the equator
Conditions favoring the growth of polyps
– Optimum temperature 250C -290C and should never fall below 200C for proper growth. This explains why coral coasts are generally found on the eastern side of land masses in the tropical regions.
– The polyps must be submerged but may be exposed during low tide only for a short period of time.
– The water must be clear and salty hence corals are not found at river mouths due to presence of silt and mud. The saltiness is also diluted. Clear water allows sunlight to penetrate.
– The waters must be shallow. Most polyps thrive at a depth of less than 10m and others up to 60m
– The absence of moving wave and tidal load. Sand is destructive to growing polyps because; it smoothens young coral and provides a loose base for the coral to grow.
N/B: Corals do not grow in polar areas due to the following reasons
Low water temperatures
Sea water of low salinity
Presence of cold ocean currents
Presence of deep submerged upland coasts
Coral Reefs
– A mass of coral is called a reef.
– Coral reefs are narrow ridges of coral rocks found at or near the surface of the sea/ocean. They are nearly parallel to the shoreline
– Coral reefs are divided into fringing reefs, barrier reefs and atolls
(a) Fringing Reefs
– This is a platform of coral which forms when coral polyps start building a reef near the shore.
– The reef extends seawards where the building is faster because there is more food and the water is clearer.
– As the reef builds seawards, it encloses a shallow lagoon with the coast.
(b) Barrier Reefs
– This resembles a fringing reef except that it is formed a long distance away from the shore.
– It is separated from the shore by a wide and deep lagoon.
– A barrier reef may form parallel to the mainland or as a ring around an island.
(c) Atolls
– These are coral reefs which are roughly circular in shape enclosing a fairly deep lagoon. They form islands
– They are found in mid oceans especially in the west and central Pacific
– They are thought to have formed due to sinking and rising of the sea level
– The rings of corals that grew around the islands were subjected to slow and gradual submergence
– As the island sunk as a result of rising sea level, the polyps continued to deposit their skeletons, the reef sustained itself through upward growth
– Because of the fact that they are found in deep oceans where their base is too deep for polyps to survive, a number of theories have been advanced to explain their origin
Darwin’s Theory
– Suggests that both barrier reefs and atolls form from fringing reef which develops around an oceanic island
– The oceanic island begins to subside; the fringing reef becomes larger and grows upwards to keep pace with the rising level of the sea.
– The seawards growth is more vigorous as there is more food and the water is clearer. The fringing reef transforms into a barrier reef that extends a great distance away from the island enclosing a deep lagoon.
– If the island continues to subside, it may reach a stage when the whole of it is completely submerged. The barrier reef then forms a ring of coral reefs called. Atolls.
Daly’s Theory
– This suggests that formation of atolls is a based on the positive changes in the sea level and not subsidence of the sea floor
– During the pre-glacial period, prevailing warm conditions favored the growth of polyps around an island.
– In the glacial period, temperatures were so low that growth of all pre- existing corals ceased. Water was held up in form of glaciers and ice sheets, the sea level experienced global fall.
– Consequently, coral islands were planed down by marine erosion to the sea level at that time.
– After the ice age, as temperatures begun to rise again, volumes of melt water was released in the oceans resulting in a global rise in the sea level.
– The higher temperature allowed the growth of coral reefs which grew faster upwards and sea wards to keep pace with the rising sea level. The reefs enclosed a deep lagoon
Murray’s Theory
– The formation of the barrier reef doesn’t involve subsidence; it starts as a fringing reef that gradually grows outwards.
– Breaking waves then disintegrate the fringing reef , the debris of which accumulate on its seaward side
– The deposited material eventually forms the base for the growth of polyps
– On the seaward side, the corals grow more vigorously due to more exposure to food, on inner side; the corals are deprived of food and die.
– Dissolved dead corals on the inner side deepens the lagoon
Significance of oceans, coasts and coastal features
Oceans
– Presence of oceans modifies climatic conditions of an area through land and sea breezes.
– Oceans provide rich grounds for subsistence and commercial fishing.
– Ocean tides and waves can be harnessed to produce tidal power.
– Oceans are natural habit for marine life/ Biodiversity conservation.
– Provides cheap free water ways to transport goods and services across continents.
– Oceans provide sites for a variety of recreational activities e.g. water skiing, cruising sport fishing and tourism.
– Oceans provide grounds for navy/ military activities
– Valuable minerals such as oil, natural gas are sometimes extracted from rocks that lie beneath the oceans.
– Sea water can be distilled to provide fresh water
– Provide grounds for scientific/ educational research
Coastal landforms
– Coral rocks are mined and used to manufacture cement
– Emerged coastal plains provide land for settlement
– Many coastal features- sandy beaches, coral reefs, caves, and cliffs attract tourists.
– Coral rocks are used as building materials
– Port development – submerged coasts (fiords, Rias) favour the development of deep and well sheltered natural harbors.
Action of Wind and Water in Arid Areas
Introduction
– Arid areas are lands that receive insufficient rainfall, usually less than 250mm per annum. They have little or lack vegetation covers due to moisture deficiency
– Aridity is common in desert areas
– Deserts are named according to the nature of their surfaces into
(a) Sandy deserts: -covered by large deposits of sand; known as Erg in the Sahara
(b) Stony deserts: -are covered by angular pebbles, gravels and boulders; they are known as Reg in Algeria and Serir in Libya & Egypt.
(c) Rocky deserts: -are dominated by bare rock surfaces and are known as Hamada in the Sahara desert.
– Deserts can also be classified according to their latitudinal location and the temperatures they experience into
(a) Continental deserts
(b) West coast deserts
(c) Hot deserts
(d) Cold deserts
(a) Continental deserts
– These are located in the interior of continents or on the leeward sides of high mountains
– They can be hot or cold depending on their latitudinal location i.e. those on the tropics are hot e.g. Sahara (Africa) and Arabian while those in temperate/polar areas are cold e.g. Gobi (Central Asia), Greenland and Patagonian (South America)
(b) West Coast Deserts
– These are found on the western coasts of continents
– They are mainly characterized by offshore trade winds and cold ocean currents
– Examples include Atacama (South America), Namib (Africa) and Californian (USA)
Action of Wind in Arid Areas
– Wind action is more effective in the hot deserts e.g. Sahara compared to the cold deserts. This is due to the following factors
Presence of loose and unconsolidated dry masses of mud, sand and gravel that can be easily transported, eroded and deposited by wind
Occurrence of strong and tropical winds/storms within the hot deserts
Absence of vegetation cover
– Action of wind in arid areas involves erosion, transportation and deposition
Wind Erosion
– Wind erodes the desert surfaces through
(a) Abrasion
(b) Deflation
(c) Attrition
(a) Abrasion
– Weathered materials that are loose on the desert surface are picked by the wind and used to grind, scrape and polish the desert surface they come in contact with.
– The weathered materials knock against rock surface thereby polishing them.
(b) Deflation
– This involves the wind removing dry and unconsolidated material of dust and sand from the bare desert surface through rolling them on the ground and lifting them up in the air.
(C) Attrition
– This is the process where the sand grains are transported by wind collide against one another and wear each other down.
Resultant features of wind erosion in arid areas
Rock pedestals
– This is an irregular pillar of rock formed through wind abrasion in deserts/arid areas
– It forms when a mass of rock with alternating layer of resistant and less resistant (heterogeneous) rock lie horizontally in the path of wind ladened with weathered material
– The less resistant layers are heavily eroded by wind abrasion as the wind borne materials knock on them compared to the resistant rock layers that undergo little erosion
– This result in the formation of an irregular rock mass with protruding layers of resistant rocks alternating with layers of less resistant rocks called a rock pedestal or gour.
Mushroom blocks
– This is a massive rock with a broad smoothed and rounded top and a very narrow bottom.
– Forms from a homogenous rock of uniform hardness and resistance lie vertically in the path of wind ladened with weathered materials.
– Wind abrasion is more intensive at the base of the vertically laid rock mass.
– The top part of the rock undergoes slow, gradual polishing and smoothing (fewer airborne materials at this level).
– This differential abrasion results into a structure with a broad top but a very narrow base called a mushroom block
Zeugens
– A ridge and furrow landscape which is formed from a massive rock with alternating layers of resistant and less resistant rocks lying horizontally to one another and in the path of prevailing wind ladened with weathered materials.
– The top layer of hard rock is jointed/has cracks.
– Physical weathering assists in widening the joints/cracks on the upper layers of rock and causing the rock to disintegrate along the cracks/joints
– Prevailing winds then remove and carry the loose unconsolidated materials through deflation
– Abrasion continues to act on the lines of weakness, enlarging and deepening the furrows
– The less resistant rocks are eroded further leaving behind a hard standing tabular mass/ridge on either sides of the furrow called a zeugen
Yardangs
– These are elongated rock ridges of vertically laid rocks.
– They are formed when heterogeneous rocks lie vertically and to the path of prevailing wind ladened with weathered material
– Wind abrasion acts directly on the less resistant layers, removing and transporting the weathered materials by deflation.
– This results in the formation of large furrows in between the resistant rocks
– Continued abrasion in the furrows deepens them further leading to formation of high ridges (about 6m) called yardangs
Ventifacts
– These are boulders, stones or pebbles that are polished and sculptured through abrasion by windblown sand in the desert
Depression hollows
– Physical weathering and abrasion in deserts result in large scale production of unconsolidated materials of dust and sand particles.
– The loose materials are then scooped/removed by wind through deflation forming a shallow depression
– The basin is widened and deepened through continued wind abrasion and deflation forming a depression called deflation hollow.
– Wind eddies remove unconsolidated materials from the surface through deflation.
– Wind deflation, weathering and abrasion further enlarge and deepen the depression.
– The surface of the depression is lowered until it reaches the water bearing rocks/aquifer/water table.
– Water oozes out of the ground and collects in the depression to form Oasis.
Wind Transportation
– This depends on the following factors: –
Strength and speed of wind – strong winds transport more and heavier materials compared to a weak wind.
Obstacles – Intervening obstacles e.g. rock outcrops/desert vegetation on the path of a prevailing wind reduces its speed causing the wind to drop some of its load.
Nature of load – Light particles such as fine dust are easily picked up by wind and blown to far distances.
Vegetation cover/water mass – areas where the surface is covered by vegetation/ a water mass, the sand particles are bound together. This reduces the ability of wind to pick and transport these particles.
Periodic changes in weather – e.g. sudden short rains may interfere with transportation
– Wind transports its load through suspension, saltation and surface creep
(a) Suspension: – this involves the transportation of very fine particles e.g. dust that are held in the wind above the ground. They are lifted high/clear of the ground by air currents and carried to greater distances e.g. dust storms.
(b) Saltation: -this involves the movement of medium sized sand particles are lifted from the ground by eddy action then dropped on the ground by gravity. They are moved in a series of short hops or jumps along the desert surface
(c) Surface Creep: -is the movement of heavy unconsolidated large materials/small stones/pebbles are dragged along the ground by wind current
Wind Deposition
– When the speed/strength of wind is reduced, the rate of transportation is reduced, the wind therefore deposits its load
– The factors that influence the rate of wind deposition in arid areas include
Presence of intervening obstacles – checks the speed of wind forcing it to drop some load.
Nature of the desert surface – moist grounds impedes the transportation of materials close to the ground due to friction. The materials are dropped.
Strength and direction of wind – When the wind slackens, it begins to drop some of its load. Similarly when winds blowing from different directions meet, collision occurs resulting in some of the load being dropped.
Amount of load carried – Materials carried by overloaded wind constantly collide among themselves causing some of them to be dropped.
Variation in weather conditions – Moist conditions/showers lead to deposition of the load suspended in the air.
Resultant features of wind deposition
(a) Sand dunes
– This is a low ridge or hills of sand that have been accumulated and sorted by wind
– They mainly occur in the interior of deserts and along low lying coasts
– They are further classified into
Barchans.
It develops when sand particles accumulate around an obstacle that lies in the path of wind.
The obstacle causes the wind to deposit some of the sand by trapping it on the windward side to form a low hill/ridge.
Continued deposition makes the mound of sand to grow bigger and blow over to the leeward side.
Eddy currents on the leeward slopes lead to formation of a shallow depression and a concave slope.
Continuous accumulation and forward movement of sand on the windward slope and the effect of wind eddies on the leeward slopes results into the formation of a crescent shaped dune called a barchan
– Barchans may be found as individual or as a group of hills of sand
(ii) Seif Dunes
– These are sand dunes that area deposited parallel to each other by troughs. They are parallel to the path of prevailing wind
– As the prevailing winds blow between the dunes, it creates eddies that move sand towards the sides
– This lead to accumulation of sand on the sides of the dune. The dunes are lengthened/elongated by the prevailing winds to form long and narrow steep ridges called seif dunes.
More illustration
These are elements formed in desert areas which are long and parallel to reach other separated by roughs.
They are formed in areas where there are prevailing winds which are interrupted by strong cross-winds.
The cross-winds divide the sand side by side thus heading them into long parallel done which are separated from each other by trough.
The ridges of sand are then known as safe.
(iii) Transverse and wake dunes
– These are wave-like shaped sand dunes that are separated from one another by a flat bottomed trough.
– They are formed by light to moderate winds that blow from one direction.
– This leads to an accumulation of sand in a series of transverse ridges/dunes.
– If the sand dune forms on the leeward side of the larger dune trailing away in the direction of wind to form a wake dune
(b) Loess
– These are fine unconsolidated light colored dust that is blown by wind further away from their places of origin
– They form when desert sand and dust storms pick up loose dust materials, transport and deposit them in the neighboring wetter region
– Gradually they accumulate to form fertile soils with greater thickness called loess
(c) Draas
– These are similar to seif and transverse dunes only that they are higher compared to seif and transverse dunes (about 200m)
Action of water in arid areas
This produces the following features
(a) Wadis
– This is a deep sided dry valley in arid lands formed when flash floods occur on steep and undulating landscape
– They are formed by strong surface run offs/flash floods that cut small rills that later develop into gullies
– Continued erosion by the streams enlarge the gullies rapidly to produce steep sided valleys called wadis
(b) Bajadas/Bahadas
– This is a continuous gentle sloping fringe of angular scree, gravel and coarse sand around the margins of an inland basin in a desert landscape. They can also form along the base of a mountain range in semi arid areas
– They form when a series of alluvial fans unite/join/coalesce together at the point where the stream/river leaves a constricted/narrow valley
(c) Inselberg
– This is a steep isolated round topped mass of rock standing in an extensive flat area in arid areas
– It results from wind erosion and sheet wash that removes the weathered material to leave a mass resistant rock standing on its own to form an inselberg
(d) Mesas and buttes
– Mesas are extensive flat topped residual tablelands that are capped with resistant rock layers in ASALs
– Buttes are also flat topped hills capped with resistant rock layers which remain after denudation of a plateau in ASALs. They are less extensive compared to mesas
– Mesas and buttes are formed within plateaus comprising of resistant sedimentary rocks that are not easily eroded by sheet floods
– The less resistant surface layers of rocks undergo physical weathering and later removed by sheet floods until a horizontal layer of rock that protects the layers beneath from erosion is exposed/reached
– This results in residual hills with tabular shapes called Mesas
– Continued erosion reduces the mesas to buttes
(e) Pediment
– This is a gently sloping rock platform with bare or thin layer of deposited loose materials/debris stretching away from the foot of a ridge or mountain in ASALs
– They are formed through the following processes: –
When a slope retreats i.e. when progressive back wearing of soil profile occur in the course of weathering and erosion, the steep mountain/hill front then retreats forming a low angle slope known as pediment
Lateral planation by streams, sheet floods, rills and downwash resulting from rain storms
(f) Pediplain/Pediplane
– These are extensive low and sloping lands formed in ASALs when large scale adjacent pediments join up due to widespread surface water erosion in arid areas
– When pediments surround an original highland, the slopes at the edges of the highland continue to retreat all round forming extensive pediments
– Continued water erosion reduces the highlands to residual hills that are eventually eroded to form a continuous plane with many concave surface called pediplanes/pediplain
(g) Playas
– This is a basin of inland drainage that contains a shallow fluctuating lake that is usually saline
– They originate from wind deflation to form depressions in ASALs
– Water from torrential downpours in ASALs flow into the depression to form small fluctuating lakes called playas
(h) Salinas
– When playas dry up due to intense evaporation from high temperatures in arid areas, it leaves a hard salty crystal surface called salina/salar
(i) Dry river valleys
– During the short and wet season in arid areas, sheet and flash floods will collect in river valleys to form fast flowing streams.
– During the dry season, such river beds remain dry to form dry river valleys in ASALs
Significance of the resultant features of action of wind and water in arid areas
Sand harvested from desert surfaces is used in building and construction
Water from oases and pans provide water for irrigation and domestic uses
Desert landscape are ideal for military training and testing of weapons as well as experimental grounds for spacecrafts this is because they are sparsely settled
The unique desert features e.g. yardangs, rock pedestal attract tourists who in turn bring foreign exchange
Desert surfaces can be used for recreation such as the Dakar motor rally
Loess/alluvial deposits have fertile soils suitable for agriculture
Sand dunes are unstable and hinder establishment of infrastructure
Desert soil is infertile thus hinder agriculture
Action of Water in Limestone Areas.
Introduction
Underground/ground water refers to water that exists/derived below the surface of the earth.
It’s contained in the available air spaces, cracks and joints in the soil and in the rocks beneath the surface which are above an impermeable layer
Sources of underground water
Rainwater: – which infiltrates and percolates into the lower parts of rocks.
Melt water: – which infiltrates the ground and eventually percolates through the rocks
Lake and sea water: – may enter the ground by seepae and percolates through the rocks to become underground water.
Magmatic water – this is the water that gets trapped in the rocks beneath the surface during volcanism. It’s also called plutonic water.
Ways in which underground water may reach the surface of the earth
a) Through wells drilled into artesian basin.
b) Capillary action i.e. upward movement of water through the rocks by capillary. The rocks should be permeable i.e. they should have pores (porous) or have cracks/joints (pervious) e.g. limestone and chalk
c) Springs – occur in areas where saturated rock layer is exposed to the surface.
d) Through streams
Zones of underground water
Water table: – this is the upper surface of the zone of saturation of underground water in permeable rocks. Water table can be permanent or temporary. Permanent water table is the lower level reached during the dry season and is permanently saturated. Temporary water table refers to the highest level nearer to the surface reached during the rainy season
Zone of permanent saturation: – this is the region where all the rock pores/air spaces are permanently filled with water. It is also known as phreatic zone.
Zone of intermittent saturation: – here, the water content fluctuates according to season. During the rainy season, the rocks are saturated while in the dry period the layer is unsaturated.
Zone of non-saturation: – this is found immediately below the earth’s surface (permeable layer). It is where the water never remains in the pores for long to saturate the rocks. The top part of this zone is called the soil water belt.
Aquifer/aquafer: – this is the layer of permeable rock that can hold water in its mass and allow it to pass through
Factors influencing the existence of underground water
Much of groundwater originates from the surface of the earth. Occurrence of ground water thus depends on factors that influence the rate of infiltration such as;
Amount and nature of precipitation.
The amount of rainfall that infiltrates into the ground depends on the type, amount and intensity of the rainfall. Light rain which falls over a long period of time infiltrates longer compared to a heavy downpour which is short-lived hence saturates the surface thus blocking the passages through which water infiltrates. Also, areas with reliable rainfall have more underground water than those with unreliable rainfall.
Gradient of slope
Steep slopes reduce infiltration, as much water is lost through surface run-off while on gentle slopes, water remains longer on the ground allowing infiltration.
Amount of Vegetation cover
Presence of vegetation cover increases the rate of infiltration as they slow down the speed of surface run-off, holding water for a longer time. Bare surfaces increase surface run-off.
Nature of rocks
Permeable rocks allow water to enter and pass through them. The more the permeability of surface rocks, the higher the rate of infiltration. A permeable rock can be pervious or porous. Pervious rock is one with cracks, fractures, joints or fissures through which water enters and passes. Some rocks like clay and unjointed chalk are porous and allow water to enter them but don’t allow water to pass through them. This is because on absorbing water, clay particles expand thus narrowing the air spaces between them.
Level of saturation of the ground
Dry, porous soil allows much infiltration. While high amount of water in the soil reduce the rate of infiltration as the air spaces are filled up with water sealing off any further percolation.
Rate of evapotranspiration
A high rate of evapotranspiration that is caused by low moisture content in the atmosphere reduces the amount of water available for absorption into the soil.
The existence of underground water lead into the formation of the following:
Springs
– This is a point on the earth’s surface where underground water flows naturally onto the land surface.
– It occurs where the water table is exposed on the surface along a slope
– It can be permanent or intermittent
Springs occur in the following ways
a) Where a permeable rock overlies an impermeable rock. A spring occurs where the two rock layers meet the earth’s surface.
b) Where an aquifer lies on the upper side of a dyke which out-crops. A spring may form at the line where the dyke and the aquifer intersect.
c) At the foot of a steep scarp slope underlain by impermeable rock layers
d) Where there is well jointed rocks e.g. limestone are saturated to the level of the water table. The water guided by the joints flow out of the junction with impermeable rock and runs down the hill side as a spring. Such springs are called Vauclusian springs
Wells
– These are holes sunk/dug into permeable rock to reach the water table. Water from the underground seeps out of the water table
Artesian Basin and artesian wells
– Artesian basin is a layer on the earth’s crust in which one or more aquifers are enclosed above and below by an impermeable layer
– The whole system of rocks around the basin forms a broad syncline or depression with one or both ends of the permeable rock are exposed on the surface to allow rain water to percolate.
– If a well is sunk into the aquifer on an artesian basin, water will normally come to the surface by hydraulic pressure so long as the mouth of the well is below the water table.
– Such a well is called an Artesian well.
Ideal conditions for formation of artesian well
a.) The aquifer must outcrop in a region which is a source of water e.g. a rainy area or beneath a lake/must be exposed in an area of sufficient rainfall
b.) The aquifer must be sandwiched between impermeable rocks so that it can retain water.
c.) The aquifer must dip towards a region where the land surface is lower than it is at the exposed end of the previous formation
d.) The mouth of the well must be lower compared to the intake area to allow the water to be forced to the surface by pressure with no need of pumping.
– Examples of artesian basins are the London and Australian artesian basins
Problems associated with availability of underground water.
Over-exploitation due to population pressure. Reduced rainfall and polluted rivers make many people turn to groundwater thus reducing what is available.
Global warming has led to high evaporation rates. This has reduced underground water sources.
Pollution from agro-chemicals has led to a lot of chemicals in the water that percolates to the ground.
Destruction of water catchments areas interferes with hydrological cycle and reduced the amount of rainfall. Consequently, underground water has also been reduced.
Significance of underground water
Springs are sources of many rivers e.g. Yala that provides water for domestic, industrial and irrigations uses among others
Wells, springs, boreholes, oases, provide water for domestic and industrial uses e.g. Mzima Springs provide water to Mombasa Town.
Ground water provides water for irrigation farming e.g. cotton, bananas in Taveta grown using water from Mzima Springs.
A line of springs at the foot of an escarpment can attract settlements.
At the mouth of many hot springs, valuable minerals salts may be deposited and mined to earn revenue, create employment opportunities
(vi) In areas under volcanic influence, underground water is heated by hot magma to form geysers and hot springs that are sources of geothermal power and tourists attraction – earn foreign exchange
Action of Water in Limestone Areas and Resultant Features.
– Karst region is a limestone region where action of water has created unique features on the surface as well as underground.
– The resultant landscape is called karst scenery and it applies to any area of limestone landscape that has developed similar features to those of karst region
– The creation of these features is mainly due to the following two main reasons;
Limestone is highly impervious because of the clear joint bedding.
Limestone is soluble in ordinary river water and rain water.
Characteristics of a karst landscape
It has thin soils.
The landscape lacks surface drainage.
Has poor/scrub vegetation as well as some shrubs and grasses with stunted growth.
The surface is rocky and rugged i.e. consists of numerous outcrops of bare rugged rocks.
It has a subterranean network of underground drainage , caves and caverns.
Exhibits numerous residual hills and solution hollows.
It has deep steep sided dry valleys.
Reasons why there are few settlements in a karst landscape.
The areas are rocky
They have thin soils
They have poor vegetation
There is inadequate water supply
They have a rugged surface.
Factors influencing the development of karst scenery
a. The surface rocks and the rocks below should be thick limestone, dolomite or chalk (soluble in water)
b. The rocks should be resistant and well jointed
c. A hot and humid weather to accelerate weathering processes
d. Water table in the limestone rocks should be deep below the surface to allow the rocks above to form conspicuous features
Features of action of water in limestone areas
– Reaction between limestone rock and rain water leads to the development of various features in the karst region. Such features can be surface or underground
Surface features in limestone areas
– Rain water reacts with carbon (iv) oxide to form a weak carbonic acid. This carbonic acid reacts with calcium carbonate in the limestone and chalk rock to form a bicarbonate (calcium bicarbonate) soluble in water
– The calcium bicarbonate dissolves causing the joints in the rock to widen and the limestone surface to become rugged
– This leads to formation of the following features: –
(a) Grikes and Clints
– These are irregular gullies that traverse limestone surface, separating various limestone blocks called clints
– These gullies develop when water action widens and deepens the joints in the limestone rock blocks (clints) standing protruded
Formation of Clints.
All rain water sinks into the ground leaving the surface dry in a karst landscape
Rainwater infiltrates through well-jointed limestone rocks.
Through corrosion /solution process, deep grooves develop.
This eventually leaves behind a low –flat –topped ridge land called Clints.
In karst topography clints form rock blocks in between grikes/shallow is depressions.
(b) Swallow/sink holes
– This is a vertical hole in the ground through which rain water/river water disappears into the ground
– The water widens and deepens the joints especially where such joints converge leading to the development of a vertical hole/shaft
– The holes are slowly deepened as the surface water sinks through them to form swallow or sink holes
(c) Dolines
– This is a round shallow hollow or depression on the surface of a limestone region formed when several small swallow/sink holes merge or enlarge due to continued process of solution
– The swallow hole is widened through solution until the rock blocks between the hollows are completely dissolved to form a doline
(d) Uvalas
– These form when continued solution dissolve the rock blocks between dolines leading to their collapse or merger
(e) Poljes
– As the dissolving of limestone continues underground, several uvalas may collapse to form a very large depression in karst scenery called poljes
– During the rainy season, the polje may be filled with water to form a temporary lake.
(f) Dry Valleys
– This is part of a river in which water nolonger flows in a karst region
– It forms when river water disappears into the swallow hole
Underground features in limestone areas
(a) Caves and caverns
– These are underground chambers formed in limestone areas due to carbonation and solution process along the joints of limestone rock
– At first, a tunnel forms, continued solution enlarges the tunnel to form a cave.
– The process of cave formation may continue, widening and deepening the existing cave to form a cavern
(b) Underground streams/rivers
– When water sinks down into impermeable rock layers, underground streams or rivers may form and flow for longer distances until they reappear on the surface as springs
– These streams may be effluent or influent
– Effluent streams are fed by water table over their level while influent streams intersect the water table and flow into it from the ground water reservoir (they are fed by water table below their level)
(c) Stalactites
– These are columns of limestone that hang vertically from the roof of a cave
– They form through deposition of drops of water containing calcium bicarbonate that has seeped through joints and crevices in limestone rock
– The calcite in calcium bicarbonate is deposited due to evaporation and release of carbon (iv) oxide in water
– The drops of calcium bicarbonate therefore crystallize and then deposited at the roof of the cave
– This process is repeated over time with more crystals of calcium bicarbonate being formed
– A column of limestone grows from the roof of the roof of the cave downwards as crystals accumulate to form a stalactite
(d) Stalagmites
– These are underground stumpy rock masses that grow from the floor of the cave upwards
– When drops of water containing calcium bicarbonate hangs on the roof of a cave, some water drips onto the floor of the cave
– This water spread out, evaporates and leaves behind crystals of calcium carbonate
– This process continues with time and the crystals grow upwards towards the roof of the cave to form a stalagmite.
(e) Limestone pillars
– This is a column of limestone that connects the roof and the floor of the cave
– They are formed in the following ways
When a stalagmite forms directly below a stalactite, the two grow towards each other and eventually meet forming a continuous column that touches the roof and the floor of the cave called a limestone pillar.
When a stalactite grows from the roof of the cave till it touches the floor of the cave.
When a stalagmite grows from the floor of the cave upwards till it touches the roof of the cave.
(f) Karst windows
– Small underground outlets to the surface from the roof of a cave/cavern
– They form due to continuous carbonation by rain water at the surface or rising of the water table due to heavy rain leading to the formation of cavern.
– Continuous growth of the cavern and collapse of its roof leaves a hole called a karst window i.e. small outlet from a cave to the surface
(g) Karst bridges
– Karst window enlarges due to continuous collapse until a small part of the roof left known as a karst bridge.
Significance of the resultant features of action of water in limestone areas
a. Tourist attraction. The surface and underground features of a karst landscape form scenic beauty which attract tourists who in turn bring foreign exchange e.g. limestone pillars, stalactites, stalagmite, etc.
b. Limestone blocks are used for building houses
c. Limestone is also a raw material in the manufacture of cement.
d. Karst landscape is rugged, rocky hence discourages settlements
e. Limestone from karst region is used as a raw material in the iron and steel industry
f. Collapse of dolines and poljes in water table may lead to formation of lakes in the karst area thus providing water for domestic and irrigation
Glaciation
Introduction
Glaciation: – is the action of moving ice on the surface of the earth. It involves erosion, deposition and transportation. i.e. the process by which landscape is sculptured by the action of moving ice
Ice: – refers to solid water formed by freezing and condensation of atmospheric water vapor
Snow: – are falling pellets of frozen water from the atmosphere
Glacier: – is a mass of ice of limited width moving outwards from an area of accumulation
Ice sheet: – is a large and continuous mass of ice that covers a large area of a lowland
Ice cap: – is a permanent cover of ice on earth’s surface covering smaller sections of land
Ice berg: – permanent floating ice in large water bodies e.g. oceans
Movement of Ice
Ice moves outwards from its area of accumulation through the following processes: –
Basal slip
Extrusion flow
Plastic flowage
Basal slip
The weight of ice causes the ice layer in contact with the rocks beneath to melt slightly.
This creates a film of water which acts as a lubricant between the ice and rock surfaces.
The force of gravity then causes the ice to slip and slide over the underlying rock.
Extrusion flow
When ice accumulates, it builds up to great thickness at the centre.
The resultant weight compresses the layers of ice beneath forcing them to spread out where there is less pressure.
Plastic flowage
Within a mass of ice, great pressure is exerted on the layers at the bottom, sides and centre.
This pressure causes some ice particles to melt slightly thereby shift their position slightly downhill before refreezing
Factors influencing the rate at which ice moves.
Gradient of the land- Ice moves faster on steep slopes compared to gentle slopes due to the influence of the force of gravity
Thickness and weight of ice – Thick glacier moves faster as a result of own weight exerting pressure at the bottom. This induces slight melting hence faster movement
Friction – Movement of ice within a valley glacier is faster at the centre where friction is least than at the sides and at the bottom.
Season – movement of ice is faster during summer because the ice thaws more frequently
Processes of Glaciation
This involves glacial erosion, glacial transportation and glacial deposition
Glacial Erosion
This involves plucking, abrasion and sapping
(a) Plucking/Quarrying
– This occurs when ice at the base and the sides of a glacier freeze onto the rocks
– The rocks are then pulled and carried away by the moving ice
– It is common in well jointed or faulted rocks
(b) Abrasion
– This is caused by rock debris that is embedded in a glacier.
– These debris scratch, scrape and polish the rock surfaces over which the glacier moves.
(c) Sapping
– This refers to the breaking of rocks through alternate freezing and thawing of the water contained in the cracks between the glacier and the floor/side of the mountain.
Factors influencing glacial erosion
Nature of the underlying rock
Well jointed/faulted rocks are easily eroded by plucking process since the joints allow water to enter into the rock.
Soft rocks are eroded faster by abrasion compared to hard/resistant rocks.
Availability of debris
Debris acts as erosive tools. The more the debris embedded in the ice the more effective is abrasion process.
Speed of the glacier
The faster the speed the greater the erosive energy.
The thickness and weight of the glacier
A thick glacier exerts great pressure on the underlying rock causing weathering.
The rock debris embedded in the glacier is pressed down by the thick glacier to erode by abrasion.
Glacial Transportation
Materials transported by a glacier is called moraine. It consists of a variety of materials such as rock fragments, sand, gravel and boulders
Moraines are of the following types:
a. Ground moraine: – load carried at the base or beneath a glacier
b. Lateral moraine: – load carried along the sides of the glaciers
c. Medial moraine: – load carried on the surface but at the centre
d. Terminal moraine: – material deposited by the glacier at the point where it melts.
a – lateral moraine
b- Medial moraine
c- Terminal moraine
Glacial Deposition
Sometimes, parts of a glacier may become so heavily ladened that its ability to transport its sub glacial moraine is reduced or stop, deposition then occurs.
Glacial deposits are divided fluvio-glacial and till deposits
Fluvio – glacial deposits are materials deposited by water from melting ice in a glacier whereas tills are moraines/materials deposited by ice on melting
Factors influencing glacial deposits
a. Gradient or slope of the area: – gentle slopes allow for the accumulation of large sheets of ice and subsequent deposition of fluvio-glacial material (materials deposited by melt water).
b. Stagnation of glacier: – leads to pressure being exerted at the base of the glacier which in turn leads to melting of the base. The melt water then carries and deposits materials underneath the ice.
c. Friction: – between the moving ice and the rock surface leads to deposition of the heavy materials underneath the ice.
d. Weight of the glacier: – heavy glaciers tend to be deposited faster/more
e. Amount of glacial drift:-(till and fluvio glacial deposits). When a glacier has so much sub glacial moraines, it becomes too heavy forcing it to deposit some of its load.
Resultant features of glaciation in highlands/highland areas
Cirques/corries
These are deep and wide hollows at the head of glaciated valley or high up above the sides of the valley.
Formation
Snow accumulates in a shallow pre- existing depression on a mountain side
The snow gets compacts into ice to form a cirque glacier
The ice erodes the bottom of the hollow by abrasion , making it deeper
Frost action and plucking operates on the sides of the hollow√ ,making it steeper.
Eventually a deep and arm chair shaped called a cirque is formed.
Arêtes
These are narrow sharp edged steep ridges that separates two corries/cirques
They form when two cirques cut back to back through headward recession i.e. backward cutting of the walls of a cirque through plucking and nivation
This results into very steep and sharp ridges called arêtes
Pyramidal peak
This is a sharp and steep sided peak surrounded by cirques/corries.
It forms when cirques develop on all sides of a mountain
Frost action (through freeze and thaw/plucking) causes blocks of rocks on the mountain to be broken down resulting in the back walls of the cirque to be steepened and deepened
The cirques then start to cut back simultaneously and form a sharp peak called a pyramidal peak
Examples of pyramidal peaks include Corynder and Delamere on Mt. Kenya. Also Albert, Margherita and Alexandria peaks on Mt. Ruwenzori
R- Pyramid peak
S- Arête
T –Tarn/ Corrie Lake
iv. U shaped valleys/glacial trough
These are flat and nearly flat bottomed valleys with steep sides and a U shaped cross sectional profile.
A pre-existing river valley is filled with ice/glacier
As ice moves downstream, tributary glaciers increase the amount of ice in the main valley.
Glacier erodes the V-shaped valley by plucking and abrasion.
The interlocking spurs are trimmed into truncated spurs.
The glacier deepens, widens and straightens the valley floor forming a U-shaped glacial trough
Other erosional and depositional features formed within the glacial trough are alluvial fans and lateral moraines
Hanging valleys
During the formation of a glacial trough, a small valley is left hanging above the major or over deepened valley called a hanging valley.
Formation
Initially, there exists a main valley and tributary valleys/ may be of pre – existing rivers.
Ice occupies these valleys.
The valleys get eroded by ice through abrasion and plucking.
The main valley is eroded more because it contains more ice than the tributary valleys.
When the ice finally retreats by melting and the tributary valleys are left at a higher level than the main valley to form a hanging valley.
Hanging valleys are common on the middle slopes of Mt. Kenya where they form waterfalls e.g. Vivienne falls
Fjords/fiords
This is a submerged glacial trough on a highland coast formed after a glaciated valley is drowned/submerged by sea/ocean.
Action of ice through plucking and abrasion results in the widening and deepening of the lower sections of an already existing river valley.
With time, glacier disappears after melting leaving behind a steep sided valley.
When there is a rise in the sea level, the straightened and deep glacial valley is drowned/submerged by the sea water to form fiords/fjords.
They are mainly found in temperate lands along the Scandinavian countries
Rock basin
This is a depression within a glacial trough where differential erosion has taken place especially areas that have less resistant rocks.
At the point where two glaciers converged erosion is greater resulting in the formation of a glacial depression called a rock basin.
They also form in areas with less resistant rocks where the glacier removes these (less resistant rocks) through abrasion and plucking; leaving behind a shallow depression called a rock basin
Later, during the post glacial period, water may accumulate in the rock basin/depression/hollow to form lakes called finger or ribbon lakes
Resultant features of glaciation in lowland areas
These include both erosional and depositional features
Erosional features
Ice eroded plains
These are extensive and almost level lowlands that were previously under ice sheets.
During glacial transportation, ground moraine erodes the rocks on the existing landforms through abrasion and plucking to form long and extensive plains called ice eroded plains.
Depressions
Lowland glacial areas may comprise of less resistant rocks that are easily eroded by ice sheets/glacier.
The glacier scoops out the materials from the surface through plucking and then lowers it to form shallow depression.
This depression may later fill with melt water to form a glacial lake.
Roche Mountonee
This is a rock outcrop that has been eroded by the glacial processes of abrasion and plucking.
Abrasion polishes and smoothens the upstream side of the rock outcrop whereas plucking will make the downstream end to steep and rugged.
They are common in mounts Kilimanjaro and Ruwenzori.
Crag and tail
A crag is a steep-edged rocky outcrop or a hill side rock projection which protects a mass of less resistant/softer rock (tail) on the downstream side of the glacier from ice erosion.
The crag usually lies on the path of oncoming ice; the ice moves over and around the crag but only slightly erodes its sides. The material that was being carried by the glacier is deposited on the downstream/leeward side.
Such deposits and the softer rocks form an elongated tail
Depositional features
Erratics
This is a large boulder rock which has been transported by a glacier so that it rests on a country rock which is different from it i.e. it has no relationship with the rock material found in the area of deposition.
They are deposited on the inlands when the ice melts
Boulder trains
This is a group of erratics obtained from the same bedrock and which are deposited with their apex pointing to the origin of the deposited materials in a linear form
Tills
This refers to unsorted and heterogeneous mixture of rocks, clay and sand that are transported and deposited by the ice sheet on melting.
They are of two types namely: lodgment and ablation tills.
Lodgment tills are deposited over the ice at the base as a glacier reaches its melting point and the ice moves. The moving ice aligns the debris onto the sub glacial surface.
Ablation tills are deposited when the ice melts
Kames and eskers
Kames are isolated hills made of sand and gravel which have been deposited in layers by glacial water
They are built by streams emerging at high levels from temporary and stagnant ice covers.
As the glacier front recedes, unsupported back of deposits collapses leaving a steep faced hill called kames.
Eskers are long winding ridge of coarse sand and gravel that is formed by streams that flow continuously beneath/within the ice but in a parallel direction to the moving ice
As the ice front recedes, the streams continuously deposit the materials to form a long winding ridge called eskers.
Terminal moraines
This is a long ridge of moraine formed by extensive deposition of moraine along the edge of an ice sheet.
It is formed when the ice remains stagnant for a long time causing the ice at the edges of the ice sheet to melt
Outwash plain
This is a wide and gently sloping plain of gravel, fine sand and clay
It forms when large ice sheets stagnate on a gently sloping landscape and start melting along the edges.
The sub glacial melt water spreads out carrying fine materials which are deposited further down slope as the ice retreats.
Pre-existing valleys are buried by these fluvio-glacial materials.
The unconsolidated clay, silt, sand and gravel are deposited in mass covering a wide area forming an undulating plain called an outwash plain.
Drumlins
These are smooth and long hills deposited and shaped under an ice sheet or a very broad glacier.
They are formed beneath the ice due to friction between the bedrock and the boulder clay.
This results to deposition of clay at the valley bottom.
Further deposition leads to large mounds of till forming.
The moving ice streamlines the till that had been deposited irregularly resulting into elongated egg-shaped hills called drumlins.
Significance of Glaciation
Outwash plains, old glacial beds and tills are at times very fertile thus leading to the development of agriculture e.g. wheat producing regions within the Canadian prairies.
Some glacial lakes provide natural waterways e.g. the Great Lakes of Canada and North America thus facilitates transport and communication.
Glaciers on highlands may form sources of river e.g. R. Tana on Mt. Kenya.
Waterfalls resulting from hanging valleys provide suitable sites for the generation of HEP .
Glaciated mountain regions and their resultant features e.g. cirques, pyramidal peaks, etc. attracts tourists during winter for games/sports hence earning foreign exchange.
Sheltered waters in the fiords provide suitable breeding grounds for fish and sites for construction of natural harbours.
Sand for building and construction can be harvested from outwash plains, kames and eskers.
Glaciation results into rugged landscape that makes settlement and construction of transport and communication difficult.
Extensive areas of land are sometimes turned into glacial lakes by deposits from moraine thus reducing the amount of land available for settlement.
Some outwash plains may contain infertile sandy soils that hinder agricultural practices.
Field work
Meaning of a working Schedule
It is a time able /activity plan showing events /activities and the corresponding time that each event /activity will be undertaken during the field study
What is the importance of preparing a working schedule in field study?
It enables students to complete their field study in time
Enables the students to divide themselves in working groups
It makes the students’ field study more organized
By using a working schedule the students are able to evaluate their objectives and hypotheses
The students are able to collect adequate data since the working schedule aids in good time management
The students are able to estimate the overall time required for the study
Name three underground features you are likely to study. – Stalactites
Stalagmites
Limestone pillars
Carverns
End of topic
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Past KCSE Questions on the topic
Mass Movement
1. a) State two conditions which may influence the occurrence of landslides
b) Using the diagram (in question paper), name
(i) The type of mass movement shown
(ii) The features marked P and Q (2mks)
2. Explain five ways in which soil creep occurs. (10mks)
3. Describes the effects of soil creep. (6mks)
4. Define the following:
a) Mass wasting.
b) Mass movement. (2mks)
5. Name and explain three process of slow mass movement. (4mks)
6. Explain the factors that are responsible for rapid mass wasting.
7. List the evidences of soil creep. (4mks)
The Hydrological Cycle
1. (a) The diagram below shows the hydrological cycle. Name the stages marked
E, F, and G (3mks)
(b) Differentiate between watershed and a catchments area (2mks)
2. State four factors that determine the amount of surface run-off.
3. What is hydrological cycle? (2mks)
4. Explain factors that influence percolation of voter. (8mks)
5. (a) What is cyrosphere? (2mks)
(b) Name the significance of hydrological cycle. (4mks)
6. List other forms of precipitation other than rainfall that may also form major inputs into the system. (4mks)
7. What factors can influence surface run off or overland flow. (5mks)
8. In what ways can we sustain the process of the hydrological cycle? (8mks)
Action of Rivers
1. (a) Name two types of the coastal deltas (2mks)
(b) State two conditions that lead to deposition of silt at the mouth of a river
(2mks)
2. The diagram below shows river Mandera. Use it to answer question (a)
(a) (i) Name the process that take place at each of the points marked P
and Q. (2mks)
(ii) Name the feature formed at the point marked R (1mk)
(iii) Describe how an Ox- bow lake is formed (5mks)
(b) State five characteristics of a flood plain (5mks)
(c) Explain three causes of river rejuvenation (6mks)
Your class is required to carry out a field study of a river
(i) What would be the advantages of dividing the class into groups according to the stages of the long profile of a river? (4mks)
(ii) What would be the disadvantage of using secondary data in this kind of a field study? (2mks)
3. (a) State two factors which influence the occurrence of surface run- off
(b) The diagram below shows a waterfall. Name the feature marked X, Y and
Z
4. Describe three ways in which rivers transports its load.
5. Describe the following drainage patterns
(i) Dedritic.
(ii) Trellis.
(iii) Centipetal.
6. a) State two factors that influence the rate of erosion by the river in its
upper course.
b) (i) Define river rejuvenation
Name two features that result from river rejuvenation
7. Explain the following:
(a) River basin
(b) Watershed
(c) Catchment area
(d) River regime (8mks)
8. With examples from Africa, explain the differences between the following river features:
(a) Inland delta and alluvial fan.
(b) Estuarine delta and an estuary.
(c) Bluff and river cliff.
(d) Levees and river bank.
(e) River valley and river channel.
(f) Paired terrace and unpaired terrace.
(g) Drainage pattern and drainage system,
(h) Misfit river and deferred river,
(i) Antecedent drainage and superimposed drainage. (18mks)
9. Describe how a river erodes its channel through the following processes
(i) Abrasion
(ii) Hydraulic (4mks)
10. (a) (i) In which stage is the river at ‘A’
(ii) Name 3 features found at the above stage. (3mks)
(b) (i) In which stage is the river at ‘B’
(ii) Which are the characteristics of the river at stage B?
(iii) Describe the characteristics of the river at the above stage C.
(4mks)
(c) In which stage is the river at C.
11. Explain the significance of rivers to man. (10mks).
a) Name the features shown by the photograph. I and II. (2mks)
b) State the conditions necessary for formation of these features. (3mks)
LAKES.
1. Give three processes that lead to formation of lakes.
2. Describe how Lake Victoria was formed.
3. Explain how Lake Victoria influences the climate of the surrounding areas.
4. What is a lake?
5. State three ways in which lakes are formed.
6. Explain how each of the following lakes were formed :
(a) Victoria
(b) Tanganyika
(c) Chala
(d) Sare
(e) Kivu (15mks)
7. State the differences between the lakes on the eastern and western areas of East African Rift Valley. (6mks)
8. With reference to specific lakes in East Africa, explain the significance of lakes in
the region. (8mks)
Oceans, Seas and Their Coasts.
1. Use the diagram below to answer question (a)
(a) Name the coastal features marked H, J, K, L and M (5mks)
(b) (i) State four conditions necessary for the formation of a beach (4mks)
(ii) Describe three processes involved in marine erosion (6mks)
(c) You are planning to carry out a field study on the depositional features along the coast of Kenya
(i) State five objectives you would formulate for your study (5mks)
(ii) Give five methods you would use to record the information
collected (5mks)
2. (a) Name two types of submerged coasts. (2mks)
(b) Explain now the following factors determine effectiveness of wave
erosion along the coast.
(i) Nature of the material transported by waves
(ij) Nature of the coastal rocks. (4mks)
3. State two causes of submerged coasts. (2mks)
4. Name two features that result from submergence of coasts. (2mks)
5. Define term coastline (2mks)
6. What are destructive waves?
(2mks)
7. Name three resultant features of wave erosion. (3mks)
8 Describe formation of cliff. (5mks)
9. Describe formation of a wave-cut platform. (5mks)
10. Name three types of coast. (3rnks)
11. (a) Describe formation of coral coast. (5mks)
(b) Explain the significance of coral coast to Kenya.
12. Distinguish between shingle beaches and sand beaches. (6mks)
13. Name three types of submerged coasts. (3mks)
14. Name two types of movements of ocean water. (2mks)
15.
(a) Name features marked A, B, and C.
(b) Describe the formation of feature marked C.
Action of Wind and Water in Arid Areas
1. The diagram below represents a barchan. Use it to answer questions (a)
(a) Name
(i) The feature marked X (1mk)
(ii) The air current marked Y (1mk)
(iii) The slope marked Z (1mk)
(b) Give two ways in which wind transports its load (2mks)
2. a) (i) Two process through which wind erodes the surface
(ii) Three ways through which wind transports its load
b) (i) How an oasis is forced
(ii) How zeugens are formed
c) You are supposed to carry out a field study of a semi-arid area in Kenya.
(i) Two ways of preparing for the Field study
(ii) Information that would be collected through observation of the arid area
(iii) Measures to be recommended for controlling desertification.
3. Explain the process of abrasion. (2mks)
4. Name four features of wind erosion. (4mks)
5. Describe formation of zeugens, (4mks)
6. List features of wind deposition. (4mks)
7. Describe formation of wadis. (5mks)
8. Differentiate between suspension and saltation. (4mks)
9. Name four types of desert surface (4mks)
10. Identify and describe the processes of wind erosion. (6mks)
11. (a) Explain how wind transports its load.
(b) State the factors influencing wind transportation. (3mks)
12. Explain the formation of the following features:
(a) Bajadas.
(b) Pediments. (6mks)
13. Students carried out field study on desert landforms.
(i) State two type of information they collected through observation.
(ii) Which measures would they have recommended to control desertification?
Underground Water
1. The diagram below show some features of a Karst scenery. Use it to answer questions (a)
a) Name the features marked P, Q, and R. (5mks)
b) Describe carbonation as a process of Chemical weathering (3mks)
2. State three conditions necessary for the development of Karst scenery, (3mks)
3. Give two reasons why there are few settlements in a Karst landscape. (4mks)
4. Explain factors influencing formation of springs. (8mks)
5. Distinguish between the following.
(i) Effluent streams and influent streams. (4mks)
(ii) Artesian basins and artesan well. (4mks)
6. Name three surface features of Karst landscape. (3mks)
7. What are stalactites? (2mks)
8. Explain the significance of limestone regions. (8mks)
Glaciation
1. (a) (i) What is an ice sheet? (2mks)
(ii) Give two reasons why there are no ice sheets in Kenya (2mks)
(iii) Explain three factors that influence the movement of the ice from the place where it has accumulated (6mks)
(b) Describe how an arête is formed (4mks)
(c) The diagram below shows types of moraines in a valley glacier
(i) Name the type of moraines marked S, T and V (3mks)
Explain four positive effects of glaciation in lowland areas. (8mks)
2. a) (i) What is a glacier? (2mks)
(ii) Distinguish between valley glaciers and ice sheets (4mks)
3. The diagram below shows a glaciated upland area
(a) Name the feature marked P, Q, and R (2mks)
(b) How is a U- shaped valley formed? (5mks)
4. a) Describe how pyramidal peak is formed. (6mks)
b) Explain the significance of upland glaciated features to human activities.
(6mks)
c) Students from a school near Mt.Kenya were planning to carry out a field study on the glaciated features on the top of the mountain.
(i) Give the reason why it would be difficult to undertake the field study on the glaciated features on the mountain. (4mks)
(ii) Describe how students would use a photograph of Mt.Kenya to identify the glaciated features on the mountains. (3mks)
5. Differentiate between snout and snow niche. (4mks)
6. Name three glaciers on Mt.Kenya. (3mks)
7. Describe the formation of a glacial trough. (3mks)
8. What is ice cap? (2mks)
9. Name three resulting features of glacial erosion on Mt.Kenya (3mks)
10. What is a nivation hollow? (2mks)
CHAPTER NINE
Specific Objectives
By the end of the topic the learner should be able to:
(a) Define soil, soil profile, soil catena, and soil degeneration/degradation and soil erosion;
(b) Discuss the composition of soil and the processes of soil formation;
(c) Describe the properties and characteristics of soil;
(d) Describe soil profile and soil catena;
(e) Explain soil degeneration/degradation;
(f) Classify soils according to soil orders;
(g) Discuss the significance of soils;
(h) Discuss ways and means of managing and conserving soil;
(i) Identify different types of soils and their uses within the local environment
Content
a.) Definition of soil.
b.) Composition of soil.
c.) Soil forming processes.
d.) Properties and characteristics of soil.
e.) Soil profile and catena.
f.) Soil degeneration/degradation, including soil erosion.
g.) Classification of soils: zonal, intrazonal and azonal.
h.) Significance of soils.
i.) Management and conservation of the soil.
j.) Field work – identification of different types of soils and explanation of uses within the local environment.
Introduction
Definition
Soil is the top most/uppermost layer of loose and unconsolidated materials that overlie the crustal rocks and on which plants grow.
It is composed of disintegrated rock fragments, mineral particles, humus, water and air.
It is derived from different types of rocks making the earth’s crust through the processes of weathering.
Composition of Soil
a. Inorganic matter: – mainly mineral particles derived from parent rock such as silicates, calcium, sodium, etc.
b. Humus/soil organic matter: – is the product of decomposed tissues of animals and plants as well as animal remains
Humus is important to soils because:
– It supplies the plants with food and minerals
– It is fertile and produces high agricultural yields
– It has high water retention capacity in the soil
– It promotes the development of a structure that favors circulation of air and water.
– It contributes to further weathering of rock through decomposition
– It is a source of food for soil microorganisms
c. Soil water:- is dissolved in the minerals
d. Soil air: – is contained in the pores and air spaces between the soil particles
Soil forming processes
Through weathering
This involves breaking and disintegration of parent rocks through physical and chemical processes.
This (weathering) results to regoliths that are further broken into smaller and finer particles to form soil.
Through decomposition of organic matter
This involves the accumulation and decomposition of decaying plants and animal matter on the ground surface.
This is done through mineralization and humification
Mineralization is the biological and chemical breakdown on dead plant tissues by soil microorganism to produce simple soluble organic substance
Humification involves regrouping of the mineralized materials into large molecules to form humus
Through leaching
Leaching is the removal of soluble mineral matter in solution from the upper layer/horizon to the lower horizons of the soil
The following leaching processes lead to formation of various types of soils
Eluviation: – this is the physical or mechanical washing down of fine mineral particles from the upper layer of the soil into the middle and lower layers. These materials are moved in suspension by water percolating downwards
Illuviation: – is the deposition or accumulation of the materials that have been washed down from the upper layers to the lower layers through eluviation. It takes place where rainfall is greater than evaporation leading to the redeposition of soil materials that have been leached to the middle layer. Compaction and cementation results into the formation of a hard soil
Note
Leaching is affected by the following factors
– Solubility of minerals in the soil
– Amount of vegetation cover
– Amount of precipitation
– Soil porosity
– Gradient of slope
Factors influencing soil formation
Nature of parent material
This determines the rate and type of weathering i.e. some parent materials weather rapidly and form soils fast while others that are resistant to weathering lead to least formation of soils.
It also determines the soil texture and porosity of soil to allow circulation of air and water.
Climate
Climatic conditions affect the rate of weathering taking place on a given rock through seasonal variation in rainfall and temperature.
Areas with heavy precipitation (rainfall) are heavily leached and weathered compared to drier areas, they therefore have deep soils.
High temperatures promote rapid faster weathering and chemical changes in the soil. (cold temperatures slow these processes).
Winds act as agents of soil erosion, blowing fine sand and dust and depositing them far away forming rich fertile soils.
Living organisms
Plant roots may penetrate the soil making it to become porous leading to the biological weathering hence formation of soil.
Areas with dense vegetation covers have fertile soils because of the decomposition of the plants’ leaves or remains.
Plants’ roots improve soil porosity, depth and aeration.
Worms and other burrowing animals mix organic remains with soil mineral components leading to soil formation in the process.
Human activities e.g. mining, quarrying, deforestation, grazing and application of fertilizers may change the nature of soils lead to weathering.
Topography
Soils on mountain slopes are heavily leached hence have thin soils.
Plains and valley bottoms have deep soils due to deposition of weathered and eroded materials.
Time
Duration taken by soil to form influences its characteristics (depth and maturity).
Deep and well developed soils take longer time to form.
Properties of soil
Soil texture
This refers to the composition of a particular soil in terms of the size of its particles.
Soil texture can be coarse with large particles e.g. sandy soils, fine with smooth and small particles e.g. clay soils or loamy i.e. a mixture of particles of different sizes.
Importance of Soil Texture.
It determines the amount of water available in the soil i.e. coarse gravel has large air spaces and are therefore porous and don’t retain water for long/fine gravel have small air spaces and water enters in them at a slower rate. They also hold water for longer
It influences the ease with which plant roots can penetrate the soil – coarse grained soils are easily penetrated
Soil structure
This refers to the way soil particles are grouped into aggregate compound particles.
It is described from the way the soil particles are joined into groups such as Granular/crumb (consists of small, soft porous aggregates); Platy (particles are arranged on top of one another in thin horizontal plates); Prismatic (aggregates are arranged vertically); Blocky (irregular pieces of soil with sharp corners and edges).
Soil structure influences the rate at which soil absorbs water as well as the ease with which soil can be cultivated.
Soil acidity
Soils can be acidic or basic/alkaline.
It changes in moist/humid climates as percolating ground water leaches out soluble minerals.
The soil then becomes deficit of lime leading to salinity and alkalinity.
Soil color
This is used in describing soil. Soils may be red, brown, yellow or black in colour
Soil colour is influenced by:
– Type of parent material from which a soil developed.
– The drainage of the area in which the soil is found. (well drained-red soil, poorly drained-grey/brown/yellow).
– The content of organic matter present in the soil.
– The extent of leaching.
Soil porosity
This refers to the amount of pore spaces in a soil sample.
It’s determined by soil texture and structure
It influences soil water retention capacity/drainage.
Soil permeability
This refers to the movement of water in the soil. It depends on the soil texture i.e. fine textured soils are impermeable
Soil depth
This is the mass of a unit volume of dry soil/ the amount of dry soil overlying a parent rock.
Soil depth is influenced by the following factors;
Nature of the bed-rock/ the ease with which it weathers.
The length of time the soil has taken to form.
The vegetation cover existing in the area.
The climate of the place.
The rate of weathering of the mineral matter.
Soil profile
This is the vertical arrangement of different layers/horizons of soil from the surface to the bedrock:
Soil Catena
This is the arrangement of soil on a mountain or slope from the top to the bottom or the sequence of different soils down a slope.
Soils are derived from the same parent material but vary with relief and drainage.
The mountain top has laterite cap, the slope has light and thin soil and the bottom of the slope has thick deposits of soil.
Factors influencing the development of a soil catena
Relief
Slope influences drainage which in turn influences the moisture content of the soil.
Soils on the upper slopes are generally well drained and thin because of high rate of erosion.
On the gentle slopes the soil is thick/ deep because the rates of erosion and weathering are balanced. On valley floors the soil may be peat or alluvial due to deposition.
Drainage
The degree of slope and the amount of moisture are the major factors influencing changes along a slope.
Generally, well drained mature soils are found at the hill tops while thin, stony dry and immature soils are found on the steep slopes. Grey soils (formed through reduction of iron from the red-yellow ferric form to the blue-grey ferrous state under poor drainage) and peat may be found on valley bottoms.
Leaching.
Where percolation of soil solutions tend to be horizontal, soluble salts are removed from the soils of the upper slopes to the lower slopes. Other minerals, humus and clay may be transferred in suspension in the process of eluviation
Transport of debris.
Surface run-off and mass wasting are responsible for the down-hill movement of soil. This results the accumulation of deep soils on the lower gentle slopes. The steep slopes are left with thin, stony and immature soils with little organic matter and moisture called Xeromorphic soils.
Soil Degeneration/deterioration
This refers to the decline in soil quality/ usefulness through changes in its physical, chemical and biological properties.
Soil degeneration can be physical, chemical or biological
Physical degeneration is the decline in the usefulness of soil in which the texture, structure, moisture and quantity of the soil is affected. It is due to the following causes
– Poor land-use practices such as overgrazing
– Excessive soil erosion due to heavy rainfall
– Drought causes changes in the soil structure, texture and moisture content
– Over-cultivation
– Use of heavy farm machines.
Chemical degeneration refers to the decline in the usefulness of a soil due to a change in the mineral nutrients and soil pH. It is due to the following causes: –
– Monoculture
– Over-cropping
– Excessive or wrong application of fertilizers
– Excessive leaching
– Excessive drought also leads to accumulation of salts in the top soil
Biological degeneration refers to the decline of the organic content of the soil as well as its vegetation cover. This can be due to overgrazing, deforestation, burning of land and soil water logging.
Soil Erosion
This is the removal of the top soil by the action of moving water, wind, glaciers, mass movements and human activities.
Conditions favoring soil erosion
Natural conditions
Length, angle and nature of the slope. Generally steep slopes accelerate erosion.
Mass wasting especially landslides and soil creep can aid soil erosion.
Climatic conditions. Arid areas are prone to sheet and wind erosion.
Nature of the soil texture. Areas with volcanic ash are vulnerable to soil erosion
Human conditions
– Monoculture/ over-cropping lead to soil exhaustion thus making the soil vulnerable to erosion
– Overstocking leads to overgrazing which reduces vegetation cover thus exposing the soil to erosion
– Ploughing up and down a slope provides channels for surface run-off.
– Bush fallowing may leave land abandoned or unprotected against erosion.
– Deforestation and burning of vegetation exposes the soil to agents of erosion
– Cultivation of crops in marginal areas loosen the soil in the dry seasons resulting in wind erosion
– Cultivation of steep slopes, catchment areas or along river banks
– Excavation works trigger off soil erosion.
Types of Soil Erosion
Splash Erosion
This is caused by heavy and sudden rainstorms that hit and loosens unconsolidated particles of soil on the earth’s surface
The impact of the heavy drops throws away or splashes the soil particles
Rill Erosion
The rain water cuts small channels called rills as it flows over the surface.
It is most prevalent when rainfall exceeds the rate of infiltration
Gulley Erosion
Moving water or glaciers on the surface of the earth surface may cut deep and large channels through widening the existing rills.
Sheet Erosion
This is the uniform removal of the top soil by rainwater moving downslope immediately after heavy downpour occurs in a flat area.
Wind
Prevailing winds may carry fine soil particles away and deposit them elsewhere
Effects of Soil Erosion
Sand eroded from steep slopes is deposited on the river beds and can be harvested for building and construction
Soil erosion loosens productive top soils thus lowers agricultural productivity of land.
During soil erosion, rich soils may be deposited e.g. alluvium that create fertile lands for agricultural production
Destruction of vegetation cover during soil erosion may lead to aridity and desertification
Eroded sediments from farmlands and dumping sites may contain pollutants/agrochemicals that may kill aquatic life if reaches oceans/seas/lakes and river. They also make the water unfit for human consumption
Eroded sediments may fill water reservoirs constructed for HEP generation/irrigation thus requiring dredging which is expensive
Also eroded alluvial deposits on river beds make the river channel shallower resulting into frequent flooding
Soil erosion may destroy structures e.g. buildings, bridges, roads as it weakens their foundations
Significance of Soils
Soil gives physical support/anchorage for the rooting system/a medium on which plants grow.
Soil forms habitat for bacteria necessary for breakdown of organic matter into humus. Bacteria are necessary for cycling carbon, nitrogen, calcium, potassium and sulphur.
Soils provide mineral elements to plants
Soil is a medium through which plants absorb water as soils contain water and air spaces.
Some soils e.g. clay is used in making ceramics such as pots
Some soils contain valuable mineral elements e.g. alluvial gold.
Soils are used in building and construction e.g. clay in making bricks, sand for construction and limestone for cement making.
Classification of Soil by order
Soil order is the grouping of soils according to specific properties and factors such as age, texture, color and climate.
Based on these, soils are classified as zonal, Intrazonal and azonal
Zonal soil order
These result from the prolonged influence of climate and biological factors on soil forming processes.
Such soils have undergone long time soil formation processes under good drainage.
They are mature soils with well-developed soil profiles.
They are further subdivided into the following sub orders.
Podzols
– These are found in higher latitudes and forested areas which are generally humid with precipitation all year.
– Such soils are heavily leached and have low fertility.
– They are majorly found in the Scandinavian countries of Europe.
ii.) Podzolic soil
– These are found in areas with deciduous forests and hot and hot humid climates such as Zaire basin, Kenya highlands. Such soils favor pines and oak.
iii.) Tundra soils
– These occur beyond 600 north in pole-ward treeless area experiencing tundra climate such as Iceland, Coastal Newfoundland, Northern edge of Europe and Asia
– Such soils are poorly drained given the permafrost conditions and low rates of evaporation
– They consist of bog and hummocky marshlands hence unsuitable for cultivation but can support sparse natural pasture
iv.) Latosols
– These form conditions of high rainfall and temperatures especially areas of basaltic plateaus such as Kericho-Sotik plateau, Uasin Gishu, Trans-Nzoia, Laikipia, Athi- Kapiti plains.
– They are black due to the presence of high content of titanium salts in basalt bedrocks
– Have low organic content; when ploughed it crumbles into dust during dry season or cracks; plastic when wet; heavily leached
v.) Pedocals
– These are common in semi-arid and sub humid grasslands. Are dark coloured, rich in calcium carbonate and gave little leaching
– They are further subdivided into;
Chernozems:-They are dark coloured top soils with high organic matter content found in semi-arid lands. They are well drained and associated with long-grass vegetation. They have loose crumbled texture rich in minerals and bases. In Kenya, Chernozems are found at the bottom of Nyambene Hills in Meru County
Vertizols: -are dark, cracking clay soils or black cotton soils; fine textured, plastic and sticky; usually poorly drained and have a high clay content (they are referred to as black cotton soils). They are mainly found in plains, lowlands, plateaus and flooded river valleys. They are suitable for growing cash and subsistence crops e.g. cotton, rice, maize, sorghum. In Kenya, Vertizols are found in Machakos, Kitui, Tana River, Kirinyaga, Kano plains, Uyoma Peninsula (Siaya County)
vi.) Nitosols
– These are deep, porous and friable soils of the highlands
– They are very fertile hence used to grow a variety of food and cash crops
– In Kenya, they are known as Kikuyu Red Loam and are found in the Kikuyu plateau, around Nyeri and Marsabit hills
– They are well aerated, shiny and have a high capacity of moisture storage
vii.) Phenozems
– These are dark brown and relatively fertile soils common in the prairies of Canada
– In Kenya, they are found in Narok and Kajiado
– They are generally fertile and have good physical structure
– They are good for growing cereals
viii.) Sierozems
– These are soils that form in desert conditions with little seasonal rainfall and high temperatures
– They are mostly found in large parts of northern Kenya.
– They contain very little humus
– They lack distinct profiles and most horizons comprises of fragments of parent rock
– They are rich in calcium carbonate due to excessive evaporation. The salts may harden to form Mesas
– They are saline
– They are loose grained and porous with coarse texture
b.) Intrazonal soil order
– These are soils formed under poor drainage conditions/systems
– They are further classified into: –
Hydromorphic soils
– These are soils formed in waterlogged areas e.g. flat uplands, marshes, bogs and swamps
– In Kenya they are found in Kisii highlands, Lorian, Lotikipi, Yala swamp and parts of Kano plains
ii.) Halmorphic Soils
– These are soils formed under arid and semi-arid conditions through the influence of soluble salts (salinisation)
– They are further classified into solonchak, calcimorphic and andosols
Solonchak: -contain a lot of salts/are saline. They are light coloured and found in depressions in ASALs. They are generally infertile and are poorly drained. In Kenya, they are found in Amboseli, Tana River, North Eastern Kenya and around Lake Turkana
Calcimorphic: – these are formed by calcification of limestone soils. They are rich in lime. They are mainly found in grassland areas with plenty of humus in the upper zones of the soil profile. They are productive and are used for growing maize and cotton. In Kenya, they are found in North Eastern and Coast Provinces
Andosols:-are volcanic soils formed from recent volcanic activity. They are highly porous, have high organic matter content and water storage capacity. They are fertile, well drained and support extensive agricultural activities like coffee, wheat, tea and maize growing. In Kenya, they are found on the slopes of Mt. Elgon, Cherangani, Maua Hills, Chyulu, Meru, Embu, Central Province, Kisii, Nyamira, Busia and Upper Rift Valley Provin.
c.) Azonal soil order
– These are young soils that have not undergone full soil formation processes.
– They lack well developed soil profiles due to recent formation
– They are found on steep slopes and areas with poor drainage
– They are further sub grouped into
Lithosols
These are pronounced in slopes that experience excessive erosion and erosive run-off.
Their fertility depends on the parent material.
They are found in high latitude areas of Kenya
Regosols
Lack genetic horizons developing.
They develop from deep unconsolidated rock or soft material deposits.
They are formed in recent alluvial deposits hence lack distinct profile.
They are common in mountainous parts of Kenya e.g. around Lake Turkana.
Alluvial soils
These are young soils developed from alluvium of recent origin.
Arenosols
Management and conservation of soil
Soil management
This involves controlling the process and activities that would cause deterioration of the soil through measures such as;
Nature of Soil Management Measure(s)
Acidic soils Adding agricultural lime to raise their pH level
Saline Soils Adding good quality irrigation water in sequences to dissolve the accumulated salts
Sodic (Alkaline) Soils Adding gypsum then good quality irrigation water to leach out the sodium
Deteriorating soil fertility Application of plant and animal manure
Excessively wet soils Constructing drainage ditches and shallow waterways to divert the water from the land to natural valleys/reservoirs
Flooded soils Building dykes, embankments or levees along the river banks
Maintenance of soil texture Returning crop residue to the soil
Eroded Soils Terracing, construction of water diversion channels upstream, mulching
Soils with poor water retention Adding humus to the soils
Soil conservation
This refers to measures that are taken to protect the soil from destruction or intentional planning to make the best use of soil resources while protecting and preserving its quality for sustainable productivity.
Measures of soil conservation
1. Crop rotationinvolves alternate growing of different crops on a given piece of land to prevent/minimize soil exhaustion
2. Mixed farminginvolves integrating animal and crop husbandry. It improves soil fertility as animal waste and plant remain assist in retaining soil fertility
3. Cover croppingforms a bumper that reduces the impact of rain-drops; the roots bind the soil firmly.
4. Mulching: – involves the use of plant remains are used to cover cultivated ground. It is important because
– reduces evaporation of water from the soil
– protects the soil from erosion
– increases humus content
– increases the rate of infiltration of water into the soil
– provides habitat for burrowing animals which churn the soil and increase permeability and aeration
5. Contour ploughingi.e. ploughing across the slopes helps to check surface run-off
6. Strip croppinginvolves planting of different crops in narrow alternate belts of land especially on slopes which are too steep to be terraced.
7. Afforestation– planting trees where none existed before and reforestation– planting trees to replace the cut ones. These trees conserve the soil in the following ways
– decayed vegetation matter provides humus which binds soil particles together
– the roots bind soil particles together
– it increases the rate of infiltration of rainwater, thus reducing surface run-off
– leaf cover reduces the force of rain drops which would otherwise cause splash erosion
– vegetation act as wind breakers thus preventing soil erosion
8. Regulation of livestock numbersto reduce overgrazing
9. Bush fallowing: – cultivating land for a period then allowing it to remain idle without cultivation for some time to help improve the soil quality
10. Controlling bush firesthat exposes the soil to agents of soil erosion
11. Intercropping/mixed croppingi.e. growing two or more crops concurrently on the same piece of land to help improve the soil’s nitrogen content
12. Proper ploughing methodse.g. digging with a fork jembe/ox plough
End of topic
Did you understand everything?
If not ask a teacher, friends or anybody and make sure you understand before going to sleep!
Past KCSE Questions on the topic
1. a) (i) What is soil catena?
(ii) Draw a labeled diagram to show a well-developed soil profile. (5mks)
(iii) State three characteristics of the soils found in the arid regions of Kenya. (3mks)
b) Give three factors that determine the colour of soil.
c) Describe how laterization occurs. (6mks)
d) Explain how the following farming practices cause soil erosion.
(i) Burning (2mks)
(ii) Continuous application of fertilizer on farm lands. (2mks)
(iii) Monocultures. (2mks)
2. (a) Name two types of soil according to texture. (2mks)
(b) State two ways in which humus improves the quality of soil. (2mks)
3. What is soil? (2mks)
4. Identify classification of soil according to order. (3mks)
5. Describe formation of soil through decomposition of organic matter. (3mks)
6. How does salination occur? (3mks)
7. What do you understand by zonal order soil?
8. List four soil conservation and management practices. (4mks)
9. What do you understand by podzolisarion?
CHAPTER TEN
Specific Objectives
By the end of the topic the learner should be able to:
(a) Define vegetation;
(b) Discuss the factors that influence the distribution of vegetation;
(c) Identify and describe the characteristics of major vegetation regions of Kenya and the world;
(d) Discuss the significance of vegetation;
(e) Identify different types of vegetation and explain their uses within the local environment.
Content
Definition of vegetation.
Factors that influence the distribution o f vegetation.
Characteristics of major vegetation regions of Kenya and the World.
Significance of vegetation.
Fieldwork on identification of different types of vegetation and explanation of their uses within the local environment.
Introduction
Definition of vegetation
All the plants that grow together in any area form its vegetation.
The vegetation of an area is defined as a community of plants such as trees,shrubs, herbs and grasses that cover a place and give it a distinct character.
Plants that grow together in a particular habitat are referred to as a plant community.
A plant community is defined as an assemblage of plants that grow together in a particular physical habitat or site.
A distinction is frequently made amongst natural semi-natural ( derived or secondary ) vegetation and cultivated vegetation.
Natural (climatic climax ) vegetation
Natural vegetation is a plant cover that grows and spreads through natural means of seed dispersal without interference of external modifying influence.
The term climax vegetation describes the vegetation that has established itself without interference in relation to the particular physical environment of climate, relief and soils.
Therefore, climax vegetation describes a state of equilibrium (balance) having been attained. This climatic climax community will be dominated by plants, which of all those available, can complete most successfully in the existing physical conditions.
Derived (Semi-natural) Vegetation
This type of vegetation that is in process of recovering from man’s disturbance but has yet to reach a new climax.
Derived vegetation is also referred to as secondary or semi-natural form of vegetation.
This is because it owes origin to the interference of the previous natural or climax vegetation but man.
Semi-natural vegetation is wild in the sense that it has not been planted by humans, yet its characteristics are attributed to such influence.
In fact, much of what was formerly thought to be natural vegetation is semi-natural.
For instance, if a tropical rainforest is cleared then neglected, it rapidly turns into a secondary forest where the species are similar to the original but are less luxuriant and less developed in form.
For example, the savanna,the savanna grassland may be the result of forest clearance by shifting cultivation.
Cultivated Vegetation
This is the type of vegetation planted by people.
Examples of cultivated vegetation include some forests in the Kenya highlands, crops, hedge plants such euphobia, cypress and key apples.cultivated crops and forest Plantations form the principle components of the vegetation cover over significant percentage of the Earth ‘surface.
Factors influencing vegetation Distribution
The factors that influence vegetation distribution can be grouped into four main classes: Physiographic or geomorphic factors (altitude, terrain, drainage and aspect)
Climatic or atmospheric factors (light, temperature, humidity, wind et cetera).
Edaphic and pedagogical factors (soil properties which affect vegetation growth such as soil organisms, soil nutrients, air of the soil, soil water and soil texture).
Biotic and anthropogenic factors (effects of other plants animals and people such as competition, seed dispersal, cross-pollination, grazing and trampling, cultivation and burning.
Physiographic (Geomorphic) factors
The major physiographic factors that affect vegetation growth and distribution include altitude, terrain and drainage.
Altitude (Height above sea level)
Temperature decreases with increasing altitude.
Altitude affects the temperature and rainfall that in turn affect vegetation.
For instance, the red mangrove is typical sea level vegetation while the bamboo is typical vegetation on highlands and mountains.
Terrain and drainage
Terrain is the physical appearance of an area. It is denoted by the steepness and ruggedness of the land.
Gentle slopes are more conducive to stable development of vegetation than steep and rough slopes.
On the other hand, aquatic plants due to poor drainage can only characterize flat lands that are waterlogged.
Steep rugged slopes are exposed to rapid erosion and mass wasting.
For example, sometimes plants bend – up slope due to soil creep. Such slopes are also more vulnerable to vegetation destruction by agents such as human beings.
Steepness of land has indirect influence on vegetation since it directly influences the rate at which precipitation is drained from the surface.
On steep slopes, runoff is rapid and water dose not remain available to plants for a long time.
On gentle slopes however, much of the precipitation can penetrate the soil and become available to the plants longer, hence more luxuriant vegetation can grow on such slopes.
Aspect
This refers to the direction of a slope.
The influence of aspect upon plants is direct through increasing or decreasing the exposure to sunlight and prevailing winds.
Slopes facing the sun have warmer and drier environment than slopes facing away from the sun and thus lying in the shade for longer periods of the day.
This effect is more pronounced in mid-latitudes than within the tropics.
The influence is so strong that quite different plant formations are found on the slopes facing north from the slopes facing south.
For instance, in the Alpine region of Europe, the south-facing slopes have thick and deciduous woods with varieties like the elm, poplar, alpine maple, birch, apples and pears, while the colder north-facing slopes are covered with coniferous species like spruce, silver fir, larch, scotch, pine, yew, juniper and the hardly arolla pine.
This is because the slopes facing north are colder and more arid.
Climatic or atmospheric factors
Plants depend directly on the atmospheric for certain fundamental materials and conditions, necessary for their successful growth and reproduction.
The climate influences vegetation in a number of ways particularly through its various elements namely sunlight, precipitation, temperature, humidity and winds.
These elements have both direct and indirect influence on vegetation. Sometimes, they interact in their influence but some of them have strong direct influence in isolation.
Sunlight
Light is necessary for photosynthesis, the process which provides the energy for all other plant functions. Other requirements being satisfied, the amount of solar radiation that the green plants can utilize will set the limit for the maximum quantity of plant growth and production.
Light, however, varies in quality, intensity and duration. That part of the solar spectrum absorbed by chlorophyll is the visible white light.
Infra-red and ultra-violet light are not utilized in photosynthesis. Ultra-violet light is known to be harmful to bacteria and is believed to exert a retarding effect on vegetation development.
All plant life is inevitably subject to alternating periods of light and darkness. For some plants, this is a factor of significance.
A particular length of day (or night) or a given photoperiod is an essential requirement for the production of flowers and seeds.
Additionally, leaf fall from many deciduous trees of temperate latitudes in autumn is thought to be determined by day-length. The response of plants to duration of daylight is called photoperiodism.
The significance of photoperiodism emerged as a result of long periods of experimentation, particularly with plants of economic value, under controlled laboratory Conditions.
It has implications on the horticulturalists who can regulate the photoperiod artificially in their green houses to produce short-or long-day blooms all year round.
Furthermore it has been realized that certain crops, such as onions and potatoes when deprived of optimum day-length for flower and seed production show increased vegetative development.
Obviously, for those plants that exhibit photo-periodism, the length of day may be the critical factor limiting their latitudinal distribution and their spread into areas where all other conditions might otherwise be quite suitable for their existence.
Precipitation
The influence of rainfall on vegetation is quite obvious. The processes of germination, photosynthesis, growth, flowering and fruiting require some water.
Areas that receive heavy and reliable rainfall have luxuriant vegetation growth.
Areas that have little unreliable rainfall have poor and scanty vegetation.
The vital processes of photosynthesis, growth and flowering activated by light, can, however, only take place in the presence of water.
Water is the medium by which mineral nutrients enter and are transported through plants.
Water is also necessary for the maintenance of leaf turgidity without which photosynthesis cannot operate efficiently.
Temperature
Temperature determines the rate at which plant processes of germination, growth, photosynthesis, transpiration, flowering and fruiting take place.
Each plant species requires specific temperature associated with each of these functions.
The temperature in a given area determines the rate of growth of plants.
For instance, plants of the same species in tropical lands grow faster than the ones in temperate lands.
In colder climates, fewer numbers of plant species are capable of surviving.
A large number of tropical species cannot survive below the freezing point.
Whether a plant will be able to grow in a certain area or not will depend on whether the requisite amount of heat is available for a period long enough to allow the completion of its life cycle.
An early and broad classification of plants according to the temperature conditions distinguish the following:
Megatherms: Plants of tropical and sub-tropical regions with at least four months averaging over 20c.
Mesotherms:Temperatures between 10c and 20c
Microtherms: In regions with eleven to eight months averaging less than 10c and
Hekisotherms: of the polar belts where all months have average temperatures of less than 10c
Wind
Wind is another climatic factor, which though not essential for plant growth, can exert a considerable influence on the form of plant.
Increased wind force, particularly when combined with low atmospheric humidity, can through its effects on evaporation greatly increase the rate of transpiration.
Even under conditions of plentiful soil moisture, it may put a strain on the plant’s water balance as severe as that in completely arid regions.
In areas exposed to high wind force, such as along coastlines and at high altitudes, the height to which plants grow may be limited by their ability to absorb and transport water upwards rapidly enough to replace that lost by transpiration.
Plants in exposed habitats are subjected to wind-shearing which may lead to retarded growth or may be inhibited by excessive transpiration.
It may also cause the curvature and malformation of branches and trunks of trees, as well as physical damage.
In addition wind is an important factor in dispersal of seeds and pollination.
Edaphic and pedological factors
Edaphic and pedological factors are those soil properties that affect plant growth and distribution.
For the majority of land plants, the soil is the medium, that part of their habitat, in which they are anchored and from which they obtain, by way of their root systems, the water and most of the mineral nutrients necessary for their existence.
The main edaphic and pedological factors that influence vegetation growth and distribution include:
Inorganic or mineral material.
Organic matter content.
Soil texture and Soil pH.
Inorganic (Mineral Material) and Organic Matter
Inorganic nutrients produced mainly by rock weathering are necessary for vegetation growth.
Inorganic minerals together with organic are the major determinants of soil fertility.
The main sources of nutrients are either rocks or organic matter. In this case they exist as complex insoluble compounds.
They are released by weathering in the former and decomposition in the latter, as simple soluble forms making them available for plant use.
Plant roots can only absorb these nutrients from the soil solution. Plant growth can be regarded, or the presence of a particular species excluded from a given habitat because these nutrients:
Lacking from the soil.
become available for use by plants too slowly or
Exist in incorrect proportions and are therefore not adequately balanced in the soil.
Soil Texture
In any soil, the proportion of the various soil fractions present determine the physical property known as its texture.
The texture of a soil is one of its most important and basic properties.
It determines the relative ease with which roots can penetrate into the soil.
It affects the nutrients supplying ability of the soil. It influences, too the water content, aeration and temperature, all of which are essential for the living organisms of the soil, plants included.
Soil pH
The pH of a soil also affects the relative availability for plant growth of those mineral nutrients present.
At approximately pH 6.5-when the reaction of the soil solution is just about neutral-all minerals are sufficiently available to satisfy plant requirements and there is enough calcium to counteract acidity, maintain the stability of the clay/humus complex, and promote crumb structure.
Under conditions of increasing alkalinity, however, certain minerals may be rendered insoluble or their absorption by the roots of certain plant species inhibited in some way.
Biotic and Anthropogenic Factors
The biotic or the biological factors which influence plant growth and distribution are those which result from the action of living organisms. The main biotic and anthropogenic factors influencing plant growth and distribution include:
Competition.
Effects of animals
Effects of human beings.
Competition
The establishment of a given plant species in an accessible and physically favorable site will depend on its ability to compete for space, light, water and soil nutrients with other potential occupants.
Competition, or ‘the struggle for existence ‘ between plants of the same or different species arises because the resources of a habitat are insufficient to meet the demands of all the plants available and capable of growing there.
The relative success of individual plants or species in this competitive struggle will dependent upon their ecological requirements, their life forms, their vigour and density of growth and their seasonal development.
Competition is most intense between individuals of the same or different species, which make similar demands on the same supply of light, nutrients or water at the same time. Competition is the principal biotic factor which under natural conditions, determines those plants that will be able to co-exist in a given habitat.
Whereas the physical factors of soil and climate are permissive, that of competition is selective.
Effects of animals
Biotic factors also include those related to the activity of the animals that live among and are dependent upon the plants growing in a particular area.
In contrast to those of plants, the effects of animals are primarily direct; in some cases they may be necessary for, in others antagonistic (against) to, the successful growth if certain plants.
Many plants are dependent on animals for seed dispersal and for cross-pollination of their flowers.
In the letter instance, animals-and more particularly insects-may be absolutely essential for the survival of a plant species in an area; it will not be able to exist if the pollinating agent is scarce or absent.
The most outstanding and conspicuous effects of animals however, tend to be antagonistic rather than beneficial. Plants are the basic food producers and are therefore, naturally inevitably fed on by animals.
In any habitat, a close relationship exists between the types and numbers of plants and those of the animals that can be supported directly or indirectly by them.
The effects of human beings
There are relatively few areas left where the vegetation cover is completely natural, in the sense of being the result solely of the interaction of the physical and non-human biotic factors.
Humans actions have been both direct and indirect. They include:
Modification of the physical environment in such a way as to encourage or discourage the presence of certain plants in particular areas.
Creation of new habitats such as quarries, coal bings, railway cuttings or bomb sites.
Alteration or modification of habit through the addition or extraction of minerals and water to and from the soil.
Pollution of soil, air and water which has been responsible for making certain physical habitats more or suitable for particular plants.
Accidentally or deliberately introducing plants to areas where formerly they did not exist for example e.g the water hyacinth in Lake Victoria and salvinia molesta in Lake Naivasha.
Clearing and cultivation giving preference and protection to some plants at the expense, or to the exclusion of others.
Being directly instrumental in identifying the destructive, antagonistic effects of animals on plants. For example he has drastically increased the numbers of certain types of animals at the expense of others and there are many animals whose numbers he has reduced almost to the point of extinction.
Increasing the numbers of domesticated grazing animals such as sheep, cows, goats and horses and reducing the number of animals that would normally compete with them for food.
Accidentally and deliberately starting fires as a means of either modifying or destroying natural vegetation cover.
Characteristics of the major vegetation regions of Kenya
Other than in a few protected areas, such as the forest reserves and national parks, very little of the origins natural vegetation cover of Kenya still remains. What we see today is the secondary or derived vegetation.
Relief, especially altitude, in conjunction with rainfall and soils have produced several different types of vegetation in Kenya, which can generally be identified as:
Forest vegetation
Savannah vegetation
Arid and semi-arid vegetation and
Heath and moorland.
Characteristics of forest vegetation in Kenya
In Kenya, the forest vegetation consists of evergreen and deciduous trees.
The evergreen forest are found at the higher altitudes and consists of various plant species such as bamboo, olive and podo trees.
The forested areas of Kenya can be sub-divided into :
Plateau and lowlands forests, which are found in some parts of the Lake Victoria region and at the coast around river Sabaki and Arabuko Sokoke. Mangrove forests are common in areas affected by tides.
Mountain or closed forests found on the mountainous and highland areas of the country. These are characterized by such trees as podo, cedar and camphor. Mountain forests occur in areas with an altitude above 1,800 metres. At about 3,000 metres, mountain forest gives way to dense thickets of bamboo and this zone in turn gives way to heath and moorland zone described below.It is important to note that apart from classifying forests on the basis of altitudinal zonations as done above, the forests of Kenya can also be classified according to their growth habit; that is according to the different types of trees and how these trees are grouped and grow together. On this basis the following types of forests can be recognized:
Closed forests such as the Kakamega and Aberdare forests.
Woodland fit example the Nyika woodland.
Bamboo for example on high mountains like ,Mt. Kenya and the Aberdares.
Mangrove forests, like those along the coast.
Characteristics of savanna vegetation in Kenya
The word savanna usually describes open grasslands with scattered woodlands or bushes. This type of vegetation occupies large areas of Kenya especially in the lake Victoria region as well to the south and east of Mt. Kenya.
Grasslands are also found in parts of the coastal region and southern Kenya. The savanna vegetation can be divided into two sub-types namely:
Savanna woodland which has a more or less continuous cover of trees with spreading canopies. The commonest trees in this sub-category are the thorny and drought resistant acacia. Also common in the baobab, a tree characteristics of the Nyika region.
Savanna grassland which is characterized by being more open and by having fewer trees dotted or scattered over the landscape. In,some literature, this sub-type is often referred to as scattered tree grassland. Savanna lands support a great variety of trees including many which are of economic importance. These trees include shea butter nut, baobab, acacia, silk cotton tree (kapok), borassus palm and locust bean tree. The acacia trees are common throughout the savanna lands. They gave an umbrella shape with Thorny branches and small leaves. The dominant grass species include the elephant grass (hyparrhenia) and cymbopogon afronardus.
Characteristics of Arid and semi-arid vegetation in Kenya
A vast area of Kenya consists of plains which have very little rain and very high temperatures. For this reason, these areas support arid and semi- arid vegetation.
The arid and semi-arid lands that receive less than 625mm of rainfall annually carry their own characteristic vegetation. This dry-land vegetation is of two types :
Bushland and thicket which is dorminant in areas that receive about 375 to 625 mm if rainfall annually. This sub-type consists of bushy, thorny and often tall acacia trees, separated by thorny shrub growing between them. It is unusual to find grass growing within the bushland and thicket type of vegetation.
Semi-desert and desert scrub vegetation. In areas that receive below 375mm rainfall annually, the the vegetation becomes short ( stunted). Scrub and bush are more common, often separated by wider areas or spaces of bare ground. Grass is rare except in areas with depressions where the water table is closer to the surface.
In the drier northern and north-eastern parts of Kenya, hard and short grasses are most dormant. Spiny shrubs, cactus and short thorny trees are characteristic of semi-arid and arid vegetation of Kenya. The arid and semi-arid vegetation has developed special mechanisms that enable it to survive and reproduce under the severe condition of limited moisture supply, high day temperatures and low humidity.
Key
Characteristics of heath and moorland vegetation
This vegetation type is found on the highest mountains above the tree line, generally about 3,500 metres above sea level.
The vegetation here is characterized by afro-alpine plants which are adapted to extreme cold and strong winds.
Heath vegetation is of the scrubby type.
It consists of low-growing evergreen shrubs with small bell-shaped pink or purple flowers.
The term moorland describes hand area covered with heath vegetation, coarse grass and mosses.
In Kenya, the heath and moorland vegetation is dormant on the upper slopes of Mt. Kenya and the Aberdare Ranges.
Characteristics of major vegetation regions of the world
On the basis of the quantity and quality of plants in a place, the world’s major vegetation types can be identified as:
Forests (tropical rain forests, tropical monsoon forests, deciduous forests, coniferous forests, mixed forests).
Grasslands (tropical savanna, temperate grasslands, arid and semi-arid grasslands montane grasslands).
Desert vegetation (hot and cold desert vegetation).
Alpine or montane vegetation.
Forests
The equatorial forests
These are also called tropical rainforest.
These forests are found within a belt that extends roughly 4 to 5 north and south of the equator.
Due to the hot and wet conditions that prevail, these forests have attained a very rich and luxuriant growth.
This is because the area has average annual temperatures ranging between 24 to 27 and heavy rainfall well distributed throughout the year.
Characteristics
The rainforests have closely set trees with three distinct canopies or layers.
The crowns of the trees form a continuous canopy of foliage which provides a dense shade for the lower layers.
The highest canopy rises to about 40 metres protruding above the second canopy which is 30 metres high.
This in turn towers above the lower canopy ranging from 5 to 15 meters high.
The lowest canopy consists of young trees of different stages of growth and some stunted tree species.
The trees are tall, smoothed barked and with no branches at the lower sections.
The trunks are commonly buttressed at the base by radiating wall-like roots.
Some trunks bear fruits and flowers, for example, cacao (Theobrona Cacao), lianas and other climbers such as the thick wooded vines are supported by the big trunks of the tall trees.
These climbers rise to the top canopy to receive light. Such climbing plants are known as ephiphytes because they grow on others and depend on them for support.
Examples of ephiphytes include orchids, mosses, lichens and ferns. Some epiphytes are partial parasites, for instance, the stranglers like the strangling fig (fucus).
The stranglers start off as ephiphytes in earlier growth but eventually conquer their hosts in their stages where upon they grow into giant trees on their own.
Trees found in these forests have broad leaves to protect them from collapsing during the intense midday isolation and high temperature, a factor that would render them useless for photosynthesis. The leaves are generally drip-tip in shape.
This shape is probably to permit the leaf to shed water easily, thus dry more quickly after rain.
The dry leaf discourages excess epiphyte population and also enables maximum transpiration efficiency in the humid conditions of the rain forests.
Other low growing plants that have special adaptation to the equatorial forest are the saprophytes.
These are completely devoid of chlorophyll and so depend on nutrients from the soil.
They are therefore closely associated with fungi which decompose humus for them.
They enter a symbiotic relationship with a fungi as a survival technique.
The fungi benefit from this symbiotic existence.
Equatorial forests have a varied number of plant species within a small portion.
For instance, as many as 1,500 species may be found in square kilometer.
This makes it difficult to exploit them for economic purposes as they are not found in uniform stand.
The typical species of the equatorial forests in Kenya are camphor, mvule, Elgin teak and plateau bamboo in the western parts of Kenya and ebony and mahogany.
The thick canopy cuts out the sunlight so that there is little ground cover of vegetation growing in the gloomy shade at ground level. However, along rivers and where man has cut down the vegetation, dense scrub quickly grows and less luxuriant secondary forests develop.
The rain forest trees are very straight with smooth trunks, which helps to make them a valuable source of timber.
Lianas hanging from the branches get longer as the trees grow taller, and epiphytes such as fern and orchids grow attached to the branches.
The roots of trees in the tropical rain forests tend to spread sideways rather than penetrate down, and massive buttress roots develop which help to support these tall trees.
Tropical rain forests have many different hardwoods exploited for commercial purposes.
Important hardwoods include; mahogany, ebony, iroko, sapele, okoume, samba, teak, and greenheart.
Tropical rain forests are found in the Amazon and Zaire basins, west African coast, New Guinea, Burma, Vietnam and Malaysia. The world distribution of tropical rain forests in the figure below.
Tropical Monsoon Forests
The tropical monsoon forests are in many respects structurally similar to the equatorial forest.
They occur on windward coasts roughly stretching from 10 North and south of the Equator to the Tropics of Cancer and Capricorn respectively.
They occur along monsoonal coasts where seasonal variation in rainfall is marked climatic feature.
During the intensely wet season,monsoonal winds are onshore while during the dry season, the winds are offshore.
The monsoonal forests are clearly adapted to this seasonal change since many species in it are deciduous.
The most widely distributed formation of the tropical or monsoonal forests is the Indo-Malaysian formation.
It extends outside the tropic of cancer in northern India around Assam and beyond the tropic of Capricorn in south-east Australia.
This belt contains broad areas of the tropical monsoon forests. It covers Bangladesh, Burma, Vietnam and the Philippines.
It extends over the islands of Sri-Lanka, Java and some of the pacific islands, the tropical monsoon forests have been nearly completely cleared to give way to human activities.
They are also found on the east facing slopes in Asia. These forests are also found on the east African coasts and the southern parts of the west African coast.
Characteristics
The true monsoon forests are mainly deciduous(shed their leaves during dry season) and less dense due to the long dry season.
They have a variety of tall equatorial forests. Some of the species in the tropical monsoon forests include camphor, ebony, sapele and pinkado, teak and bamboo.
Plants of particular tree species predominate an area for example teak in Burma, Sal in India and eucalyptus in Queensland.
The trees grow fast due to abundance of sunlight and moisture. The trees are tall, rising up to about 30 meters.
However, they lack a continuous canopy.
Coniferous Forests/boreal forests
They only occur between 45-75 north and south of the equator.
They are mainly found in the north American and the Eurasian continental belts.
The southern continents have only limited tracts on mountain sides such as the Andes and limited formations in New Zealand and Tasmania.
This is probably due to the narrowness of continental masses in the Southern Hemisphere.
Characteristics
Coniferous forests are conical in shape to combat the snow fall during winter.
They also have needle-shaped leaves, a characteristic that enables the trees to reduce water loss by transpiration during winter when all the moisture is frozen in the soil.
A quick receiver and pick up of the processes is possible when spring time comes.
Coniferous trees can only withstand the winter cold to a point beyond which they cannot survive.
This is especially towards the poles. The tree species are found on uniform stands. The major species are spruce, fir, pine and larch.
Tough coniferous forests are common in low latitudes, these forests are also found on high altitudes such as high mountain sides of the tropical areas.
In most coniferous forests, a thick carpet of mosses occurs.
The forest species are generally few and large tracts of forests can consist of only one or two species of trees.
The needle-leaf forests of North America, Europe and Siberia, where they are known as the Taiga, are composed of evergreen conifers such as the spruce, fir and pine.
The eastern and north-central Siberia and the Asiatic boreal in northern Japan and Manchuria is dorminated by the larch and the dwarf pine in drier places where they shed their needles in winter.
In the western Caucasus range of central Europe, the oriental spruce and fir are found.
On the Atlas ranges, the larch is common. Similar forests are found on the Himalayas in Kashmir and Napel.
In Burma and southern China or tropical mountains, coniferous forests exist on rugged terrain.
Deciduous Forests/summer greens
They are found in the middle latitude landmasses of the northern Hemisphere.
In America, they stretch from the Appalachian Mountains to the Mississippi across Minnesota, Michigan, Pennsylvania and New England. Riverine, deciduous forests are found along Missouri, North Platte, South Platte and Arkansas.
In Asia, a deciduous forest zone occurs around the yellow sea in west Korea, Shantung and Kwatung Pensular in China extending into the lowlands of Hopeh, Manchuria and the extreme South East of former U.S.S.R.
In the Southern Hemisphere, deciduous forests only occur in inland valleys such as on the leeward slopes of the Chilean Patagonia and Terradel Fuego in south America.
Characteristics
The trees are tall and have broad leaves which give them a continuous, dense canopy in summer making the forest very thick.
In winter, the trees remain dormant but build up wood in summer.
There are lower layers of weak shrubs and small trees between the tall trees.
The main species are hardwood and include the oak, birch, ash, sycamore, basswood, maple, chestnut, hickory hornbeam and beach.
The native oak of Shuntung was used to feed silkworm to produce wild silk.
Trees shed their broad-leaves in autumn and remain bare in winter to minimize loss of water by transpiration.
As water availability improves on the onset of spring, the trees regain their leaves and remain green in summer. Many trees grow in stands of the same species.
Mixed Forests
Conifers between latitude 45-75 north and south five way to broad-leaved summer green deciduous forests in warmer well watered localities.
In a zone of transition, two formations exist side by side. This transitional zone is therefore referred to as the mixed forests.
The trees species are not necessarily intermingled on individual basis.
Areas rich in mixed forests include Alberta and Saskatchewan Provinces in Canada and Central Siberia in Russia, where the birch, aspen and the willow are common.
The European Russia has clear mosaics of spruce and oak stands in Estonia.
In Europe, mixed forests are found on the Scottish highlands, the central Massif and the Cantabrian mountains in northern Spain.
There is also a continuous stretch extending eastwards from northern Alps, Alsace, Central and Northern German and South and Central Sweden. Pine, spruce, silver, fi, oak, birch and beach are present in the mixed forests of Germany.
In Eastern Asia, mixed forests occur in the midst of the boreal forests especially in the middle Amur valley, northern and eastern Manchuria, North Korea and southern Hokkaido and northern Kyushu Islands of Japan. Native species are the maple, birch, beech, poplar and oak.
The native ash and the keyeki are still common in these areas. Associated conifers in these are Japanese cypresses and Japanese cedar and fir.
In North America, a zone of mixed forests stretches from Minnesota through Wisconsin and southern Michigan to northern parts of Pennsylvania and New York.
In New Brunswick and Nova Scotia in Canada as New England in U.S.A., mixed forests were dorminant before economic activities such as industrialization, urbanization and agriculture changed the landscape.
Before that, the sandy out wash plain areas in Minnesota. Wisconsin and Michigan were occupied by stands of white and red pine while the richer soils were mainly occupied by stands of oak, hickory, maple and the beech.
The Mediterranean forest communities include the maquis(French) or Macchiaz (Italian).
They occur in the Mediterranean lowlands which are partly coniferous and partly broad-leaved.
In the southern Hemisphere, such formations are found in limited portions in Chile, New Zealand, Tasmania and South Africa. Here, the coniferous forests are not extensive enough to give noticeable transition to mixed forests and deciduous formations.
Characteristics
Mixed forests may take on characteristics of either the coniferous or deciduous forests.
Grasslands
Grasslands can be categorized into the following classes.
Tropical Savanna
Temperate grasslands.
Arid grasslands.
The mountane grasslands
Tropical Savanna
Tropical savanna occurs in tropical continental areas approximately between latitudes 10 North and South of the Tropics.
Characteristics
The tropical savanna is a mixture of trees and grass at varying degrees.
The more the rainfall, the denser the trees and the taller the grass.
Therefore, the tropical savanna can be sub-classified into tall grass and woodlands, parklands, thornbush and scrub in the order of decreasing rainfall.
The tall grass and woodlands consists of trees spaced widely apart permitting the growth of grasses and shrubs at a lower level.
This type of vegetation in Africa has been variously described as ‘dry forest,’ or ‘miombo woodland’ (in Tanzania) and tree steppe (in Zambia, Malawi, and Angola).
No actual stratification or formation of canopies is observable in the woodland communities as in the rainforests.
The dominant trees hardly exceed 20 metres in height and are mainly flat topped and spreading.
The grasses dominate the undergrowth and are mainly tall and belonging to many genera (species).
Thus vegetation type experience a prolonged seasonal drought for four to seven months.
However, a definite dry period lasting between four to five months is always experienced.
The rainfall hardly exceeds 800mm on average.
Most of the trees and shrubs therefore, assume special adaptation to his harsh condition.
Some shed their leaves during the prolonged dry season to check evapotranspiration. Some have wax bark and spiky leaves and thorn. The grasses dry up completely.
Annual grass fires are frequent. These grass fires periodically destroy the vegetation cover.
This has led to the contention that savannah woodlands are but a secondary form of vegetation derived from the former more luxuriant climax vegetation.
The tree species in the woodlands are dominated by the combretum variety in Kenya and most of Eastern Africa. The dominant tall grasses include the elephant grass (Hyparrhenia). Cymbogon afronardus is predominant in the high grass areas of the Lake Victoria Basin, where it is called Osinde.
In the highland areas like M.t Kenya, Kikuyu grass dominates.
The parklands are dominated by grass with a few isolated trees that are lower in height than those of the woodlands.
The parklands are generally treeless except along the rivers where water is available.
Red oat grass (Themeda triandra) dominates the Kenya parklands such as the Maasai Mara and Amboseli. Short acacia trees ( 1.8 to 2.4 m) are the dominant trees.
The taller acacia are found in the watered areas like along river valleys. Acacia is a high,flat topped tree and is well adapted to the drought-prone areas. Star grass is found on the riverine sections.
Thornbrush and scrub are found on the rainshadow areas in the tropical region.
They have drier vegetation, consisting of dry desert scrub and desert grass.
In these areas, rainfall is usually less than 650mm annually and is very unreliable.
The zone is dominated by acacia and euphorbia varieties.
This type of vegetation is typical of the Nyika plateau of Kenya.
Many tree species are stunted and have scaly barks. Drought resistant plants such as the baobab, euphorbia, commiphora and acacia can survive under the harsh environment created by poor soil, wind, aridity and a high rate of evapotranspiration.
Such vegetation type is evident in Makueni District.
During the unusually wet seasons, a rich growth of quick growing grass occurs.
The seeds from this grass are capable of sprouting for many years after the rainy season.
The cycle of germination, growth, flowering and seeding us extremely short (1 to 2 months).
Temperate Grasslands
These are also known as mid-latitude grasslands.
Five main zones of temperate grasslands are recognized over the world these are:
The prairies of North America
The Pampas of Argentina
The Veld of South Africa
Downs of Australia and New Zealand.
The Prairies of North America
The prairie grasslands in North America cover a big portion of south central Canada in the province of Alberta and Saskatchewan.
It stretches to the Gulf coast in south-eastern Texas (U.S.A).
They also have extensive formations on the plateaus and basins to the west and in central Valley of California, in Kentucky’s Blue Grass region and the Nashville Basin to the Tennessee.
They also stretch to the Mid-west plains in Illinois and western Indiana.
The prairies formation is sub-divided into three categories namely:
The true prairie
Mixed prairie and
The pacific and Palouse prairies.
The true prairie is found in a great area from south-central Alberta and Saskatchewan through southern Manitoba and middle west to the east central Texas, Oklahoma, central Kansas and Nebraska across the Dakotas into south Saskatchewa.
Characteristics of the Prairies
The dominant grasses would attain a height of 1 to 1.2metres before human interference.
A mixture of sword-forming grasses occur in these areas as well as bunch grasses like the common stipa grass.
In spite of general ‘tussocky’ appearance, particularly in winter, the true prairie forms a continuous sward or widespread sward-forming dwarf grasses include the buffalos grass and gramma grass while the mid-height grasses include stipa grass.
The mixed variety gives way to xerophytic type of grasses in drier zones, for example South West Texas, Southern New Mexico and Arizona where dwarf species alone dominate.
These cover the ‘desert plains.’ Cactus and saga brush are also found.
The mixed prairies is found in most of the Great plains.
It is mixed in the sense that it is composed of grasses of two distinct life-forms;
Those growing to a height of one metre and the dwarf grasses whose fruiting stems reach only a few centimetres high.
These are similar to the Palouse Prairie which was found over extensive areas of basin and plateau country in east Washington and Oregon, south Idaho and northern Utah as well as the Palouse itself.
These areas are dominated by bunch grasses while the true prairie and the mixed prairie have turf or sward grasses.
The blue bunch wheat grass is dominant on the Palouse prairie.
Grazing has also interfered with the original vegetation and sagebrush invasion has been rampant.
The Steppe of Eurasia
The same stappe has been applied to the wild grasslands of Europe and Asia (Eurasia).
The life forms are on the whole identical to the prairies of North America.
The areas include the semi-deserts of Caspian Sea area and Central Asia.
Characteristics
The species are very similar to the prairies. Sod-forming grass (a piece of slice of earth together with grass growing on it) are common.
In the Eurasian steppes, tussocky grasses are also found.
These form tufty grass or clumps of grass.
The grasses grow luxuriantly over one metre high.
Numerous broadleaved herbs were associated with them, providing flowery natural meadows in summer.
Today, these are still found in the riverine zones such as the Dniester and Dnieper river bends in the former U.S.S.R.
The dwarf, turf-forming grasses are dominant in the northern end of the Caspian Sea.
A similar type of vegetation was indigenous in the lowlands of Manchuria (northern China).
Today, short grass steppes are still very extensive in the eastern part of inner and outer Made Mongolia.
The Pampas of Argentina
Characteristics
The Pampas of Argentina were predominantly grass covered.
The Pampas are dominated by species of feather grass and melic which are similar to the tall prairies of North America.
North of Buenos Aries along River Uruguary, however, are found forests of a considerable extent.
The dominant species of the moist pampas were bunch grasses where a large percentage of the soul surface lay bare between individual tussocks.
In lower areas south of Bahia Blanco in Argentina, there was grass but towards the north and the Andean foothills, xerophtic shrubs occurred.
The veld of South Africa
The South African grasslands are known as the veld. These are confined to the eastern parts of South Africa interior.
Characteristics
The grass here is fairly extensive with little or no mixture of trees or shrubs.
Treelands are found on the ‘Sand Veld’ south of the Kalahari and Griqualand.
The true grassveld in the eastern slopes of the high plateau of South Africa is dominated by the red oat grass which forms a level sward.
Thus natural vegetation gas however, been reduced to rangeland.
Grass fires have destroyed the red oat grass and so the wire grass and blousaad grass are gradually becoming dominant.
The two may oust the red oat grass completely in the long run.
In better watered areas, taller grasses of Andropogon genus make a formation locally known as “Tambookie.”
The southern grasses are similar to the grass species in the savanna grasslands of the Eastern Africa with only a slight variation in species.
The Downs of Australia and New Zealand
In Australia, a tree savannah belt extends to the coast of the south eastern part of the sub-continent.
Characteristics
There are tall grasses dotted with isolated trees.
The areas of shrub and semi-desert of western Victoria and Southern Australia have patches of dominant grass.
Both mid-latitude and tropical species are represented in the Australian “savannas.”
These grasses in Australia are never nourishing pasture grasses and the ranching has been a consequent human activity.
The Canterbury plains in the south islands of New Zealand have extensive grasslands.
The grass is tussocky and very uniform in structure and appearance.
Occasionally, this sea of waving bunch grass is dotted sparsely with cabbage trees, sedges and herbs due to micro-climates.
Almost the whole of this grassland has been replaced by cultivated vegetation.
Heavy grazing by rabbits and other domesticated animals has altered the vegetation immensely.
Arid Grasslands
Thus is a grassland formation limited to sandy areas, saltpans and limestone areas in mid-latitudes areas.
The lime-accumulating horizon is close to the surface.
Since the rainfall is very low, a rock-like crust of the lime (CaCO3) or gypsum (CaCO3) called Caliche in North America and tosca in Argentina forms near the surface.
In Russia where humus content is higher, such habitats are referred to as Soloti or Soloth.
Characteristics
In the bog areas of Britain, heath is found where the dominant plants are present.
The herbaceous dwarf shrubs, like the ling, occur in some parts while Blanket bog formations occur in Western Ireland.
Bog moss is also dominant in N.W. Scotland.
In wet bog areas, lofty hygrophytic and halophytic grasses grow.
On the chalk areas of S.E. England, the calcareous heath occurs.
The Mediterranean area around Mediterranean Sea and Chaparral in America, us dominated by shrubs, spiny plants which are near-leafless with leathery drought-resistance foliage known as maquis.
Tropical species include the wild olive, the oak and the broom.
Montane Grasslands
These grasslands occur on mountainous areas of the world.
They are most extensive in places such as Sri Lanka, East Africa and Europe where the length of the growing period allows.
Characteristics
They generally occur in irregular patches of grass.
In higher latitudes, they are commonly found above the tree line where they grow and mature within a short vegetative period.
On the Alpine mountains of Europe, they occur as rich grasses that form pastures which allows the farmers to practice transhumance.
On East African mountains, these grasses occupy the mountain slopes up to 3,000m where the bamboo begin, to dominate.
They form thick tufts of grass.
In Sri Lanka where the grasslands are called Patana, they grow above 1,800m.
Desert Vegetation
There are two types of desert vegetation:
a.) Hot desert vegetation
b.) Cold desert vegetation
Hot Desert Vegetation
Covers major tropical deserts such as the Sahara, Namib and Kalahari in Africa.
The Arabian, Iranian and the deserts in Asia. Atacama and Chilean deserts in South America and Arizona and Mexican region in North America.
Characteristics
Scarse vegetation cover varying from short bushes to bare sandy grounds.
Xerophytic plants of various types survive in this area. This plants are highly tolerant to drought and can survive in dry area
Deciduous bushes and shrubs like acacia are common.
Salt- tolerant plants called halophytes grow in areas with poor drainage, saline and alkaline soils.
Stomata of the leaves of these plants are protected from excessive exposure to evaporation by being sunk in pits below the level of the leaf surface.
The reduction in the size and volume of leaves which in many deserts plants may be reduced to mere vestigal spines or scales.
Cold Desert Vegetation
Cold deserts are found in polar regions and on extremely high mountains where it is very cold and frigid.
It is arid because the water available to plant life is scarce due to freezing.
Cold deserts of the world are most extensive in the Northern Hemisphere in Eurasia and North America on high latitudes (66.5 to 90N).
This region is called the Arctic Tundra as it is close to the Artic Circle and North pole.
In the Southern Hemisphere,such vegetation is found in the Antarctica and sub-Antarctica tundra around the latitute 70 south.
Alpine or Montane Vegetation
On high mountains, vegetation varies with altitude, soils, aspect, shelter, winds and other local physical variations.
Characteristics
Immdediatley below the snow line is a zone of alpine tundra vegetation.
Below the alphine zone is the sub – alphine vegetation zone which gradually changes into the mountane forests.
Lower down,grasslands and even semi-deserts scrubs are found.
The height of the snowline and therefore the tundra zone,on mountains varies with latitude.
It is higher up the mountains in the hot – tropical region but lower down in temperate lands.
In east Africa and Mexico,below the snowline is the alpine tundra vegetation which occurs at about 4500 metes above the sea level.
Such alpine vegetation is found on mts Kilimanjaro,Meru ,Kenya Aberdares and Elgon.
This vegetation occurs at 3,600 metres in Western Himalayas,3,000 metres in Sierra Nevada,2,100 metres in the Swiss Alps and the Caucasus and at only 1,200 metress in Alaska.
The variation is due to diffrences in latitude.
X – Rainforest
Y – Bamboo forest
Z – Health and moorland
On both mid-latitude and tropical mountains, below the snowline a tundra vegetation zone is well developed.
The conditions and formations are very similar to those of the Artic tundra.
The zone changes into more luxuriant growth of forests then grasslands towards the base of the mountains especially in the tropics.
For example, considering the favorable slope aspect of the high mountains in East Africa, it is possible to encounter vegetation types ranging from the rainforests right up to the tundra type from the mountain foot to the top.
In North America, the rocky Mountains alpine formations is well developed.
The species below the snowline are similar to those found in Canadian Artic tundra.
The leeward sides of mountain ranges have a poorer vegetation than the windward sides.
The transitional zone of shelter on mountain slopes have transitional vegetation.
For instance, the north facing slopes of the central Asian mountains contain richer alpine vegetation with cushion-like rosette plants along with alpine sedges and grasses.
Alpine vegetation, especially in the tropical and mud-latitude areas, experience high light intensities with consequent day-time warming throughout the year.
These characteristics explain more luxuriant forms such as tree heathers that are giant varieties of the dwarf counterparts in the artic tundra. On undulating sections of mid-latitude high mountains, bogmoss dominates.
In north west Scotland, the deer’s hair grass, the ling, the bell-heather, bog mytles rushes and sedges are found.
Although the mountains of East Africa form a relatively small area, they support a wide range of world vegetation types.
Three main altitudinal belts have been distinguished:
The uppermost alpine belt, that is the tundra counterpart.
The sub-alpine ericaceous belt, that is the flower belt.
The forest belt which includes the mountain bamboo.
The alpine belt and sub-alpine belts occur between 3,000m to 4,200m above sea level.
These include heath and moorland. Due to a wide diversity of conditions caused mainly by aspect, the alpine belt varies from short alpine grass such as alchemilla to stands of giant senecia and lobelia.
The sub-alpine ericaceous belt below is dominated by heathers, for example, the tree heather and flowers. Tussock grasses are also found.
In general, vegetation in this zone varies from mixed shrub and grass moorland to a dense growth of tree heather and from short Erica (flowers) heathland to thickets of up to 10 metres on wetter mountains such as Mt. Kenya, Aberdare and the Ruwenzoris.
At about 3,000 metres on wetter mountains, the bamboo belt occurs. This may mix with other trees that become dominant lower down.
Such forest trees become a dominant formation on the wetter lower slopes.
The higher forest mountains include rain forests varieties such as the pencil and the dry cedar.
The leeward lower slopes have grades of the savanna that become poorer to semi-desert scrubs, for example, the masai steppe on the slopes of Mt.Kilimanjaro.
Economic significance of Vegetation
-Medicinal value
-For aesthetic value/beauty
-Habitat for wild animals
-Sources of building /construction materials e.g timber
-Source of fodder/feeding of animals/food for man
-Control of soil erosion
-Influence of rainfall formation
-Source of raw materials for industries e.g pulp and paper industries
-Forests protect water catchments area
End of topic
Did you understand everything?
If not ask a teacher, friends or anybody and make sure you understand before going to sleep!
Past KCSE Questions on the topic
1. The map below shows some vegetation regions of the world.
Use it to answer questions (a) to (c).
Name the temperate grasslands marked H, J and K.
Describe the characteristics of the natural vegetation found in the shaded area marked N.
i) Explain four ways in which the vegetation found in the area
marked M adapts to the environment conditions of the region.
You are required to carry out a field study of the vegetation within the local environment:
i) A part from identifying the different types of plants, state three
other activities you will carry out during the field study.
ii) How will you identify the different types of plants?
2. The diagram below represents zones of natural vegetation on a mountain in
Africa. Use it to answer question (a) (i) and (ii)
a) (i) Name the vegetation zones marked W, X and Y. (3mks)
(ii) Describe the characteristics of the savanna vegetation. (6mks)
(iii) Name the temperate grasslands found in the following countries:
Canada (1mk)
Russia (1mk)
Australia (1mk)
b) Explain three causes of the decline of the areas under forest in Kenya.
(6mks)
c) You are supposed to carry out a field study on the uses of vegetation in the
area your school.
State three reasons why it would be necessary to visit the area before the day of the study. (3mks)
Give four uses of you are likely to identify during the study (4mks)
3. (a) What is a natural vegetation? (2mks)
(b) State three characteristics of Mediterranean vegetation (3mks)
4. Explain three measures that the Kenyan government has taken to reduce the
Decline of natural vegetation cover. (6mks)
5. How do the following factors influence distribution of vegetation in Kenya.
(i) Variation in rainfall
(ii) Variation of temperature
(iii) Variation of altitude/relief.
(iv) Aspect
(v) Soil
(vi) Human activities (10mks)
6. State two reasons why mountain tops have no vegetation. (2mks)
7. Define vegetation. (2mks)
8. Name areas where coniferous forests are found. (3mks)
9. State characteristics of temperate grassland. (5mks)
10. Distinguish between secondary vegetation and planted vegetation. (4mks)
11. State two ways in which vegetation is significant to human and physical environment. (5mks)
(a) Name the type of photograph and type of vegetation. (2mks)
(b) Describe how the vegetation is adapted to climatic conditions of the
region. (3mks)
GEOGRAPHY (312)
PAPER TWO
INTRODUCTION
Questions in this paper will mainly test topics Statistics , Photographic interpretation andhuman and Economic Geography
Economic and human geography topics include:
Mining
Forestry
Energy
Industries
Population and urbanization
Trade
Tourism
Transport and communication
Agriculture
Management and conservation of environment.
The time allocated for this paper is 2 ½ hours.
The paper consist of a total of 100 marks.
The paper shall consist of two section: : Section A and B
Section A
This section will have 25 marks compulsory short answer questions
Section B
This section will have 75 marks
One compulsory question on either statistics or photographic interpretation (25marks).
A choice of four (4) essay questions on Human and Economic Geography, candidates to answer any two (2).
CHAPTER ONE
Specific Objectives
By the end of the topic the learner should be able to:
(a) Define the term statistics;
(b) Identify types and sources of statistical data;
(c) Identify and describe methods of collecting and recording data;
(d) Analyses, interpret and present statistical data using appropriate graphical methods;
(e) Explain the advantages and disadvantages of each method of data presentation.
Content
Definition of statistics.
Types of statistical data.
Sources of statistical data
Methods of collecting data.
Methods of recording data.
Analysis of data by working out arithmetic mean, median, mode, percentage, range.
Statistical analyses, interpretation and presentation by use of Line graphs, Bar graphs, Polygraph (combined line and bar graphs), Wind rose’, Comparative/group line and bar graphs, cumulative bar graphs, proportional circles, pie charts, divided bars/rectangles, population pyramids and Age-Sex pyramids.
Analysis and interpretation o f dot and choropleth maps.
Discussion of the advantages and disadvantages of each method of data presentation.
Definition of statistics
Statistics refers to the facts and figures collected and arranged in a systematic manner.
Statistics may be regarded as an art or a science, which is concerned with the interpretation of numerical information.
Statistical Data
This refers to the actual facts and figures collected from various areas and arranged in an organized manner
Statistical Methods
These are techniques of collecting, recording, analyzing, presenting and interpreting statistical data with a view to drawing valid and useful conclusions from them.
Types and Sources of Statistical Data
Statistical data are categorized into two main types:
Primary data
Secondary data
Primary Data
These include all the facts and figures collected first hand through different methods like:
Oral interview
Direct observation
Questionnaire
The data has not been documented therefore it can be said to be original data.
Secondary Data
These includes all the facts and figures collected and recorded in textbooks, journals, statistical abstracts and other written materials.
The sources of secondary data are called secondary sources.
Sources of secondary data include:
Textbooks
Statistical abstracts
Census reports
Geological reports
Newspapers
Characteristics of secondary data
Discrete – It is non – continuous over time and may be given in whole numbers. Examples of discrete data include the number of population in a specified country e.g. 10 people, 1000 people.
Note:
In discrete data there is no decimals or fractions it only has whole numbers.
Continuous – This kind of data is continuously distributed over time for example data about temperatures, distance, population growth etc. The values also contains decimals and fractions. 10.5 km, 2.67%.
Methods of Data collection
The main methods of data collection include:
Questionnaire
It uses questions to gather information.
It consist of a list of questions related to the topic being researched on.
Types of questionnaire
Personal Interview Questionnaires.
Rigid Questionnaire
Advantages
The researcher is able to seek clarification of unclear response by asking supplementary questions.
The researcher is able to win the respondents trust and dispel any fears that the respondents might have.
Direct contact with respondents provides the researcher with an opportunity to gauge the accuracy of the answers given.
Direct contact with respondents provides the researcher with an opportunity to gauge the accuracy of the answers given.
Comparisons can be made easy because similar questions are used for all the respondents.
They are useful sources of first-hand information.
Rigid questionnaires when posted to the respondents reduce fieldwork expenses.
Disadvantages
Travelling expenses inflate research costs.
A lot of time is also lost in movement.
The questionnaire may not be effective where the respondent is illiterate or where there is a language barrier.
Mailed questionnaires usually bring back insincere and inaccurate responses especially where opinion questions are involved.
Questionnaires when mailed may never reach the respondent.
Interviews
It is a direct discussion between the researcher and the respondent when they meet face to face or indirect when they converse over the phone.
Advantages of interviews
The researcher is able to seek clarification for ambiguous responses.
They provide an instant source of information.
They can be used to extract information from illiterate people.
Direct contact with the respondents enables the researcher to estimate the accuracy of the responses.
The researcher is in a position to dispel any fears from the respondent and therefore ensures that truthful answers are given.
Disadvantages of interviews
Susceptible to bias
Time consuming compared to other data methods.
May be seen as intrusive to the respondent.
Language barrier may arise.
Observation
This method involves direct visual observation of the geographical phenomena.
Advantages of observations
It provides reliable data.
It saves time.
It provides first hand data.
Disadvantages of observation
This method is subjective since it is based on personal observations.
Very expensive due to travelling cost.
It is affected by weather conditions.
Visual impairment may limit the effectiveness of this method.
It may not be possible to collect data on past activities.
Taking measurements
Data can be obtained in the field using measurements such as pacing, estimations, counting, using instruments.
Advantages of Measurements
It is easy to measure and read information shown in the instruments.
Data obtained is accurate.
It is a quick way of collecting data.
Disadvantages of Measurements
Sometimes the data obtained may be inaccurate
Errors may occur.
Secondary sources (Content Analysis)
This involves a researcher gathering secondary data by extracting/examining previous research work.
Secondary sources include:
Journals
Periodicals
Census reports
Textbooks
Maps
Advantages of using content analysis
It is easy to collect data.
Inexpensive.
Gives access to old information.
Disadvantages of using content analysis
The available information could have been biased and thus emphasized prejudiced.
The data could be outdated and in some cases irrelevant.
In some cases the secondary data may have been inaccurately collected.
The available data may appear in a format that is not appropriate.
Experimentation
This is an act of conducting a test or investigation to provide evidence for or against a theory.
Advantages of Experimentation
First hand data is obtained.
It can lead to further discoveries.
When properly conducted it give accurate results.
Disadvantages of Experimentation
Time consuming.
It may be expensive.
Use of defective instruments may lead to inaccurate data.
Improper handling of equipment and chemicals may lead to accidents.
Sampling
A sample is small part of anything intended as a representative of the whole.
Sampling is the process by which a representative portion of the phenomena under research is selected for analysis.
Population is the phenomena under study.
Types of sampling methods
Random
This sampling technique is useful where the phenomena under research is not distributed in any particular order.
Systematic
This method is useful where the phenomena is large and evenly distributed. The objects for study are selected at regular intervals.
Stratified
This involves the selection of study samples on the basis of the groups or categories of the similar elements of the phenomena.
Advantages of sampling
It is less expensive.
It saves time.
It avoids bias.
Disadvantages of sampling
A poorly selected sample can lead to misleading information.
It is not suitable to an unevenly distributed population particularly the systematic sampling.
Methods of Recording Statistical
This involves the recording of figures and facts collected in the field to ensure that all details are available for analysis.
Tabulation
This is recording of data by arranging facts of figures in form of table or list.
Photographing
This capturing what observed in the field and storing it inform of photographs. This is done by use of a camera to record geographical information.
Note Taking
This involves the making of short notes during an interview so that no information given is lost.
Labelling of Samples
Once the samples are collected in the field they should be put in polythene bags and clearly labelled by naming them.
Filling in the questionnaires
The data is recorded by filling – in the information as instructed in the questionnaire.
Mapping
This involves the drawing of a sketch map to show the distribution of various items in an area.
Field Sketching
This involves the preparation of a simple sketch of what is observed in the field.
Tape recording
This can be done when one is collecting data through an oral interview where one uses tape recording device to record conversation.
Tallying
Used when the data is collected through counting. One counts and puts a vertical strike for every item counted, on the fifth count one puts a diagonal crossing the four strokes
Analysis of Data
Statistical analysis means examining the recorded figures and facts in detail so as to explain the meaning and features of the data.
Methods of Analysis of Data.
Calculation of percentages
The data collected may be converted into percentages to make it more meaningful.
Example
In the study of a farm, 20 hectares where devoted to tea and the total acreage is 100 hectares. Find the percentage under tea.
Solution
20/100 x 100=20 %
Measures of central tendencies
Central tendency is the outstanding general characteristics of the data. The main measure of central tendency are:
The mean
The median
The mode
The mean
The mean also known as arithmetic mean is obtained by dividing the sum of the number of all the values with the number of observations made.
Example
The population densities for five sub- locations are found to be 10,11,14,20 and 20 persons per 〖km〗^2 then the arithmetic mean (average) is:
((10+11+14+20+20))/5=15 persons
Mathematically, the following formulae is used.
X ̅=(∑▒x)/N
Where x ̅ is the mean.
∑▒x is the sum of individual values observed.
N is the number of observations.
The median
This is the middle value in given set of data arranged in a rank. To obtain the median, all the values are arranged in an ascending or descending order and then the middle value is determined.
Example
Find the median 5, 9, 10, 30, 12, 20, and 17
Solution
5, 9, 10, 12,17,20,30
12 is the median
Note:
When the set is an even number we simply add the two middle numbers and divide by two to get the median.
The Mode
This is the most frequent recurring value in a set of data.
Example
Find the mode 4 5 7 9 5 2 8 4 9 5 1 5
Solution
The mode is 5 because it appears the most i.e. 4 times
Measure of dispersion
Measure of dispersion show how the data provided is spread out. The main measure of dispersion is the range. The higher the range, the more dispersed the data is and the lower the range, the less dispersed it is.
The range is obtained from subtracting the higher value from the lower value.
Formulae for calculating the range
R = XL – XS
Where R is the range
XL is the highest value
XS is the lowest Value
Statistical Presentation of Data
This is the method of putting collected, recorded and analyzed data in a form that brings out meaning to other people.
The type of method of data presentation depend on:
The type of data being presented.
The information being put across.
Method of Data presentations
These are one or two dimensional drawings that show the relationship between two types of data.
When one variable changes, it causes a change in another variable.
The first one is called an independent variable while the second one is called dependent variables.
In drawing a graph the independent variable is put on the x – axis while the dependent variable is put on y – axis.
Types of graphs.
There are two main types:
Simple line graph
Simple bar graph
Simple line graph
This is one dimensional diagram that shows the relationship between two variables.
It is a useful method for presentation of continuous data, such as temperatures.
A simple line graph may be either curved or straight with sharp angular turns.
Curved simple graphs are used to present continuous data like the mean monthly temperature, population growth rate and changes in air pressure.
Straight simple line graphs with sharp angular turns are used to represent data which may have some discontinuity.
Construction of a simple line graph.
Draw the x and the y axes on the graph paper.
Choose a suitable scale for the variables noting that the x-axis is for independent variable and y- axis for the dependent one.
Plot the values accurately using small faint but visible dots.
Join the faint dots by a smooth curve as shown below.
Example
Construction of a simple line graph using curved line
Month J F M A M J J A S O N D
Temp 29 29 30 28 27 26 26 26 26 27 28 29
Example
Construction of a simple line graph using a straight line.
Year 1980 1981 1982 1983 1984
Harvest in ‘000 bags 2050 2600 1800 1950 3000
Solution
Advantages of simple Line Graphs
It is easy to construct and interpret.
It is easy to read since it shows the trend.
It enables easy comparisons of variations in the associations between two variables.
It does not involves lengthy and tedious calculations.
The trend of the relationship can easily be seen.
Exact values can easily be estimated.
Disadvantages of line Graphs
The causes of the illustrated relationship cannot be established from the graph.
It shows no comparisons between two or more sets of data.
Does not give a clear visual impression on the quantity of the data.
It ignores some details of change and may give a false impression on the continuity of some data.
Simple Bar Graph
This is a two dimensional diagram which shows the relationship between two variables.
This graph is composed of single separate vertical or horizontal bars with each bar presenting a given value.
The length of the bars should be the same and conveniently chosen. (Usually 1 cm wide).
The length of the bar is equal to the value being presented.
The space between two adjacent bars should be constants.
Construction of simple bar graphs
Draw the x and y axes. The x-axis is for independent variables.
Decide on the width of the bars and the width of the space to separate the bars. (The same space should separate the x-axis from the first bar).
Find a suitable vertical scale so that the bars do not become too long or too short.
Then plot in the values with small faint but visible dots placed in the middle of the top line will form end of each bar.
Neatly draw the outlines of all the bars and label them if necessary.
Example
The table below shows the quantity of minerals produced in tonnes. In the year 2004 – 2005 use it to answer question (a) and (b)
Minerals Amount in metric tonnes
Year 2004 2005
Soda-ash 70,000 130,000
Fluorspar 200,000 370,000
Salt 98,000 55,000
Others 240,000 295,000
(a) (i)Using a scale of 1cm to represent 50,000 metric tonnes draw a simple bar graph based on the data above . (8mks)
(ii) State two advantages of using bar graph (2mks)
(iii) Calculate percentage increase in soda ash production between the year 2004 -2005
Solution
Advantages of Bar graphs
They allow ease in comparison/interpretation.
They give clear visual impression.
They are easy to read.
They are easy to construct..
Bars and individual units are suitable to present population of countries.
Disadvantages of Bar graph
Difficult to choose a suitable scale when the value for each variable differ by a great magnitude.
It does not show relationship between the same types of data such as temperature or rainfall amounts of more than one place.
The causes of variation in the variables cannot be established from the graph.
Example
The table below gives the figures for the 2009 population census per county for the central region of Kenya.
COUNTY POPULATION
Kiambu 1623282
Murang’a 942581
Nyeri 693558
Nyandarua 596268
Kirinyaga 528054
Besides bar graphs, name three other methods that can be used to represent the above data. (3 marks)
Draw a simple bar graph to represent the data in the table above. Use a scale of 1cm to represent 200,000 persons. (6 marks)
Solution
(a) Other methods of data representation.
– Divided rectangles
– Proportional circles
– Pie chart
(b.) Simple bar graph
Combined line and Bar graphs
This graph is a combination of the line and bar graphs.
It is mainly used to show the relationship between two types of data especially temperature and rainfall as shown below.
Construction of combined line and bar graph
The only difference in construction is that temperature figures are plotted on the right hand side of the y-axis while rainfall amounts are plotted on the left side.
Advantages of combined Line and Bar Graph
It is easy to construct and read.
It shows the relationship between two different types of data such as the relationship between temperature and rainfall.
Disadvantages of combined line and Bar Graph
It does not show relationships between the same types of Data.
It is difficult to choose a suitable scale when the value for each variable differ by a great magnitude.
The causeof variation in the variables cannot be established from the graph.
Example
The table below shows the data for temperature and rainfall of station X.Draw a combined line and bar graph to represent the data.
Month J F M A M J J A S O N D
Rainfall in mm 20 40 100 140 280 440 270 70 140 200 80 30
Temperature 27 28 28 28 27 25 25 24 25 26 28 26
Solution
Wind rose
This is a statistical chart that is used to show diagrammatically the average frequency and direction of the wind at a given place.
The wind rose may be drawn in its correct place on a map.
The length of the column shows/represents the frequency of wind in the given direction.
Construction of a Wind Rose
The centre of the wind rose is a circle of any given size. An octagon may be used instead of a circle.
The number of calm days is written inside the circle or sometimes they, may be indicated immediately under the wind rose.
Eight points of the compass are sufficient.
The length of the columns or arms is drawn proportional to the actual number of days.
Direction of the winds N NE E SE S SW W NW Calm Total number of days
Number of days 3 3 1 1 2 7 6 4 4 31
Advantages of a simple Wind Rose
It is easy to construct.
It gives a good visual impression.
It is easy to read and interpret
Disadvantages of wind Rose
It does not show the speed of wind.
It does not show the comparison of wind direction.
Statistical Methods (II)
Compound (cumulative) Bar Graphs
Comprise of one or more bars drawn vertically or horizontally with each bar subdivided so that each portion represents a component of the data that makes the whole.
Where two or more bars are drawn, each bar is separated with an equal space between them.
Suitable for presenting data depicting the total value of several items.
Construction
Find the totals for each year and find the cumulative totals for the data.
Draw x and y axes and decide on the widths of the bars and the space between the bars.
Find a suitable scale by considering the largest and smallest values in the set of statistics being represented.
Draw the outline of each bar with its components and shade each component differently. The part of each bar representing the same component should have the same shading for comparison purposes.
Derive a comprehensive key to indicate what each shading represents on the graph.
Label the axes to show what the y and x axes represent.
Put a short and clear title in the space above the graph stating what the graph is representing.
Interpretation of Compound bar Graphs
Observe the trend of the bars.Look for the total of the variables of each bar in the period given.
Compute the trend of an individual variable against the successive totals of each bar.
Comment on the trend of each variable.
From the interpretation,suggest possible reasons to exaplain the trend of the variables obtained.
Example
The table below shows crop production in Kenya for a period of five years in 1000 kilograms. Use it to answer question (a)
CROP/YEAR 2005 2006 2007 2008 2009
Coffee 1000 900 800 700 800
Tea 700 700 600 680 600
Cotton 500 400 300 600 350
pyrethrum 300 200 300 440 450
(a) (i) Using a scale of 1 cm represent 200 kilograms present the above data using a compound bar graph.(9 marks)
(ii) List two advantages of using a compound bar graph to represent statical data. (2 marks)
Solution
(ii) Advantages of using a compound bar graph to represent statical data. (2 marks)
Facilitates comparison of data
A number of variables can be represented in one bar
Changes /trend is easy to trace
Good visual impression
Example
The table below shows kenyan’s visible Trade (kfm) From 1982 to 1986.Use it to answer questions below.
YEAR 1982
1983 1984 1985 1986
IMPORTS 900
905 1100 1200 1340
EXPORTS 570
650 780 800 980
(i)Draw a comparative bar graph to represents the data (5mks)
(ii)State two disadvantages of using a comparative bar graph (2mks)
Solution
COMPARATIVE BAR GRAPH SHOWING KENYAN’S VISIBLE TRADE BETWEEN 1982__198
Marking points
The title (1mk)
Key (1mk)
Correct bar each year ( ½=2 ½mks)
Correct labeling of axes each (1/2=1mk)
Vertical scale (1/2 mk)
Disadvantages of using a comparative bar graph
The general movement of trend of any component is difficult to follow.
Not suitable for cooperation of the totals in each year where there are many groups of bars.
The bars tend to emphasize too much on the quantifies while Flactuations are ignored
Proportional Circles
This method employs the use of circles of various sizes to represent different sets of data.
Each circle is drawn to a size proportional to the total value of data it represents .
For example,the smallest value is represented by the smallest circle while the largesst value is represented by the largest circle.
Construction procedure
Two approaches may be employed in the construction of proportional circles namely:
Use of circles with diameters proportional to the total values.
Use of circles with areas proportional to the total square roots of the total values.
Use of circles with diameters proportional to the total values
Round off the totals to the nearest thousands to obtain round figures for ease of working.
Select a suitable scale for the diameter which will in turn be proportional to the total values.
Use the radii figures to draw the different circles.
Use of Circles with Areas Proportional to the total values
The proportional circles may be draw by drawing circles whose areas are proportional to the square roots of the absolute values.
Find the square roots of each set of Data.
Choose a suitable scale for the use in calculating the different radii of the circles.The scale should neither be too big nor too small.
This is to ensure that the sizes of the ircles is convenient.
Then draw circles using the different radii.
Advantages of proportional circles
Give clear comparisons of total values of Data.
Give a good visual impression.
Can be combined with other methods on the same maps hence aiding in data analysis.
Disadvantages
They are tedious and time consuming to construct.
It is difficult to establish the actual total values for each period.
It is hard to obtain a suitable scale if the variations in the values is too big.
Divided rectangle
The table below shows items exported from country X .Use it and answer the following questions
Export item Weight in tones
Maize
Coffee
Oil palm
Spices 13600
11000
1600
850
(a) (i) Draw a divided rectangle of 15cm in length to represent the above data(show your calculation) (9mks)
(ii) Give two advantages of a using the above method for statistical representation (2mks)
Solution
Total production = 27050
(a) (i) Maize = 1
Coffee= 1
Oil palm= 1
Spices = 1
Divided rectangles showing items exported from country X
(ii) Gives clear impression
-Comparison of variables is easy
-Easy to construct.
-Can be used to represent a wide range of data (2×1=2mks)
Pie charts/divided circles/pie- graphs
These are circles drawn and subdivided to represent statistical data.
Each segment of the circle represents a given component of the of the data.
The size of the segment is equivalent to the quantity of the value of the component.
Types of pie charts
Simple pie charts.
Proportional divided circles.
A simple Pie Chart (Divided Circle)
This involves drawing a circle of a convenient size representing a complete set of recorded data.
The circle is then sub-divided with each segmnent representing a component of the set data.
The circle is then sub-divided with each segment representing a component of the set data.
The size of the circle is conveniently chosen and has no relationship with the quantity of the data to be represented.
It is the segment that passes statistical message.
It is used to represent such data as crops produced in each division of a given district or quantities and value of imports and exportsof a given company.
Each component is calculated as a percentage of the whole and then convented to degrees.
Construction
The construction of a simple pie chart takes the following steps:
Systematically convert each component as a percentage of the whole and then convert the percentages into degrees (not that 360 is equivalent to 100% or total data).
Draw a good circle of convenient size using a pair of compass. The circle should neither be too large nor to small. It should preferably be on a plain paper.
From the centre of the circle, using a protractor, measure and draw each calculated angle representing each component. It is advisable to start with the largest segment and end with the smallest in a clockwise direction.
Label the segments appropriately. The segments may be shaded to give a good visual impression.
Give the pie chart a title and if necessary, a key.
The above steps can be illustrated in the example below.
Crops Land use
coffee 300 ha
Tea 150 ha
Other crops 50 ha
Total 500 ha
The data given above can be presented using a pie chart as follows.
Calculate the angle for each component
Coffee
300/500 x 〖360〗^0=〖216〗^0
Tea
150/500 x 〖360〗^0=〖108〗^0
Other crops
50/500 x 〖360〗^0=〖36〗^0
A pie Chart showing land use in area A
Interpretation of simple pie charts (Divided circles)
The circle in this case represents the total value of variables. From the circles, it is easy to establish the contribution of a variable in percentage.
From the pie chart it is also possible to suggest the possible reasons responsible for variation in the data.
Advantages of a simple pie chart
It gives a clear impression of individual components.
It can be used to represent a wide range of statistical data.
It is easy to read and interpret.
It clearly shows individual amounts and clear comparisons of different quantities can be made.
Disadvantages if simple pie chart
Its construction requires a lot of calculation.
Small quantities or decimals may not be easily represented.
They do not show trend.
Proportional Divided Circles
This is a case where two or more divided circles are drawn with each circle representing a separate set of statistical data.
The sets may have different total quantities or value.
The size of the circle is proportional to the total quantity or value of the set of data being represented. The proportionately drawn circles are then subdivided just like the simple pie charts.
Construction of proportional divided circles take the following steps:
Find the square roots of the totals for each set of data.
Using the figures obtained in (I) above, find a suitable scale for the radii of the circles taking care that the circles do not become too large or too small.
For each set of data, calculate the percentages and angles as in simple pie charts.
Draw the circles using the scale in (ii) above the insert the details just like in simple pie charts labeling each component. In each of the circles, shade the same components in the same way as above.
Give the proportional divided circles a title, and if necessary a key.
The steps explained above are illustrated in the following examples.
The table shows causes of deaths in year 2004 for countries X,Y and Z
The above data is represented using proportional divided circles as follows:
Calculate the square root of each of the totals so as to determine the radius of each circle.
Note that the radius is obtained from a chosen scale.
Country HIV/AIDS Roads Accidents Drug abuse Total
X 10,000 2,000 2,400 14,400
Y 3,000 4,100 1,000 8,100
Z 500 270 130 900
Size of the circles:
√14,400 = 120
√8,100 = 90
√900 = 30
Scale: Let 1 cm represent 20.
Radius of circle for country X = 6cm
Radius of circle for country Y = 4 1/2 cm
Radius of circle for country Z=1 1/(2 )cm
Country X:
HIV/AIDS – 10,000 represent
10,000/14,400 x 100=69%
69/100 x 360=284.4^0
Road accidents – 2,000 represent
2,000/14,400 x 100=14%
14/100 x 360=50.4^0
Drug abuse – 2,400 represent
2400/14,400 x 100=17%
17/100 x 360=61.2^0
Country Y:
HIV/AIDS – 3,000 represent
3,000/8100 x 100=37 %
37/100 x 360=133.2^0
Road accidents – 4,100 represent
4,100/8100 x 100=51 %
51/100 x 360=183.6^0
Drug abuse – 1000 represent
4,100/1800 x 100=12 %
12/100 x 360=43.2^0
Country Z:
HIV/AIDS – 500 represent
500/900 x 100=56 %
56/100 x 360=201.6^0
Road accidents – 270 represent
270/900 x 100=30 %
30/100 x 360=183.6^0
Drug abuse – 130 represent
130/900 x 100=14 %
14/100 x 360=50.4^0
Interpretation of proportional Divided Circles
The circles represent the proportion of the variable in each category.
The segments in each circle describe the nature of the variable.
In the proportional circles given HIV/AIDS which presently has no cure is the leading cause of death is n countries X, Y and Z.
The size of the circle represent the total number of deaths, country X has the highest number of deaths followed by countries Y and Z.
Example
The table below shows green tea volumes delivered to kericho tea factory by various Lorries versus the acreage from which the tea was plucked. Use the data to answer the questions that follow.
Lorry Tea delivery in kgs Acreage from which green tea was picked.
A 2,000 20
B 8,240 43
C 11,000 70
D 5,300 35
E 5,700 30
TOTAL 32,240
Draw a pie-chart with a radius of 5cm to represent the green tea deliveries by the various Lorries. Show your calculations. (6mks)
State two disadvantages of using the above method in presenting data. (2mks)
Identify three other methods that can be used to present the above data. (3mks)
(a) (i) A = 2000 x 3600 = 22.30
32240
B = 8240 x 3600 = 920
32240
C = 11,000 x 3600 = 122.80
32240
D = 5300 x 3600 = 59.20
32240
E = 5700 x 3600 = 63.60
32240
A Piechart showing green tea deliveries to kericho Tea Factory.
Radius must be exactly 5cm.
– Its construction requires a lot of calculation.
Small quantities of decimals may not be easily represented.
They do not show the trend.
Past KCSE Questions on the topic
1. The table below shows petroleum production in thousand barrels per day for countries in the Middle East in April 2006. Use it to answer question (a)
Country Production in ‘000”
barrels
Iran
Kuwait
Qatar
Saudi Arabia
United Arab Emirates
Iraq 3800
2550
800
9600
2500
1900
a) (i) What is the difference in production between the highest and the lowest producer. (1mk)
(ii) What is the total amount of petroleum produced in April 2006 in the region? (1mk)
b) State three conditions that are necessary for the formation of petroleum (3mks)
2. The graph below shows percentage value of some export commodities from Kenya between 1999 and 2003. Use it to answer questions (a) and (b)
(a) (i) What was the percentage value of the tea exported in the year 2000. (2mks)
(ii) What was the difference in the percentage values of the horticultural products and coffee exports in 1999? (2mks)
(iii) Describe the trend of the value of coffee exports from 1999 to 2003 (3mks)
(iv) Explain three factors which may have led to the increased export earnings from horticultural produce in Kenya between years 1999 and 2003 (6mks)
(v) Give three advantages of using simple line graphs to represent data. (3mks)
(b) State four reasons why Kenya’s agricultural export earnings are generally low (4mks)
(c) State five reasons why the common market for Eastern and southern Africa (5mks)
3. (a) Define the following terms
– Statistics
– Statistical data
– Statistical methods (6mks)
(b) State two types of statistical data. (2mks)
(c) Write down two types of questionnaires. (2mks)
4. (a) What factors must be considered in selecting methods of data collection.
(3mks)
(b) Differentiate between discrete dataand continuous data giving relevant examples. (4mks)
5. (a) What is sampling (1mk)
(b) State 3 types of sampling. (3mks)
6. (a) Name two main methods used in analyzing statistical data. (2mks)
(b) What is the significance of statistics in geography? (5mks)
7. (i) Name two types of graphs that you have learnt about. (2mks)
(ii) What are the advantages of using graphs named above in representing statistical data? Give advantages. (4mks)
8. (i) What is a questionnaire?
(ii) State four advantages of using questionnaires in collection of’ statistical data. (4mks)
(iii) Explain oral interview method. (2mks)
9. Explain the following methods of data recording.
– Tabulation
– Photographing
– Tape recording
– Tallying
10. What is data? (2mks)
11. Marks 72, 60, 65, 70, 65, 80, 65, 70, 80, 84, 63, 75, 63, 71, 74
Use the data above to find out mean and mode. (4mks)
12. With the help of data above explain how median is obtained. (3mks)
CHAPTER TWO
Specific Objectives
By the end of the topic the learner should be able to:
(a) Define the term mining;
(b) Explain the factors that influence the occurrence of minerals and mining activities;
(c) Describe methods of mining;
(d) State the location of the major minerals of East Africa and show them on a map;
(e) Explain the significance of locally available minerals in Kenya;
(f) State and account for the problems facing the mining industry in Kenya;
(g) Explain the effects of mining on the environment;
(h) Describe the occurrence of specific minerals and their exploitation in selected countries.
Content
Definition of mining
Factors influencing the occurrence of minerals and their exploitation
Methods of mining.
Distribution of major minerals in East Africa
Significance of minerals in Kenya.
Problems facing the mining industry in Kenya.
Effects of mining on the environment.
Study of Trona on Lake Magadi in Kenya ,Gold and diamonds in South Africa and Petroleum in the Middle East
Definition of the term mining.
Mining is the process of extracting valuable minerals from the earth’s crust
Ways in which minerals occur
Minerals may occur in beds and seams
Minerals may occur as weathered products
Minerals may occur in alluvial or placer deposit
Minerals may occur in veins and lodes
Minerals may occur as evaporates
Factors influencing exploitation of Minerals
The value of the minerals
Minerals that are of high value are often mined at a very high cost because of their high demand. Such minerals fetch high prices that lower the cost of extraction.
The size of the mineral Deposit
Where the mineral deposits are relatively small, labour intensive methods that are relatively cheap are employed if the value of such minerals is very high
The quality of Ore
The higher grade ores are more economical to exploit than lower grade ores because they yield a large amount of metal and they are also easier and cheaper to smelt.
Method of mining
Minerals that occur at near the surface can be cheaply mined using open-cast mining method. Minerals that occur at greater depths in the earth’s crust are expensive to extract especially by deep shaft method. Such minerals can only be extracted if they area of high value
Technology
Mining requires advance technology from exploration up to the actual mining and processing stages. If there is lack of this technology mining process will be greatly affected.
World market prices
Fluctuation of world market prices affect the expected incomes by the exporting countries. When the prices are low, mining activities is shaken due to inadequate funds.
Transport system
When minerals occur and there are transport systems, then it is cheap to exploit them. Mineral deposits in remote areas with poorly developed transport system are less likely to be exploited.
Capital
Mining involves a large outlay of capital. Most developing countries generally have inadequate capital to exploit their own minerals. This has therefore, given foreign investors an upper hand over the local people in the mining industry.
Methods of mining
The type of mining adopted depends on:
The mode of occurrence.
Relative ease.
The expense to be incurred.
The most common methods are:
open cast mining
underground mining
Alluvial mining
Open cast mining
There are two methods of open cast Stripping and hill slope boring
Stripping
Employed if the mineral deposits occur very close to the surface
Unwanted materials lying on top of the mineral deposits are removed.
If surface materials are soft, they are removed/by one excavators but if they are hard, explosives are used to loosen the materials.
Excavators are used to dry up the mineral deposits.
The extracted ore is loaded into lorries using excavators and transported to the processing plans.
Hill – Slope Boring
If coal outcrops on hill slopes, boring instruments known as Augers may be employed to remove it.
These augers are very large with a diameter of 1.5 metres and can reach as far as 105 metres below the ground.
They drill out huge pieces of coal and bring them to the surface for transport by waiting trucks.
Underground mining
It is applied if the mineral deposits are covered by a great thickness of rocks.
Types of underground mining
Drift or adit method
Shaft method
Solution method
Drilling method
Drift or adit Method
Where the mineral occurs in gently sloping veins or seams that are exposed on the side of a hill or valley.
It may be possible to exploit it from adits.
Adits are horizontal or gently inclined tunnels which are dug into the hillside.
Copper mining in Kilembe western Uganda.
Shaft method
In cases where the mineral bearing rock does not outcrop or where it occurs in very steeply inclined seams,vertical shafts have to be sunk.
From the shaft,horizontal tunnels or galleries are driven outwards until the vein of the mineral bearing rock is reached.
The mineral bearing rocks are usually blasted loose by explosives
Then transported along the tunnel to the shaft by light railway or conveyor belt.
It is then brought to the surface by a type of a lift called a cage that moves up and down the shaft.
The cages are also used in transporting the miners and their equipment to and from the working levels.
The galleries must be supported by timber pit props or steel concrete beams to hold up the roofs and must be ventilated and kept free of water.
Problems of shaft mining
Sometimes mines get flooded with subterranean water.
There are occasional emissions of poisonous gases.
The dust produced causes respiratory diseases.
Sometimes tunnel collapse causing deaths of the miners.
Solution Method
Underground mining may be done by people who are on the surface.
For minerals such as salt, Potash, or Sulphur, pipes with super-heated water/steam may be sunk down to the deposits.
The mineral dissolves into the water, which is then pumped to the surface.
At the surface, the water is evaporated and the mineral extracted.
Drilling Method
It is commonly used in the exploitation of petroleum and natural gas.
The deposit is reached by boring wells.
The petroleum or gas is then brought to the surface either under its own pressure or pumping.
Alluvial mining (placer mining)
Sometimes a mass of sand or gravel contains particles of gold, tin or platinum which have been eroded from exposed veins, washed down by water and laid down as alluvial deposit e.g. tin in Malaysia, gold in South West U.S.A and Diamonds in South Africa.
When minerals occur as alluvial deposits,they are usually recovered by placer mining methods.
Placer mining methods
Panning
Dredging
Hydraulic mining
Panning
The method involves digging out the sand/gravel which contains mineral particles and mixed with water from the river in a shallow pan.
The mixture is then whirled such that the lighter particles of sand/gravel are pushed on the sides of the pass white the heavier mineral particles are at the bottom of the pan which are easily removal by hand as the waited mineral.
Dredging
It is advanced form of placer method.
Where deposits are large enough, a dredger is employed.
It floats on a larger pond and may be used to dig up waterlogged alluvium.
For smaller or less accessible deposits, a ground pump is usually used.
The material is passed over sloping channels with a series of traps, which catch the heavier particles while the waste material is washed away.
This method is used in the extraction of soda ash at Lake Magadi.
Hydraulic mining
When alluvial deposits occur on a valley side or form thick terrace deposits.
A powerful jet of water under high pressure is directed at the hill or terrace side.
Then gravel and mineral grains are recovered and washed out.
Significance of mining in Kenya.
Mineral provide raw materials for industries.
Minerals lead to development of transport and communication e.g. road, railways, telephone.
Mining creates employment.
Mining leads to development of settlement / towns e.g. Magadi town.
Minerals are exported to earn foreign exchange.
Mining leads to development of social amenities e.g. hospitals, schools.
Distribution of Major Minerals in East Africa
The chief mineral exports in the region include:
Diamonds
Copper
Soda ash
Uganda
In Uganda copper is the most important mineral deposit.
The kilembe copper mines are located in a valley on the Eastern side of Ruwenzori Mountains.
Copper occurs in the form of copper sulphide ore (chalcopyrite).
The copper mineral ore also contains small percentage of cobalt.
There are huge cobalt concentration at Kesese.
Other important minerals in Uganda
Limestone which is mined near Hima in North- West Uganda and in Tororo.
Phosphate also mined near Tororo is used for fertilizer manufacture.
Tin ,wolfram and Beryl are mined inSouth West Ankole and Kigezi.
Tanzania
Large deposits of diamonds are found at Mwandui in Shinyanga District.
Good quality coking coal lies in the Ruvuma river basin to the eastern side of Lake Malawi and in Kivira – Songwe.
Other important minerals found in Tanzania
Tin found near kyerwa.
Mica found near Morogoro.
Coral limestone found near Dar-es- salaam.
Iron ore found near Chunga.
Kenya
Soda ash is the most important mineral found in Lake Magadi.
other important minerals found in Kenya
Fluorspar that is found in rock layers on the slopes of the Kerio Valley.It is mined at Kimwarare.
Limestone which is found in areas with coral rocks.The mines for Limestone are found at Bamburi near Mombasa,Athi – River near Nairobi, Sultan Hamud, Kerio Valley Koru and Homa bay.
Diatomite which is found in Kariandusi ,near Gilgil and at Gicheru in the Nyandarua ranges.
Salt which is found on the surface of Lake Magadi and at the shore of the indian ocean. Salt is mined at Ngongoni near Malindi.
Natural carbon dioxide which is found at Kereita near uplands and in Esageri near Eldama Ravine.
Gold is found in small deposits in Kakamega and at Macalder in Migori Districts.
Gemstones are found in small deposits in different parts of the country.The best gemstones are Rubies found near Voi and garnet at Mwatate in Taita Taveta Districts.
Titanium which is found in Kwale District.
Soap stone,which are formed at Tabaka in kisii District and used for sculpture.
Negative effects of mining on the environment
Mining causes land destruction / ugly land / badlands.
Mining causes pollution of environment air, water, soil and also noise.
Mining causes loss of bio-diversity – animals migrate, vegetation cleared.
Leads to soil erosion since land remains bare.
Mining may lead to landslides.
Mining may lower the water table of a given place.
Problems facing the mining industry in Kenya.
Insufficient capital for the exploitation of mineral has led to reliance on loans from the developed countries. Loans may not always be available, so exploitation may be delayed.
Foreign companies manage most of the mining activities. They remit some export revenues to their countries, thus reducing the country’s export earnings. This has hampered the development of the mining industry.
Remoteness and poor transport systems hinder exploitation of minerals in that areas with mineral deposits are inaccessible.
Insufficient skilled personnel leading to dependency on expatriates for prospecting minerals and mining.
Kenya has small mineral deposits which ae uneconomical to work for.
Air is polluted by dust and smoke emitted from blasting, quarrying and processing of mineral ores. The polluted air is harmful to human health.
Derelict land caused by mining activities is dangerous to both people and animals.
Tip-heaps and mini-holes make the land ugly and unusable for agriculture and settlement
Ways in which mining derelicts can be reclaimed
Planting trees
Creating parks to attract tourists
Landscaping for settlement or farming.
Refilling the holes.
Exploitation of Minerals in Selected Countries
Trona on Lake Magadi in Kenya
Soda ash occurs in form of cystals called Trona on the floor of the Great Rift valley.
The Trona deposits occur naturally in Lake Magadi as a solution of different sodium salts.
Mode of Formation
Rain water in the neighboring areas percolates into cracks on the floor of the Rift valley.
High underground temperatures heat the water, which dissolves the soda salts abundantly found in the underground rocks strata of the Rift valley.
The heated water forms springs that eject the dissolved water to the surface.
The dissolved solution flows to lake Magadi where due to high temperatures it’s rapidly evaporated leaving behind solid crystal of Tron on the surface of the Lake.
Extraction and Processing
A dredger is used to excavate Trona from crystals from lake bed.
The crystals are fed into crushers and mixed with a solution from the bed of the lake called liquor.
The mixture is then pumped through a pipeline to the factory.
At the factory the Trona crystals are cleaned then the liquid is removed and pumped back.
Cleaned crystals are heated and converted into soda ash.
The soda ash is then reduced into required sizes and packed for exports.
Uses
Used in the manufacture of glass,soap,caustic soda and detergents.
It is also used in other industries that include paper making,oil refining and textile industries.
Ways in which soda ash contribute to the economy of Kenya/Benefits
It is exported to earn foreign exchange which is used in the economic development of the country.
It creates employment opportunities.
It provides raw materials to the manufacturing industries leading to industrialization eg the glass manufacture.
It has led to development of social amenities in the area
It has led to the growth to magadi town
Led to the growth of both local and foreign tourism
Provide revenue to the government through taxes.
Problems facing Trona mining in L. Magadi.
Competition from other countries with large deposits of soda ash/Limiting of markets.
Low market price of salt/trona.
Very high temperatures making it quite unfavorable for human settlement.
High cost of hiring labour leading to reduction in profile.
Gold in the Republic of South Africa
Gold appears in grains in solid rock.
It is found in a rock called banket that takes the form of beds of hard conglomerate.
The ore is usually found in quarts veins,metamorphic rocks or in redistributed sediments.
In south Africa 60 large – scale gold mines are located within an arc of 320 km in length called the ‘Golden Arc’.
This covers the orange Free state and Transvaal Provinces.
The main area is the Witwaterand(the Rand),Ogendaalrus and Lydenburg.
The Witwatersrand region is the world’s largest gold producer.
Method of Extraction
The gold bearing rock is drilled and blasted underground.This gold bearing reef is reached by sinking vertical shafts since the rocks rocks dip down sharply to great depths of upto 6,000 m.
From the vertical shafts,horizontal shafts at different levels are run to the banket and when this is reached,other horizontal shafts are cut along the line of the reef.
By working upward and downwards from from these shafts,the banket is removed from the reef. It is then hauled the shaft to the surface.
Extraction of gold involves crushing the hard banket into small chips that are in turn mixed with water and ground until it is as fine as flour or pulp to get the gold.
Alluvial gold is recovered by panning.
Processing and Marketing
After the preliminary concentration of the ground pulp ,as much as 94% of the gold is removed by solution in cyanide.
The content is called potassium gold cyanide.The solution is not pure gold because it contains amount of uranium.
Thesolution is then mixed with zinc dust causing the solution to precipitate out leaving uranium.
This is fed into the sulphuric acid tanks which dissolves the uranium.
Gold is melted out and formed into bars at Gemstones town on the rand.
Contribution of Gold to the Economy of South Africa.
It earns the country foreign exchange which is used as a means for paying international debts.
It offers employments to many people raising their standrds of living.
It has led to widespread urbanization contributing to the formation of the witwaterstrand conurbation.
It has formed a broad based market for other industrial operations.
It has led to the development of Modern infrastructure and amenities.
Problems Facing Gold Mining
The costs involved in mining gold have increased greatly.
Due to increasing demand to provide higher wages, married quarters and other social amenities this has led to additional cost in acquiring labour.
A lot of water is needed for processing gold but the ever increasing population in the Rand also needs water, yet this area receives seasonal rainfall.
The Rand mines are becoming deeper.This has led to pressure bursts underground and ground shatters as the ore is removed. This is due to the great pressure from the heavy weight of the rocks above.
The gold gradebeing worked now is of poorer quality than that of some years back.
Exhaustion of the minerals because gold is a non – renewable resources.
Diamonds in the republic of South Africa
The formation of diamonds is connected to volcanic activity.
These diamonds are found within the igneous rocks ,in pipes that molten rock slowly solidifies after eruption.
We have gem diamonds and alluvial diamonds.
Gem diamonds
These diamonds form at greater depth and are carried up into the pipe during an eruption.
After millions of years, the intrusive rock is gradually eroded eventually exposing to the surface the pipe containing the diamonds.
These diamonds are obtained by open cast mining.
Alluvial diamonds
These diamonds are formed when the volcanic pipes are eroded along with it.
These diamonds and rocks are deposited in the sea or can be in the process of being transported by the rivers to the sea.
Diamonds were discovered in 1866 on the banks of Orange River and they occurred in rocks called kimberlite.
The kimberlite diamond deposits occur in broad belt that extent from the western orange Free State to central Transvaal.It thus includes Koffie, Jagersfantein, Kimberley and Pretoria. The rock at Kimberly is mined with shafts and underground tunnels.
Processing and Marketing
The first stage is the blasting of the rock (ore) that is then lifted to the surface.
At the surface the rock is then crushed into small pieces.
It is then washed and some of the dirt is removed.
The remaining rock that includes diamonds is passed over a rotating table.
This table is covered with grease that repels water that is made to flow over it.
The wet piece of rock will not stick to the grease but will slide off the table as waste.
On the other hand the diamonds do not get wet in the water and so they stick to the grease.
When the rotating table is stopped, the grease with the diamonds is removed. This is done repeatedly.
Contribution of Diamond to the Economy of South Africa
Provides employment opportunities.
It earns foreign exchange.
It has led to the growth of urban centres.
It has contributed to the development of infrastructure e.g. Roads and Railways.
Problems Facing Diamonds Mining in South Africa.
Fluctuations in the world market prices.
Low mineral content in the ore making it processing elaborate and expensive.
High cost of mining and processing of diamonds.
Labour competition with other sectors of the economy such as manufacturing.
Continued mining has led to reduced diamond reserves s most mines are becoming depleted.
The distribution of Major minerals in East Africa
Key
G – Gold D –Diatomite R – Rubies S – Salt
L – Limestone Ti – gypsum C – Copper Sp – Soap stone
F – Phosphate Fe- Iron T – Tin A – Asbestos
Petroleum in the Middle East
The major oil producers in the middle east are:
Saudi Arabia
Iraq
Iran
Kuwait
United Arabs Emirates
All the oil producing countries are members of OPEC
Mode of Formation
Oil forms from the remains of many small creatures that lived in shallow lagoons about 100 to 200 million years ago.
The decaying remains of these creatures mixed with the mud at the bottom as sediments.
Over the years, these sediments pilled on each other slowly transformed into sedimentary rocks.
Gradually, the animals remains were converted into oil and gases as shown below.
Example
The diagram below shows the occurrence of petroleum in the earth’s crust.
Name the substances in the areas labelled L, Mand N.
L – Petroleum oil
M – Water
N – Gas
Give two by-products obtained when refining crude oil.
Tar
Wax
Bitumen / pitch / asphalt
Grease lubricants.
Resin / petrol chemicals
Past KCSE Questions on the topic
1. The table below shows petroleum production in thousand barrels per day for countries in the Middle East in April 2006. Use it to answer question (a)
Country Production in ‘000” barrels
Iran
Kuwait
Qatar
Saudi Arabia
United Arab Emirates
Iraq 3800
2550
800
9600
2500
1900
a) (i) What is the difference in production between the highest and the lowest producer (1mk)
(ii) What is the total amount of petroleum produced in April 2006 in the region? (1mk)
b) State three conditions that are necessary for the formation of petroleum (3mks)
2. Use the map of East Africa below to answer questions (
a) (i) Name the railway terminuses marked P, Q R (3mks)
(ii) In each case give the main commodity transported by the railway
lines marked s and T. (2mks)
b) (i) State four reasons why road network is more widespread than railways in East Africa. (4mks)
(ii) One of the problems facing road transport is the high frequency of accidents. Explain four conditions of roads in Kenya that may lead to accidents. (8mks)
c) i) Name three physical regions through which River Tana passes
(3mks)
ii) Explain thee effects of land pollution can be controlled
d) State four ways through which land pollution can be controlled (4mks)
3. The diagram below show the occurrence of petroleum in the earth’s crust.
Use it to answer questions (a)
a) Name the substances in the areas labeled L. M and N (3mks)
b) Give two by-products obtained when crude oil is refined (2mks)
4. Use the map of Africa to answer question (a) (i)
i) Name the minerals mined in the areas marked S, T and V.
ii) State two formation in which mineral ores occur.
b) Explain four problems, which Zambia experiences in the exportation
of copper.
c) Explain three ways in which coal contributes to the economy of
Zimbabwe.
d) Describe three negative effects of open cast mining on the environment.
5. a) Explain how deep shaft mining is done (2mks)
b) Disadvantages of using the above method (2mks)
6. Explain four effects of land dereliction on the environment. (4mks)
7. Describe how panning mining is carried out. (3mks)
8. Identify four problems facing gold mining in South Africa. (4mks)
9. (a) In what ways has Kenya benefited from the mining of soda ash in Lake
Magadi? (2mks)
(b) What are the negative effects of mining on the environment? (4mks)
10. (a) Explain what is meant by placer mining. (2mks)
(b) Name three mining methods.
11. Describe the occurrence and exploitation of Trona in Kenya till it is ready for
marketing.
12. Name seven significances of minerals in Kenya. (7mks)
13. Explain diamond and gold in South Africa under following headings:
– Occurrence
– Extraction
– Benefits to the economy
– Problems (10mks)
14. Name five uses of soda ash. (5mk)
CHAPTER THREE
Specific Objectives
By the end of the topic the learner should be able to:
(a) Define forest and forestry;
(b) Discuss the factors that influence the distribution and types of natural forests;
(c) Discuss the significance of forests and forest products to Kenya;
(d) Identify and explain the problems facing forestry in Kenya;
(e) Discuss ways and means of managing and conserving forests in Kenya;
(f) Compare and contrast softwood forests in Kenya and Canada;
(g) Demonstrate the ability to manage and conserve forests and forest resources.
Content
Definition of forest and forestry.
Factors influencing the distribution and types of natural forests.
Importance of forests and forest products to Kenya.
Problems facing forestry in Kenya.
Management and conservation of forests – with specific emphasis on Kenya.
Related study on softwood in Kenya and Canada.
Definitions
Forest
A forest is a continuous and extensive land covered with a closed stand of tall trees, usually of commercial value.
Forestry
Is science of planting caring and using trees/forests and their associated resources or the practice of managing and using trees/ forests and their associated resources
Factors influencing the Distribution and types of Natural Forests
Climate
Very cold conditions discourage the growth of forests.
In tropical areas where temperatures are high, forests grow faster than in temperate regions.
Forests requires heavy precipitation throughout the year hence they will not grow in areas where precipitation and relative humidity are low.
Altitude
Altitude affects temperature and rainfall.
Low tempreture results in slower forest growth and small size while high temperatures produce more luxuriant growth.
With an increase in either latitude and altitude there is generally a decrease in the size, luxuriance and the rate of growth of forests.
Soils
Deep, well-drained and fertile soils supports plant life hence having variety or dense forest cover.
Human activities
Human have cleared forests to give room to farming and settlement.
Some trees have been cut to provide timber for fuel and building materials.
This has led to destruction of many forested areas.
Topography
Forests do not grow on steep mountains where the surface is bare rock,the soils are thin and temperateures are low.
Windward slopes of high mountains like Kilimanjaro and Kenya usually receive higher rainfall amounts and therefore are forested.
The leeward slopes are covered with scrub vegetation.
Types of Natural Forests and Their Distribution
The major natural forests of the world are:
Tropical hardwoods forests.
Temperate hardwood forests.
Coniferous forests.
Tropical hardwood forests
They are part of the rain forests which occur in equatorial lands between latitudes 5^0 North and South of the equator.
Examples are the African equatorial equatorial lands from Guinea to the Democratic Republic of Congo,Amazon Basin and South East Asia lowlands.
The main hardwoods in West Africa are mahogany, iroko, sapele, ironwood, rosewood and ebony.
Meru oak and elgon olive are hardwoods found in Kenya.
Characteristics
The forests is evergreen because they have variety of species which shed their leaves at different times of the year.
The trees are tall with straight smooth trunks and form extensive canopies.
The trunks are large in size and bulky with protruding giant buttress roots, which make trees difficult to cut and hull.
They take a very long time to mature compared to soft softwoods.
Temperate Hardwood Forest
They mainly occur between latitudes 〖30〗^(0 ) 〖 and 50〗^0 north of the equator.
These include areas like the eastern part of North America ,western,Southern and Central Europe,northern China,Japan ,northern and Eastern Australia.
Examples of temperate hardwoods include oak,beech,poplar,elm and ash.
Characteristics
Trees are deciduous,that is they shad their leaves in autumn and remain leafless in winter.
Have trees with broad leaves.
The number of species per tree is less as compared to those in the tropics.
Deciduous redwoods are durable and strong like tropical hardwoods,but are not so bulky and difficult to exploit as tropical hardwoods.
Coniferous Forest
These forests are found between latitudes 〖50〗^(0 ) 〖 to 70〗^0 North of the equator.
Covers most of the Scandinavian countries,the northern part of the former U.S.S.R especially Siberi and the western,central and eastern parts of North America.
The major species include pines,spruce and forg.
They are mainly softwoods.
Characteristics
Trees are light in weight.
The trees are evergreen.
The trees occur in pure stands.
The trees are tall about 30 metres in height and have straight trunks.
The trees have conical shape, which prevents accumulation of snow upon the branches, thus allowing snow to slide off easily to the ground.
The trees have thick barks,which protects the trunks and branches from frost.
The trees have hardneedle – shaped leaves which help reduce evapotranspiration during the summer.
Coniferous trees in temperate lands take a long time to mature because of the extreme cold conditions.
Distribution of world‘s natural forests
Note
Forests can be categorized as either natural (exists without the effort of man) or planted (created by man through Afforestation and Re-afforestation programmes.
Difference between Natural and Planted Forest
Natural Forests
Has thick undergrowth
Trees are not in pure stand i.e. trees are of mixed species
Trees grow close to each other
Trees are not taken care of
Trees don’t grow uniformly i.e. mature at different times
Trees grow without a patters
Timber exploitation is difficult due to dense undergrowth and inaccessibility
Planted Forest
• Little or no undergrowth
• Trees are in pure stand
• Trees are spaced
• Trees are taken care of
• Trees grow uniformly and mature at the same time
• Trees grow in a linear pattern
• Timber is easy to exploit.
Importance of Forest and Forest Products in Kenya
1. Protection of water resources – forests play a crucial role in protecting the catchments areas for rivers.
2. Modification of climate – Forests prevent excessive evaporation from bare ground and add moisture to the atmosphere by transpiration thereby creating a micro-climate through higher humidity and lower temperatures.
Trees also trap rain-bearing clouds making forested areas to receive higher precipitation amounts.
3. Forest break the speed of winds i.e. act as windbreakers. Trees are planted at the edge of farms for this reason.
4. Preservation of wild and indigenous genetic resources – Forests provide natural habitat for a wide range of wildlife thus aid in Biodiversity conservation.
5. Reduction of soil erosion – The forest canopy breaks the force of falling rain before it reaches the ground; trees roots bind soil particles preventing loss of soil through surface run-off. Also prevent siltation of rivers and water reservoirs thus assist in controlling floods.
6. Improvement of soil quality – The decaying lead litter add humus to the soil thereby improves soil structure (water retention ability).
Other functions of forests are:
Forests help in the purification of air.
Forest are a source of wood fuel – Biomass.
They are a source of industrial raw materials e.g. Pulp and paper; rubber latex, gums and resins (used in machine belting, electrical insulation and casing of golf balls); wax, cork, Tannin for leather tanning.
Source of food – fruits and nuts root tubers.
A wide variety of medicinal plants are found in the forest e.g. Cinchona tree for quinine.
Forest are of aesthetic value and useful in recreation and tourism.
Fibres production – many different kinds of fibre are gathered from forests are used in making of stiff brushes.
Forests are used in scientific research.
Honey – forests are ideal sites for bee keeping which is a source of revenue to the farmers.
Help in preservation of cultural heritage (e.g. the Kenya shrines).
Employment opportunities for those engaged in lumbering as well as exploitation of other forest resources, carpenters, forest guards and officers, timber merchants.
Forests are a source of timber used in building and construction.
Forest exploitation has stimulated development of infrastructure thereby open up such areas.
Primary forest resources that may be exploited
Timber
Poles
Firewood
Grass
Honey
Wax
Mushroom
Bamboo
Fruits and nuts
Tubers
Resins
Gum
Fibre
Pulp and paper
Wood products obtained from lumbering include; timber, bark, sawdust, plywood, fibre boards, pulp and paper.
Reasons why hardwood tree species in Kenya are in danger of extinction
High demand for hardwood has led to over exploitation.
Population pressure on land has led to increased logging of trees to provide land for settlement and farming
Hardwoods take a long time to mature and this affects their regeneration after being exploited.
Problems facing the commercial exploitation of Tropical Rain forest in Africa.
(i) Species diversity
The trees rarely grow in pure stands of the same species. The occurrence of very many species make it difficult and expensive to locate the valuable species and to remove them from the forest once they have been cut.
(ii) Thick undergrowth
This creates a jungle environment which makes haulage of logs very difficult.
(iii) Inaccessibility
Some forests are located in remote areas with poor transport network. Numerous waterfalls along river courses make river transport impossible.
(iv)Existence of buttress roots
Makes the felling of trees bothersome.
(v) Harsh climate
The hot humid climate makes working conditions unfavorable. The heavy rainfall all year results in muddy roads which become impassable.
(vi)Habitats
Forests are habitats for dangerous wildlife, biting insects which discourage their exploitation.
(vii) Lack of capital
This makes the lumbermen to use poor techniques of extraction instead of modern methods.
(viii) Slow growth of trees
This makes replacement to take long time.
(ix) Less elastic demand for hardwood.
Tropical rainforests also face problems of pests and diseases, fire outbreaks and indiscriminate felling. This has led to a reduction in total land coverage as well as a decline in the quality of timber.
Stages of timber extraction from a natural forest.
Lumbering is the extraction of timber from forests for economic purpose.
Preparation -The area to be exploited is surveyed to locate the needed species.
– Routes to these areas are planned and constructed to open up the forest.
– Camps for the lumbermen are established
c.) Felling – Trees are cut down by axes, power saws and the braches removed.
– Trunks are then cut into suitable lengths.
d.) Extraction – Logs are moved to collection points on the network access roads, water ways and rails Logs are then transported to the mills.
e.) Replanting – New seedlings are planted in places of felled ones to ensure forest regeneration.
Note
Order should be sequential.
Problems facing Forestry in Kenya
(i) Encroachment due to population pressure and need for more land for settlement and farming.
(ii) Pests and diseases e.g. Aphids outbreak (1990’s) destroyed large areas of cypress forests.
(iii) Forest fires especially during the dry season destroy bamboo and conifers which ignite easily.
(iv) Game damage – Increasing population of grazers such as elephants, overgrazing by wild animals cause damage to young forest trees.
(v) Over exploitation through logging, charcoal burning, wood fuel lead to scarcity of forest products.
(vi) Excisions refer to the allocation and conversion of forest land into private land. Tracts of land have been excised to create room for agricultural show grounds and Nyayo Tea Zones.
(vii) Poor management of forest resources for example delay in replanting trees after logging leads to harvesting of immature trees or may necessitate importation of timber and other forest products. Kenya Power and Lighting Company imports poles from Tanzania.
Measures being taken to conserve forest in Kenya
Forest management refers to the effective planning and control of forests and forest resources.
Forest conservation – refers to the protection of forests against interference and destruction by people.
Forest may be conserved by the followed measures.
Afforestation is the planting of trees in order to establish a forest where none existed before.
Afforestation is encouraged in Kenya for the following reasons;
– To ensure continuous supply of wood fuel, timber and raw material for pulp and paper industry.
– To reduce importation of forest products hence save foreign exchange expenditure.
– To expand the habitat for wildlife.
– To create scenic beauty for recreation and tourism
– To protect the water catchments areas hence maintain hydrological cycle.
– To create micro-climates
– To prevent soil erosion
– To create employment opportunities
Re-afforestation – refers to the planting of trees in areas where forests have been cleared e.g. Abardares, Ngong, Kabarnet, and Mt. Kenya.
Setting up of Nyayo Tea Zones – begun in the 1990’s where edges of some forests were cleared and tuned into tea plantation.
Aims
(i) To create a kind of protective buffer belt between the settled area and the forest. The zone made it difficult for people to cross the tea zone in order to reach the forest as this amounted to trespass.
(ii) Discourage squatters and neighboring communities from encroaching on the forests.
(iii) Alleviate poverty by providing employment to the local communities.
Legislation – e.g. The forest Bill 2000 required private energy generation companies to invest in forest conservation since they benefit from forest resources.
Creation of forest Reserves – The government has gazetted some forests and neighboring areas as forest reserve e.g. in Mau, Aberdares, Arabuko Sokoke.
Community Participation
Certain communities use forest as their Shrines e.g. the Kaya forest of the Kenyan coast.
Certain traditional cultural practices assist in forest conservation e.g. taboos on some forest products.
The shamba system seeks to involve landless communities in forest conservation. They provide unskilled labor in the tree plantation and in return are allowed to interplant the trees with food crops. As they tender for their crops the trees are also taken care of. The community is also allowed to utilize some forest products e.g. Honey Butterfly farming in Arabuko Sokoke.
Shortcomings of the shamba system afforestation program in Kenya
– It encourages arbitrary cutting/uprooting of trees.
– Leads to interference of forestland by human settlements/squatters.
– Leads to poaching of forest products by farmers.
– Leads to browsing of young tress by domestic animals
– Leads to competition for soil nutrias between trees and crops.
– Encourages planting of illegal crops e.g. bhang.
Forest management measures
1. Public awareness/campaign on the importance of forest through mass media, spear headed by Green Belt Movement, NGOs, UNEP, UN- Habitat etc.
2. Forest research stations have been established to intensify research on soil requirements for different species of trees as well as ways of controlling pests and diseases e.g. ICRAF – International Centre for Research in Agro forestry.
3. Establishment of forest training school at Londiani and Department of Forestry at Moi University to oversee forest management and conservation.
4. Introduction of faster maturing trees of high commercial value e.g. Eucalyptus, Pines, and Cypress.
5. Reduction of wastage of forest resources by encouraging recycling of forest products.
6. Forest protection by employment of forest guards who patrol the forests to keep off illegal loggers.
7. The government has slapped a total ban on logging in indigenous forests.
8. Kenyan’s are being encouraged to use alternative sources of energy e.g. solar, biogas and energy saving jikos to ease pressure on forests for wood fuel. Zero rating tax on cooking gas is a step in the right direction.
9. Attempts to improve tree-cutting practices through selective harvesting and rotational felling of trees followed by replanting National tree panting day.
What is Agro forestry
This refers to a tropical land use system involving the mixture of tree planting, crop growing and livestock rearing on the same piece of land simultaneously.
Benefits of Agro-forestry. The practice of Agro-forestry was started in the 1970’s due to the following benefits.
It maximizes the use of land.
It is a sustainable source of biomass (charcoal and firewood).
Trees create a micro-climate within the firm.
Some agro-forestry trees are of medicinal value.
Tree products such as fruits, poles, timber etc. are used or can be sold to earn income to the farmer.
Livestock dung increases soil fertility.
The leaves and pods of some trees are used as animal fodder as they are rich in fat, protein etc.
Leaf litter adds organic material and minerals to the soil.
The trees increase soil water retention thus reduce soil erosion.
Characteristics of trees for Agro forestry
– The tree should be fast growing/maturing.
– Tree should yield good quality timber
– Tree leaves and pods should be palatable and nutritious so as to provide fodder.
– It should be fruit bearing.
– Tree should have nitrogen fixing abilities
– Tree should be deep rooted to allow weeding of the food crops and limit competition for soil nutrients
– It should be thornless.
Examples of trees are- calliandra colothyrsus, acacia mellifera, sesbania sesba, terminalia brownii, adansonia digitata
Factors that have favored the establishment of softwood forests in Kenya Highlands.
(i) The Kenya highlands experience a cool climate which enables conifers to flourish. Absence of severe winters ensures tree growth all year round.
(ii) The highlands receive heavy rainfall of over 1000mm.
(iii) Some parts of Kenya highlands are rugged and steep. Such areas discourage settlement and agriculture leaving the forest to flourish.
(iv) High demand for timber and wood products in the country encourages tree faming.
(v) Kenya highlands have fertile acidic volcanic soils.
(vi) Availability of cheap and ample labor.
(vii) Hydroelectric power is readily available to the few sawmills and paper factory in Webuye.
(viii) The government’s efforts to create forests through implementation of afforestation and re-afforestation programmes.
Major lumbering areas in Canada
– Newfound land
– Nova Scotia
– Quebec
– New Brunswick
– Prince Edward Island
– Ontario
– British Columbia
Explain five factors favouring forestry in Canada
(i) The low temperature experienced discouraged settlement and other forms of land use, leaving forestry as the alternative economic land use. Conifers thrive in the long severe winters (-250C).
(ii) The ruggedness of the landscape and thin soil discourage agricultural leaving forest to thrive.
(iii) Availability of large expanses of land owing to the low population density.
(iv) Heavy rainfall on the windward slopes of the mountain ranges encourages growth of conifers.
(v) The valley bottoms along the cost provide good sites for paper mills and clay used is smoothening the paper surface.
(vi) There are many waterfalls used to generate hydro-electric power for use in the paper mills.
(vii) Coastal location favors exportation of timber products (sawn timber, veneers, pulp, newsprint). Major timber exporting ports are Vancouver, Halifax, Quebec and Prince Rupert.
(viii) The numerous rivers provide cheap transport system, and water for timber processing.
(ix) There’s ready market in Canada and abroad for forest products especially pulp and newsprint.
Highlight four problems facing forestry in Canada
(i) Periodic forest fires destroy large areas of forests.
(ii) Pests and diseases attack (Aphids) also destroy forests
(iii) The forests in northern parts are not accessible in winter because of snow.
(iv) The harsh, cold conditions do not allow trees to mature quickly. This slow growth had led to overexploitation.
(v) The north has a rugged terrain which hinders its accessibility.
Importance of Lumbering in Canada
Lumbering provides employment opportunities e.g. tree farmers, lumber jerks as well as worker in related industries.
Exports of forest products earn foreign exchange.
It has stimulated the improvement of infrastructure to open up the country.
It has led to the establishment of many pulp and paper factories.
Characteristics of soft wood forests in Canada
– Evergreen trees characterized by narrow, needle-like leaves.
– There’s little undergrowth in these forests
– Trees have conical shape
– Trees have shallow roots
– Trees species occur in pure stands
– Trees have straight trunks
– Trees have thick barks with a lot of resin.
– Trees take a long time to mature (50-70 years)
– Trees are tall and close to each other.
Major tree species
Pines, Larch, Red Spruce, Balsam Fir, Hem lock, Parana, Douglas fir.
Uses of conifers
Pulp and paper making, Furniture, synthetic e.g. rayon, acetate
Economic uses of the bank of trees
Source of latex
Source of Tannin used in leather processing
Gums used in making chewing gums
Cork used to close bottles
Resins
Have medicinal value
Compare forestry in Kenya and Canada Kenya Canada
There are both exotic and indigenous softwoods
Forests have dense underground
Forests are mainly planted
Forest are in the highland only do not grow in areas beyond 3000m a.s.l
Trees grow faster due to high temperatures
Main trees are indigenous
Little undergrowth
Mainly natural
Forests extend from the foot of the mountain to their summits
Slow growth due to low
Another way of comparing Softwood Forests in Kenya and Canada Under sub topics
Growth
Several unites in Canada show down growth of trees hence take long to mature
while in Kenya trees mature faster due to cool climates in the highlands.
Harvesting
In Canada harvesting is done through clearing cutting while in Kenya selective cutting is used.
In Canada harvesting is done in summer while in Kenya it takes place throughout
In both cases machines are used for logging. 2mks
Marketing
Most of Canada’s wood products are exported to USA/ Britain/ Europe while wood products in Kenya are sold locally with few being exported to USA and Europe.
Transportation
Transportation of logs in Kenya is done using tractors, lorries, trucks and trains while in Canada, it is done using mobile cable steel bars, skiing on ice-covered ground and also floating down rivers.
Distribution
In Kenya, softwood forests are found mainly in the highlands while in Canada they are found both in highland and lowland areas. In Kenya softwood forests cover a small percentage of the total land area while in Canada they cover large tracts of land.
Climate:
In Canada, due to low temperatures, softwood tree species take many years to mature while in Kenya, moderate to high temperature encourages faster growth and maturity to take short time/few years.
Past KCSE Questions on the topic
1. a) i) What is forestry? (2mks)
ii) Explain three factors that favour the growth of natural forests on the slopes of Mt.Kenya. (6mks)
iii) State five factors that have led to the reduction of the area under forest on the slopes of Mt Kenya. (5mks)
b) Explain four measures that the government of Kenya is taking to conserve forests in the country. (8mks)
c) Give the differences in the exploitation of softwood forests in Kenya and Canada under the following sub-headings;
i) Period of harvesting; (2mks)
ii) Transportation (2mks)
2. Explain factors favouring forestry in Canada
3. List two species of indigenous hardwood forest trees in Kenya. (2mks)
4. Name two industries associated with forestry. (2mks)
5. Explain three measures being undertaken to conserve forests in Kenya. (6mks)
6. Explain four problems that are being experienced in exploitation of hardwood forests in Kenya. (8mks)
7. Explain three reasons why only a small part of Kenya is forested. (6mks)
8. Outline three consequences of forest depletion in Kenya. (3mks)
9. State the factors favouring forestry in Kenya. (8mks)
10. Name four secondary products of forests. (4mks)
11. List eight major indigenous tree species in West Africa. (8mks)
12. (a) Define agro-forestry. (1mk)
(b) Outline four benefits of agro-forestry (4mks)
CHAPTER FOUR
Specific Objectives
By the end of the topic the learner should be able to:
(a) Identify types of photographs;
(b) Describe parts of a photograph;
(c) Estimate sizes of features appearing on photographs;
(d) Draw sketches from photographs;
(e) Identify and interpret features from photographs.
Content
Types of photographs.
Parts o f a photograph.
Interpretation of photographs by estimation of actual sizes of features, sketching from photographs, studying and describing natural and human features and activities on photographs.
Definition
Photograph
A photograph is an image or a picture of an object recorded by a camera on a light sensitive film or paper.
Types of Photographs
Classified according to the viewpoint from which they were taken.
The classes are:
Ground photograph
Aerial photographs
Ground Photographs
These are photographs taken from the ground with the camera held level to the object.
The person taking the photographs stands in a position where he can see the object directly infront of him/her.
Objects far away from the camera are not a;ways shown.
The objects near the camera appear big and clear.
An area hidden from the eye of the camera by an object is called the dead ground.
Ground photographs are further classified into:
Ground general view.
Ground close up (particular view).
Ground obliques
Ground Close-up
The camera is focused on one major object,such as an animal,a crop or a car.
This object may block out the other things behind it.
Close ups are the most common types of photographs.
Ground close-up photographs
Ground General View Photographs
These photographs are taken with the camera held horizontal to the ground facing the area focused on.
The objects in the photograph become progressively smaller as the distance from the camera incrases.
Examples
Identify the activity on the photograph below pastoralism
Name he type of photograph above ground general view
Draw a rectangle representation of the photograph
Example
Study the photograph below and use it to answer question (a)
(i) Name the type of photograph shown above (1 mark)
Ground general view
(ii) What time of the day was the photograph taken if the camera was held facing south? (1mark)
Evening
(iii) Draw a rectangle measuring 16cm by 9cm to represent the area of the photograph. On it sketch and label the main features shown on the photograph (5 marks)
(iv) Describe the landscape of the area represented by the photograph. (3marks)
The land rises from the foreground towards the background
The area covered with vegetation is slightly raised.
The area in the background has bare rock surfaces/rock outcrops.
The area in the foreground is gently sloping
Ground oblique
This is taken while the photographer is standing on higher ground than the object.
The camera is tilted downwards towards the object.
Since it this photograph is taken from a raised point it tends to clearly bring out more details of features such as valleys and slopes.
A ground oblique photographs
Aerial Photographs
Photographs taken from the air using aircrafts,ballons,parachutes and sometimes satellites.
Types
Vertical aerial photographs
Oblique aerial photographs.
Vertical Aerial Photograph
These photographs are taken from vertically above as illustrated in figure 3.5. The camera lense focuses vertically on the area to be photographed.
As a result, only the tops of features like hills, trees and buildings can be seen as shown in below.
These types of photographs are used for making maps.
Oblique Aerial Photograph
These are photographs taken from a low flying aircraft with the camera tilted at an angle and cover a relatively large area as shown in below.
The objects nearer the camera are larger than those far away. Although these photographs are similar to ground obliques, they cover large areas and the features on them appear smaller and more obscure.
Parts of photograph
For the purpose of location and interpretation of features, a photograph is divided into three main parts namely:
Foreground:This is the part nearest to the camera.
Middleground:This is the part in the centre of the photograph.
Background:This the part farthest from the camera.
Each of these parts is sub-divided into left, middle and right as indicated in below.
Left Background Middle Background Right Background
Left middle ground Middle Middle ground Right Middle ground
Left foreground Middle Foreground Right Foreground
Position of the camera.
Interpretation of Photographs
Estimating Actual sizes of Features on photographs
Height of objects can be estimated by the use of other familiar objects shown in the photograph. For example, the height of a crop like tea can be estimated using a familiar object like an adult human being standing where the crop is growing.
It is, however, not possible to accurately determine sizes of unfamiliar objects shown in a photograph.
In photographs, images grow progressively smaller from the focal point outward, that is, from the foreground to the background.
Drawing a Sketch from a photograph
To draw a sketch from a photograph, the following steps should be followed:
Draw a rectangular or square frame preferably of the same size as the photograph.
Identify the required features and plot them in the frame appropriately. Use clear simple lines and avoid unnecessary shading.
Label the required features and give your sketch a title. Interpretation of Physical
Features and Human Activities on a Photograph
To interpret a photograph, it is important to study it in an orderly manner starting from the foreground through the middle of the background and then left to right.
A photograph usually has different aspects of physical features such as hills, valleys, vegetation and drainage features as well as human-made features such as farms, bridges, roads and houses.
Relief
Major relief features which can be deduced from a photograph include the slope, hills, plains, plateaus, ranges, escarpments and valleys.
Several clues can be used to describe the relief of a given area in the photograph. These clues include:
Hilly landscapes may be a likely indication of a highland area, while dissected landscape in a hilly area indicates that the place has undergone heavy erosion. Undulating or gently rolling landscape, on the other hand may indicate that the area has undergone little or minimal erosion or may be used as an evidence to show that the landscape is young of recent origin.
The shape of hills can also give clues to the formation and age of such hills with smooth tops are a likely indication of young volcanic hills, which have been least affected by erosion. Rugged hills with protruding rock pillars, toes or plugs may indicate that the hills ate old and have been heavily affected by erosion.
The human activities taking place in a photograph can also give clues to the nature of the landscape. For instance, presence of irrigation activities may suggest that the area shown in the photograph is a plain or is a gently sloping. Terraced landscape, on the other hand, indicates that the area represented in the photograph is steep and therefore vulnerable to erosion. Terracing is therefore meant to reduce or control soul erosion. Particular crops in a photograph can also suggest the relief of a place. For example, crops like tea indicate that the area covered in the photograph is a highland while presence of coconut plantations is evidence that the photograph represents a coastal area. Different human-made features in the farms can also give clues to the relief represented in a photograph. For instance, combine harvesters in a farm are likely indication of a plain or gently rolling terrain.
The type of drainage in a photograph can also provide a clue as to the nature of relief in an area. For instance, the presence of swamps may suggest that the area is flat and hence waterlogged. A lake on top of a hill is a likely indication of a crater lake and can hence also be used as a clue to show that there has been volcanic activity in the area. Long narrow lakes with a valley stretch running parallel to the hills or ranges in the adjacent vicinity are likely indications of faulting. Different forms of communication lines can be used to interpret the landscape. For instance, a road between two hills can be an indication that the hilly area is characterized by passes. A winding railway is an indication of a rugged landscape.
Vegetation types shown in a photograph can also be used as a clue. In the tropics, cone-shaped trees with thin leaves can be used as evidence to show that the photograph represents a highland area.
Drainage
The common drainage features that may appear on photographs include rivers, lakes, oceans, swamps, ponds, wells, boreholes and irrigation channels. On a photograph, water surfaces generally appear brighter than the surrounding features like vegetation and can easily be identified.
When interpreting drainage, the following guidelines may be used:
Rapids and waterfalls would indicate a river that is flowing through a hilly landscape or is in its youthfull stage.
Meanders indicate the middle stage of a river as the river enters less steep land or almost flat land. Some of the meanders may be cut-off from the main river and from ox-bow lakes (ox-bow lakes appear crescent shaped). The presence of a flood plain in a photograph is an indication that the river is in the old stage. The presence of a delta may be identified by the river breaking into many channels before entering the sea.
Major rivers are joined by the tributaries. The main stream and all its tributaries form a river or drainage system. On some aerial photographs (especially those taken from near the ground surface), one may notice that drainage systems form different patterns on the surface. These depend on the general structure of that surface.
If part of a river is included in a photograph, one may determine the direction of flow by looking at the general relief. Rivers flow from higher ground (source) to lower ground.
Vegetation
To describe the vegetation type from a given photograph, the following aspects need to be taken into account:
The type of vegetation: It is made of trees, grass, shrubs, swamps or thicket?
The height and shape of vegetation, that is:Are the trees tall, short, cine shaped, umbrella shaped? Are the leaves broad, needle shaped or thorny? Are the stems bulky?
Density of vegetation, that is: Are the trees close together or scattered? Is there any undergrowth?
Vegetation species that is i.e: It is one type of vegetation? Are the trees of the same species? Is it possible to name or identify some vegetation species? Is the vegetation planted by human beings or natural?
Using the information gathered from a photograph, it is possible to identify different vegetation types such as tropical rainforest grasslands, woodland vegetation, scrubs and desert vegetation. It is also possible to differentiate between natural and planted vegetation. Planted vegetation usually appear in rows (patterns) with little undergrowth and have the same tree species of similar heights.
Climate
Different aspects of climate may be deduced from a photograph in the following ways:
Temperatures
These can be deduced from the kind of agricultural activities practiced in the areas shown by the photograph. For example, the presence of sugarcane plantations would suggest high temperatures while the presence of tea and dairy farms would suggest cool and temperatures. The manner in which the people in the photograph are dressed can also be used to describe the temperature experienced in an area. For example, people in a hot place will wear light cloths while those in cold areas will dress warmly.
Rainfall
Rainfall amount received in an area can be deduced from the kind of agricultural activities practiced. For example, dairy farming and the growing of crops like tea and coffee would generally suggest that in the area where they ate grown is likely to have sufficient and reliable rainfall which is evenly distributed while short scrub or Bush land may be an indication of insufficient rainfall.
Human-made Features
A wide range of human-made features may be recorded in photographs. These may include:
Settlement
Thus is shown in photographs by houses. The houses may be arranged in different ways to give settlement patterns. Fir example they may be grouped together to form nucleated patterns. Settlement is indicated by the presence of people, population distribution and density. Other indicators of settlement include social facilities such as schools, churches, health centers and playgrounds.
Agricultural Activities
These include both crop farming and cattle rearing. Crop farming is indicated by crops seem in the photograph, people preparing land fir crop planning, weeding or harvesting. Cattle rearing is indicated by the animals shown in the photograph, vast grazing land, cattle dips and ponds.
It is important to note the factors that favor an agricultural activity and the evidence fir each factor. These factors include:
High rainfall.
Gentle topography.
Availability of water for irrigation.
Good transport network.
Availability of markets.
Availability of labour.
Livestock keeping may be favoured by availability of vast grazing lands
Planted Forests
Planted forests are common in photographs. They may be identified by their appearance. They are of similar height, species and appear in rows.
Fishing
Fishing is indicated by fishing vessels, people casting nets and fish traps.
Mining
This is indicates by a mine or quarry, people undertaking a mining activity or a mineral processing factory.
Manufacturing
Thus is indicated by factory buildings with large chimneys or people engaged in a processing activity like jua kali artisans.
Past KCSE Questions on the topic
1. The photograph provided shows a tea growing area in Kenya. Use it to answer questions (a) and (b)
a) (i) What evidence in the photograph shows that this is a ground
general-view type of photograph? (2mks)
(ii) Draw a rectangle measuring 15cm by 10cm to represent the area of the photograph. On it sketch and label the main features shown on the photograph. (5mks)
(iii) Identify two features from the photograph that show that this is a small scale tea farm. (2mks)
b) Describe the stages involved in the cultivation of tea from land preparation to the stage shown on the photograph.
(i) Name two districts in the Eastern province where tea is grown.
(2mks)
(ii) Explain four ways in which the Kenya Tea development agency (KTDA) assists small scale tea farmers in Kenya (8mks)
2. What is the type of photograph shown?
3. Name each of the following:
(i) Crop under cultivation (2mks)
(ii) Type of farming (2mks)
(iii) Other groups of crops in this type of farming. (2mks)
(iv) The province in Kenya where this photograph was taken. (2mks)
4. Name five problems facing this type of farming in Kenya. 5mks
5. Name two major export destinations (countries) for farm produce shown. (2mks)
6. Name three physical features at the background of the photograph. (3mks)
7. Draw a rectangle of 12cm by 7cm to represent the area covered by the photograph.
CHAPTER FIVE
Specific Objectives
By the end of the topic the learner should be able to:
(a) Define agriculture;
(b) Discuss the factors that influence agriculture;
(c) Explain types of agriculture;
(d) Locate the major cash crop growing areas in a map of Kenya;
(e) Discuss the growing of selected cash crops in different countries;
(f) Compare and contrast farming practices for selected cash-crops in Kenya and other countries;
(g) Discuss pastoral farming in Kenya;
(h) Compare and contrast dairy farming in Kenya and Denmark beef farming in Kenya and Argentina;
(i) Carry out fieldwork on agricultural activities in the local environment.
Content
a.) Definition of agriculture.
b.) Factors that influence agriculture.
c.) Types of agriculture.
d.) Crop farming distribution of major cash crops in Kenya, a study of tea, sugar-cane and maize in Kenya, a study of cocoa in Ghana and oil palm in Nigeria and comparative studies of coffee in Kenya and Brazil, wheat in Kenya and Canada and horticulture in Kenya and the Netherlands.
e.) Livestock farming pastoral farming in Kenya comparative study of dairy farming in Kenya and Denmark and beef farming in Kenya and Argentina.
f.) Field work – collect, record, analyze, and present data on agricultural activities in the local environment.
Definition
Agriculture
Defined as the science and art of growing crops and rearing livestock
Importance of agriculture
Provision of employment opportunities
Earns a country foreign exchange through exports
Provides raw materials for industries
Stimulates the development of infrastructure
Provides income to farmers and raise their living standard
Provides market for industries products e.g. farm input and machinery
Factors that influence Agricultural activities
i.) Climatic factors
Different crops for example require varying limits of rainfall, humidity and temperature.
Temperature affects crops maturity, ripening of fruits and determines soil moisture content as well as influences the rate of photosynthesis and transpiration.
Crops such as cocoa, oil palm require high relative humidity.
ii.) Topography
Crops like tea, coffee do well in higher altitude about 1525m while rice, cotton, sugarcane require lower altitudes.
Lowland eases cultivation and mechanization of agriculture.
Soil
Different crops require different types of soil in terms of mineral composition and drainage.
Biotic factors
The presence of and/ or absence of parasitic plants, insect pests and disease largely influence the type of agriculture.
Social factors
The type of farming practiced depends on the culture of the farmers concerned e.g. Systems of land ownership and inheritance have led to uneconomical subdivision of land limiting extensive farming.
Religion e.g. pigs not kept /eaten by Muslims, Hindus and Jews
Traditional diet – some crops are traditionally grown e.g. bananas –Uganda, yams –Nigeria.
Certain cultures limit use of modern technology in farming.
Economic factors
Such as operational costs of agriculture, marketing expenses, price fluctuations, government policy (subsidies) and international agreements on quota system.
Types of Agriculture
Simple Subsistence Farming
– It is also referred to as shifting cultivation
– It involves growing of food crops for family’s requirements
Characteristics
– The plot is normally sited in virgin forest
– Forests are cleared by fire hence the name slash and burn
– Cultivated areas are usually scattered and separated by thick forests
– Cultivation is done by use of primitive / simple implements such as hoes and sticks
– Farmers grow food crops for family use e.g. yams, cassava rice beans, bananas
– Farm produce is homogenous
– Mixed cropping is practiced
– The land is left fallow to regain fertility
– Field rotation is practiced
– Cultivators live in temporary huts which are readily abandoned
– The plots are abandoned when yield decline
Limitations of Shifting Cultivation
– Burning destroys soil organic matter
– Soil loses its fertility quickly (no attention)
– The system requires vast tracts of land for rotational cultivation
– It is wasteful as the land is left fallow
– It cannot produce enough food for a growing population
– The yields are low
Note:
Shifting cultivation is being phased out due to the following reasons
Land tenure systems that allows for individual ownership.
Need for more food due to population growth.
Population pressure on land leading to subdivision of land.
Sedentary Subsistence Agriculture
– In this system, farmers give attention to the land and crops; crop rotation is practiced
– Cultivators stay permanently in one spot
– Many animals are kept to supplement the food crop.
Characteristics
– The fallowed fields are frequently re-used since the community occupies a permanent dwelling place
– Sometimes it is combined with cash crop farming and forestry
– Draught animals e.g. oxen, buffaloes, horses are kept
– Farming methods are very intensive and involves use of simple implements
Intensive Subsistence Farming
– A type of agriculture where a lot of energy is put on farm work to sustain a large and fast growing population
– It is characterized by two types of agriculture namely
a. Intensive subsistence agriculture dominated by wet paddy
b. Intensive subsistence agriculture dominated by other food crops
Plantation Farming
– This is a specialized commercial cultivation of cash crops on extensive tracts of land usually by scientific methods.
Characteristics
– Farming is scientifically managed
– The farms are very large more than 40ha/100ac
– Mechanization is embraced in the operations
– Crops grown are usually export /market oriented
– A great deal of capital is involved
– Monoculture is practiced
– Hired labour is employed
– Most farms are foreign owned
Problems facing plantation farming
– Climatic hazards (Harmattan winds, hailstones, frost)
– Insect pest and diseases
– Monoculture –soil exhaustion.
Extensive Mechanized Grain Cultivation
– This is the cultivation of grain on large scale marked with dominance of wheat e.g. Canadian and American prairies pampas, Veldt, Downs and Canterbury plain of New Zealand.
– In Kenya it’s practiced in Uasin- Gishu, Nakuru and Narok
Characteristics
– Farms in the mid-latitudes range from 240-16 000ha settlement, is confined in farm estates.
– Farming processes are entirely mechanized from field preparation to harvesting.
– Wheat is the principle crop in temperate areas
– Grain is raised on un-irrigated land since it requires little rainfall (325mm per annum)
– The farms are owned individually
Mediterranean Agriculture
– Farming is intensive and highly specialized
– Subsistence farming is practiced alongside commercial farming e.g. wheat, barley, vegetables for local consumption, while olives, grapes, oranges, and lemons for export.
Mediterranean agriculture has four aspects;
a.) Viticulture-Cultivation of grapes for wine making
b.) Orchard farming –Citrus fruits, dates, olives, figs
c.) Cereal and vegetable cultivation- wheat, barley, beans, lentils, carrots, onions,tomatoes
d.) Limited animal husbandry – keeping of sheep, goat ,and cattle
Mixed Farming
– Involves growing crops and also keeping livestock on the same piece of land
Characteristics
– Crops are grown and livestock kept on the same farm
– The farms are moderate in size and grow a variety of crops
– A portion of the farm may be left for animal pasture
– On some farms, parts of the land is devoted to fruit trees i.e apples,pears ,strawberry and vegetation crops.
– High capital expenditure.
Crop Farming
Distribution of Major Cash Crops in Kenya
– Generally, crops are grown anywhere in Kenya with favourable physical and climatic conditions.
– Cash crops are mainly grown in the southern parts due to
Climatic conditions in the south favors the growth of a variety of crops e.g. temperature varies from warm to cool, rainfall ranges between 800 – 2000mm and many areas in this region experience dry and sunny spells in between the rainy seasons.
The soils are volcanic in the Kenya highlands, rich alluvial in the lowlands around the Lake Basin. These soils are fertile and support a variety of crops.
High population that provide adequate labor in the farms.
The colonial government and European settlers introduced cash crops in these areas due to the prevailing conditions
-The principle cash crops grown in Kenya are:
Crop Counties where it is grown
Tea Kericho, Trans Nzoia, Kakamega, Kisii, Kiambu, Nandi, Embu and Meru
Rice Busia, Kisumu, Embu and Kirinyaga
Coffee Kiambu, Trans Nzoia (around Mt. Elgon), Meru, Vihiga, Kisii and Machakos
Sugar cane Migori, Kisumu, Busia, Kakamega, Kwale
Cotton Homa Bay, Busia, Meru and Machakos
Cashew nuts Kilifi
Pyrethrum Nakuru, Kisii, Kiambu (around Limuru), Nyandarua
Sisal Kiambu (around Thika), Taita Taveta, Baringo and Kilifi
Wheat Narok, Uasin Gishu, Nakuru
Maize Bungoma, Trans Nzoia and Uasin Gishu
Wattle Uasin Gishu and Kiambu
Major crops grown in Kenya and their distribution
Tea farming in Kenya
Growing Areas Western Highlands Eastern Highlands
Kericho Nyambene
Nandi Murang’a
Kakamega Nyeri
Cherangani Hills Kiambu
Maragua
Conditions necessary for growing tea
Physical conditions
A well distributed annual rainfall of between 1300-1800mm (high) well distributed throughout the growing season/with no dry season
Warm temperatures of between 180C to 240C during the growing season
Highlands and hill slopes with good natural drainage preferably an altitude of 1000-2200m above sea level.
Well drained, deep, fertile and friable soil to allow root penetration, should be slightly acidic with no calcium
Protection from strong sunlight and violent winds
Human conditions
Large pool of labor for field preparation, weeding, pruning and picking of tea leaves.
Good and passable transport routes for quick delivery of picked tea to the factory for processing.
Capital for buying farm inputs and paying labour and setting up tea factories
Cultivation of Tea
– This is done on either plantations or small scale holdings
– The land is first cleared
– Tea cuttings/seedlings are raised in a nursery
– After about 18 months, the seedlings are transplanted into the already prepared farms
– Weeding, application and pruning are done at intervals till it attains maturity
Note
– The main tea species grown in Kenya are Assam and China
Harvesting of Tea
– Tea is ready for harvesting after 2 – 3 years.
– Tea is harvested by picking the two top leaves and a bud at the tip of each shoot
– The picked tea is then put in aerated baskets ready for transport to the collection centres (they have to transported as fast as possible for processing as their quality deteriorates if they start withering)
Processing of Tea
– The leaves are then transported to a collection point and then to the tea processing factories for sorting out and weighing
– They are then spread out on long wire trays
– The leaves are then dried by blasting warm air from below the trays
– They are then passed through a set or rollers to chop or crush them
– The leaves are then placed in containers for fermenting, reducing the tannic acid and changing color to grey
– The fermented leaves are then roasted and dried over fire until they turn black in color.
– The dried leaves are then sifted, graded and classified
– The graded tea is packed ready for marketing
Marketing of Tea
– Some of the tea is consumed locally but a greater percentage is exported to Europe and Middle East/sold on the international market
– Marketing of tea is done by the Kenya Tea Development Authority (KTDA)
Other functions of KTDA include: –
– KTDA also promotes production of tea among small scale farmers
– It also sensitizes the small scale farmers on high quality tea production
– It also ensures prompt collection of tea payments from tea buyers
Achievements of KTDA
Provision of farm inputs e.g. fertilizers and seedlings to small scale tea farmers
It assists in marketing of tea i.e. the farmers have a good bargaining base through KTDA.
It has financed many tea processing industries.
It has increased the total tea production by assisting small scale tea farmers
Problems Facing Tea Farmers in Kenya
Pests and diseases e.g. black tea thrip, red spider mites, beetles, weevils and root rot that reduce the quality and the quantity of the tea in the farms – leads to marginal profits.
Poor and dilapidated feeder roads in the tea growing area lead to delays in collection and delivery of green tea leaves causing wastage.
Adverse weather conditions e.g. prolonged droughts and hailstorms that destroy the tea crop reducing the quality and quantity of the yields.
Delayed payments of delivered tea and mismanagement of tea funds from the cooperatives that lowers the farmers’ morale – farmers uproot tea crop to grow horticulture.
Fluctuations in the prices of tea at the world market making them to incur marginal profits.
Competition from fast maturing horticultural crops has made some tea farmers to uproot their crops to venture in horticulture.
High costs of farm inputs e.g. fertilizers that reduces the farmers’ profit margins
Significance of Tea Farming in Kenya/Importance of Tea Growing to Kenya’s Economy
Foreign exchange earnings through export of tea.
Creation of employment opportunities as many are employed in the tea farms to weed and pick tea, in the tea processing factories thus improving their living standards.
It leads to development of tea related industries e.g. tea processing and packaging industries.
Development of infrastructure e.g. roads to link the farms, collection centres, factories and markets
The main Tea growing areas in Kenya
Sugar Cane Farming in Kenya
– Main sugar cane growing areas/counties in Kenya
1. Western Kenya Sugar Belt
Kakamega County – Kabras and Mumias.
Busia County – around Nzoia.
Bungoma County
Nyanza Sugar Belt
Kisumu County – Chemelil, Miwani, Kibos, Koru and Muhoroni.
Migori County – South Nyanza Sugar Belt at Awendo
3. Coast Sugar Belt
Kwale County – Ramisi
Conditions favouring Sugar Cane Growing in Kenya
High temperatures of 200C –27 0C throughout the year.
A dry sunny season near the harvest time to promote sugar accumulation.
High rainfall of 1200 – 1500mm throughout the growing period.
Deep, fertile and well drained soils that are water retentive preferably alluvial, clay or black cotton soils.
Gently sloping/undulating lowlands that allows mechanization .
Good infrastructure in terms of roads for delivering cut cane to the factories
Abundant and cheap labour supply especially during planting, weeding and harvesting (dense population around the sugar belt).
Large capital outlay for acquiring farm inputs and machinery
Cultivation of Sugar Cane
– The land is first cleared, ploughed and then reploughed
– Sugar cane is then planted vegetatively i.e. from cane cuttings that are planted in furrows
– Fertilizers are applied at the early stages
– Weeding and spraying against pests and diseases are done at regular intervals till the crop attains maturity
Harvesting of Sugar Cane
– This is done after about 18 months
– It is cut manually using pangas or machetes
– The cut/harvested cane is loaded onto trucks/tractors and quickly transported to the factory (to preserve sugar quality)
Processing of Sugar Cane
– At the factory, the canes are mechanically cut with rotating knives/shredders
– The cut cane is then washed with sprayed water to remove impurities.
– The washed cane is then crushed between rollers to obtain raw juice.
– The raw juice is then filtered to remove insoluble matter
– The filtered juice is then boiled with lime and allowed to crystallize to form raw/brown sugar
– The brown/raw sugar is refined and graded ready for marketing
Note
– Bi products from sugar cane processing include cane residue (bagasse) and molasses
– Cane residue is used as fuel, manure, fodder and raw material in paper production
– Molasses is used to process industrial alcohol
Outgrower Schemes
– This is an arrangement where a sugar cane processing factory assists small-scale farmers in its surrounding areas to increase production and supply of cane to the factory.
– They help the small scale farmers to grow and sell their sugar cane to the factories
– They also manage the local sugar cane processing factories
– Their other benefits include
Increased sugar cane production to meet the local needs.
Availing to farmers selected seed cane/cane cuttings for high quality sugar.
Availing fertilizers and other farm inputs to the farmers.
Constructing and maintaining access roads to the farms.
Provision of credit facilities to the farmers to improve their farms.
Availing extension services to the farmers.
Provision of tractors for ploughing and paying for labour during harvesting
Undertaking transportation of cut cane from the farms to processing factories
Marketing of Sugar
– This is done by various wholesale outlets and individual sugar processing factories
Problems Facing Sugar Cane Farmers in Kenya
Stiff competition from sugar imported from COMESA countries.
Pests and diseases such as ratoon stunting, yellow wilt, leaf spots, white scales, termites. These lower yields and quality of sugar cane.
Delayed payments to farmers and mismanagement of funds in sugar factories kill farmer morale.
Fire outbreaks before maturity during dry season that destroy large acreage of cane
Adverse weather conditions such as excessive rainfall, prolonged drought that lower the quantity of the yield.
Expensive farm inputs (fertilizers, pesticides) lead to low income returns.
Overproduction of sugar cane leads to lower prices.
Competition for land use from other crops – cotton, maize.
Poor transport network leads to delay in the collection and delivery of cane.
Low payments – excessive deductions and taxation of farmers’ income.
Significance of Sugar Cane Growing
Creation of employment opportunities in sugar estates and factories.
Saving foreign exchange that would have been used to import sugar by producing sugar for domestic consumption.
Industrial development through creation of sugar processing industries and provision of raw materials to sugar related industries.
Urbanization/growth of towns e.g. Mumias, Awendo and Muhoroni. These are provided with basic social amenities
Uses of Sugar
– Used in baking
– Brewing soft drinks
– Sweetening beverage and fruit juice making
– Confectionary making
Main Sugar – Cane growing areas
Maize Growing in Kenya
– Maize is grown almost everywhere in Kenya. This is because it tolerates a wide variety of climatic conditions and soils. But the main maize growing counties in Kenya include
Trans-Nzoia
Nakuru
Bungoma
Uasin Gishu
Conditions Favouring Maize Growing in Kenya
– Moderate to high temperatures ranging between 150C and 270C
– Rainfall of between 635 – 1145mm during the growing period. However maize tolerates a variety of rainfall ranging from 380mm and even above 2500mm depending on the location – semi arid regions or highlands
– Grows in a wide range of soils (acidic podzols to strongly leached red soils) should be deep and rich in nitrogen.
– Undulating/rolling and gently sloping topography to allow mechanization
– Altitudes of 0 to 2200m above sea level where there is no frost
Cultivation of Maize
– The land is first cleared and ploughed
– The seeds are then sown at the beginning of rains by manual dibbling or mechanically by maize planters
– Constant weeding during the growing period is done to keep out weeds.
Harvesting of maize
– This is done after about 4 – 12 months depending on the variety and the area where it is grown
– The harvesting is done by hands for small scale farmers or using combine harvesters for large scale farms
Processing of maize
– Maize grains are weighed and then put on trays
– Any undesirable grains and broken cobs are removed.
– It is then sieved to remove unwanted particles – soil, rocks, and cobs.
– The maize is passed through a milling machine that grinds it into flour according to the desired grade.
– The flour is then packed appropriately ready for sale.
Uses of Maize
– Grains are used as food for human consumption
– Grains are used to manufacture cooking oil, making starch and industrial alcohol
– Maize stalks and cobs are used as domestic fuel
– Maize stalks and cobs are used as animal feeds
– Stalks and cobs are used as manure
– Grains are used as animal feeds – cattle, horses, sheep, poultry
Give four significance of growing maize in Kenya
– Maize is a staple food to many Kenyan communities
– Maize cobs and stalks provides domestic fuel
– Maize farming creates employment opportunities and source of income to farmers
– Maize provides raw materials for industries – alcohol, vegetable oil, rayon and plastics
– The stalks, leaves and other remains are used as cattle feed
Problems Facing Maize Farmers in Kenya
– Adverse weather such as prolonged drought and frost lower crop yield thus low income.
– Pests and diseases such as stalk borers, armyworms, birds, aphids, stalk rot, white leaf, duce the maize yields in the farms.
– Low prices arising from bumper harvest discourage farmers
– Dumping of cheap imported maize from COMESA and European Union.
– Delayed payments by National Cereals and Produce Board lowers the farmers’ morale.
– Expensive high quality seeds have forced farmers to use uncertified seeds.
– Expensive farm inputs e.g. fertilizers, pesticides lead to marginal profits
– Poor marketing strategies e.g. through middlemen who exploit farmers by buying the produce at low prices.
– Lack of sufficient/appropriate facilities compels farmers to sell their produce at throwaway prices for risk of weevil attack thus low profits.
– Poor crop yields arising from soil exhaustion due to prolonged planting of maize/monoculture
Cocoa in Ghana
– Main cocoa growing areas in Ghana are
Accra
Kumasi
Takoradi
– Other cocoa growing countries in Africa are Nigeria, Ivory Coast and Cameroun
Factors favoring Cocoa Growing in Ghana
– High relative humidity (over 75%) throughout the year
– High annual rainfall 1300 – 1500mm well distributed throughout the year
– High temperature all year of between 240C – 270C throughout the year
– Deep well drained soils rich in humus (loamy soils, light clay)
– Lowland/low altitude below 750m above sea level.
– Absence of strong winds that may blow off premature cocoa pods.
– Young trees require protection from direct sunlight i.e. shade condition
– Sufficient sunshine when pods are ripening
– Plenty of labour for cultivation and harvesting
Cultivation of Cocoa
– This is done on small scale holdings and plantations
– The land is first cleared and ploughed
– Cocoa seeds are raised in a nursery
– After about 4 – 5 months, the cocoa seedlings are transplanted into the prepared fields
– Application of manure and weeding is done to improve the quality
Harvesting of Cocoa
– This begins during the fifth year. It is done twice a year
– The ripe pods are cut from the trunk and branches by use of a long knife.
– The pods are heaped at a central place awaiting delivery to the collection points.
Processing of Cocoa
– The pods are split open with a sharp knife and the beans embedded in the pulp removed/scooped out by hand.
– Beans are heaped and covered with banana leaves to ferment /drain away the juicy pulp.
– The fermented beans are washed, cleaned and then dried in the sun till they turn brown.
– Dry beans are sorted out, graded and packed in bags to be delivered to collecting centres
– Importing countries further process cocoa through cleaning, roasting and removal of husks to produce cocoa nibs.
– Cocoa nibs are ground into powder and cocoa butter is separated
Marketing of Cocoa
– From the marketing centres, the dry cocoa beans to the ports of Accra, Tema and Takoradi by rail or road
– They are then shipped to Europe and other African countries
Problems facing Cocoa Farming in Ghana
Prevalence of cocoa diseases and such as the swollen shoot, manillla disease, black spots, and pests e.g. capsid bug destroy the crop leading to low yields.
Monoculture/over cultivation of cocoa over time has contributed to poor soils and low yields.
Fluctuation in production due to adverse weather especially drought and dry Harmattan winds that reduces humidity and destroy the cocoa pods.
Competition from other land uses e.g. settlement and subsistence agriculture in the cocoa growing areas has reduced the acreage.
Overdependence on cocoa leads to economic uncertainties especially during price fluctuations.
Smuggling of cocoa across the borders leads to loss of/minimal profits.
Poor roads that are impassable during the rainy seasons create difficulties in transportation to collecting centres.
Use of hired labour which is sometimes not available as some are immigrants.
Contribution of Cocoa to Ghana’s Economy
It is a major foreign exchange earner in Ghana through the export of cocoa
It has created employment opportunities thus raising the living standards of the cocoa farmers through earning income
Oil Palm in Nigeria
– Oil palm fruit resembles a green coconut but smaller than the coconut. Palm oil is contained in two parts of the fruit – in the pericarp (fibrous fleshy outer coating) and in the kernel (a nut inside the pericarp)
– The main oil palm growing areas in Nigeria are
Port Harcourt
Calabar
Sapele
Factors Favouring Oil Palm Growing in Nigeria
High rainfall of over 2000mm that is well distributed throughout the year
High temperatures of between 210C and 300C throughout the year
High (relative) humidity of 80% – 90% during the growing period
Protection or shelter from strong windsFertile, deep and well drained soils
Altitude of below 750m above the sea level that is gently sloping
Cultivation of Oil Palm
– The land is first cleared and then ploughed
– Oil palm seedlings are then raised in a nursery
– The seedlings are then transplanted onto the already prepared fields after some time
– Weeding and control of pests is done regularly till the crop attains maturity
Harvesting of Oil Palm
– This is done after about 3 – 4 years
– It is done by cutting the base of the bunch containing the fruit using harvesting knives
– The harvested fruits are immediately collected and transported in trucks/lorries to the processing factories
Processing of Oil Palm
– At the factory, the fruits are sterilized by passing through hot steam to arrest acid development.
– The sterilized fruits are then passed through stripper where the individual fruits are stripped of the stalks and other unwanted materials.
– The fruits are then put in digesters for further cooking to soften them into pulp.
– The pulp is then separated from the kernel and then pressed to extract oil by the oil extractors.
– Extracted oil is then kept in settling tanks to allow unwanted material to settle.
– The oil is then packed in containers ready for marketing
Marketing of Palm Oil
– A greater percentage of the palm oil produced is consumed locally in Nigeria as cooking oil
– Most of the kernel and kernel oil is exported to Europe and USA
Uses of Palm Oil
In making cooking oil
Crushed nuts are used as animals’ feeds.
The leaves of oil palm tree are used for roofing, making baskets and brooms.
The shells and fibre are used as fuel.
The fruit is a raw material in soap and candle making industries.
The stems of the plant are used as building poles.
The sap from the stem is used for making wine/other alcoholic drinks
Case Studies
Coffee in Kenya and Brazil
Coffee in Kenya
– Varieties of coffee grown in Kenya are the Arabica and Robusta
– Coffee is grown small holdings as well as in plantations
– The main coffee growing counties in Kenya are as below
Province Counties
Central Murang’a, Nyeri, Kirinyaga, and Kiambu
Nyanza Kisii, Nyamira, Kisumu (Nyabondo), Homa Bay (Oyugis)
Western Bungoma, Vihiga and Kakamega
Coast Taita Taveta (around Wundanyi)
Eastern Meru, Embu, Machakos, Makueni and Tharaka – Nithi
Conditions Favoring Coffee Growing in Kenya
Cool to hot climates with temperatures averaging between 〖15〗^0C – 〖30〗^0C but not fall below 〖11〗^0C.
High rainfall of about 1000mm – 2000mm well distributed throughout the year
Fertile, deep and well drained volcanic soil.
High altitude of between 610 – 2000metres above sea level.
Undulating/gently sloping landscape/topography to ensure the soils are well drained.
Young trees should be sheltered from direct sunlight.
About two months dry period for ripening of the pods
Cultivation of Coffee in Kenya
– The land is first cleared and then ploughed
– The coffee plants area first raised in a nursery for about six months
– After this, they are then transplanted into the main fields
– The young coffee plants are sheltered from winds and strong sunlight by trees or artificially made shades
– Pruning, mulching, weeding and spraying against pests and diseases is regularly done
Harvesting of Coffee in Kenya
– Harvesting begins after 3-4 years; ripe berries are handpicked then delivered to the factory the same day
Processing of Coffee in Kenya
– At the factory, the coffee berries are passed through a machine that removes the outer covering pulp; a process referred to as skinning
– The beans are the heaped in a tank to undergo fermentation for about 14 hours
– The beans are then washed in clean water
– They are then cured by drying them in the sun
– Two layers of the inner coffee husks are then peeled off by machines
– The layers are then winnowed, graded and sorted according to size and quality
– The beans are then roasted at temperatures of about 1000C
– They are then ground into powder and packed ready for marketing
Marketing of Coffee in Kenya
– Most of Kenya’s coffee is handled through cooperative societies who own factories
– The cooperatives then sell the processed beans to the Kenya Planters Cooperative Union that in turn passes them to the Coffee Board of Kenya which arranges for overseas auctioning.
Problems facing coffee farmers in Kenya
Overproduction leads to price fluctuations discourages farmers
Pests and diseases such as leaf rust, root rot and coffee berry disease lower the quality and output
Delayed payments on coffee delivered to cooperatives kill/lowers farmer morale
Climatic hazards such as prolonged drought, excessive rain, frost destroy the crop in the farms
Soil exhaustion due to monocropping.
Labour shortage especially during harvesting.
High costs of farm inputs.
Stiff competition from alternative crops with high returns
Importance of Coffee Growing to Kenya’s Economy
Foreign exchange earnings through export.
Creation of employment opportunities.
Establishment of coffee related industries.
Infrastructural improvement and development e.g. construction and maintenance of feeder roads in the coffee growing areas
Coffee in Brazil
– Brazil is the leading coffee producer and exporter in the world
– Coffee growing is done in Sao Paulo, Ribeirao and Preto
Conditions favouring coffee growing in Brazil
Deep, porous, volcanic soils that are rich in humus and potash.
Adequate rainfall of around 1525mm per a year and a dry period to allow the berries to ripen.
Warm and humid climate of South East Brazil and moderate temperatures of 〖140〗^0 C-〖260〗^0C
The rolling Brazilian plateau around Sao Paolo that are wet and well drained
Availability of cheap labour due to dense and high population.
Well developed transport system (railway) that connects various plantations to export ports
Problems facing coffee growing in Brazil
Soil exhaustion and erosion as little attention is paid to soil with no attempt to renew fertility or manage erosion. Land is abandoned once yields decline.
Climatic hazards such as frost, drought lowers the yields/farmers incur great loss for instance frost has made coffee estates to be replanted with sugarcane and Soya beans.
Over production leads to price fluctuations .This is encouraged by new plantings consequent upon high returns or coffee booms.
Increased competition from other world coffee producers such as West Africa, Colombia, East Africa.
Introduction of new crops on speculative basis such as tobacco, sugarcane and cotton has reduced the acreage of coffee.
Solution to problems
Prohibiting new planting to reduce/minimize overproduction.
Buying and storing surplus coffee when there is overproduction to supplement poor harvests.
Encouraging crop diversification and mixed farming to reduce overreliance on coffee.
The government lobbies for higher quotas for coffee in the international market
Establishing an institute that manipulates the amount of coffee released to the world market by creating artificial shortages so as to maintain high prices
Significance of Coffee Growing in Brazil
Foreign exchange earnings through exports
Creation of employment opportunities
Improvement of infrastructure through construction of roads and railway lines
Comparison of Coffee Farming in Kenya and Brazil
Similarities
– Both countries grow similar species of coffee i.e. Arabica and Robusta
– In both countries, coffee is a major foreign exchange earner
– In both countries the coffee farms are scientifically managed
Differences
– In Kenya the production is on a small scale while in Brazil the production is on large scale
– In Brazil , the farms are exclusively on coffee while in Kenya the farmers practice mixed farming alongside coffee growing
– Kenya relies heavily on artificial fertilizers to curb soil exhaustion while in Brazil farmers rely mainly on natural soil fertility/minimal use of artificial fertilizers
Wheat Growing in Kenya and Canada
Wheat Growing in Kenya
– The main wheat growing counties in Kenya are Nakuru, Narok, Uasin Gishu, Nyandarua, Meru, Trans Nzoia, Laikipia and Elgeyo Marakwet
Conditions favouring wheat growing in Kenya
– An open rolling topography provides adequate drainage and facilitates the use of machinery.
– Moderate to high rainfall ranging between 500mm – 1270mm during the growing period
– Warm temperatures of 150C – 200C for at least three months to enable maturity of wheat
– Warm and dry sunny period to enhance ripening and harvesting of wheat
– Deep and fertile well drained volcanic soils
– High altitude areas ranging between 1500 – 2900m above the sea level to reduce incidences of pests and diseases
Cultivation of Wheat
– The land is first cleared and ploughed using tractors
– The land is then harrowed to allow weeds and stray wheat grains to germinate and be killed during the next harrowing
– Fertilizers and manure are added to the land after the last harrowing
– Wheat seeds are then sown using drills pulled by tractors or broadcasting in case of small scale farmers
– Spraying the crop against weeds and weeding is done at regular intervals till it attains maturity
Harvesting of Wheat
– This is done manually by cutting the wheat heads using sharp knives/sickles for small scale holdings or using combine harvesters (reaps, threshes the wheat and bales the straw in a single operation) for large scale farmers
Processing of Wheat
– The harvested wheat grain is threshed in the field or using the combine harvesters
– The grain is then milled to obtain wheat flour
Marketing of Wheat
– Producers sell the wheat directly to the millers or through the National Cereals and Produce Board
Importance of Wheat Farming in Kenya
Development of wheat related industry e.g. bakeries and confectionaries.
Development of infrastructure especially roads in the wheat growing areas.
Creation of employment opportunities as wheat farmers earn income thus improving their living standards.
Problems facing wheat farming in Kenya
Pests e.g. dustry brown beetle, cereal weevils, quelea birds and diseases e.g. stem rust, brown leaf rust that reduce the quality and quantity of produced wheat
Price fluctuations in the domestic markets due to broking by middlemen; farmers get very low profits.
Inadequate capital/high costs for buying farm inputs (machinery and fertilizers) leads to marginal profits
Wheat Farming in Canada
– Canada is the leading wheat producer and exporter in the world
– Wheat is grown in the Canadian Prairies provinces of Saskatchewan, Alberta and Manitoba.
Factors favoring wheat growing in Canada
Suitable climate characterized by warm summer temperatures of about 150C and mean annual precipitation of 460mm that are ideal for wheat growing.
Warm summer temperatures of about 150C ideal for wheat growing.
Gently rolling/undulating landscape that allows mechanization.
Availability of cheap tracts of land on account of her small population density and majority of people live in urban centres and cities.
Elaborate transport network through extension of the railway into the prairies facilitates transport of wheat to the markets.
Fertile prairies’ soils with high potassium content essential for wheat growing
Ready market in the urban population and the neighbouring countries
Cultivation of Wheat in Canada
– Wheat is mainly grown on plantations/through large scale farming
– The entire processes from land preparation to harvesting is heavily mechanized
Marketing of Wheat in Canada
– Majorly consumed in the Canadian urban centres and cities
– The rest is exported through the Great Lakes and St. Lawrence Seaway to Europe, Africa and Far East.
Problems facing wheat farming in Canada
Difficulty in transportation during winter season when much of Canada is under snow. This leads to delays in delivery to the markets
Pests and diseases e.g. cereal weevils and stem rust destroy the wheat in the fields leading to low yields
Price fluctuations of wheat in the world market affecting the farmers’ income/leading to difficulties in planning ahead.
Adverse climatic conditions e.g. excessive drought and hail that affects the production.
Monoculture that leads to soil exhaustion requiring the use of fertilizers
Importance of Wheat Farming in Canada
Foreign exchange earnings through exports.
Industrialization through the development of wheat related industries.
Creation of employment opportunities/source of income.
Production of wheat for domestic production
Comparison between Wheat Farming in Kenya and Canada
Similarities
– Mechanization is done in both the countries – sowing and harvesting
– It is done on a large scale in both the countries
– In both countries wheat is grown in areas with gentle sloping.
– Wheat farming is favoured by a dry sunny spell for harvesting in both countries.
– Problems experienced in both countries are the same.
Differences
– In Kenya, wheat farming is less mechanized while in Canada it is less mechanized
– In Kenya, wheat farming is mainly for local consumption while in Canada wheat farming is done mainly for export
– In Kenya, wheat farmers do mixed farming alongside wheat production whereas in Canada, the farmers are specialized in wheat farming.
– There is more government support towards wheat farming in Canada through incentives and subsidies while in Kenya these are lacking.
– There are more extensive tracts of land suitable for wheat farming in Canada than in Kenya.
– Wheat farming in Canada benefits from more advanced scientific research which is not available in Kenya.
Horticulture and Market Gardening
– Horticulture refers to the intensive cultivation of vegetables, fruits and flowers for sale and export.
– Market gardening is an intensive cultivation of vegetables and fruits for sale in the nearest urban centre.
Differences between Horticulture and Market Gardening
– In horticulture, fruits, flowers and vegetables are grown while marketing gardening involves growing of fruits and vegetables only
– Horticulture is export oriented while market gardening is local market oriented
– Horticulture is less labour intensive/highly mechanized while market gardening is more labour intensive/less mechanized
– Horticulture adheres to high international quality requirements and standards of hygiene while market gardening lack standard/quality requirements
– Horticultural farms are highly scientifically managed while farms engaged in market gardening are less scientifically managed
Features/characteristics of Horticulture in Kenya
It requires a lot of farm inputs e.g. fertilizers, pesticides and herbicides hence needs high capital outlay
The farms are smaller in size except for the large scale flower farms in Naivasha
Farms are located in areas with good and reliable transport infrastructure since horticultural products are highly perishable
Advanced scientific techniques of crop production are applied to ensure high yields
Factors favouring horticultural farming in Kenya
The hot and wet climate favours the growth of tropical crops while the cool and wet conditions in the highlands suit temperate crops (plums, pears, apples grapes)
The fertile volcanic soils that are well drained and rich in nutrients favour the growth of a variety of crops
High population in the rural areas provide labour in the farms and in urban centres that provide ready market.
Investment by large companies such as Del-Monte ,Pan African foods, Oserian that provide capital for the horticultural industry.
Technical and financial assistance by the German Agricultural team who carry out research, and train farmers.
Establishment of Horticultural Cooperative Union and Horticultural Development Authority to help farmers export their products.
The government through its export promotion drive is encouraging the diversification of export crops with the aim of broadening the country’s export base.
Improvement of road network to enhance accessibility to local and overseas markets.
Cultivation
– Fruits and vegetables are grown in open fields
– Flowers are grown at the shores of Lake Naivasha and in Kibwezi
– There is increased use of greenhouses in the growing of fruits, flowers and vegetables
Description of Greenhouses
– They are large in size – resemble warehouses/go downs – spacious
– Their framework is made of wood or metal tubes
– They are covered by translucent heavy polythene material to allow small amounts of sunshine/heat
– The polythene falls freely and can be raised to desired heights to control humidity
– The moisture/water is availed to the plants by sprinkling/irrigation
Reasons for increased use of greenhouse in horticultural farming
It is easier to control the amount of moisture that flowers require
The plants are protected from excessive rainfall, hailstones and drought thus ensuring maximum yields
Spread of pests and diseases is controlled as chemicals (pesticides) are used more effectively and efficiently.
Plants are protected from the damaging effects of strong winds and airborne diseases.
Semi artificial climate is created within the greenhouse which is uniform for all plants in there.
Crops are grown all year round since external climatic conditions do not affect their growth.
It is easy to control weeds through application of herbicides
Production
– Floriculture is the practice of growing flowers. It is mainly concentrated in Central, Eastern and parts of Rift Valley in Murang’a, Nyeri, Kirinyaga, Embu and Kericho counties
– The main flowers grown include roses, orchids, carnations, gladioli, solidago, lilies, anthurium and chrysanthemum
– The flowers are mainly for export to Europe
– A large variety of vegetables are grown in Kenya such as: –
Starchy tubers: – cassava, yams and potatoes.
Root crops: – carrots and turnips.
Pulses: – leguminous peas, beans, lentils, soya beans and groundnuts .
Green vegetables: – cabbage, cauliflower, kales and green grams.
Miscellaneous vegetables: – onions, tomatoes and chillies
– Fruits grown in Kenya are for local consumption and a few are exported. The main fruits grown are citrus (grapes, oranges, lemons and tangerine), deciduous fruits (apples, pears, peaches and plums) and tropical fruits (bananas, dates, pawpaws, pineapple and avocadoes)
Marketing
– Most of the horticultural products are consumed locally mainly by the urban population
– A small portion of the produce (flowers)is exported
– The farmers transport the fruits and vegetables to the collecting centres
– They are then checked and graded
– The buyers and middlemen then transported to airports in refrigerated trucks ready for external markets
– The major destination for the flowers are Europe and the Middle East
Problems Facing Horticultural Farming in Kenya
Pests and diseases lower crop yields e.g. aphids, nematodes, birds, worms, rodents (pests); blight, black rot, bacterial wilt
Inefficient marketing system that lacks proper organization lead to rotting of produce
Stiff competition on the international market by other horticultural producers (Israel, Netherlands).
Price fluctuations due to overproduction results to marginal profits.
Climatic hazards (frost, hailstones, prolonged drought) that destroy the produce in the farms.
High freight charges and production costs that lead to marginal profits (due to hiked costs of farm inputs and airfares).
Seasonal floods that make the feeder roads impassable during the rainy season limits accessibility between the farms and collecting centres/leads to delay in delivery of the products.
Inadequate refrigeration facilities may lead to reduction in quality of highly perishable produce.
Importance of Horticultural Farming to Kenya’s Economy
It is a major source of raw material for local horticultural industries e.g. fruit canning, manufacture of vegetable oils thus stimulating industrialization and other related industries such as freight services, pesticides and banking services.
Export of flowers, fruits and vegetables earns foreign exchange
Creation of employment opportunities since it provides a source of income to farmers hence raising their living standards.
It has stimulated expansion and development of transport infrastructure through construction of roads and airports to facilitate the delivery of horticulture products to various markets.
It has ensured effective/maximum use of land and even reclamation of swampy areas.
Horticulture in the Netherlands
– Netherlands or Holland is highly specialized in horticulture
– The horticultural farming areas in the Netherlands include
The Wasteland: – this includes The Hague, Hook of Holland and Rotterdam. It mainly grows vegetables e.g. carrots, lettuce, cucumbers, spinach, and grapes.
Leiden – Harlem area: – this includes Aalsmeer near Amsterdam and mainly grows flowers.
Arnhem – Nijmegen area: – includes Guelderland, Limburg and Utrecht and it mainly grows fruits
Factors favouring horticultural farming in the Netherlands
The coast of Netherlands is washed by the warm Gulf Stream Current making it free from ice/frost thus favours growth of fruits throughout the year
Fertile soils: – the sandy coastal dunes, which are well drained and quickly warmed up in spring, are ideal for Horticulture.
Advanced technology in the Netherlands e.g. the use of greenhouses with heating systems has led to highly developed horticultural farming.
Highly developed transport system e.g. good harbours, canals, navigable rivers, roads and railway lines eases and quickens the movement of horticultural crops in/outside the country.
Central location of the Netherlands in Europe makes it accessible to external/foreign markets.
Ready Market from the populous urban areas and Europe (high purchasing power)
Highly organized marketing systems due to well-developed cooperatives to market the produce, supply inputs, organize auctions and advance credit to farmers.
Availability of skilled labor with a long tradition in floriculture has ensured high production and quality packaging.
Extensive and successful research in horticulture has led to high quality crop varieties and effective pest and disease control
Cultivation
– The horticultural crops are grown in open fields as well as in greenhouses
– The vegetables grown in the Netherlands are tomatoes, cucumber, lettuce, cauliflower, melons, and spinach among others
– Flowers include tulips, chrysanthemum, roses, carnations and lilies
– Fruits; apples, pears, cherries and red currants
Marketing
– The farm produce is transported by road, railway and air to the nearest market
– Some of the produce is sold locally with the major local markets are concentrated in the major urban centres in the Netherlands
– Majority are exported to the major foreign markets e.g. Britain, Germany, Sweden and France.
– The produce are sold by auction
Importance of Horticultural Farming to the Economy of Netherlands
Foreign exchange earnings through export
Creation of employment opportunities thus source of income
It has contributed to development of good transport infrastructure network in the Netherlands.
It has encouraged polderization – reclamation of land from the sea for expansion of horticulture farms .
Development of related industries through provision of raw materials
Problems facing Horticultural Farming in the Netherlands
Occasional weather changes such as unexpected frost affect the crops grown in the open fields leading to loss of yield.
.
.
Comparison between Horticulture Farming in Kenya and the Netherlands
Similarities
– Greenhouse technology is applied in the both the countries
– Similar vegetables and flowers are grown in both the countries
– Horticultural products are export market oriented in both the countries
– In both countries there is use of green houses on the horticultural land
Differences
– Horticultural farmers in the Netherlands are highly skilled due to long history while in Kenya the farmers are less skilled due to short history
– In the Netherlands, there is higher local demand for horticultural products due to higher incomes of the locals/citizens while in Kenya there is lower local demand for horticultural products due to lower incomes of many citizens
– Netherlands is centrally located in Europe thus has a wider foreign market within easy reach while in Kenya, freight charges limit access to European market
– In the Netherlands the scale of production is large while in Kenya small scale
– Netherlands unlike Kenya has well developed means of transport which enhances fast movement of horticultural products.
Livestock Farming
– This refers to the rearing of domesticated animals such cattle, sheep, goats, pigs, horses, camels and poultry for subsistence and sales
– It is divided into the following: –
Traditional livestock farming.
Livestock ranching.
Commercial livestock farming
Traditional Livestock Farming
– This is also referred to as nomadic or subsistence pastoralism or pastoralism
– It is the extensive grazing of livestock on natural pasture involving constant and seasonal migration of the nomads/pastoralists and their livestock in search of water and pasture; a process referred to as transhumance
– It is mainly practiced in the arid and semi-arid lands e.g. in Turkana, Wajir, Garissa, Mandera, Kajiado, Narok and Marsabit counties
– The pastoral communities in Kenya include Maasai, Samburu, Somali, Borana, Turkana and Pokot
– In other parts of Africa, it is practiced by the Fulani (West Africa), Hottentots (Southern Africa – Botswana, Republic of South Africa and Mozambique) the Tuaregs of North Africa and the Nuba of Ethiopia and Sudan
Characteristics of Nomadic Pastoralism
It involves constant and seasonal migration of the pastoralists and their livestock in search of water and pasture
Large herds of animals are kept i.e. emphasis is laid on quantity and not quality of the animals
Many kinds of animals are kept.
The nomads rely on natural pasture for grazing
The animals are grazed communally
The animals of low quality and weakened by diseases/high incidences of pests e.g. ticks and diseases e.g. foot and mouth, rinderpest
Animals are kept as a sign of wealth and for slaughter during social functions
Factors favouring Nomadic Pastoralism in Kenya
– The grazing areas are free from tsetse fly due to hot and dry conditions.
– Availability of large tracts of land for grazing due to the sparse population in Northern and North eastern regions.
– Availability of natural pasture in the wooded savanna lands.
– The gentle slopes/undulating terrain enable easy movement of stock from one place to another.
Problems facing pastoralism in Kenya
Prolonged drought leads to shortage of water and scarcity of pasture.
Overstocking leads to overgrazing hence poor pastures.
Pests and diseases such as rinderpest, east coast fever, foot and mouth, ticks and tsetse fly reduce the quality of the animals.
Low quality local breeds e.g. zebu, boran that yield little milk and provide low quality meat.
Animals are frequently attacked by wild animals.
Shortage of extension/veterinary services due to their nomadic nature.
Insufficient marketing systems, lack of information on market conditions makes them be exploited by middlemen.
Frequent livestock raids/cattle rustling.
Low level of education and culture hinder them from practicing modern methods of livestock farming.
Competition for range pastures with wildlife.
Poor transport connection hinders accessibility to potential markets.
Fire outbreaks destroy huge tracts of the grassland hindering their regeneration/reducing pasture land.
Steps taken by Kenyan Government to Improve the Quality of Livestock in the areas practicing Nomadic Pastoralism
Establishing demonstration ranches to sensitize pastoralists on better methods of animal husbandry.
Cattle dips have been constructed to control pests.
The government is encouraging group ranching to enable the pastoralists to view livestock keeping as a commercial undertaking.
Boreholes have been sunk and dams constructed in the practicing areas to provide water for livestock.
Introduction of drought resistant nutritious grass.
Encouraging cross breeding of indigenous breed with hybrid breeds to improve the quality of livestock.
Improvement of transport system in the areas to facilitate transportation to the markets.
Establishment of Kenya Meat Commission to guarantee market for livestock.
Establishment of Anti Stock theft police to curb cattle raids.
Educating the pastoralists on land carrying capacity so that they control the number of livestock.
Research centers have been established for pest and disease control.
Provision of veterinary and extension services.
Livestock Ranching
– This is the large scale and extensive rearing of cattle for meat products
– In Kenya it is mainly done in the Rift Valley Province in Laikipia County
Characteristics of Livestock Ranching
Large herds and flocks are kept on large tracts of land
The ranches are highly specialized and produce only one product
The ranches are scientifically managed to ensure high quality production
Products are mainly for sell/few are exported
Commercial Livestock Farming
– This involves the rearing of animals for sale/export of their products
– It involves dairy and beef farming
Dairy Farming in Kenya
– This is the practice of keeping livestock for milk and milk products.
– It is divided into highland and lowland commercial dairy farming
– Highland commercial dairy farming is practiced in the Kenya highlands in the following counties
Province Counties
Rift Valley Nakuru, Laikipia, Uasin Gishu, Laikipia, Kericho, Nandi and Bomet
Central Kiambu, Kirinyaga, Nyeri, Murang’a
Western Kakamega, Vihiga and Bungoma
Eastern Meru, Embu, Machakos & Makueni
Nyanza Kisii, Nyamira and Migori
– Lowland commercial dairy farming is carried out in the coast province in Kilifi and Kwale counties
– The types of dairy cattle kept in Kenya include
Friesian/Holstein Block.
Guernsey.
Alderney
Ayrshire
Sahiwal – local/indigenous
Conditions favouring dairy farming in Kenya
Low temperatures (150C-180C)/cool conditions are ideal for survival of high quality exotic breeds, which have low tolerance to high temperatures.
Heavy rainfall throughout the year ensuring availability of pasture all year round
Fertile volcanic soils that ensure constant growth of pasture and high quality nutritious grass.
Permanent water sources from rivers and lakes due to heavy and reliable rainfall
Low incidences of tropical pests and diseases due to cool conditions
Well established transport infrastructure in terms of roads that ensures quick transportation of milk to processing plants and to the markets
High population in the Kenya highlands and the neighbouring urban centres that offer ready market for the dairy products
– Artificial Insemination is used in the breeding of the dairy cattle – semen collected from good breeding males/high quality bulls and placed in the reproductive tract of dairy animals to ensure high milk production
Milk Processing
– This is done by the Kenya Cooperative Creameries and private creameries located in major urban areas
– At the creameries, the milk is weighed and recorded against the farmer’s name
– The milk is then processed into liquid milk, Ultra Heat Treated (UHT) milk, powdered milk, butter, ghee and cheese
– It is then packed ready for marketing
– The milk is then sent to distributors/depots for sale
Problems facing dairy farming in Kenya
Stiff competition from imported milk and milk products and from alternative land uses e.g. horticulture, tea and coffee.
High incidences of pests and diseases e.g. ticks, foot and mouth, rinderpest that reduce the quality of dairy cattle thus low milk yield
High costs of farm inputs has limited and minimized the mechanization of the dairy farms.
Poor management of dairy cooperatives results to misappropriation of funds leading to delayed payments that lowers the farmers’ initiatives.
Prolonged and abrupt droughts that lower the quality/quantity of pasture resulting to low yields.
Poor roads that is impassable during the rainy season. This leads to delays in delivery of milk to the creameries
Measures the government of Kenya has undertaken to improve dairy farming.
Reopening of Kenya cooperative creameries and improving its management to provide ready outlet to milk produced by farmers.
Holding agricultural shows/trade fares to offer education on good dairy farming management
Improved and intensified extension services to update the farmers on ways of improving their stock/dairy cattle.
Improvement of/extending access to credit facilities e.g. revamping of Agricultural Finance Cooperation.
Introduction of high quality breeds through artificial insemination and cross breeding.
Setting up demonstration projects such as Emali Livestock Multiplicity Project for breeding of high quality bulls.
Building cattle dips to control tick borne diseases.
Improving road network in the dairy farming areas.
Setting up cooling and processing plants in various parts of the country.
Funding of research institutes for disease and pest control.
Dairy Farming in Denmark
– Dairy farming is one of the major agricultural activities in Denmark
Factors that favouring dairy farming in Denmark
– Cool climate (10oC-15oC) which is ideal for high quality dairy cattle/low incidences of pests and diseases due to the cool conditions.
– Low-lying and relatively flat landscape for grazing of dairy cattle.
– Fertile soils that support good pasture and highly nutritious fodder crops.
– Reliable rainfall (1500mm) throughout the year supports plenty of pasture.
– Well-developed cooperative movements, which advance credit to farmers.
– Advanced technology leads to high production e.g. operations in all the farms are heavily mechanized.
– Availability of market both locally and in the rest of Europe due to dense population in Denmark and the neighbouring European countries.
– Well-developed transport network for easier movement of milk and finished products to the markets.
Organization of dairy farms in Denmark
– The dairy farmers in Denmark depend mainly on fodder. This is because climatic conditions do not favour the growing of grass all year round and also fodder is more nutritious compared to natural grass
– During the winter (6 months between to), the dairy animals are kept indoors and fed on fodder
– The rest of the months (summer), the dairy cows are grazed outdoor on natural pasture
– Dairy farming is done by individual farmers on very large scale. The farms are heavily mechanized e.g. machines are used in milking
– Every dairy farmer belongs to a dairy cooperative that provides research, processing and credit facilities
– Types of animals kept are Danish Red (traditional cow), Friesian, Ayrshire, Jersey, Guernsey and Alderney.
Milk Processing in Denmark
– The dairy cattle are milked using machines provided to the farmers by the co-operative
– Fresh milk is processed next to the farms
– Liquid milk is treated through pasteurization, sterilisation, homogenization and ultra-heat treatment
– Pasteurization is heating the liquid milk to temperatures of about 750C for about 20 seconds to kill harmful bacteria
– Sterilisation involves heating the pasteurized milk for a short time at 1000C to ensure that all the bacteria that could have survived pasteurization are killed. This ensures that the milk stays longer without going bad
– Homogenisation involves breaking up and distributing fat particles in the liquid milk. It ensures that a layer of cream does not form on top of the milk
– The liquid milk is then heated beyond 1000C through ultra-heat treatment and packed ready for consumption
– Other by products from milk processing include butter, cheese and ghee
Marketing of Dairy Products in Denmark
– This is done by the co-operatives
Problems facing dairy farming in Denmark
Fluctuating weather conditions between winter and summer affects the growth of fodder and natural grass, making it expensive to feed the dairy cattle
Competition from other dairy producers in the world market
Dairy cattle diseases e.g. mastitis affect the dairy cattle
Pollution.
Inadequate Market.
Similarities between dairy farming in Kenya and Denmark
Exotic and traditional breeds are kept in both countries.
Artificial Insemination and cross breeding is practiced in both countries.
Both countries, dairy farmers sell their products to the co-operatives.
Both open and zero grazing are used in the two countries.
Milk processing is similar in both the countries.
Dairy products are similar in both the countries e.g. liquid milk, cheese and butter
Differences between dairy farming in Kenya and dairy farming in Denmark
In Denmark, the practice is carried out throughout the country while in Kenya; it is restricted to the cool areas especially the highlands.
In Denmark, the cattle depend on fodder crops and commercial feeds while in Kenya they depend on natural grass with limited use of fodder and commercial feeds.
In Denmark, mechanization is widely used while in Kenya, it is limited especially on small-scale farms.
In Denmark, dairy farmers are highly specialized while in Kenya farmers practice mixed farming.
In Denmark, all farmers have access to Artificial Insemination, in Kenya; Artificial Insemination is limited to most farms.
In Denmark, high yields are achieved throughout the year because animals are kept indoors and fed on fodder in winter while in Kenya dairy yields are affected by climate changes and drought.
In Denmark, dairy products are mainly for export while in Kenya; dairy products are consumed locally.
In Denmark, the cooperatives are highly developed and have enough funds, in Kenya; dairy cooperatives are young and lack adequate funds to advance to farmers.
In Denmark, cattle are kept indoors in winter and autumn while in Kenya; cattle are grazed outdoor throughout the year.
Beef Farming
Beef farming in Kenya
Involves rearing of cattle for meat products.
Mostly done in the following areas
Laikipia
Nakuru
Kwale
Kajiado
Trans Nzoia
Kilifi
Done at a small scale for subsistence/nomadic pastoralism.
Also done in ranches that scientifically managed.
Livestock ranching is a modern and scientific method of rearing one type of animal for commercial purposes on extensive land, which is fenced and divided into paddocks.
Characteristics
High quality animals are reared through selective breeding.
Movement of beef cattle is confined within the ranch.
Animals are owned and grazed on individual basis not communally.
Farmers practice artificial insemination and cross breeding.
One type of animal is reared.
Fodder crops are grown to supplement the natural pasture.
Pests and diseases are controlled.
The ranches have piped water, cattle dips, etc.
Breeds of beef cattle kept include
– Aberdeen Angus
– Hereford
– Charolais
– Zebu
– Boran
– Short horn
– Galloway
Factors that favors beef farming in Kenya
Extensive flatlands with natural pasture/grass that offer room for extensive grazing especially within the Nyika plateau and the Rift Valley region
Moderate rainfall of about 750mm or above which ensures supply of pasture/water.
Moderate temperatures of about 28oC lowers pest and disease incidence/favours survival of exotic breeds
Presence of watering sites such as Lorian, Lotikipi and Saiwa swamps/several permanent rivers that provides water for the beef cattle.
Ready market due dense/high population in the practicing areas.
The communities have a long tradition of cattle keeping.
Problems experienced by beef farmers in Kenya.
High temperatures in some areas are unsuitable for pedigree/exotic breeds.
Natural grass of poor quality/low nutritional value.
Tsetse fly infested areas discourage beef farming.
Poor soils prone to erosion to sustain pasture.
Unreliable rainfall leading to shortage of water and scarcity of pasture.
Kenya tropical environment encourages spread of pests and diseases (spread by wild animals) e.g. ticks, tsetse flies, nagana, east coast fever
Competition for rangeland between beef farmers and wildlife.
Steps taken by government of Kenya to improve beef farming
Decontrolling the price of meat products.
Funding research in Animal pest and Disease control.
Introduction of pedigree/exotic cattle and encouraging cross breeding with local breeds to improve their quality.
Introduction of drought resistant high quality grass.
Educating beef farmers on modern methods through trade fairs, tours and seminars.
Investigating the prevailing market situations and make appropriate recommendations.
Creating ranching schemes in arid and semi-arid lands.
Encouraging setting up of group ranches.
Other uses of beef cattle products.
Bones are used to manufacture fertilizers.
Horns and hooves are used for making glues/adhesives.
Hides and skins for making leather shoes, bags and belts.
Provision of cooking fat.
Beef Farming in Argentina
– Argentina is located in South American continent and is one of the leading beef producer in the world.
Factors favouring beef farming in Argentina
Physical factors
Moderate and well-distributed rainfall throughout the year of about 1000mm favours growth of pastures and regular supply of water for cattle.
The moderate temperatures of 10oC-24oC favour the growth of grass all year round.
Fertile soils washed from the foothills of Andes by rivers are deposited in the low-lying areas, giving rise to good natural pastures.
Extensive and rolling grasslands (pampas) at the foot of Andes Mountains provides good sites for natural grazing and pasture.
Availability of highly nutritious temperate grass.
Human factors
Well-established railway network eases accessibility.
Adequate capital to mechanize farm operations and install refrigeration facilities.
Highly organized cattle ranches, which are fairly mechanized.
Availability of market locally in the European countries.
Introduction of exotic breeds (short horn, Hereford) ensures high quality meat.
Replacement of natural pasture with alfalfa, which is highly nutritious and matures faster.
Organization of Beef Farms in Argentina
– Beef cattle are reared in ranches that are heavily mechanized
– Each ranch has a manager, meat packing factories, farm houses, windmills and transport facilities
– The beef cattle are fattened using cultivated pasture
Distribution of Beef farms in Argentina
– The farms are evenly distributed
– The major farms are located around Chaco, Formosa and Santiago del Estero
Processing & Marketing of Beef in Argentina
– The beef cattle are slaughtered then transported to the meat packing plants by trains
– The meat is packed in tins
– Ships with refrigeration facilities carry the beef to external/overseas markets
Significance of Beef Farming in Argentina
It has led to the growth and development of towns e.g. Bahia, Blanca and Rosario
Creation of employment opportunities as managers in the beef farms, and other beef related industries.
It has promoted industrialization through development of beef related industries such as canning.
It has earned Argentina foreign exchange through export to Europe and Middle East.
Improvement of infrastructure through establishment of roads and railways that link the farms and processing/packing plants
Processing and Marketing of Beef Products in Argentina
– The beef cattle are slaughtered then transported to meat packing plants by trains
– At the plants, they are put in cold storage and packed into tins
– Ships with refrigeration carry the packed beef products to external/overseas markets
Problems facing beef farming in Argentina
Diseases such rinderpest, foot and mouth that reduce the quantity of beef products
Stringent sanitary conditions in the world market
Local and international economic and political crises that affect the production
Comparison between beef farming in Kenya and Argentina
Similarities
Both countries keep similar breeds of beef cattle e.g. Aberdeen Angus, Hereford, shorthorn, etc.
In both countries, the beef cattle are kept in ranches that are scientifically managed
Both countries keep local and exotic breeds
Beef products are for local consumption in both the countries.
Beef farming is mainly practiced on extensive undulating landscape
Differences
In Kenya, beef farming is carried out by both pastoralists and commercial ranches whereas in Argentina, beef farming is done on extensive ranches
Kenya has inadequate/lack adequate pastures for grazing beef cattle while Argentina has extensive natural pasture in the pampas
In Kenya, beef farming is done on a small scale/less mechanized while in Argentina, beef farming is heavily mechanized and done on a large scale.
Argentina has ahigh local market for beef while inkenya the market is limited.
Farmers in Argentina has more access to capital needed for beef farming while in Kenya the farmers have inadequate capital.
Past KCSE Questions on the topic
1. a) State two climatic conditions that favour the growing of oil palm in
Nigeria. (2mks)
b) Give two problems experienced in the marketing of palm oil in
Nigeria. (2mks)
2. The photograph provided shows a tea growing area in Kenya. Use it to answer questions (a) and (b)
a) (i) What evidence in the photograph shows that this is a ground
genera-view type of photograph? (2mks)
(ii) Draw a rectangle measuring 15cm by 10cm to represent the area of the photograph. On it sketch and label the main features shown on the photograph. (5mks)
(iii) Identify two features from the photograph that show that this is a small scale tea farm. (2mks)
b) Describe the stages involved in the cultivation of tea from land preparation to the stage shown on the photograph.
c) (i) Name two districts in the Eastern province where tea is grown.
(2mks)
(ii) Explain four ways in which the Kenya Tea development agency
(KTDA) assists small scale tea farmers in Kenya (8mks)
3. (a) State three physical conditions that are necessary for the growing of cocoa
(3mks)
(b) Give three economic problems experienced in cocoa farming in Ghana
(3mks)
4. a) Give three physical factors that favour coffee growing in Kenya highlands.
b) State two problems facing coffee farming in Kenya
5. a) i) Name two provinces in Kenya where wheat is grown on large
scale (2mks)
ii) Explain four physical conditions that favour wheat growing in Kenya (8mks)
b) Compare wheat farming in Canada and / Kenya under the following
i) Storage (2mks)
ii) Transportation (2mks)
iii) Marking (2mks)
c) i) Explain three climate problems that affect wheat farming in
Canada (6mks)
ii) Give three uses of wheat (2mks)
d) Name two districts in Kenya where wheat is grown on commercial scale.
(2mks)
e) Name two wheat producing provinces in Canada (2mks)
f) Explain five factors which enable Canada to produce more wheat than
Kenya. (5mks)
6. a) State five physical conditions required for the growing of tea in Kenya
(5mks)
b) Explain four problems experienced in small scale tea farming in Kenya
(8mks)
7. The map below shows some major tea growing areas in Kenya.
a) Name the areas marked W, X and Y. (3mks)
b) Give two reasons why there was an increase in tea production over the
given period. (2mks)
c) Describe the stages through which tea is processed from picking to the time it is ready for marketing. (5mks)
8. Name major cocoa growing areas in Ghana. (3mks)
9. List suitable conditions for cultivation of cocoa. (4mks)
10. Name types of commercially cultivated coffee. (3mks)
11. Explain ways in which Brazilian government responds to problems facing coffee industry. (6mks)
12. Name four uses of maize. (4mks)
13. List four problems facing maize farmers. (4mks)
14. Outline stages in industrial processing of cocoa. (5mks)
CHAPTER 12
AGRICULTURE – LIVESTOCK.
1. a) Name two exotic breeds of dairy cattle reared in Kenya. (2mks)
b) State three physical conditions that favour dairy farming in Denmark
(8mks)
2. a) Explain four ways in which the government of Kenya assist nomadic
pastoralist to improve the quality of their livestock
Explain three factors that favour beef farming in Argentina.
State three environmental conditions which favour commercial beef farming in Kenya. (3mks)
Name two exotic breeds of cattle reared in commercial ranches in Kenya.
(2mks)
3. Mention three problems facing beef farming in Kenya. (3mks)
4. State five human factors that have favoured beef farming in Argentina. (5mks)
5. State differences in dairy farming in Kenya and in Denmark. (6mks)
6. What effort is Kenyan government making to improve dairy farming? (5mks)
7. What is nomadic herding? (2mks)
8. State five features of nomadic herding. (5mks)
9. Explain two efforts Kenyan government has made to improve beef farming. (4mks)
10. Explain four physical conditional that favour dairy farming in Kenya. (8mks)
9. The table below shows data on average milk yield in kg per cow in Denmark.
Year 1990 1991 1992 1993 1994 1995
Yields (Kg) 5243 6693 7398 7610 7792 7946
(a) (i) Draw a divided rectangle 15cm long to represent milk yield in
Denmark.
(ii) State two advantages of using divided rectangles.
(b) (i) Explain three factors that have favoured dairy farming in Denmark.
(6mks)
(ii) State 3 problems facing dairy farmers in Kenya.
(c) Explain why beef farming is more developed in Argentina than in Kenya.
CHAPTER SIX
Specific Objectives
By the end of the topic the learner should be able to:
(a) Define land reclamation and rehabilitation;
(b) Discuss the factors that influenced the location of selected irrigation schemes in Kenya, the significance of the schemes and the problems that are experienced in carrying out irrigation farming in Kenya;
(c) Describe the methods that are used in land reclamation and rehabilitation in Kenya;
(d) Compare the methods of land reclamation in Kenya and the Netherlands,
Content
Meaning of the terms land reclamation and rehabilitation.
A study of Mwea-Tebere and Perkerra irrigation schemes.
Importance of irrigation farming in Kenya.
Problems experienced in irrigation farming in Kenya.
Methods of land reclamation and rehabilitation in Kenya.
Comparative study of land reclamation in Kenya and the Netherlands.
Definitions
Land reclamation
Land reclamation is the process of converting less productive land into a more productive state for agricultural or settlement purposes.
Land rehabilitation.
Land rehabilitation is the process of restoring degraded / improvised / damaged land back to useful state.
Methods which are used in reclaiming land in Kenya.
Irrigation
Draining of swamps
Control of floods
Introduction of drought resistant crops.
Control of soil erosion.
Afforestation (Agroforestry / Re-afforestation)
Improvement of soil through the use of manures/ fertilizers
Control of pests (Tsetse fly)
Methods that are used to control tse tse flies in Kenya.
– Bush clearing of tsetse fly habitat.
– Spraying using insecticide.
– Using of traps.
– Construction of buffer zones.
Factors which should be considered when selecting a wasteland to be reclaimed for agricultural use.
– The size of the area- i.e. big enough to justify reclamation.
– Soils should be fertile to minimize the cost in improving them. (Fertilizers)
– Minimal incidence of pests and diseases/controllable.
– The climate should be suitable / favorable for the intended agricultural use.
– Availability of capital to initiate the project i.e. cost effectiveness.
– Availability of skilled manpower.
– The land should be undulating for mechanization or irrigation.
– Accessibility of the area.
Benefits that have resulted from the reclamation of Yala swamp.
– Has led to control of floods in the area.
– Has created employment opportunities and raised living standards.
– Has stimulated development of infrastructure.
– Has increased the amount of agricultural land.
– Mosquitoes were controlled.
– Better farming methods were introduced.
– Increased agricultural output due to introduction of new crops.
Rivers which cause large scale flooding in Kenya.
Nyando,
Nzoia,
Tana,
Kuja,
Yala,
Ewaso Nyiro
Ways in which floods affect people.
– People are displaced.
– Disrupts transport and communication system.
– Causes soil water logging which lowers crop production.
– Leads to loss of property and lives.
– Creates stagnant water in which disease causing micro-organisms breed e.g.
Mosquitoes, Bilharzia snails.
– Floods disrupt farmers calendar/wash away crops/leads to food shortages.
Methods through which floods can be controlled.
– Construction of dams to check the velocity and volume of rivers downstream.
– Construction of dykes which restrict the outflow of rivers / raised river
Embankments.
– Construct diversion channels to realign meanders and restrict flow of river / drain
flooded areas. – Planting of vegetation / forests in the river catchment areas to
Reduce the surface run-off and increase seepage.
– Clearing of drainage systems / dredging / deepening and widening to facilitate
Easy flow of water.
Aims of the Lambwe valley project.
To develop 13,000 ha of land for both livestock and agricultural production,
To suppress the tsetse fly population through the use of insecticides and bush clearing.
To treat domestic animals so as to reduce the risk of infection.
To treat human cases of sleeping sickness.
To treat wild animals e.g. Bush buck, warthog, buffalo, impala which act as tsetse fly hosts.
Ways in which tsetse fly was controlled in Lambwe valley.
– Clearing the bushes.
– Sterilizing the male tsetse fly.
– Spraying the bushes with insecticides.
Problems faced in the control of tsetse fly in Kenya.
– Clearing bushes leads to total destruction of bushes therefore exposing the soil toagents of erosion.
– The tsetse fly became resistant to insecticides.
– Some insecticides sprayed are harmful to man, animals and the environment, cause pollution.
– The method of sterilizing the male tsetse fly is quite sophisticated.
– The areas infested are extensive therefore costly to spray.
Types of irrigation.
– Overhead / sprinkler
– Drip irrigation.
– Basin irrigation.
– Canal/Surface irrigation
Advantages of irrigation over natural water supplies.
– Ensures steady and reliable water supply.
– Cultivation can be done all year.
– River water brings in silt (fertile)
– Enables cultivation of marginal areas.
– Controls floods.
– The dam can be used to generate H.E.P., improve navigation on rivers, lead to development of fishing industry and modify local weather.
Conditions necessary for irrigation scheme.
– The land should be gently sloping to allow water to flow by gravity.
– The area should be drained by permanent rivers to supply enough water all year.
– The area should be sparsely populated to reduce cost of relocation.
– The area should have clay soil which allows only limited water seepage.
– The area should be dry and receiving inadequate rainfall to support crops.
Irrigation schemes in Kenya.
– Mwea Tabere – Rice – Perkerra – Water melons, onions, chilies
– Bura – Cotton – Bunyale – Rice
– West Kano – Sugar cane -Kibwezi – Fruits / vegetables
– Katilu (Turkwell) – Maize (Turkana)- Ishiara – Tobacco
– Kibirigwi – Vegetables
Factors that influenced the location of Mwea Irrigation Scheme.
– Presence of perennial rivers Thiba and Nyarnindi provided adequate water all year.
– The Mwea plains have black cotton soil suitable for rice farming as it retains water.
– The area receives inadequate (poorly distributed) rainfall, hence unsuitable for rainfed agriculture.
– The land is gently sloping hence gravity flow of water in the channels.
– The area has high temperatures hence low pest and disease incidence.
– The undulating relief is suitable for mechanization.
– Need to engage political detainees 1950’s.
– To create land to settle those whose lands were taken by white settlers.
– The plains were sparsely populated.
Ways through which tenants in Mwea have benefited from thescheme.
– Has created job opportunities/source of income/improved living standards.
– Has provided land to many people who did not have farms before.
– The reservoirs created for irrigation have controlled flooding in plains.
– Has led to economical use of otherwise idle/barren land.
– Has enhanced food security, through rice production.
– The scheme has stimulated development of infrastructure to transport rice to market.
– Horticultural and food crops have been introduced e.g. maize and beans.
– Provision of social amenities – schools, hospitals.
Main rivers which supply water to Mwea Tebere irrigation scheme.
R. Thiba
R. Nyamindi
Environmental problems faced by farmers in Mwea-Tebere irrigation scheme.
Incidences of water borne diseases e.g. bilharzias/Malaria.
Pest infestation which lowers production e.g. Quelea birds.
Water weeds which compete with rice for nutrients e.g. Rhizome weeds.
Silting in the canals reduces the amount of water.
Low water table in the rivers during the dry season.
Methods used to rehabilitate land in Kenya
Afforestation and Re-afforestation
Bush fallowing
Planting cover crops
Mulching
Manuring
Construction of glabious
Drainage trenches on floaded areas.
Benefits of Perkera Irrigation Scheme
Made use of unproductive semi-arid land into productive land.
Supplied agricultural produce to the local market
Created employment opportunities for local population.
Raised the standards of living of many farmers.
Experienced by farmers in the Mwea scheme.
– The stagnant water encourages breeding of snails, mosquitoes which spread diseases.
– Disease and pests lower yields e.g. birds.
– Siltation of canals and weeds interfere with the flow of water and dredging is expensive. – Shortage or high costs of labour, especially during planting and harvesting.
– Delayed payments discourage farmers forcing them to sell rice individually at low prices.
– Shortage of extension officers makes it difficult for farmers to get technical advice.
– Overpopulation has created pressure on the existing facilities such as water.
– Unplanned irrigation developments have overstretched the water supply.
– High prices lead to marginal returns.
Factors which influenced the establishment of Perkerra Irrigation Scheme.
– Presence of R. Perkerra to supply abundant water all year.
– Gently sloping land allows water to flow by gravity, easy mechanization.
– Availability of fertile soils in the Njemps plains.
– Availability of extensive land.
– Semi-arid conditions of the area.
– Area was sparsely populated due to the pastoral lifestyle of the inhabitants.
– The large population of ex-detainees needed to be occupied in a productive way.
Crops grown – Onions, water melons, pawpaw, chilies, and cotton.
Others – seed maize, beans, kale, tomatoes.
Problems faced by farmers in Perkerra scheme.
– Obstruction upstream and drought leads to fluctuation in water supply, thus affects the acreage under cultivation and crop failure. The solution is the construction of a dam upstream.
– Land tenure issue – farmers are yet to be issued with title deeds.
– National Irrigation Board policy that farmers prepare their land is constrained by financial inadequacy.
– Inter-ethnic Conflict – between Tugen and Njemps.
– Diversification – especially growing of maize has led to abandonment of other crops such as onions, cotton, pawpaw etc.
– Livestock – human conflict.
Problems facing irrigation farming in Kenya.
– Silting and occasional flooding
– Unreliable rainfall
– Pests and diseases
– Soil erosion
– Soil exhaustion – Mismanagement of irrigation boards
Significance of irrigation farming
– Settlement of people (landless)
– Infrastructure
– Social amenities
– Industrialization
– Food security
– Foreign exchange
– Source of income
– Employment creation
Factors which favored land reclamation in the Netherlands.
– Availability of capital
– Incentives by the Dutch government to get ways of ending the flood disasters
– Advanced technology especially the invention of the rotating turret for windmills.
Define the term Polder
It is an area of low lying reclaimed from sea which is enclosed by dykes
Benefits of land reclaimed in the Netherlands
– The barrier dam created fresh water lake of Ijssel , to provide water for industrial and domestic use.
– The lake has shortened the coastline by 320 km hence save fuel and time spent in movement ; the saving earned is used to develop other sectors of the economy.
– The polder have improved the drainage system thus reduces the work of flooding in the area the use of dykes ,canals , ditches.
– The reclaimed land has increased arable land which are fertile and are used for crop cultivation and dairy farming.
– The road connecting the province of North Holland and Friesland has been significantly shortened hence saving of fuel.
– The degree of soil salinity in the polders has been lowered by the fresh water lake (Ijssel) thus promoting rearing of livestock.
– Basin during winter thus prevent natural drainage
Process of polderization in the Netherlands.
– Construction of ring dykes separating the polders from the rest of water body/sea.
– Construction of ring canals used for draining water pumped out of the polders.
– Erection of a water pump/windmill for pumping water out of the polder
– Water is pumped out into the canals
– Land is allowed to dry
– Soil is desalinized by flushing with fresh water or planting hardy plants
– Deep ploughing to mix the soil with leached nutrients, addition of fertilizers
– Dividing the land into economic units
– Infrastructure (roads, electricity, and piped water) is laid out
– Establishment of social amenities
– People are settled
– Introduction of crops starting with the hardy crops (barey, oat)
Factors that favor farming activities in polder land.
– Relatively high rainfall
– Fertile, well-drained clay soil
– Cool temperatures/low rate of evaporation
– Flat land easy to mechanize
– Good infrastructural facilities
– Large market for agricultural produce
– Scientific farming hence high yields
Main crops grown in polders.
– potatoes, sugar beet, flowers, barley, oat, fruits, wheat, fodder crops, rye.
Main reclamation projects in Netherlands.
– The Zuider Zee project – 5 polders
– The Delta Plan Project – 5 polders (2 x
Reasons for reclaiming swamps in Kenya.
– To free area from pest / water borne diseases.
– To reduce flooding and associated effects.
– To acquire agricultural land with profitable farming / settlements.
– To develop the remote areas with infrastructure and social amenities.
Benefits which Kenya gets from irrigation farming
– It has raised standards of living of people because of sale of crops bring dried income.
– Has helped to settle the landless people in some schemes like Mwea – Tabere.
– Hard saved the country foreign exchange because Kenya can rely on domestic rice than importing.
– Leads to rehabilitation and development of the surrounding area by reclaiming dry land, and also putting infractural like schools and hospitals.
– Has helped in the control of environmental hazards like flooding through correction of dykes or dams
– Has created employment in the scheme hence raising of living standard
– Has led to the growth of urban centers thus solving the problem of rural – urban migra
Past KCSE Questions on the topic
1. (a) Give two methods used to reclaim lend in Kenya. (2mks)
(b) Outline the stages through which land is reclaimed from the sea in the
Netherlands. (5mks)
2. (a) Difference between land reclamation and rehabilitation. (4mks)
(b) Five ways through which land is being reclaimed. (5mks)
(c) Describe of polderization process in Netherlands. (4mks)
(d) State three benefits that resulted from the reclamation of the YalaSwamp.
(3mks)
3. (a) State the objectives of Mwea irrigation scheme. (4mks)
(b) State the conditions that favoured establishment of Mwea irrigation
scheme. (4mks)
(c) Explain problems faced by rice farmers in Mwea irrigation scheme.
(5mks)
(d) State benefits of Perkerra irrigation scheme. (5mks)
(e) Explain factors that limits Perkerra irrigation scheme. (8mks)
4. Differentiate between horticulture and market gardening. 4 mks
5. Outline three problems facing horticulture farming in Kenya. 3 mks
6. Name five irrigation schemes in Kenya. 5mks
7. State two factors that favour the occurrence of tsetse flies in OlambweValley.
8. State measures that were taken by Kenyan government to control Tsetse flies in OlumbweValley. 5 mks
9. Givethree conditions that made Mwea suitable for establishment of irrigation
scheme. 3 mks
10. Explain two effects of tsetse flies on humans and livestock. 4 mks
11. (a) Differentiate between land reclamation and land rehabilitation. 4 mks
(b) State the reasons for theestablishment of Mwea-Tebere irrigation project.
(c) Explain five problems facings Mwea -Tebere irragation scheme. 5 mks
12. State the problems facing Perkerra irrigation sceme. 5 mks
13. (a) Outline the benefits which Kenya derives from irrigation farming. 5 mks
(b) What are the problems experienced in irrigation farming in Kenya. 5 mks
14. (a) Apart from irrigation, list other methods of land reclamation in Kenya.
(b) Briefly describe the methods listed in 12 (a). 5 mks
15. State the benefits of Yala-Bunyala project. 5 mks
16. (a) What is a polder. 5 mks
(b) Describe the stages involved in 1f reclamation of a polder. 5 mks
(c) State five benefits of land reclamation in Netherlands.
17. State the main differences between the methods of land reclamation in Kenya and Netherlands. 6 mk
CHAPTER SEVEN
Specific Objectives
By the end of the topic the learner should be able to:
(a) Define the terms fishing and fisheries;
(b) Explain the factors that influence fishing;
(c) Account for the location of the major fishing grounds of the world;
(d) Identify types and names of fish and describe methods of fishing;
(e) Discuss fresh water and marine fisheries in East Africa;
(f) Assess the significance of the fishing industry in Kenya;
(g) Discuss the problems that face the fishing industry in Kenya and their possible solutions;
(h) Compare and contrast fishing activities in Kenya and Japan;
(i) Explain ways and means of managing and conserving fresh water and marine fisheries.
Content
Definition of fishing and fisheries
Factors that influence fishing.
Distribution of the major fishing grounds of the world.
Types and names of fish.
Methods of fishing.
Fresh water and marine fisheries in East Africa.
Significance of the fishing industry in Kenya,
Problems facing fishing in Kenya and their possible solutions.
Comparative study of fishing in Kenya and Japan.
Management and conservation of fresh water and marine fisheries
Definition
Definition of terms
Fishing is the exploitation/harvesting of fish and other aquatic/water resources e.g. whales, seals, crabs, lobsters, prawns, oysters, etc. for economic purposes.
Fisheries are water bodies or areas where fish and other aquatic resources are reared or caught in large numbers. They include rivers, lakes, oceans, seas, dams, ponds, etc. they are also referred to as fishing grounds.
Factors influencing fishing
These include the factors that affect the survival of fish in the fisheries as well as those allowing fishing to take place.
They include: –
Presence of fishing grounds:- these depend on the supply of fish food/planktons in the water bodies. This requires the oceans and other fishing grounds to be: –
Shallow to allow sunlight to penetrate for phytoplankton.
Land derived minerals nutrients from along the coasts with several river mouths.
Upwelling/well oxygenated waters where warm and cold currents converge.
Cool waters of temperate latitudes
Cool climate:- cool temperatures (about 200C) are ideal for plankton growth and survival.Hence most commercially important fish species are found in temperate latitudes. Cool temperatures also reduce perishability of fish.
Occurrence of ocean currents: – areas washed by warm ocean currents have fewer fish species and population compared to those washed by cold ocean currents. Also large shoals of fish are found in areas of convergence of warm and cold ocean currents – waters mix and spread out/distributes water temperature; bringing to surface some fish nutrients, helps in supplying more oxygen in the water necessary for plankton growth.
Nature/configuration/orientation of the coastline:- indented/irregular coastlines encourage deep sea fishing because they allow breeding of fish – they are sheltered from strong winds and ocean currents, anchorage of ships and development of ports. Deep coastline with wide continental shelves encourage growth of plankton hence have large population of fish.
Capital:- a large capital base is needed to conduct large scale commercial fishing i.e. for purchasing fishing gear, vessels and refrigeration facilities.
Technology: -modern fishing gears enable fishermen to conduct fishing deep in seas/lakes/oceans.
Market: – areas with large populations offer good market for the fish especially if the population is a fish eating one.
Labour: – fishing is highly labour intensive hence fishing thrives in areas of high population e.g. Asia, Europe, North America, etc.
Transport and refrigeration facilities:- large scale commercial fishing requires that the fishing grounds be served with efficient network of roads to enable delivery of caught fish to the market when still fresh (fish is highly perishable). In areas that are far away from the market, refrigeration facilities are required during transit.
Types of Fish
Fish can be classified according to habitat into fresh water fish and saline/salty/marine water fish.
Fresh water fish are those fish species that live in fresh inland waters – lakes, rivers & ponds/dams.
They include tilapia, trout, nile perch, pike, eel, carp, sturgeon, dagaa, etc. Marine/salty water fish are those that live their entire lives in saline fisheries such as ocean and seas.
Fish can also be classified according to the communities they live into
Type of fish Description Examples
Types of fish Description Examples
Pelagic Live near the water surface or at shallow waters,Live in large groups and move in shoals,they are small in size. Herring,Tuna ,Sardines,Mackerel,Brisling.
Anadromous FFish species that are migratory in Nature,their movement is necessitated by safer and suitblen breeding grounds. Salmon
Pilchard
Demersal Live closer to the bottom of water bodies,
They are larger in size,
They feed on other small fish/sea animals Cod
Cat fish
Haddock
Halibut
Flounder
Dog fish
Scate
Hake
Fishing Methods
These are the techniques that are used to catch/exploit fish.
They depend on the type of fish to be caught, fishing environment and the level of technology.
They can be traditional or modern.
Traditional fishing method include
(a) Harpooning: – involves the use of spears, arrows, sticks, stones, etc. to strike the fish in shallow water. It is commonly used in shallow waters where the fish is visible. The catch is limited hence employed for subsistence fishing. It is dangerous in areas infested with crocodiles and hippos
(b) Use of baskets: – this involves use of woven baskets with narrow cone shaped opening used in shallow waters and ponds. A bait (food put on a hook to catch fish) is placed inside the basket which is then laid at the bottom of the shallow pond. Fish are attracted by the bait and get into the basket but are unable to get out. The basket is then removed with the fish inside.
(c) Use of barriers/traps: – in areas characterized by frequent flooding, barriers made of reeds & sticks are constructed along the river course during the floods to catch fish. The barriers hold up water containing the fish, when the water level drops below the height of the barriers as the floods subside, the fishermen scoop the fish out of the barriers.
(d) Use of herbs: – in calm waters, some fishermen may crush some herbs and sprinkle them in water containing fish. These herbs make the fish unconscious as they take it in; the fishermen then collect the fish using their hands.
(e) Hook and line: – this involves use of baited hooks attached to a line that attracts fish. Once the fish is trapped onto the hook, the hook is pulled out together with the fish.
(f) Use of gill nets: – these are nets with meshes that only let the head of the fish through; trapping the fish by the gills. Once the net has trapped enough fish, the fish are then taken out by hand.
Limitations of traditional fishing methods
The catch is very limited.
The methods are restricted only to shallow waters/the methods are not applicable in deep waters.
In case the fishing ground is infested with hippos and crocodiles, the fishermen risk attack that can lead to loss of life.
Modern fishing methods are used for large scale commercial fishing. They include: –
1. Drifting
This is used to catch pelagic fish.
Drift nets that are held vertically in the water by fitting floats on the upper side and weights at the bottom end of the net.
The net is held closer to the surface where the fish swim in large shoals.
As they (fish) try to go past the drift net, they get trapped by their gills.
Once the net has caught enough fish, drifters/powerful boats haul it and the catch to the shore.
2. Seining
Catches both pelagic and demersal fish.
Fishing boats assisted by smaller boats/dories spread out the seine nets with small meshes into the lake/sea/ocean.
The boats remain stationary and the nets held into position using floaters on top and weights at the bottom.
Fish is then allowed time to get trapped into the net.
Once the net is full, it is hauled over and the fish emptied onto the ship
3. Trawling
This is used to catch demersal fish that live in deep sea.
It uses a trawl net that is pulled along by ships/trawlers along the sea bed, affecting all the fish along its path.
Once the net is full, it is hauled into the ship and the fish emptied on board.
4. Line Fishing
This is commonly used to catch certain type of demersal fish in shallow waters with rugged terrain where trawl/seine nets cannot be used.
Long lines that are baited are sunk into depths of about 100m into the sea. The lines are suspended by floats on the upper ends and dragged along by small boats.
The baited hooks in the lines attract fish hence they get caught.
The hooks are then drawn up and the fish removed on board
Distribution of major fishing grounds of the world
This depends on the nature and type of the ocean currents flowing along a given coast.
Coasts washed by cold ocean currents have a lot of fish because the resulting cool temperatures favour plankton growth. Also temperate coasts where cold and warm currents converge form major fishing grounds as the warm current moderates the temperatures making such coasts ice free.
They include: –
(a) Atlantic fishing ground
(b) Pacific fishing ground
(c) African fishing ground
(a) Atlantic Fishing Grounds
These are found in the Atlantic ocean
This is further divided into
North West Atlantic Fishing Ground
This is located in the north eastern coasts of North America from the eastern coasts of Canada to New England in the USA through the provinces of Quebec, New Brunswick and Nova Scotia.
The main fish species caught here include cod, herring, haddock, mackerel and lobster.
The fishing methods used here include seining, trawling and drifting
Factors that have favored the development of North West Atlantic Fishing Ground
Broad and shallow continental shelf leading to flourishing of fish as it provides ideal conditions for plankton growth.
Convergence of the cold Labrador and the warm Gulf Stream currents at these grounds leads to cool temperatures for plankton growth and making it free from ice; allowing fishing to be conducted throughout the year.
Dense population especially in the USA provides ready market for the fish.
Rugged landscape and cold climate in the immediate hinterland discourage agriculture leaving fishing as an alternative economic activity.
Advanced technology e.g. highly developed ship building and fishing industries equipped with modern preservation and processing facilities that allow fishing to be conducted all year round.
North East Atlantic Fishing Ground
This is located in the north western part of Europe.
It passes through France, Germany, Denmark, Norway, Finland, Spain and Portugal.
It is the leading fish exporting region in the world.
The main fish species caught here are cod, herring and mackerel.
The main fishing methods employed along these grounds are trawling, drifting and line fishing
Factors that favours fishing in the North East Atlantic fishing ground
High latitude ranging from temperate to polar regions; experiencing cold temperatures that encourage growth of plankton, survival and preservation of fish.
Broad and shallow continental shelf that favours the growth of planktons.
Indented coastline in Britain, Norway and Ireland with narrow fiords that provide sheltered waters for development of fishing ports and breeding of fish.
Mountainous landscape especially in Norway does not favour agriculture making fishing the most appropriate alternative economic activity.
The ground is washed by the warm Atlantic Drift Current that raises the temperatures and making it ice free thus fishing all year round.
Dense population in the Western Europe provide ready market for the fish.
Advanced/high technology has enabled development of modern fishing equipment and preservation/processing facilities
Fishing grounds in South Atlantic Ocean
There are minor fishing grounds along the Atlantic coast that are found in the southern hemisphere. They include: –
South West African/Namibian Coast: – covers the coast of Namibia and Cape Province of the Republic of South Africa. It is rich in fish because it is washed by the cold Benguela current; results into upwelling of water hence rich in planktons.
Mauritanian Coast: – this is found in the North West African Coast. It is rich in fish since it has a wide and shallow continental shelf and presence of the cold Canary current that allows plankton growth.
West Coast of South America: – this covers the coast of Peru in South America. It is rich in fish because of the cold Peruvian current and the wide and shallow continental shelf.
(b) Pacific Fishing Grounds
This is further divided into
North West Pacific Fishing Ground
– This is the largest fishing ground in the world.
– It is located off the coast of North East Asia extending from Barring Sea through the sea of Okhotsk, Sea of Japan, Yellow Sea up to East China Sea through the following countries; Japan, China, Malaysia, Indonesia, North & South Korea and Eastern Coasts of Russia.
North West pacific fishing grounds
– The major fish species caught in these grounds are salmon, tuna, bonito, mackerel,sardine, cod, Pollack.
– Fishing is highly developed along this ground because of the following reasons:-
1. Broad, shallow and extensive continental shelf that favours the growth of planktons
2. Convergence of the cold Oyasiwo and warm Kurosiwo currents that makes the coast ice free allowing fishing all year round (warm Kurosiwo), provides ideal conditions for plankton growth (cold Oyasiwo)
3. Dense population in the Asian countries that lie astride the fishing ground e.g. Japan and China provide labour and ready market for the fish.
4. Indented North East Asian coastline with numerous islands, bays and sheltered inlets that favour fish breeding and development of fishing ports.
5. Advanced technology especially in Japan has encouraged the development of fishing and facilitated transport of fish e.g. through ship building and refrigeration of ships.
6. Limited agricultural potential especially in Japan and Eastern Russia with rugged landscape that discourages agricultural development; leaving fishing as alternative source of food.
ii. North East Pacific Fishing Ground
– This is located along the western shores of North America, stretching about 1200km from the Alaskan coast (USA) southwards through British Columbia (Canada) to the Californian Coast (USA) through Washington DC and Oregon states.
– Fishing is also done along the major rivers in this region (mention some)
– The main fish species caught in this ground are salmon, tuna, sardines, herring, Pollack and allaska.
– Others include crabs, shrimps, oysters and prawns
Factors favouring fishing in this ground include:
1. Indented coastlines with many fiords, rias and river estuaries that offer good sites for fish breeding and development of fish ports.
2. Cool waters as a result of high latitudinal location that favour plankton growth.
3. Convergence of the cold Californian and the warm Labrador currents along the segrounds lead to cool temperatures that favour plankton growth
4. These grounds are free from ice all year round since the cold temperatures are moderated by the warm Labrador Current flowing into the area. This ensures fishing throughout the year.
5. Advanced fishing technology that has provided modern fishing equipment and preservation facilities.
(c) African Fishing Grounds
– Africa is not a major exporter and producer of fish and fish products despite having numerous rivers, lakes and being surrounded by seas and oceans. This is because: –
a. Ocean waters are warm/coasts washed by warm ocean currents that limit plankton growth (give example)
b. The coastlines are straight/regular thus discourages fish breeding and development of fishing ports. (expose with an example – Indian Ocean coastline).
c. Ocean waters are shallow due to growth of corals/coral reefs
d. The continental shelves are narrow.
– Fishing grounds in Africa are both marine and inland
Marine Fishing Grounds
– This is done in the seas and oceans that surround the continent along the coasts of Republic of South Africa, Sierra Leone, Namibia, Ivory Coast, Angola, Kenya, Nigeria, Ghana, Morocco, Mauritania and Guinea. (Find which seas and oceans support these countries).
– The Republic of South Africa is the largest marine fish producer in Africa. due to: –
Convergence of cold Benguela and warm Mozambique current leads to mixing of waters.
Provide nutrients and adequate conditions for planktons’ growth.
The main fish species caught in Africa are sardines, crabs, tuna, stock fish, whales, lobsters, herring and mackerel.
ii. Inland Fishing Grounds
– This is conducted in the interior of the African continent in lakes, rivers, ponds and dams.
– It is done on small scale and for subsistence but commercial fishing is done on some lakes e.g. Victoria but also for subsistence.
– In lakes, it is done in Victoria, Chad, Tanganyika, Kyoga, Bangweulu, Malawi, Albert and Mweru. (Use Moran Atlas to locate these lakes)
– Human made lakes/dams for HEP production also support fishing e.g. Volta, Caborra Bassa, Kariba, Orange, Nasser and Kainji
– The main fish species caught in lakes include herring, shell fish, cat fish, Nile perch, trout,dagaa, tilapia and eel.
– Fishing is also done along the courses of some rivers in Africa on a small scale. Theserivers include Niger, Tana, Zambezi, Limpopo, Senegal, Congo, Nile, Pangani, Orange and Ruvuma.
– The main fish caught in the rivers are salmon and pilchard
– Fishermen in inland fishing in Africa use traditional methods where the catch is limited.
Fishing in East Africa
Fresh Water/Inland Fishing Grounds in East Africa
– In East Africa, fresh water fisheries are more developed compared to marine fishing grounds (accounts for over 50% of the total tonnage of fish catch in East Africa)
This is due to the following reasons: –
1. There are more inland fishing grounds compared to marine fishing grounds
2. Small and narrow continental shelf of about 6km limiting plankton growth
3. Inadequate capital for buying modern marine fishing equipment.
4. Regular coastlines with few indentions/inlets for fish breeding and development of fishing ports.
5. Warm coastal waters that limit fish varieties.
6. Low demand for marine fish species compared to fresh water fish.
(a) Kenya
– The major inland fishing grounds in Kenya are Lakes Victoria, Turkana, Naivasha, and Baringo. (expose on Lakes Nakuru, Elementaita and Magadi)
– Limited fishing is also done on ox bow lakes e.g. Kanyaboli, Shala, Bilisa, Jipe and Sare
– Some reservoirs also sustain fish e.g. Masinga, Kamburu and Kiambere
– Small scale fishing is also done along the lower course of rivers Tana, Nzoia, Athi, Sondu and Nyando.
– Lake Victoria is the main inland fishing ground in Kenya. The dense population in the surrounding areas offer ready market and labour for the fishing industry.
– In Lake Victoria – the fish species are many but the most popular ones are tilapia, Nile perch, dagaa/omena and herring.
– Tilapia and Nile perch are also popular in Lake Turkana while in the remaining lakes, tilapia is the most popular.
– In Lake Turkana, fishing is less developed due to sparse population to offer labour and market.
(b) Uganda
– Fresh water fishing is the only type of fishing as Uganda is landlocked and is more developed compared to compared to Kenya.
– Lake Victoria is the main fishing ground. Others include Lakes Kyoga, Edward, George, Albert and Katwe.
– Inland fishing is also done in rivers such as Kagera, Semliki, Katonga, Kafu and Nkusi among others.
– Tilapia is the main fish caught in all the lakes in Uganda. Nile perch is found in lakes Victoria,Kyoga and Albert.
– Fishermen use motorized boats to enable them travel far into the lake where the catch is large.
– The lakes have numerous islands that provide anchoring and resting grounds for the fishermen.
– There is dense population along/around the lakes providing labour and market for the fish.
– The Ugandan Fish Marketing Cooperation has set up processing and preservation plants next to the fishing grounds. (Fort Portal for Lake Albert (freezing plant and Jinja a processing plant where fish is filleted)
(c) Tanzania
– This is the leading fishing country in East Africa.
– Lake Victoria is the main inland fishing ground in Tanzania with popular species of tilapia, Nile perch and dagaa.
– Other fishing grounds in Tanzania are lakes Rukwa and Malawi as well as rivers such as Malagarasi, Ruaha – Rufiji, Ruvuma, Mara, Kagera, Wami and Nkululu.
– Fishermen use modern fishing equipment for their fishing expeditions.
– Trawling is the main method employed in catching fish
– Large population around the lakes especially towns of Bukoba, Mwanza, Musoma provide markets.
– A processing plant at Kigoma preserve and process fish for sale to other parts of the country.
Marine fishing in East Africa
– This is carried off the coasts of Kenya and Tanzania in the Indian Ocean.
– Tanzania accounts for more tonnage of fish caught compared to Kenya although marine fishing in Tanzania and Kenya are similar in characteristics.
– It is less developed in both the countries due to the following factors : –
1. Warm waters due to tropical location and the warm Mozambique current limits plankton growth and a number of fish.
2. Narrow continental shelf and deep offshore waters.
3. Low technology and limited capital that limits marine fishing to the inshore waters.
4. Stiff competition from highly developed and industrialized nations e.g. Japan, Korea and Norway with advanced technology.
5. Limited market due to sparse population in many coastal towns (apart from the Tanzanian islands of Pemba, Mafia, Zanzibar)
6. Low fish eating culture among the local communities
– Fishing in both the countries is done on a small scale (Kenya – 10%, Tanzania – 13%)
– It is mainly done for subsistence.
– Fishermen use small boats/dhows – few are motorized while majority use wind
– The fish species caught are similar since the fishing grounds are linked e.g sardines, tuna, mullet, bonito, kingfish, queen fish, barracuda (pelagic), cod, streaker, black skin, catfish (demersal) and lobsters, crabs and prawns (crustaceans).
Fish Farming in Kenya
– Fish farming is the keeping/rearing of fish in ponds for commercial purposes.
– Reasons for its development include:-
Fish farming occupies less space compared to other especially agricultural activities.
It is free from territorial disputes and conflicts.
It leads to the development of related industries e.g. fish processing, canning, fertilizer making and boat construction.
4. Creation of job/employment opportunities – building and management of the fish ponds/farms
5. Fish is a source of food/supplement animal protein.
6. Some fish in the ponds e.g. trout are exported hence earn foreign exchange.
7. Allows better and maximum utilization of land and water resources especially swamps/dams with no agricultural use.
8. It is less exposed to dangers of deep sea or lake fishing-storms, drowning.
9. It assists in the conservation of rare species, which might face the danger of depletion or extinction.
Ways through which the government is encouraging fish farming in Kenya
Provision of technical and financial assistance to fish farmers by the Ministry of Livestock.
Setting up demonstration farms/hatcheries to sensitize on proper management of fish farms through the Lake Basin Development Authority.
Government’s food policy encourages communities fish to set up fish farms/embrace fish eating culture..
Significance of fishing
1. Fishing creates employment opportunities directly as fishermen or indirectly through fish related industries.
2. Source of medicine & cooking fat e.g. cod liver oil, Scotts emulsion.
3. It has led to economic diversification by providing alternative source of food & income hence reducing overdependence on agriculture.
4. Fishing has led to the development of fishing ports and fishing villages and towns e.g. the ones along the shores of Lake Victoria.
5. Source of food – relatively cheaper source of proteins and vitamins compared to meat/beef.
6. Industrialization: – fish related resources and activities provide raw materials for related industries e.g. fertilizer and animal feeds making, lubricants, medicines, cosmetics, fish processing, net and boat making, canning, etc.
7. Infrastructural development – promotes development of feeder roads that link the fishing grounds to the main roads, provision of electricity, etc.
8. Source of foreign revenue:- some of the fish may be exported to earn foreign income
Problems facing Fishing in Kenya and their possible solutions
1. Environmental limitations: – tropical location hence warm waters which limit the number and variety of fish in marine fisheries.
Solution: – increasing research to get varieties of fish species that can survive under these tropical conditions and introduce then in our fishing grounds. These research centres include Fresh Water
Research Station – Nairobi, Sagana Fish Farming Centre – Kirinyaga and Marine Fisheries
Research Station – Mombasa
2. Over fishing/overexploitation of fish resources – this is caused by indiscriminate
fishing/overharvesting of fisheries, use of small meshed nets, seining and trawling. It endangers the natural replacement of certain species since with time the fish species reduce because young fish are not allowed time to mature.
Solution: – More vigilant surveillance of the fisheries, licensing of fishermen to control their numbers and activities, restocking overfished areas, prohibiting small meshed gill nets, introduction of fish farming to reduce overdependence on natural fisheries, banning/prohibiting fishing for some time to let the fish regenerate.
3. Pollution: – of fisheries by industrial and agricultural wastes, sewage disposal and oil spillage make the water less habitable for plankton growth and thriving of fish. This reduces the amount of fish.
Solution: – strict legislation should be put in place to check disposal of industrial wastes into fishing grounds, industries are encouraged to treat their wastes before releasing them into lakes and rivers
4. Poaching & competition from well-developed fishing nations: – fishermen from Asia and Europe using advanced equipment and fishing methods reduce the amount of fish. Also the fish and sales proceeds land back in their countries.
Solution: – the KWS patrols the Indian Ocean to monitor and restrict stray fishermen from Kenyan waters – arrest and confiscate their fishing equipment.
5. Presence of water weeds: – some fishing grounds e.g. Lake Victoria is infested with water hyacinth along the lake shores. This chokes the fishing boats and hinders the fishermen from reaching far areas with a lot of fish.
Solution: – local community, NGOs and the government to make attempts in removing the weeds from the lake
6. Inadequate capital: – most fishermen in Kenya use traditional methods of fishing that limits their catch due to lack of adequate capital for purchasing advanced fishing equipment and refrigeration facilities. This limited marine fishing in deep seas with a variety of fish and a lot of catch.
Solution: – provision of loans to the fishermen through financial institutions and government agencies, encouraging fishermen to form cooperatives so as to assist them in raising the required capital.
7. Poorly developed transport network: – some roads leading to the fishing grounds area poorly maintained and impassable during the rainy season. This leads to delay in delivery of caught fish to the processing plants/factories hence go bad since fish is highly perishable.
Solution: – government is making efforts to improve/develop the roads leading to such grounds, local fishermen through their Saccos to purchase refrigerated vehicles to facilitate transport, fishermen to use other methods of preserving fish e.g. salting, smoking, and drying to preserve fish
8. Limited market:- the demand for fish in the country is small because; fish eating is less popular with most communities, some fishing grounds e.g. Lake Turkana are located in sparsely populated areas and fish is more expensive compared to other sources of protein.
Solution: – the government should encourage the local communities to embrace fish eating as an alternative to red meat – through establishment of fish farms.
9. Accidents within the lakes & ocean:- sometimes during the year, fishing boats and canoes capsize to the lakes and in Indian Ocean due to strong winds and prevailing storms. This leads to loss of fishing equipment and even life. The fishermen are therefore prohibited from venturing into far waters with a lot of catch and variety.
Solution: – fishermen are encouraged to use bigger boats that are motorized; these can withstand storms and strong winds
10. Inter boundary conflicts: – sometimes, Kenyan fishermen are arrested by Uganda and Tanzania authorities for straying into their waters along the boundary of Lake Victoria. They often lose their catch and fishing equipment.
Solution: – Kenyan policemen to patrol the boundaries to ensure the fishermen remain within the Kenyan waters.
11. Lack of fish cooperatives: – most fishermen do not belong to fish cooperatives through which they can market their catch. They therefore sell their catch through middlemen hence realize marginal profits.
Solution: – fishermen should be encouraged to form and join fish cooperatives to assist them market their catch, get funds/acquire loans to improve their fishing practices.
Fishing in Japan
– Japan is the leading fish producer and exporter in the world (it accounts for 15% of the world’s total catch)
– It is located in the North West Pacific Fishing ground.
– Fishing is done around all port cities of Japan but the major fishing ports are Nagoya, Nagasaki, Kushiro, Osaka, Yokohama,
Factors favoring fishing in Japan
1. Japan has many naturally indented coastlines provides well-sheltered grounds for breeding of fish as well as suitable sites for port construction.
2. The rugged and mountainous terrain limits agricultural activities hence fishing is a viable economic activity.
3. The shallow and extensive continental shelf allows sunlight to penetrate thus encourages growth of planktons.
4. The convergence of warm Kurosiwo and the cold Oyashio ocean currents helps produce ideal breeding grounds for fish/upwelling of ocean water bring planktons to the surface.
5. Ready market from the densely populated neighboring Asian countries e.g China and Korea.
6. Presence of advanced technology has led to use of powered trawlers, refrigerated vessels fitted with processing plants.
7. Long history of fishing and sea going culture of the Japanese people.
– In Japan, fishing is highly developed and mechanized. The fishermen use radars that locate specific areas with large shoals of fish.
– Japanese fishermen use long lines, trawling and seining methods to catch fish.
– The fish caught is sold as fresh, canned, dried and frozen.
– The fish is consumed locally. The large Japanese population (above 130million) provides ready market for the fish.
– Others are exported.
– Popular fish species caught: –
In the cooler northern seas – cod, salmon, herring, halibut, allaskan and Pollack.
In the warmer southern waters – sardines, mackerel and tuna
Others include crabs, oysters, lobsters and octopuses
– Fishing and marketing of fish is done by cooperatives formed by the fishermen. These cooperatives advance loans to the fishermen to improve and expand their fishing activities.
– Fish farming is also practiced in fresh water ponds and dams.
The factors that favoring fish farming in Japan include
1. Over fished natural fisheries leading to depletion of certain species hence need for fish farms where such species are reared.
2. Need to supplement natural supplies to meet increased demand locally and externally.
3. Industrial pollution of the sea has rendered seawater unsuitable for fish breeding.
4. Availability of capital to establish fish farms.
5. Extensive research has enabled fish farmers to successfully rear appropriate fish species.
Comparison between fishing in Kenya and Japan
Similarities
Fish farming is done in both the countries.
Cooperative societies for fishermen is practiced in both countries.
Marine fishing done in both countries; similar species e.g. sardines, tuna, etc.
Differences
In Kenya both marine and inland fishing is done while in Japan only marine fishing is carried out.
Marine fishing is confined to Kenyan territorial waters only while in Japan marine fishing extends beyond the territorial waters up to high seas.
The marine fisheries in Kenya have few/limited fish and species whereas in Japan, the fishing ground is richer with a variety of species.
In Kenya, marine fishing is done on a small scale based on simple technology and use of traditional methods whereas in Japan fishing is done on a large scale based on advanced technology and use of modern fishing methods.
Problems facing fishing industry in Japan
Depletion of some fish species due to overexploitation as a result of high demand for them locally and abroad.
Overfishing due to use of highly advanced technology.
Water pollution through oil spillages from fishing vessels lead to reduction of fish species.
Management & Conservation of Fish and Fisheries
Management: – refers to the effective planning and control of fish resources and their habitats. It is done through: –
a. Licensing of fishermen to control their fishing activities and to regulate their numbers.
b. Banning of fishing especially when overexploitation is detected on a particular fishing ground so as to give the young fish time to mature and breed/restricting fishing to specific seasons to allow for breeding and maturing of fish. This ensures mature regeneration of fish.
c. Standardizing the size of nets used in fishing to ensure only the mature fish are caught
d. Intensifying research to know more about fish species, their habitats, breeding habits, food requirements, migratory behavior and life span.
Conservation: – refers to the careful use and exploitation of fish resources to avoid overexploitation. It includes:-
a. Encouraging fish farming to supplement the fish caught in natural fishing grounds/reduce overdependence on natural fisheries.
b. Control of foreign fishermen by monitoring their expeditions through KWS patrols and licensing their entry into the Kenyan waters especially Indian Ocean.
c. Restricting the disposal of untreated waste into the water bodies to ensure the water remains clean for survival of fish/industries to treat their wastes before disposing to water bodies.
d. Improving transport system through construction of roads connecting the major fishing grounds and the markets to reduce overexploitation.
e. Restocking the over fished areas using hatcheries and fingerlings obtained from Lake Basin Development Authority or overstocked grounds.
f. The law of the sea that restricts fishing in the exclusive zones ensures the protection of marine fisheries from external exploitation.
Significance of the international law that limits territorial waters of each country to a distance of 320km
The zone is useful for security/ military purposes.
The law ensures that countries have an extensive sea frontage from which they can exploit marine resources.
It reduces competition for marine resources especially from the developed countries with advanced technology to exploit the resources over wide areas.
It makes countries with large expanses of the sea but fewer industries to be free from international pollution.
Past KCSE Questions on the topic
1 (a) State three measures that have been taken to conserve fisheries in Kenya.
3 mks
(b) Give four reasons why Norway is a great fishing nation. 4 mks
(c) Two traditional/ subsistence methods of fishing. 2 mks
(d) Three measures the government of Kenya is undertaking to encourage fish culture. 3 mks
2. Use the map of North America to answer question (a).
(a) Name two methods of fishing used in the shaded areas. 2 mks
(b) Name two types of fish caught along the West Coast of Canada. 2mks
(c) Explain how the following factors favour fishing in the shaded areas,
(i) Indented coastline
(ii) Ocean currents 4 mks
(d) Give three methods used to preserve fish. 3 mks
(e) Explain three problems experienced by fishermen while fishing in Lake Victoria 3 mks
3. The map below shows some major fishing grounds in the world. Use it to
Answer the questions below
(a) Name the countries marked P and Q. 2 mks
(b) Explain four conditions that favour fishing in the shaded coastal waters 8 mks
4. (a) The diagrams below represents some fishing methods.
(i) Name R and S. 2 mks
(ii) Describe how the above methods are used in fishing. 4 mks
5. (a) Differentiate between fishing and fisheries. 4 mks
(b) Identify the physical and human factors influencing fishing. 5mks
6. (a) Draw an outline map of the world and locate the major fishing grounds.2 mks
(b) Account for the location of fishing grounds located in 6(a). 4 mks
7. (a) Discuss the main types of fishing. 3 mks
(b) List the traditional methods of fishing. 3 mks
(c) Describe how the following methods of fishing are carried out:
(i) Drifting
(ii) Trawling 4 mks
8. (a) (i) Apart from Lake Victoria, name other fresh water fisheries in
Uganda and Tanzania. 4 mks
(ii) Explain the factors favouring fishing on Lake Victoria. 6 mks
(b) Explain why marine fisheries are underdeveloped in East Africa. 5 mks
9. (a) State the significance of fishing to the economy of Kenya. 5 mks
(b) (i) Describe the problems facing fishing in Kenya. 5 mks
(ii) Identify the solutions in b(i) above. 5 mks
10. Draw a table showing the similarities and differences between fishing in Kenya and Japan. 6 mks
11. (a) Define:
(i) Management of fisheries.
(ii) Conservation of fisheries. 4 mks
(b) State the measures which can be undertaken to manage and conserve fisheries. 4 mks
CHAPTER EIGHT
Specific Objectives
By the end of the topic the learner should be able to:
By the end of the topic, the learner should be able to:
(a) Define the terms wildlife, tourism and eco-tourism;
(b) Distinguish between game reserves, national parks and sanctuaries domestic tourism and international tourism;
(c) Explain the factors that influence the distribution of wildlife in East Africa and factors that influence tourism in Kenya;
(d) Locate national parks, major game reserves and sanctuaries on a map of East Africa;
(e) Identify and discuss tourism attractions in Kenya;
(f) Discuss the significance of wildlife and tourism in Kenya,
(g) Discuss the problems facing wildlife is East Africa and those facing and associated with tourism in Kenya;
(h) Discuss the management and conservation of wildlife in East Africa:
(i) Discuss the future of tourism in Kenya;
(j) Compare and contrast tourism in Kenya and Switzerland.
Content
Definition of the term wildlife,
Factors influencing the distribution of wildlife in East Africa.
Distinction between game reserves, national parks and sanctuaries and their distribution in East Africa.
Location of National Parks, major game reserves and sanctuaries in East Africa.
Significance of wildlife in East Africa.
Problems facing wildlife in East Africa.
Management and conservation of wildlife in East Africa.
Definition of the terms tourism and eco-tourism,
Distinction between domestic and international tourism.
Factors influencing tourism in Kenya.
Significance of tourism.
Problems facing and associated with tourism in Kenya.
Comparative study of tourism in Kenya and Switzerland.
The future of tourism in Kenya.
Definition
Wildlife refers to undomesticated plants and animals in their natural habitats.
It includes natural vegetation, insects, birds and animals living in bushes and forests, fish and other aquatic organisms in rivers, oceans, lakes and seas.
Factors influencing wildlife distribution in East Africa
Climate
– Areas that experience high rainfall that is reliable and evenly distributed all year round lead to growth and development of big/large forests. These forests are themselves part of wildlife and are homes to several herbivores e.g. impalas, waterbucks, antelopes, etc. as well as carnivores e.g. lions and leopards. Examples Mt. Kenya and Kakamega forests.
– Areas receiving low rainfall lead to extensive grasslands that are homes for herbivores and carnivores. E.g. Serengeti national parks and Maasai Mara game reserve
– Arid areas have limited vegetation/plant growth hence have few animals.
Relief/terrain
– Rugged terrains are unsuitable for hunting animals – they are instead found in extensive and relatively level grounds.
– Certain plants grow at given altitudes.
Soil type
– Termites and rodents live in red volcanic soils because they are warmer.
– Forests thrive in deep soils while papyrus plants do well in waterlogged soils.
Vegetation cover
– Natural forests are habitats to elephants, buffaloes, gorillas, baboons and monkeys among others.
– Savanna grasslands are homes to herbivores (the grasses provide food to them) e.g. antelopes,gazelles, wildebeests, zebras, buffaloes, that attract carnivores e.g. lions and leopards that in turn feed on them.
– Areas with shrubs and bushes are habitat to animals e.g. dik dik, hyrax, warthogs, that also attract carnivores.
Drainage & presence of water bodies
– Well drained areas support many plants and animals compared to waterlogged areas.
– Fish are found in open water lakes such as Victoria, Kyoga, Malawi, Tanganyika, Baringo and Turkana. Others are found in the Indian Ocean
– Crocodiles and hippos are found in fresh water lakes and large rivers e.g. Nile, Tana, Nzoia, Ruvuma and Mara.
Human activities
– These may interfere with the habitats for animals and the animals themselves in the following ways.
Fishing methods that lead to overexploitation or overfishing may make certain types of fish extinct.
Encroaching into wildlife habitat to get space for settlement and agriculture due to increasing population. This is done through clearance of vegetation and deforestation.
Mining and quarrying activities destroy plant cover and animal habitat and even the animals themselves.
Pollution of water and land with time kills the wildlife and reduce their numbers e.g. through use of fertilizers and chemicals in agriculture to kill weeds and control pests are washed into lakes and rivers eventually killing the fish.
National parks
– These are areas set aside for the preservation of scenery, wildlife and historical sites to protect them from destruction.
– They are controlled by the central government authority.
– They are established by an act of parliament and gazetted.
– They are fenced and land use is not permitted.
– Examples in East Africa are Serengeti (Tanzania), Ruwenzori Mountains National Park
(Uganda) and Hell’s Gate National Park (Kenya)
– They also include marine national parks e.g. Watamu (Kenya) and Saadani and Tanga (Tanzania)
Game Reserves
– These are areas set aside for the preservation of wild game.
– They are managed by the local/county government authorities
– Land use is limited to grazing only.
– They may be fenced or not.
– Examples are Maasai Mara (Kenya), Selous (Tanzania) and Kigezi (Uganda)
Wildlife/Game Sanctuaries
– These are areas set aside for the protection of specific animals and/or birds that may face extinction.
– Hunting is prohibited and predators are controlled
– They may be set within the national parks
– Examples include Rhino Sanctuary in Lake Nakuru National Park.
National Parks in East Africa
NO Kenya Uganda Tanzania
A Tsavo East Serengeti Kipendo Valley
B Tsavo West Kilimanjoro Murchison Falls
C Chyulu Hills Arusha Semiliki
D Amboseli Lake Manyara Ruwenzori
E Nairobi Tarngire Queen Elizabeth
F Hell’s Gate Mikumi Bwindi
G Lake Nakuru Udzungwa Lake Mburo
H Rumi Ruaha Mgahinga
J Aberdare Katavi Mount Elgon
K Mount Kenya Mahale Mountains
L Meru Gombe Stream
M Samburu Rubondo Island
N Marsabit
P Sibiloi
Q Mount Elgon
R Central Island
S Malindi & Watamu Marine
T Mombasa Marine
U Kisite Marine
V South Island
W Malika Mari
Tanzania Kenya Uganda
Kigosi Buffalo springs Bokora
Burigi Maralal Pian – Upe
Biharamulo Losai
Ibanda Marsabit
Rumanyika South Turkana
Maswa Arawale
Kijereshi Boni
Grumeti Dodori
Ikorongo Kiunga Marine
Ngorongoro
Mkomazi Mombasa Marine
Umba Mpunguti Marine
Sidani
Pande
Significance of wildlife
Various forms of wildlife especially wild animals in the parks and reserves attract tourists thus earning foreign exchange.
Wildlife creates job/employment opportunities through people employed in wildlife management and conservation centres e.g. tour guides, game wardens, anti-poaching police units as well as in tourists’ hotels as waiters, chefs, etc. they earn income hence improve their living standards.
Wildlife has encouraged and promoted tourism leading to economic diversification and reducing overdependence on agriculture as a major source of revenue for the country.
Through management and conservation, wildlife has ensured continued survival and existence of endangered plant and animal species to be available for future tourism and future generations.
It has led to the improvement of infrastructure through the construction of roads leading to the wildlife conservation centres (parks & reserves); opening up remote areas to the rest of the country.
Wildlife provides for field study and a place for conducting research by students as well as for familiarization of the environment and the need for its appreciation.
Problems facing wildlife in East Africa
Poaching
– This is the illegal hunting for wildlife in the parks and reserves for their trophies e.g. skins, tusks, horns, meat, etc. it reduces the number of some animal species e.g. rhino and elephant to the extent of even becoming extinct.
Solution: – employing anti-poaching police units to patrol the parks, arrest and charge the poachers.
Also imposing a ban on importation of game trophies. Also establishment of wildlife sanctuaries and introduction of game ranching.
b.) Prolonged drought/adverse weather conditions
– Severe and extended drought occurring in the savanna grasslands and in the arid and semiarid lands may dry up the pasture and shrubs, forcing the birds and animals to migrate in search of the same.
– Also, the rivers and watering points may dry up leading to lack of water for drinking to many animals.
– Many animals may fail to adapt to these conditions and die thus reducing their numbers within the parks.
Solution:- brainstorm with the learners
c.) Human activities
– Increasing human population has led to pressure on the existing land. This has led to encroaching on the land reserved for wildlife. In the process the habitat is destroyed; forcing the wild animals to migrate, face extinction and disrupting their natural ecosystem.
– Pollution of aquatic habitats from sewage disposal and industrial wastes threatens the existence of birds and other aquatic wildlife; careless disposal of solid wastes in the parks e.g. plastic bottles, polythene bags threaten the existence of animals that may feed on them.
– Tourist vehicles driven over vegetation in parks destroy them hence reduce the amount of vegetation for grazers and browsers, noise from tour vehicles and presence of people disrupts the animals
– Pastoral animals compete with the wildlife for pasture.
Solution: – creation of parks where land use is prohibited/fenced to ward off encroachment. Treating of wastes before releasing into aquatic habitat, strict legislation over wastes’ disposal, driving with tour guides and along marked trails/embracing ecotourism
d.) Insecurity
– Some game parks e.g. Kidepo Valley and Kora are located in areas affected by banditry and civil strifes. During gunfire exchanges, wild animals may be killed or forced to migrate to safer areas.
– Also, lawlessness of the bandits as they may kill the animals for their trophies.
– It also discourages tourists from visiting such affected areas to watch wildlife.
Solution: – creation of tourists’ police unit to improve the security, deploying security personnel to the affected areas.
e.) Bush fires
– Fires may be started in the forests by arsonists, hunters and gatherers. These fires burn down vegetation especially during dry season; interfering with the habitat, killing some ofthe animals or even force others to migrate
Solution: – creating awareness to the local communities that live next to parks and reserves on the importance of wildlife management and conservation/domestic tourism
f.) Human – animal conflicts
– Some wild animals e.g. hippos, rhino, leopards, elephants, etc. may stray from the gameparks into the people’s farms; destroying their crops and killing their domestic animals.
– Compensation awarded by KWS is often little and paid late, forcing the local community to revenge by killing the wild animals
Solution: – free game rides to the community to improve their attitude towards livestock conservation,KWS to compensate the victims in time and attractively, creation of awareness on the need for wildlifeconservation.
g.) Pests and diseases
– Animals in the parks and reserves are occasionally attacked by pests and diseases that weaken and kill the animals thus reducing their population.
Solution: – brain storm
h.) Overpopulation of wild animals in the parks/reserves
– Some parks and reserves may be overpopulated with certain species of wild animals beyond the park’s/reserve’s carrying capacity. These animals overgraze on the pasture and shrubs leading to scarcity or absence of the same and development of arid conditions.
Solution: – translocation of such animals to other parks where they are less in number to reduce their population in such parks.
Game Ranching
– This refers to the domestication of large wild animals i.e. rearing/keeping of wild animals for meat and other products in large areas/farms
– The types of animals kept in game ranches in Kenya are impala, buffalo, oryx, ostrich,eland and Thomson’s gazelles among others.
– Such animals are always overpopulated in the parks hence kept in ranches where they can be carefully exploited for their meat.
– The areas where game ranching is practiced in Kenya include the Galana Game Ranchand the Kikopei Ranch next to Nakuru.
Advantages of game ranching over domestic livestock ranching include: –
Wild animals are more resistant to diseases e.g. Nagana, East Coast Fever, rinderpest compared to domestic livestock.
Wild animals can survive without water for longer periods compared to domestic livestock.
Under normal conditions, game animals produce more meat per unit area of land compared to domestic livestock.
Game animals are adapted to use a wider range of vegetation thus can alleviate overgrazing, soil erosion and desertification in the range lands.
The utilization of game animals under predator proof fences would reduce theft which is common in domestic livestock ranching.
Management and conservation of wildlife in East Africa
Management
– This refers to the effective planning and control of wildlife.
– In East Africa, wildlife management practices include: –
Formation of wildlife management bodies e.g. KWS, TAZANA and UWA that are mandated to manage and conserve wildlife. They involve the local communities in wildlife management thus limiting human – animal conflict.
Creating awareness on the importance of wildlife management through mass and electronic media and creation of wildlife clubs in schools.
Conservation
– This refers to the protection of wildlife against interference and destruction by human activities.
It is important because of the following reasons:
To protect the endangered animal/ plant species.
To promote tourism.
To generate foreign exchangeTo sustain the raw materials for supply of drugs
For education/ Research purposes
For aesthetic value/ natural beauty.
To keep them for posterity/ future generations
Failure to conserve wildlife in a country may lead to the following consequences: –
Increased soil erosion due to exposed surface.
Landslides and floods.
Loss of biodiversity.
Extinction of some species of plants and animals
Lead to increased aridity and desertification.
Shortage/ Lack of forest products e.g. Timber.
Decreased vegetation cover reduces transpiration and leads to reduced rainfall
The following are measures of wildlife conservation in East Africa
Tagging endangered animals with radio signal to monitor their movements.
Banning of game hunting and trade in game/wildlife products unless export permits are availed.
Establishing the Kenya Range Lands Ecological Monitoring Units (KREMU) for reasons of establishing game parks and reserves.
Establishing game reserves and national parks for protection and preservation of wild animals as well as game sanctuaries and animal orphanages to protect special species that may face extinction.
Establishing of game ranches to exploit wild animals for their meat and other products and at the same time conserving them e.g. the Galana Game Ranching Research Project in Tsavo East that raise eland, oryx and buffaloes.
Establishment of anti-poaching police units to guard against poachers.
Employing game rangers and guards to monitor animal movement and other strange activities in the park.
Creation forest reserves that contain rare species of wildlife to protect them since land uses are restricted in such areas.
Tourism
This is the practice of travelling to places of interest for leisure or enjoyment. The people who participate in tourism are called tourists and they are charged some fee. Reasons for touring include spending holidays, honeymoon, business trip, study tours and attending family functions e.g. weddings, graduations, etc.
Types of tourism
1. Domestic Tourism
– This refers to the visiting of places of interest for recreation purposes by the nationals/citizens of a country.
The government promotes domestic tourism through the following ways: –
Domestic tourists are offered favourable rates on accommodation especially during offpeak season.
Charging lower entrance fees to parks to locals.
Tourist agencies sponsor their airing of and publicity of documentaries on Kenya’s tourist sites.
Improving security in the parks by deploying tourist police personnel, forest guards,rangers.
Improving the state of roads through continuous maintenance
Problems facing domestic tourists in Kenya
Low public awareness due to inadequate advertisement locally.
Local people are familiar with the tourist attractions and hence they don’t appreciate their beauty and value.
Majority are low income earners thus cannot afford the cost of traveling and accommodation.
Negative attitude towards local tourists.
Poachers and gangsters pose security problem
Reasons why the government of Kenya encourages domestic tourism
It results into increased consumption of local wildlife products.
Money circulation is increased within the country.
Facilitates interaction between different communities and thus enhances national unity.
It increases employment opportunities.
Makes people aware of their environment.
People are able to appreciate their cultural heritage.
Makes use of the hotel facilities which are underutilized during the low tourist season.
May enhance need for conservation and preservation of the environment
2. International tourism
– This is the movement of people from one country to another for holiday or leisure.
3. Ecotourism
– This is derived from ecology and tourism
– It is an environmentally friendly form of tourism where tourists enjoy watching nature and at the same time protecting the wildlife.
– It involves management and conservation of wildlife during tours in the parks and reserves.
– This is done through the following: –
a. Use of tour guides to lead the tour vehicles along marked trails or paths to avoid destruction of vegetation.
b. Encouraging telescopic viewing of wild animals
c. Using camping sites instead of building large tourists’ hotels and lodges.
d. Creating awareness among local communities to understand and appreciate nature by visiting game parks and offering them free game rides within the parks.
e. Visiting wildlife conservation areas in smaller groups
f. Encouraging soft/green tourism in areas where the natural environment has been previously interfered with by planting trees and introducing animals in the areas e.g. Bamburi Nature Trail.
g. Use of litter bins in tourist vehicles/vans for disposal of wastes during the game rides.
Factors influencing tourism in Kenya
Variety of tourists’ attractions: – these include wild animals in their natural habitats, scenic beauty such as snowcapped top of Mount Kenya, rift valleys, historical sites and others.
Wildlife conservation measures: – through establishing game parks and reserves and a ban on game hunting has earned the country international recognition. Many lobby groups interested in wildlife conservation therefore promote Kenya as a tourist destination rich with wildlife.
Existence of Wildlife: – Kenya has a variety of tropical plants due to warm climate and abundant rainfall favouring the growth of many plants ranging from equatorial rain forests to savannah grasslands and drought resistant plants. Kenya also has a wide range of tropical animals and birds that attract tourists.
Climate: – Kenya is located within the tropics with the equator cutting through it from East to West. Temperatures range from moderate to high making the general climate to be warm and sunny hence pleasant all year round. This makes Kenya a major tourist destination especially for tourists from the temperate regions.
Promoting local/domestic tourism: – this is done by reducing the charges to major tourists’ attractions for the locals.
Presence of several tourist hotels: – there are several tourists’ hotels in major towns/urban centres and game lodges in the parks that offer excellent catering and accommodation services to the tourists e.g. Voi & Kilaguni Safari Lodges in Tsavo National Parks, Laico, Windsor, Ambassador and Intercontinental Hotels in Nairobi amongst others.
Relative peace & political stability: – Kenya has been relatively peaceful compared to her neighbours and this ensures security thus encouraging tourists to come to Kenya and enjoy the various tourists’ attraction.
Training in tourism: – training of personnel at the Kenya Utalii College and degree courses in tourism management and hospitality produces competent staff for the provision of services in the tourism industry.
Package tours: – group bookings for travel and accommodation are done in tourists’ resource countries to make them cheaper for tourists thus encouraging more.
Publicity on tourism: – the Kenya government through the Ministry of Tourism and other stakeholders in the tourism industry create public campaigns abroad to create awareness on Kenya’s tourist potential and popularize Kenya as a tourist destination. These promotions are done through exhibitions, trade fares at international level, mass media and major tourist source countries. Also through creation of Kenya Tourism Board and Kenya Tourism Development Cooperation that market Kenya as a major tourist hub.
Research programmes: – have been increased in wildlife management and conservation; also provision of veterinary services to sick animals has been done to sustain the tourism industry.
Tourists’ attractions in Kenya
a. Wildlife
– This is the main tourist attraction in Kenya. It has many game parks and reserves that contain several plants and animals in their natural setting as well in museums. There are also marine parks along the coast.
b. Beautiful scenery
– Kenya comprises of a variety of scenery ranging from mountains in the interior to the coast inclusive of snowcapped mount Kenya – for watching and mountaineering; the Rift Valley with associated escarpments and lakes with hot springs (Bogoria).
– There are also waterfalls along the courses of some rivers e.g. Nyahururu, fourteen falls, etc. as well as granitic tors such as Kit Mikae (Kisumu) and The Crying Stone (Kakamega)
c. Warm climate
– Kenya experiences warm climate all year round due to its tropical location. Many tourists visit Kenya during the winter season (October to March) to escape the severe cold seasons.
d. Sandy beaches along the Indian ocean coast
– These are found in Mombasa, Kilifi and Malindi.
– They have warm clear waters and refreshing breezes.
– They allow sun and sand bathing, swimming, sailing, water sports, fishing and playing beach games.
e. Historic/pre-historic sites
– These are sites where archeological discoveries of human fossils have been preserved. Such sites are popular with tourists and they include Kariandusi and Olorgesailie at the shores of Lake Turkana.
– Human fossils and artifacts are also preserved in museums found in major urban centres e.g. Nairobi, Kisumu and Mombasa.
– Other historical sites include Fort Jesus, Gede Ruins and Vasco da Gama Pillar in the Coast.
f. Cultural activities
– Tourists come to Kenya to learn ways of life of some communities.
– They watch traditional dances, Kenyan communities’ ways of dressing, and other cultural activities.
– The Bomas of Kenya (Nairobi) is popular with tourists to learn cultures of different ethnic groups.
g. Conferences
– Nairobi being an international centre hosts many visitors coming to attend international conferences. It also the headquarters of international organisations e.g. UN, UNEP and HABITAT and people who visit Nairobi for the international meeting/conferences take time off to tour the potential sites.
h. Agricultural shows/trade fairs
– Tourists visit Kenya each year to attend the annual agricultural shows and the Nairobi International Trade Fair to exhibit their wares.
Significance of Tourism
1. Foreign exchange earnings: – international tourists make payments in foreign currencies for the services rendered to them in the parks and hotels. This can then be used in international trade and in the improvement of other sectors.
2. Source of employment: – many people are employed in the tourist industry as chefs, waiters/waitresses in tourist hotels/lodges, tour guides, game wardens, etc. They earn income thus improving their living standards.
3. Source of government revenue: – this is earned through the fee charged at tourist sites (e.g. game parks) and license fees charged on tourist hotels, tour companies and guides.
4. Improvement of infrastructure: – the roads connecting areas of tourist attractions have been improved and even new ones built to fasten the movement of tourists to and from such sites. Also game lodges and tourist hotels have been supplied with piped water and electricity. All these stimulate development around such areas.
5. Promotion of agriculture: – tourism enhances agricultural development through supplying the tourist hotels with food i.e. there is a high demand for fruits and vegetables in these hotels and this encourages their production.
6. Wildlife conservation/protection of historical sites: – through domestic tourism, the local are able to appreciate wildlife thus reducing human-wildlife conflict. Wildlife, being the major tourist attraction in Kenya has made the government to protect designated areas through establishment of game parks/reserves.
7. Promotion of international relations: – international understanding and relations is improved as tourists visit various countries. This reduces prejudices and discrimination thus promoting trade and cultural exchange.
Problems facing tourism
Pollutionof the parks by tourists – makes the parks less attractive hence reduce the numbers
Terrorism/terrorist attacks:- Kenya has been a victim of terrorist attacks in the recent past.These have made some tourist resource countries to issue travel bans/advisories to their citizens against Kenya, reducing the number of tourists.
High travel costs:- travel costs between countries are becoming increasingly unaffordable to many potential tourists. This has forced some tourists to charter planes or travel as a group to reduce the cost of air fares. These group travels restrict the numbers of touristscoming to Kenya and the numbers of days to spend.
High tariffs:- high taxes levied on the tourists discourage many from visiting the attraction sites or to spend fewer days hence reducing the effect on tourism.
Adverse publicity abroad: – the international media may at times portray Kenya as not safe as a tourist destination. Some political issues are also exaggerated and portray Kenya as politically unstable. Such remarks discourage potential tourists.
Civil strife in the region:- civil wars within the neighbouring countries have a negative impact on tourism in Kenya. Tourist who hear of such keep of Kenya thinking that it is also politically unstable.
Kenyans’ attitude s towards tourism :- several Kenyans perceive tourism as belonging for international tourists. Domestic tourists are also discriminated upon in favour of foreign tourists. This discourages locals from patronising the hotels and parks.
Problems associated with tourism
Erosion/changes in social values.
School drop outs.
Effect on wildlife and environment.
Overreliance on tourism.
Increase in drug abuse.
Copying of foreign culture.
The future of tourism in Kenya
– This depends on: –
a.) Aggressive promotion and opening of new markets in Middle East and Asia to increase the number of tourists.
b.) Lowering of the tariffs/charges so as to encourage more tourists/spend more days.
c.) Strength of the Kenya Shilling against foreign currency – if stronger against other major foreign currencies – it becomes expensive for tourists to pay for the services. (It should depreciate to make it cheaper for the tourists)
d.) Improved security by setting up anti-terrorism laws and fighting the war against terrorists to make Kenya a safe tourist destination.
Case Study: Tourism in Switzerland
Introduction
Switzerland is a landlocked country in Central Europe. It lies astride the Alps Mountain
Ranges. It has been a great tourist nation since the 18th Century.
Major Tourist Attractions in the Switzerland
1. Mountains
– The Swiss landscape comprises of many mountains with smooth slopes and valleys e.g. the Alps. These attract tourists interested in mountain climbing, sight-seeing and in winter sports e.g. skiing.
– Other features that are related to the mountains include the hanging valleys and waterfalls that are of scenic beauty to tourists.
2. Swiss National Park
– Switzerland has a big national park with varied plant and animal species that attract tourists.
3. Lakes
– There are several glaciated lakes with clear blue waters that are beautiful to see and popular for sport fishing, sailing and swimming.
4. Variety of climate
– Switzerland experiences both winter and summer climates that facilitate various activities that the tourists can participate in e.g. mountain climbing, sport fishing and swimming during summer and skating & skiing in winter.
5. Health spas
– These are mineral springs that people consider to cure certain ailments. Also, the varied climate is conducive for people suffering from certain diseases hence popular for tourists.
6. Hike & Bike facilities
– Swiss has a unique network of hiking trails covering the whole country with paths that are well marked and maintained. These are found in the lowlands and within the mountains also.
– There are also trails for mountain biking, golfing and river rafting.
7. Advanced technology
– Switzerland has well developed industries and with well-developed infrastructure
– some people visit the country to witness the industrial development that has taken place.
Factors Favoring Tourism in Switzerland
a.) General scenery
– The Switzerland has varied scenery that include rivers, climate, glaciated, lakes, mountain scenery, etc. that attract tourists who involve themselves in sight-seeing and sports.
b.) Suitable location
– Switzerland is centrally located in Europe making it relatively accessible to the neighbouring industrialised European countries that are major sources of tourists e.g. Germany, Spain, Italy and England.
– It is linked to the neighbouring countries by excellent road, railway and air networks making travelling to and from easier and cheaper.
c.) Hospitality & culture
– The personnel handling tourists are highly trained and offer quality service and management to the tourists. They are also very hospitable (generous and friendly to visitors).
– There is also easy communication with neighbours from other countries since there are four major languages spoken in the Swiss i.e. French, Germany, English and Latin
d.) Political stability & policy of neutrality
– During the cold war between the East and West Europe, Switzerland was never aligned to any bloc. Visitors from either sides of the political divide can visit it without any discrimination.
– It has also enjoyed relative peace and political stability making it a favourite destination for people on holiday.
e.) Accommodation
– Switzerland has numerous hotels and camp sites in tourist’s sites that offer excellent accommodation facilities to the visitors.
– The hotels are fairly priced and offer good rates to groups through organisations of group travels and bookings – thus lowering the rates.
f.) Centre for International meetings
– Switzerland is the headquarter of many international organisations such as International Labour Organisation, UN, and Red Cross thus hosts many international conferences, meetings and seminars.
– People visiting the country for such meetings take time off to tour the attraction sites.
g.) Transport
– Switzerland has a well-developed transport system – in terms of means and network i.e. road network connecting various parts, there are also electric trains and cable cars and aerial lifts to carry the tourists up and down the mountains
Effects of Tourism in Switzerland
Positive Effects
1. Foreign Exchange earning
2. Local revenue
3. Source of employment
4. Training
5. Promotion of diplomacy/international relations
6. Environmental conservation
Negative Effects
1. Mountain landscape limit expansion
2. Environmental pollution
Comparison between tourism in Kenya and Switzerland
Similarities
1. Both have many hotels and lodges in major urban centres and cities within the tourists’ attractions for accommodation of tourists.
2. Both have snow capped mountain peaks with permanent glaciers that are popular with tourists.
3. Both experience political stability and relative peace that promote tourism.
4. Both have many waterfalls (Switzerland – associated with hanging valleys, In Kenya along the major river courses) that attract tourists.
5. Package tours are encouraged and organised in both the countries to make travel and accommodation fairly cheaper for the tourists.
6. Both have national parks with a variety of plants and animals in their natural settings.
7. Both countries embrace domestic, international and ecotourism.
Differences
1. The Switzerland receives more tourists thus earn more revenue compared to Kenya.
2. Kenya has a variety of scenery and landscape with physical features e.g. the Rift Valley, lakes, mountains, lakes, plains and rivers while in Switzerland, the Alps is the main physical feature that attracts tourists.
3. Kenya’s only snow-capped mountain (Mt. Kenya) is too high and steep thus less suitable for mountain sports while the Swiss has large and smooth slopes covered with snow during winter for such sports.
4. Kenya has a sea front with warm waters for sun/sand bathing, swimming, surfing and yachting whereas Switzerland is landlocked – lacks a sea front/has no access to beaches and associated sports.
Past KCSE Questions on the topic
Wildlife
Use the map of East Africa below to answer question (a) (i)
Name the national parks marked P, Q and R. 3 mks
2. Give FOUR reasons why wildlife conservation is encouraged in Kenya. 4 mks
3. State three reasons why National Parks have been established in Kenya. 3 mks
4. (a) Differentiate between game reserves and game parks. 4 mks
(b) State four steps taken by Kenyan government to promote wildlife resources. 4 mks
5. Explain three ways in which human activities are a threat to wildlife. 6 mks
6. What is wildlife? 2 mks
7. State five reasons for the need to conserve wildlife? 5 mks
8. State three types of wildlife one may find at I, Nakuru. 3 mks
9. Explain four problems the government of Kenya faces in efforts to conserve wildlife? 8 mks
10. State human factors that affect existence of wildlife. 5 mks
11. State ways in which government of Kenya can strengthen anti poaching unit.
12. (a) Define:
(i) Wildlife
(ii) Tourism 4 mks
(b) Distinguish between Same Reserves, National Parks and Sanctuaries.
(c) State five significance of wildlife in East Africa. 5 mks
13. (a) Discuss the problems facing wildlife in East Africa. 5 mks
(b) Explain the measures taken to manage and conserve wildlife in East Africa 6 mks
Tourism
1. (a) Explain the differences between the tourist attractions in East Africa and
in Switzerland under the following subheadings:
(i) Climate.
(ii) Culture 4 mks
(b) Explain five benefits that Kenya derives from tourism. 10 mks
(c) Explain four measures that Kenyashould take in order to attract more tourists. 8 mks
2. (a) Apart from historic sites, name two tourist attractions along the Coastal
strip of Kenya. 2 mks
(b) Give -three reasons why it is necessary to preserve historical sites. 3 mks
3. (a) Name two game reserves in Kenya. 2 mks
(b) Define of domestic tourism 2 mks
(c) How has the recent negative travel advisories affected Kenya’s economy?
4 mks
4. (a) Explain four measures the Kenyangovernment has taken to attract more
tourists. 8 mks
(b) Explain three factors that have led to development of tourism in Switzerland.
5. (a) Differentiate between the following
(i) Ecotourism
(ii) Domestic tourism 4 mks
(b) Explain similarities between tourism in Kenya and in Switzerland. 8 mks
6. Explain why tourism is ‘invisible export. 2 mks
7. Explain four positive effects of tourism. 8 mks
8. Explain four ways in which tourism in Kenya differ from that Switzerland. 8 mks
9. Why are some parts of Kenya not developed for tourism? 3 mks
10. What are the problems facing tourism in Kenya? 5 mks
11. State five efforts being made to improve tourism industry in Kenya. 5 mks
12. What is domestic tourism? 2 mks
13. Name tourist attractions found in Rift Valley province of Kenya. 5 mks
14. What factors hinder development of domestic tourism in Kenya? 5 mks
15. Name two historical attractions along Kenyan coast. 2 mks
16. (a) Define:
(i) Eco-tourism
(ii) Domestic tourism
(iii) International tourism 6 mks
(b) (i) State five tourist attractions in Kenya. 5 mks
(ii) Explain five factors influencing tourism in Kenya. 10 mks
17. (a) State six factors influencing tourism in Switzerland. 6 mks
(b) Explain five problems facing tourism in Kenya. 10 mks
18. Compare and contrast tourism in Kenya and Switzerland. 8 mks
19. The table below shows the number of tourists who visited Kenya.
Year
1999 2000 2001 2002 2003
No. Of Tourists 1.53 m 1.64 m 1.65 m 1.77 m 1.54 m
(a) Using a radius of 3cm draw a pie-chart to represent the above data.
(b) List three advantages of using pie-charts to represent statistical data.
CHAPTER NINE
Specific Objectives
By the end of the topic the learner should be able to:
(a) Define energy;
(b) Discuss sources and types of energy;
(c) Discuss the development of electric power projects in Kenya and Uganda;
(d) Identify and locate other hydroelectric power projects in Africa;
(e) Explain the significance of energy;
(f) Explain the impact of the energy crisis in the world;
(g) Discuss ways and means of managing and conserving energy;
(h) Identify sources and uses of energy within the local environment.
Content
Definition of energy.
Sources and types of energy.
Hydroelectric power projects in Kenya and Uganda.
Geothermal power projects in Kenya.
Location of other hydroelectric power projects in Africa.
Management and conservation of energy.
Significance of energy.
The energy crises.
Fieldwork on identification of sources and uses of energy within the local environment.
Definition
Energy
– Energy is the power needed to run a machine/do some work
Sources/Types of Energy
– Energy emitted from different sources are grouped into:
(a) Renewable sources
(b) Non renewable sources
Renewable Energy Sources
– Can be regenerated and used over a long period of time/has the natural ability to reappear after being in use
– Include the following:
Solar Energy
– It is energy from the sun.
– Can be converted into heat/chemical/electrical energies
Advantages
Cheap because absolutely free.
Available in most parts of the world.
Can be stored in batteries and used later.
Clean/environmentally friendly/free of pollution
Disadvantages
Has limited use/cannot be used to run heavy machinery.
Expensive to install because large number of solar panels are required to produce useful energy amounts.
ii) Wind Energy
– Is harnesed and used to drive windmills and sea vessels
– Wind mills pump water, grind grains and generate electricity
Advantages
Cheap
Clean
Land between the windmills can be used for other purposes e.g. agriculture
Disadvantages
Expensive to maintain.
Low energy production/many windmills needed to produce significant energy.
Not very reliable as the wind may change direction
Wave and Tidal Energy
Wave energy results from strong sea waves set in motion by wind
Are common in high pressure belts/mid latitude regions
Are used to produce electricity
In places with high sea tides mills with turbines are set up to be driven by the tides to produce energy/electricity
Advantages
Cheap as tides and waves are free of charge
Disadvantages
Available only in countries with sea/coasts
Production limited to strong waves/tides.
Generating plants may be destroyed by hurricanes/tsunamis.
Inadequate technology for their development.
Initial development costs are prohibitive
iv.) Geothermal Steam/Energy
– Is the power generated by the flow of heat from the crust/core of the earth through geysers where superheated steam is continuously being emitted from enclosed cavities
– The highest heat flows are found in areas characteristic of volcanic activity
– The power is harnessed through drilling and can be tapped to generate electricity
Advantages
Cheaper compared to other sources of energy.
Its generation is continuous because it is naturally occurring.
Cost of operating a geothermal plant is relatively low compared to a HEP station
Disadvantages
Pollution through noise.
Not available in many areas/available in areas with geysers/hot springs.
Exploration of geothermal energy requires advanced technology especially in areas without visible signs e.g. hot springs/geysers.
Energy production from hot springs is low to meet the energy needs.
Gases released together with the steam may be harmful to the environment and lead to global warming
v. Hydro power
– Is the energy derived from flowing water
– Used to drive turbines that generate electricity – HEP
– Is the most widely used renewable energy source
Advantages
Is the cleanest/most environmentally friendly energy source
Can be transmitted over long distances using cables/doesn’t have to consumed at the source.
Can be put into many uses e.g. cooking, heating, cooling, transport, lighting and running machinery.
Relatively easy to use by just switching on/off when required.
Construction of dams for HEP generation leads to creation of lakes that can be used for other purposes e.g. irrigation, control of floods, recreation
Disadvantages
Fluctuation of water levels in the reservoirs may lead to shortage of power.
Cannot be stored once generated.
Initial costs of establishing HEP projects are prohibitive.
Construction of dams may have some negative impacts e.g. resettlement of persons.
Construction of HEP plants may lead to obstruction of river courses upstream hence interfere with fish habitat
vi. Biomass
– Refers to the total organic matter found on the earth’s surface in terms of plants and animals
– These plant/animal matter can be converted into energy by biological and thermochemical processes
– The main sources of biomass energy are agricultural wastes
– Animal waste such as cow dung and human waste is used to produce biogas
– a combustible gas generated by the fermentation of organic matter e.g. cow dung
– Biogas can be used as cooking gas and in refridgerators
Advantages
Inexhaustible as long as there is organic matter.
Available throughout the world.
Cheap because uses waste products.
Production doesn’t require advanced technology
Disadvantages
Cannot be transported over longer distances.
Contributes to global warming (pollution) if burnt directly.
Requires large spaces for construction of the bio-digesters
vii. Wood
– Refers to firewood and charcoal
– Most common type of energy in developing countries
– Used domestically for cooking and heating
Advantages
Available everywhere in the world.
Cheap because no maintenance costs required
Disadvantages
Indiscriminate cutting down of trees lead to deforestation /soil erosion/disruption of rainfall patterns etc.
Dirty due to soot and smoke.
A lot of wood is required because of less energy outputs.
Pollution as the wood is burnt.
Requires big storage area
(viii) Draught animals
– Most commonly used animals are oxen/bulls, others are horses, donkeys, camel etc
– They are used to in plough/prepare farms, transport goods etc
Advantages
Readily available all over the world.
Maintenance of animals is cheap – require only food and water.
Animals are flexible i.e. can go through areas that are inaccessible by other transport means e.g. roads/railway.
Some animals can be used in ASALs
Disadvantages
Prone to diseases and fatigue.
Work that can be done by animals is restricted to rural areas.
Work that can be done by the animals is limited – they tire quickly
Non-renewable sources of energy
– Lack natural ability of regenerating/recycling
– Are likely to be exhausted if not carefully used/managed
– Include the following: –
Petroleum
– Is a fossil fuel that consists of gaseous and liquid hydrocarbons from animal and vegetation matter laid down in sedimentary rocks
– Used in agriculture, cooking, lighting and heating
– When refined several bi products are realised e.g. petrol, diesel, paraffin, bitumen, liquified gas and lubricants
– Petrol and diesel are used to fuel vehicle and machinery
Advantages
Occurs in great abundance as new oil deposits are being disocvered daily.
Has wide range of domestic and industrial uses.
Can be used to generate other sources of energy e.g. thermal electricity.
Can be transported by tankers/pipelines and stores for future use
Disadvantages
Crude oil is bulky.
Dangerous because highly inflammable.
Burning of petroleum pollutes the environment/leads to global warming.
Petroleum is relatively expensive/not affordable to many.
Prospecting of petroleum is expensive
ii) Coal
– Comprises of vegetative matter laid down in water bodies/swampy areas
– Once mined cannot be recreated/restored
– Used to provide heat for cooking/heating/lighting
Advantages
More efficient in generating thermal electricity compared to oil/petroleum.
Suitable in smelting of iron and steel
Disadvantages
Bulky – costly/difficult to transport.
Its mining leads to environmental pollution.
Dirty/pollutes the environment
iii) Natural gas
– Occurs in assocaition with petroleum i.e. normally found on top of upper layers of crude Oil.
– Composed of mixture of hydrocarbons with methane making the highest percentage
– Mainly used for domestic purposes, generating thermal electricity and for industrial activities
Advantages
Clean.
Cheap to transport in pipelines.
Free from weather changes
Disadvantages
Accidental fires may occur due to gas leakage/damaged pipes.
Pollution of environment through gas leaks.
Expensive for low income earners
iv) Thermal electricity
– Is generated by burning fuels e.g. coal, petroleum and natural gas in thermal generators/specially designed surfaces
– Water is heated to produce steam or oil/diesel may also burn in combustion chambers generating heat\steam that drive turbines connected to generators that produce electricity
v) Uranium\Nuclear Energy\atomic energy
– Derived from the alteration of atomic structures
– Involves release of heat that produces steam used to generate electricity through fission where uranium are split in nuclear reactors/power stations
– Nuclear power stations are mainly found in developed countries e.g. Britain, USA, France, Germany and Japan
Advantages
Environmentally friendly.
Produces large amount of energy in nuclear reactors.
Reliable due to long lasting supply of uranium deposits
Disadvantages
Requires heavy capital investment/expertise.
Radioactive materials are harmful to human (causes cancer) and the environment.
Nuclear leakages can cause environmental pollution.
Can result into disastrous accidents if not well planned/controlled
Hydro – electric power (HEP) stations in Kenya
– Hydro power is the main source of electricy in Kenya
– Most electricity produced in Kenya is generated from various hydro power stations found in different parts of the country
– Stations are maintained by KenGen then sold to Kenya Power that distributes it to consumers at a fee
– The major HEP station in Kenya is the Seven Forks Scheme which is located on River Tana
– The projects on Seven Forks include
Kindaruma – 40MW
Kamburu – 88MW
Gitaru – 225MW
Masinga – 40 MW
Kiambere – 144MW
Mutonga – 60MW
Grand Falls – 180MW
Name the damsmarked 1, 2, 3 and4 and thelakemarked X
– 1:Masinga
– 2:Kamburu
– 3:Gitaru
– 4:Kindaruma
-X:L.Masinga
Other HEP projects in Kenya include
Turkwell – 106MW
Sondu – Miriu – 60MW
Hydro – electric power (HEP) stations in Uganda
– The major power source and HEP project in Uganda is the Owen Falls Dam
– On the site where River Nile flows out of Lake Victoria provided a natural waterfall from where the power generation was possible
– Produces 162MW that supplies most of Uganda’s electricity and about 30MW exported to Kenya
– Was developed to an upsurge of industries in Uganda, creating a high demand for electricity and also high costs of petroleum since it is landlocked
HEP projects in Africa
– Africa has the largest concentrations and potential areas HEP generation but the potential has not been fully exploited due to
Inadequate financial resources to set up the project.
Potential sites located in remote areas with sparse population – little market.
Seasonal flactuations in the river water due to prolonged drought
HEP projects in Africa include
Akosombo – Ghana
Kainji – Nigeria
Inga – DRC
Aswan – Egypt
Kafue – Zambia
Kariba – Zambia/Zimbabwe
Caborra Bassa – Mozambique
Name the rivers marked X Y and Z
– X: River Nile
– Y: River Tana
– Z: River Zambezi
Hydroelectric power generation projects found along the rivers at positions J, K and L.
– J: Owen Falls
– K: Seven Forks
– L: Kariba Dam
HEP RIVER COUNTRY
1 Akosombo volta Ghana
2 Kainji Niger Nigeria
3 Inga andLe Marinel Congo DRC
4 Aswan Nile Egypt
5 Owen falls Nile Uganda
6 SevenForks Tana Kenya
7 Kafue Zambezi Zambia
8 Kariba Zambezi Zambia/Zimbambwe
9 Caborra Bassa Zambezi Mozambique
10 P.K. Le Roux Orange S.Africa
11 GarrieDDam Orange S.Africa
Factors favouring development of HEP project
– Hard basement rocks to provide a firm foundation for dam construction
– Presence of waterfalls to provide a massive hydraulic force head for power generation
– Regular/large volume of water to ensure continuous power generation
– Non porous rocks to prevent water loss/seepage underground
– Presence of a deep narrow valley/gorge to provide a large reservoir behind the dam/reduce cost of bulding embankments
– Government policy – availaability of land/space for setting up the plant
– Market to buy the produced HEP
– Adequate capital to set up the project since it involves high capital outlay
Role of HEP in the economy
– Creation of employment opportunities
– Development of the communication sector
– Agricultural development
– Source of government revenue
Problems facing HEP projects
– Flactuating river regime/waters due to prolonged drought and deforestation upstream leads to production of little/less power
– Inadequate capital for HEP development and maintenance
– Siltation
– Displacement of people
Geothermal power projects in Kenya
– Generated in areas with seismic/volcanic activities with numerous hot springs and geysers and fumaroles that can be used to generate electricity
– In Kenya, it is found in the following areas
Eburru – North of Lake Naivasha.
Lake Bogoria – has the highest potential.
Ol Karia
Geothermal plants are not well developed in Kenya because of the following: –
Limited number of potential sites.
Scarcity of skilled labour.
Inadequate capital investment
Significance of Energy
– For domestic uses e.g. cooking, lighting, heating
– Used in industrial sector e.g. to run the machines
– Transport sector
– Research in alternative energy to reduce overreliance on existing energy sources
– In agricultural sector for drying of cereals
– Pumping water
Energy Crisis
– This is a situation whereby the demand for oil is higher than the amount being supplied, leading to high oil prices
Causes of Energy Crisis
– Escalation in oil prices triggered by sharp rise in demand
– Uncertainities in oil supply/rapid depletion of oil reserves
– Control of oil reserves by a few oil producing countries
– Unequal pattern of crude oil distribution in the world
– Artificial shortages created by USA and Russia decide to conserve their resources and depend
on world market for their requirements
– Economic and political embargoes (wars)
– Misuse of energy sources
Effects/Impacts of Energy Crisis
– Increased petroleum prices lead to escalation in transport costs/affects tourism
– Low rate of economic growth because of over-expenditure on oil importation
– The price of commodities rises leading to inflation
– High costs of transportation
– Foreign exchange resources are almost entirely spent on oil imports creating a deficit in balance of trade
– The demand for charcoal and wood fuel increases leading to deforestation
– Oil resources are getting depleted
Management and Conservation of Energy
– Management of energy resources refers to the effective planning and control of energy sources
– Conservation of energy involves using the available resources in the most appropriate manner to ensure minimal wastage
– The following measures are used to manage and conserve energy
Search and development of alternative sources of energy other than petroleum e.g. geothermal, wind, solar, gasohol, tidal, H.E.P. etc.
Increased prospecting for oil.
Improving public transport to encourage more people to use it (reduce vehicles on the road).
Control of the importation of vehicles with high engine capacity (high tax on high capacity luxury cars).
Proper planning of the road network to reduce traffic jams.
Creating awareness by educating the public through mass media.
Development of energy saving techniques or technology e.g. energy saving jikos.
Development of wood fuel programmes through afforestation, re-afforestation and planting of fast maturing trees (eucalyptus).
Past KCSE Questions on the topic
ENERGY.
1. (a) Apart from providing power, state three other benefits of the dams along
River Tana. 3 mks
(b) State two problems that affect hydroelectric power production along river Tana. 2 mks
(c) State two factors that hinder the expansion of geothermal power. 2 mks
2. (a) Name two non-renewable sources of energy. 2 mks
(b) Explain four physical factors that influence the location of a hydroelectric power station. 8 mks
3. (a) Explain three benefits that would result from rural electrification in
Kenya. 6 mks
(b) In what three ways did the power shortage resulting from the drought of the years 1999 and 2000 affect this industrial sector in Kenya? 5 mks
4. (a) Give three reasons that make tropical countries to have the potential to
develop HEP. 3 mks
(b) Give two reasons why tropical countries are not sufficient in HEP production. 2 mks
5. Use the diagram to answer questions below.
(a) Name
(i) The HEP stations marked S & T 2 mks
(ii) Name the proposed HEP station marked U. 1 mk
(b) Name renewable sources of industrial energy other than water 2 mks
6. The diagram below shows the occurrence of petroleum in the earth’s crust. Use it to answer question (a).
(a) Name the substances labeled I, M and N. 3 mks
(b) Give two by-products obtained when crude oil is refined. 2 mks
(c) Explain efforts by Kenyan government to reduce cost on importation of petroleum. 6 mks
7. Name two main disadvantages of using coal as a source of energy. 2 mks
8. Suggest four solutions to Kenya’s energy deficit. 4 mks
9. What are the causes of energy crises? 4 mks
10. List uses of nuclear energy. 4 mks
11. Name uses of wind energy. 2 mks
12. Name two non- renewable sources of energy. 2 mks
13. Why has usage of coal as a source of energy declined? 4 mks
14. Give four reasons why Kenya has been unable to exploit high geothermal power potential. 4 mks
15. Name the various methods that can be used to conserve energy. 4 mks
16. Define biomass. 2 mks
17. (a) Define energy. 2 mks
(b) List three renewable; sources of energy. 3 mks
(c) State the disadvantages of coal as a source of energy. 4 mks
18. (a) What is the name of power projects along river Tana.
(b) Apart from hydroelectric power production, state the other benefits of the dams along the Tana. 4 mks
(c) Identify the problems facing hydroelectric power production along the Tana. 4 mks
19. (a) Apart from the Tana, name three other hydroelectric power projects in
Kenya. 3 mks
(b) State the benefits of the Owen Falls Dam in Uganda. 4 mks
(c) State the factors limiting the expansion of geothermal power production in Kenya. 4 mks
20. Apart from hydro-electric power production; state the other benefits of the dams.
4 mks
21. State the significance of energy. 5 mks
22. (a) What is energy crisis? 2 mks
(b) State the causes of energy crisis. 2 mks
23. Explain the problems Kenya faces due to overdependence on petroleum. 4 mks
24. (a) Differentiate between management and conservation of energy. 2 mks
(b) Describe the measures of management and conservation of energy. 10 mks
CHAPTER TEN
Specific Objectives
By the end of the topic the learner should be able to:
(a) Define industry and industrialization;
(b) Explain the factors that influence the location and development of industries;
(c) Describe types of industries;
(d) Account for the distribution of industries in Kenya;
(e) Explain the significance of industrialization to Kenya,
(f) Discuss the problems of industrialization and suggest possible solutions;
(g) Compare and contrast aspects of industrialization in selected countries;
(h) Carry out fieldwork on an industry in the local area.
Content
Definition of industry and industrialization.
Factors influencing the location and development of industries.
Types of industries.
Distribution of industries in Kenya.
Significance of industrialization to Kenya.
Problems of industrialization and their possible solutions
A study of the cottage industry in India, iron and steel industry in the Ruhr region in Germany and car manufacture and electronic industry in Japan.
Field work on identification of industries within the local area and a detailed study of one of them.
Definition of terms
Industry: – is an organized economic activity concerned with the processing and manufacturing of raw materials into useful products/production of goods and services for sale/consumption
Industrialization: – process of establishing manufacturing industries
Reasons for industrialization
– Economic diversification thus reducing overreliance on agriculture as a source of income/revenue
– Self-sufficiency reducing the need to import goods thus saving foreign exchange
– Creation of employment opportunities thus improving living standards
– Use/utilization of natural resources
Factors influencing location and development of industries
Capital
– Establishing an industry requires a large capital outlay/base for the following purposes: –
Purchase of land/equipment/raw materials
Putting up buildings/infrastructure
Paying wages/salaries/taxes
– Countries with plenty of capital are therefore able to industrialise faster/with greater ease compared to developing countries that lack enough/adequate capital
ii.) Raw materials
– These include mineral ores/agricultural produce/forest products
– Most are always heavy/bulky thus industries are located near them to minimise/reduce transport costs
– Some especially agricultural produce are very perishable hence need to be close to processing plants/industries
iii.) Labor
– Various industries require different types and amounts of labour
– Can be in terms of skilled and unskilled/semi skilled
– Supply of labour is certain in densely populated areas hence location of many industries in urban centres
iv.) Ready market
– All industries are commercially oriented hence their products must find outlets/market (must be sold to make operations viable economically)
– Large urban areas usually provide ready market for finished products because the people’s purchasing power is very high – large industries are therefore located near them
– Examples of commodities whose manufacturing industries must be near markets include foodstuffs, fragile equipment e.g. glass, cigarettes etc
v.) Transport and communication
– All industries require good roads/transport network for their operations e.g. to transport raw materials to the industries and finished products to the markets
– Industries are established within/near urban centres with well developed transport systems.
– Industries depend on communication networks to link with the market and suppliers of raw materials. These includes e-mail/internet, courier services, postal services, telephone/facsimile services etc
– Areas with well developed communication systems experience low transport costs
vi.) Electricity/power
– Power is very essential for the operations of any industry. The most common and affordable type of power is electricity
– Most industries are therefore located near reliable power/electricity source – urban centres where power is cheap to supply
vii) Regular water supply
– Most processing industries use considerable amounts of water hence best located near permanent water sources e.g. rivers/lakes
– Examples of such industries include coffee pulping, sugar cane processing, paper mills, brewing/soft drink making
– Water may be used in cooling/cleaning and as a raw material in some of the processes
viii) Government policy
– The government may discourage/encourage establishment of industries in one particular place for political and economical reasons
– In developing countries, the governments are decentralising industries away from the urban centres to develop the rural areas/reduce rural-urban migration
Industrial inertia
– Is a situation in which an industry continues to operate in an area even after the factors that attracted it to the area are no longer existing/present
May be caused by the following factors: –
Presence of experienced/skilled workers.
It may be expensive to move to a new site.
Established industrialised area usually has well developed transport/infrastructural system.
Types of industries in Kenya
– The main types of industries found in Kenya include: –
(a) Primary/processing
– Are also known as extractive industries
– Are involved in the first stage of changing raw materials from one form to another that is more useful/valuable
– Produce goods used to make final products
– Provide raw materials for secondary industries
– Examples in Kenya include
Mining of limestone at Bamburi and Athi River.
Fishing in Lake Victoria and Indian Ocean.
Extraction of forest products from various forests/lumbering.
Growing of agricultural crops e.g. sisal, cotton, sugar cane, tea, maize, tobacco,pyrethrum, fruits, vegetables.
Keeping of animals for milk, beef, skins
(b) Secondary/manufacturing
– Use raw materials derived from the primary industries
– Change the raw materials into semi processed or finished products
– Examples include
Coffee factories, Cotton ginneries, Steel rolling mills, Food processing, Cigarette making, Glass making, Oil refineries, Textiles, Pharmaceuticals, Paper and pulp ,Fertilizer making, Cement making. Insecticide making
– Secondary industries are further classified into heavy and light industry
– Heavy industries manufacture heavy and bulky products
– Involve heavy capital investment
– Their production is large scale
– Examples include, ship building, car manufacturing and assembly, iron and steel rolling mills, paper and pulp among others
– Light industries manufacture/process finished products that are less bulky/heavy
– Use light raw materials e.g. textile, cosmetics, toiletries, food processing, printing, electronics
(c) Assembly industries
– Involves fixing together of different products made in different industries to make valuable articles/items
– Use imported raw materials to make articles that are not locally manufactured
– In Kenya, they assemble motor vehicles, electronics, bicycles
– Majorly located in urban areas
(d) Service/tertiary
– Distribute commodities that have been produced in primary and secondary industries to consumers
– Render supply services to finished products
– Found in both rural and urban areas
– Require little capital and space
– Require specialised skills/skilled labour
– Include medical, education, finance, trade, communication, banking, insurance, transport etc
(e) Cottage Industries
– Involves making products using hands and simple tools especially in the homes
– Items are made using locally available materials
– Done on a small scale
– Examples include pottery, wood carving, soapstone carving, weaving of baskets/mats, boat making and scrap metal fabrication
– In Kenya, Jua Kali is most common and popular cottage industry Jua Kali industries
– Relies on locally available materials and tools
– Requires little capital
– Products target local market
– Are found in almost all urban centres
– Main activity involves reprocessing of old materials to produce useful items
Importance of the Jua Kali sector
– Creates employment opportunities
– Successfully uses materials that would otherwise be disposed
– Saves the country foreign revenue as they reduce the imports
– Earns the country foreign exchange as some are exported to COMESA countries
– Produces cheaper goods compared to those produced in formal industries
Distribution of industries in Kenya
(a) Agricultural Food processing industries
– Tea processing – Kericho, Kirinyaga, Embu, Kisii, Nyamira, Kiambu, Murang’a,Nandi, Meru.
– Coffee hulleries – coffee growing areas, Nairobi, Sagana
– Milk Creameries – Naivasha, Nakuru, Nyahururu, Sotik, Nairobi, Eldoret, Kitale
– Sugar refinery – Mumias, Nzoia, Chemelil, Muhoroni, Awendo, Kabras, Busia
– Fruit canning – Thika, Nairobi
– Grains Milling – Eldoret, Nakuru, Nairobi, Kisumu, Mombasa
– Soft drinks making – Nairobi, Mombasa, Nakuru, Eldoret, Nyeri, Kisumu
– Brewing/Blending of alcoholic beverages: – Nairobi and Mombasa
(b) Agricultural non food processing industries
– Cotton ginneries – Kisumu. Homa Bay, Siaya, Busia, Meru, Baringo, Tana River, Kitui
– Sisal – Kilifi, Voi, Mogotio, Uasin Gishu
– Tobacco – Teso, Thika, Nairobi, Nakuru
– Pyrethrum – Nakuru
– Paper and pulp – Webuye, Eldoret, Thika, Nairobi
(c) Non agricultural manufacturing industries
– Cement production – Athi River and Bamburi
– Oil refining – Kilindini, Kipevu, Changamwe (all in Mombasa)
– Metal box – Thika
– Glass making – Mombasa and Nairobi
– Steel rolling – Nairobi and Mombasa
Significance of industrialization in Kenya
– Employment opportunities/source of income/improvement of living standards
– Development of infrastructure e.g. roads, power and water supplies for transport of raw materials to the industries and finished products from the industries to the markets
– Source of foreign revenue/exchange through exportation of finished products
– Improvement of balance of trade by increasing the value of exports
– Urbanisation: – creation of urban centres/settlements with improved provision of social amenities
– Utilisation of natural resources e.g. minerals/forest products thus reducing overdependence on imported raw materials
– International relations: – allows interaction between various nations as they trade in raw materials and finished industrial products thus fostering good relations among the trading partners
– Enhancement of agricultural production: – since most industries rely on agricultural produce as raw materials, this will ensure their continuous supply
– Trade unions and cooperatives: – establishment of industries has led to formation of trade unions/cooperatives to protect the workers’ welfare/demand for better salaries/work conditions
– Presence of goods: – industrial development makes it possible to produce goods that are on demand in the country thus reducing importation/overdependence on imported goods
– Economic diversification reduces overdependence on agriculture as an economic activity/major source of income
Problems of industrialization and their possible solutions
1. Establishment of more industries requires more land to be set aside for industrial activities. This reduces the land for agriculture, human settlement
Solution: – decentralization of industries
2. Production of industrial waste has led to the pollution of land, air and water as the industries release/dispose their wastes into the environment/air/water bodies/land dereliction
Solution: – strict legislation/enacting laws against dumping industrial wastes through agencies such as NEMA
3. Rural-urban migration: – increase in number of industries encourages many youth to move to urban centres in search of employment opportunities. This leads to congestion of urban areas and a strain on available social amenities/increase in criminal activities, development of slum dwelling etc
Solution: – establishing industries in rural areas/improving provision of social amenities in the rural areas
4. Concentration of infrastructure and services in the industrial centre has caused an imbalance in economic development.
Solution: – Decentralization of industries
5. Depletion of natural resources: – as more industries are established the demand for raw materials also increases thus increasing the use of natural resources e.g. minerals, forests, water etc
Solution: – encouraging sustainable use of natural resources
6. Neglect of agriculture: – industrialization attracts youth to move into urban areas in search of employment away from the rural areas. This affects food production as old people are left to work on the farms. People may also neglect food crop production at the expense of cash crops that fetch more
Solution: – making agriculture more attractive through offering better prices for the agricultural produce
– Farmers encouraged to diversify their economies
7. Causes unemployment: – industrialization leads to new innovations/technologies leading to replacement of human power. Examples include computers, robots, electric trains, fork lifts, conveyors have replaced physical manpower. This reduces employment opportunities
Solution: – people are being encouraged to become self employed
– Industries are encouraged to stop staff lay offs
8. Displacement of people: – an industrial plant being established in a densely populated area may force the inhabitants of such an area to move and resettle elsewhere, this changes their social lifestyles.
Solution: – industries should be located in sparsely populated areas
9. Extradition of profits: – most industries established in Kenya are foreign owned and these send back profits to their origin countries leaving little money for local use
Solution: – increasing local share holding in multinational industries
Locals should be encouraged to establish in the country
Problems facing industries in Kenya
a.) Competition from cheap imports
– Imported industrial products from other countries are less taxed by their parent countries making them cheaper compared to the same that are locally produced.
– This makes the running of industries dealing in such products very expensive to run due to limited market and may force closure of some
Solution involves: – imposing very heavy duty on imported products that are also locally produced/improving quality of locally manufactured goods so that they can compete favourably with the imported ones
b.) High cost of energy/electricity
– Most developing countries lack deposits of fossil fuels/petroleum/natural gas leading to high costs of importing the same. This increases the production costs as they have to be imported
– The costs of alternative and available energy sources e.g. electricity are very high and these limit/marginalises the profits received by the industries
Solution: – alternative sources of energy should be developed e.g. solar/wind/biogas etc
c.) Inadequate/limited market
– Some products have a limited market as they are not highly on demand/low purchasing power of the people. This slows down production of the concerned industries
Solution: – exploring external markets especially within COMESA region
d.) Shortage of raw materials
– Some industries relying on imported raw may interrupt their operations when there is a delay in the arrival of the raw materials.
– Industries that rely on agricultural raw materials are also affected due to prolonged drought
Solution: – local raw materials could be supplemented with imported raw materials/agricultural sector should be improved to increase production of raw materials
e.) Inadequate/shortage of capital
– Most developing countries are faced with shortage of capital forcing them to borrow from international financial institutions.
– These charge very high interest rates and conditions e.g. retrenchment/some industries may close down if unable to get funding
Solutions: – governments to give loans to local investors/foreign investors should be encouraged to invest in the country.
f.) Industrial unrests
– Often workers may go on strike demanding better working conditions from their employers. This disrupt the operations of the industries leading to low production of commodities
g.) Mismanagement
h.) Shortage of skilled labour
i.) Poor infrastructure
j.) Lack of adequate technical knowledge
Case Studies
Cottage Industry in India
– A cottage industry involves people working from their homes using their own hands and simple tools/machinery
– Involves individual skill/talent
– Highly developed in India and virtually practised in every village
Activities of Cottage Industry in India
– Spinning and weaving
– Making clothes and carpets
– Silverware and brassware
– Pottery
– Making textiles
– Dyeing clothes
– Ornamental ivory
– Jewellery and trinklets
– Embroidery
– Handicrafts
Characteristics of Cottage Industry in India
– Small capital is invested
– Simple tools and machinery are used
– Uses locally available raw materials
– Most products are sold in the local market/few are exported
– Labour provided by family members
– Labour intensive
Factors that have contributed to the growth of Cottage Industry in India
– Presence of labour provided by the family members
– Urge of earning income to improve the living standards
– A long history/culture of weaving mainly done by women in homesteads.
– High demand for the products in the Asian countries.
– Highly skilled and talented workers i.e. weavers and ornamental ware makers.
– Presence of locally available raw materials such as cotton jute.
– It involves individual talent/skill passed through generations.
Benefits of Cottage Industry in India
– Created employment opportunities/source of income leading to improved living standards
– Provision of market for local products
– Foreign exchange earner through exports of brassware and ornaments/jewellery
– Diversification of economy from agriculture.
Iron and Steel Industry in the Ruhr Region of Germany
– Ruhr region in Germany is one of the leading and largest industrial complex in Europe
– Derives its name from River Ruhr; a tributary of River Rhine
– The Ruhr industrial region is located between River Lippe to the north, Rhine to the west and Wupper to the south
– One of the leading industries in the Ruhr region is the iron and steel industry
– The basic raw materials for iron and steel industry in the Ruhr region are coal, iron ore and limestone
– These are mixed in a blast furnace to produce iron. Heated iron is strengthened by adding carbon and other metals to produce steel
– Steel is used in building, making tools and machinery
– Other industries within the Ruhr region include
Engineering.
Textile industries.
Oil refining.
Electronics.
Food processing.
Cutlery and surgical instruments.
Chemical/petro-chemical industries.
Factors for the development of iron and steel industry in the Ruhr region Germany
– The region is centrally located in Europe. This offers easy access to all parts of Europe as it has direct access to all parts of Europe through water, railway, air and road.
– The region is served by navigable rivers and canals, which provide cheaper transport for raw materials and finished products.
– The region has abundant sources of energy/power such as coal, oil, H.E.P, which is a necessity in iron and steel industries.
– Availability of raw materials (iron ore, coal and limestone). It is economical to set up iron and steel industries near the source of raw materials because they are bulky.
– The dense and affluent population in central and Western Europe provides ready market for iron and steel.
– Government policy. The post war national desire to rebuild the country gave the industries an impetus to succeed.
– Presence of rich industries, which are ready to provide capital for industrial development.
Example
Below is a sketch map of the Ruhr Industrial Region. Use it to answer question (i)
Name:
The canal market U (1 mark)
The river marked V (1 mark)
The town marked W (1 mark)
Solution
Name;
The canal marked U (1 mark)
Lippesite canal
The river marked V (1 mark)
River Ruhr
The town marked W (1 mark)
Dortmund
Car and Electronics Industry in Japan
– Japan comprises of many islands and is majorly mountainous. It therefore doesn’t favour agriculture. Japan has hence concentrated in the development of manufacturing industries
– The major industries in Japan include car and electronics manufacture.
The others include:
Ship building
Iron and steel
Chemicals
Textiles
Machinery
– Examples of automobile industries in Japan include Toyota and Mitsubishi motor corporations. Electronic companies include Sony and Toshiba and they manufacture radios, televisions, computers and related accessories, cellular phones, fridges, microwaves etc
Factors for the development of car and electronics industry in Japan
Power:- Japan lacks petroleum/coal/natural gas but being mountainous with many rivers that has led to the development of HEP projects that provide energy for industrial use. Nuclear energy is also available
Advanced technology/automation/all plants are computerized has led to high/efficient and increased car/electronics production.
Geographical location:- Japan is accessible to all parts of the world via the sea which makes the importation of raw materials and exportation of cars/electronics possible.
Capital:- profits realised from other industries e.g. ship building, fishing and tourism are invested in the development of car/electronics industries through purchase/importation of raw materials.
Abundant water supply:- Japan is surrounded by the Pacific Ocean and many rivers/lakes within the islands that provide water for use in the iron and steel industry whose products are in turn used in car and electronics manufacture.
Rugged landscape: – in Japan does not favour development of agriculture and has therefore concentrated on the development of manufacturing industries to enable earn capital for importation of food.
Skilled man power: – Japanese labour is skilled and highly dedicated to the development ventures leading to quantitative and qualitative production of automobiles and electronicsAffordable products: – most of the Japanese .
automobiles and electronics are relatively cheap and of better quality. They are sold cheaper compared to the same from Europe.They are also durable, cheaper to maintain and readily available. They are therefore on very high demand all over the world.
Major car manufacturing zones in Japan
– Tokyo – Yokohama Industrial zone
– Osaka – Kobe Industrial zone
– Nagoya industrial zone
Environmental problems which have resulted from the development of car manufacturing industry in Japan.
It has led to air, noise and water pollution which is dangerous to human health and wildlife/visibility.
Dumping of industrial waste leads to environmental degradation/water or soil pollution.
Increased production of cars and the high local purchasing power has led to traffic congestion in the cities.
High demand for limited raw materials like coal has resulted to over exploitation.
Emergence of many factories has attracted large manpower which has resulted in housing problems/inadequate housing.
Application questions on Industry.
Obstacles Kenya faces as it strives to become industrialized.
Shortage of capital.
Shortage of skilled manpower.
Lack of market due to low purchasing power.
Poor infrastructure.
Poor resource endowment-the country is sparsely endowed with industrial resources. (iron, steel).
Shortage of power leading to rationing/outages, which affect industrial operations.
Most industries are owned by foreigners who repatriate much of their profit leaving less to be invested in industries.
Three problems that are experienced in Kenya as a result of industrial development.
Industries have taken over land; this has led to high unaffordable land rates.
Production of industrial waste has led to the degradation of land, air and water.
It has led to rural-urban migration depriving the rural areas of the able-bodied persons.
Concentration of infrastructure and services in the industrial centre has caused an imbalance in economic development.
Emergence of slums due to lack of housing facilities/overstretching social facilities.
Depletion of natural resources to satisfy demand.
There is erosion of social values, which has resulted from the mixing u of people of different culture/ loss of cultural values.
Four main products exported by the cottage industry in Kenya.
Wood carvings.
Stone carvings.
Mats.
Baskets.
Pots.
Ways in which Kenya is encouraging the establishment of cottage industries.
Creation of Kenya Industrial estate, which provides loans to cottage industries.
Jua kali artisans/dealers in cottage industry have been encouraged to form cooperatives to assist in marketing their products.
KIE has put permanent structures where industries can operate at low cost.
Local authorities have set aside land for use by jua kali artisans.
Reasons why jua kali is more suitable to African countries. (Why is jua kali more suitable to African countries?)
It depends on traditional skills hence no need for costly expatriates.
It helps reduce unemployment, as it is labour intensive.
Light industries need small capital to start and operate.
They depend on agricultural raw materials, which are plenty in Africa.
Can be started with low level of technology.
Light industries consume little power.
Items made suit low income people, this guarantees market.
Reasons why the development of jua kali industry is encouraged in Kenya.
It offers job opportunities to school leavers.
Helps raise living standards owing to income earned.
Makes good use of available local resources i.e. recycles materials thus reduce cost of imports.
Exported items earn foreign exchange.
Provides cheaper items to the relatively poor population.
For diversification of export goods.
To reduce rural-urban migration.
It requires less capital to establish since it is small scale.
It produces mainly for the local market thus the country saves foreign exchange.
It does not require expensive machinery since production is manual.
It facilitates decentralization of industries since it spreads easily thus checking on rural-urban migration.
It imitates the products that are already in the market thus spreading technological skills/innovation.
It operates at grass root level thus uses locally available skills.
It empowers the people to initiate projects thus reducing reliance/dependence on the government/donors.
Problems facing Jua kali artisans in Kenya.
Limited market.
Preference to white-collar jobs.
Stiff competition from imported products.
Foreign biased consumption habits of citizens.
Limited access to capital.
Factors that may influence the location of industries.
Availability of raw materials. The nature of raw materials (bulky, perishables) influence industrial location e.g. weight reducing industries are located near raw materials to reduce the cost of transporting the bulky inputs.
Availability of power/energy. Coal sites and hydroelectric power stations influence location of industries especially power-oriental industries such as copper, iron and steel smelting etc.
Availability of labour. Labour intensive industries are usually sited where cheap labour is available.
Availability of market. Industrial location may also be determined by the nature of the final product e.g., weight increasing, perishable and fragile goods are produced near the market.
Government policy of rural development may encourage decentralization of industries. Government also puts aside land for industries.
Presence/ absence of a well-developed infrastructural network (transport and communication).
External economies. Concentration of industries in a place may attract more industries to the area (industrial inertia).
Availability of land for expansion.
Why some industries are located near sources of water.
Water is used for cooling machines to avoid damage by heat.
Some industries require water as a medium through which they dispose off their waste materials.
Water is used for grading of coffee beans.
Water provides cheap means of transport.
Some industries use water as a raw material e.g. breweries.
Water is used for industrial cleaning.
Water may be used to generate hydroelectric power to turn the machines.
Differentiate between localization and delocalization of industry.
Localization of industry refers to the concentration of industries within a limited area. Delocalization is an attempt to spread industries from urban to the rural areas.
Ways through which the government of Kenya may decentralize industries.
Availing cheap land for industrial sites.
Offer tax rebates.
Giving subsidies.
Protecting such industries from foreign competition.
Encourage rural electrification.
Improving infrastructural network and social amenities.
Benefits of decentralizing industries in Kenya.
It would reduce rural-urban migration.
It would create employment in the rural areas.
It would encourage regional equality in development.
Helps open up remote parts of the country.
It would allow greater exploitation of local resources.
It would raise the standard of living of people in rural areas.
It would reduce congestion in urban centres.
To check on environmental pollution.
Problems hindering decentralization of industries in Kenya.
Some industries depend on each other for raw materials/market/services hence it is difficult to separate/relocate them.
Insecurity in some areas discourages investment in such areas.
Some private investors are discouraged by poor transport facilities in the rural areas.
Inadequate market in the rural areas discourages investors from locating industries away from urban centres.
Some areas lack energy resources.
Ways in which Kenya has benefited by assembling motor vehicles locally.
It has stimulated development of other related industries e.g. tyres, paints, service etc.
The industry has created employment opportunities for Kenyans thereby reducing unemployment problems.
Kenya saves foreign exchange by importing parts of motor vehicles instead of complete units.
It has enabled Kenya to establish trade links with her neighbors.
It has allowed transfer and development of technical skills among Kenyans.
Assembled vehicles are exported to other countries earning foreign exchange.
It has led to investment of capital within the economy.
Causes of the decline in the textile industry in Kenya.
Large- scale importation of cheap second hand clothes has reduced demand for locally produced textile products, which are relatively expensive.
There has been a decline in the production of cloth, which has led to the limited supply of raw materials for the textile industry.
Mismanagement of textile factories has led to closure of such operations.
Liberalization of the economy has encouraged business people to import textiles from other countries instead of selling locally produced ones.
Belief that imported garments are superior to locally produced ones has reduced demand for local garments.
Decline in the economy has discouraged investors who would set up textile industries in Kenya.
Industries located in the Ruhr region of Germany other than iron and steel.
Engineering.
Textile industries.
Oil refining.
Electronics.
Food processing.
Cutlery and surgical instruments.
Chemical/petro-chemical industries.
Service industry-banking, insurance, tourism.
Factors, which led to growth of iron and steel in the Ruhr region of Germany.
The region is centrally located in Europe. This offers easy access to all parts of Europe.
The region is served by navigable rivers and canals, which provide cheaper transport for raw materials and finished products.
The region has abundant sources of power such as coal, oil, H.E.P, which is a necessity in iron and steel industries.
Availability of raw materials (iron ore, coal and limestone). It is economical to set up iron and steel industries near the source of raw of raw materials because they are bulky.
The dense and affluent population in central and Western Europe provides ready market for iron and steel.
Existence of traditional industries, which led to the development of the necessary skills.
Government policy. The post war national desire to rebuild the country gave the industries an impetus to succeed.
Presence of rich industries, which are ready to provide capital for industrial development.
Factors that have led to the rapid development of car manufacturing in Japan.
Presence of advanced technology/automation has led to efficient and increased car production.
Japan produces fuel saving vehicles with a high world demand.
Japan has many natural harbours favouring development of large ports, which makes the importation of raw materials and exportation of cars possible.
Japan’s a high population with a high purchasing power provides a large local market for the cars.
Japan’s change of policy of military aggression led to their economic revolution.
Japan’s terrain is unsuitable for agriculture therefore industries provide an alternative source of employment and income.
The country has highly developed sources of power, which has encouraged growth of manufacturing industries.
Technical oriented education policy encouraged acquisition of technical skills/innovation.
Japan has a strategic location in relation to other continents. This encourages trade thus stimulates the production of vehicles.
Availability of capital to invest in industries (aid from U.S.A assisted in post war recovery).
Stability of the currency has helped boost international trade.
Factors, which have favored the development of the electronics industry in Japan.
Presence of a large local market owing to the large population with high purchasing power.
Availability of large external market.
Availability of adequate financial resources, which have helped in the setting u and expansion of the industry.
Government policy on industrialization has led to rapid development of electronics industries.
Presence of skilled manpower.
Advanced technology/research has promoted efficient methods of production and high quality precision goods competitive in the world market.
Major problems facing industrialization.
(i). Shortage of capital especially the developing countries. This compels them to loan capital of high interest rates and conditionalities such as economic liberalization and staff rationalization.
(ii) Shortage of raw materials both locally produced agricultural inputs as well as imported.
(iii) Inadequate market owing to the low purchasing power of the local population and preference to imported goods limit local market.
(iv) Shortage of skilled labor more so at managerial levels due to brain drain.
(v) Stiff competition with high quality imported goods.
(vi) High costs of energy inflate overall production costs.
(vii) Poor infrastructural network.
(ix) Lack of adequate technical knowledge vital in the maintenance and repair of the imported machines. This leads to costly delays and interruption of manufacturing processes.
Past KCSE Questions on the topic
1. (a) State two reasons why some industries are located near the sources of raw. 2 mks
(b) Give three characteristics of the cottage industry in India. 3 mks
2. (a) State characteristics of jua kali industries in Kenya. 5 mks
(b) State problems facing Jua kali industries in Kenya. 5 mks
(c) Differentiate between manufacturing and j tertiary industries. 4 mks (d) State three factors that led to the growth of iron and steel industry in the:
Ruhr region of Germany. 3 mks
3. (a) Name three agricultural non-food manufacturing industries in Kenya. 3 mks
(b) Explain three causes of the decline in the textile industry in Kenya. 3 mks
(c) Describe the measures that should be taken to control the following.
(i) Water pollution
(ii) Rural urban migration. 2mks
(d) Explain four factors which have favoured the development of the electronics industry in Japan. 8 mks
4. (a) What is industrialization? 2 mks
(b) Name a town in Kenya where each one of the following industries is located,
(i) Oil refinery
(ii) Paper manufacturing
(iii) Motor vehicle assembly. 3 mks
(c) Give five factors why the development of the Jua kali industry is encouraged In Kenya. 5 mks
(d) Name two non-food agricultural industries in Thika. 2 mks
5. State benefits of exploiting soda ash in Kenya. 5 mks
6. State two major steps currently -undertaken by the government to promote industrial growth and development. 2 mks
7. What is industrialization? 2mks
8. State three reasons why the jua kali industry is encouraged in Kenya. 3 mks
9. (a) What is an industry. (2mks)
(b) State two ways in which each of the factors affect the location and
development of industries.
(i) Raw materials
(ii) Transport
(iii) Markets 6 mks
(c) Explain why power is not considered as a major industrial locational factor in the modern world. 2 mks
10. (a) Define:
(i) Primary industry
(ii) Secondary industry
(iii) Quaternary industry 6 mks
(b) (i) What is meant by Jua Kali industry in Kenya? 2 mks
(ii) State five economic benefits of the Jua Kali industry in Kenya. 5 mks
(c) Explain the significance of industrialization to Kenya. 6 mks
11. (a) State two main industries found in the towns below:
(i) Thika
(ii) AthiRiver
(iii) Kisumu
(iv) Nanyuki
(v) Nakuru 10 mks
(b) Explain the problems associated with industrialization. 6 mks
12. State five reasons why the Ruhr region in Germany is the leading industrial centre in Europe. 5 mks
13. (a) (i) Mention four industrial regions in Japan. 4 mks
(ii) List five factors that have aided car manufacture and electronic industries in Japan. 5 mks
(b) Explain the reasons which contributedto the growth and development of the cottage industry in India. 8 mks
CHAPTER ELEVEN
Specific Objectives
By the end of the topic the learner should be able to:
(a) Define trade;
(b) Identify types of trade;
(c) Discuss the factors that influence trade;
(d) Identify the major exports and imports of Kenya;
(e) Assess the significance of trade to Kenya;
(f) Discuss the problems facing trade in Kenya;
(g) Assess the future of international trade in Kenya;
(h) Outline the role played by selected trading blocs in the economies of their respective regions.
Content
Definition of trade.
Types of trade.
Factors that influence trade.
Major exports and imports of Kenya.
Significance of trade to Kenya.
Problems facing trade in Kenya.
The future of international trade in Kenya.
The role played by the Common Market for Eastern and Southern Africa (COMESA), Southern African Development Cooperation (SADC),
Economic Community of West African States (ECOWAS) and European Union (EU) in the economies of their respective regions.
Definition
Trade is the exchange of goods and services at a certain agreeable fee with the aim of making a profit.
Types of trade
– Historically trade has been classified into barter (exchange of goods for goods) and monetary trade
– Monetary trade operates at three levels.
(a) Domestic/internal trade
– Involves buying and selling of goods and services within a country
– The goods are either imported or locally produced
– In Kenya, internal trade involve the following forms: –
Wholesalers/wholesale trade
– Purchase goods in bulk from producers and sell them to retailers
– Specialise in sale of particular goods
– Mainly found in the urban centres
ii. Retail trade
– Involve buying goods from wholesalers and selling to individual consumers
– Stock a variety of goods
– Small scale/sale goods in small quantities
– Include shopkeepers, hawkers, open air markets, departmental stores, multiple stores and supermarkets
(b) Regional trade
– Between countries that are found in the same geographical region.
– Such countries may form economic/trading blocs such as EAC COMESA, ECOWAS,
EU, SADC etc
(c) International/external/foreign trade
– Involves trade between two or more countries
– Can be bilateral or multilateral
– Involves exports (goods sold to other countries) and imports (goods bought from other countries)
– Can also be classified as visible and invisible
Visible trade refers to import and export of tangible goods
Invisible trade involves the exchange of services, which can earn foreign exchange without the transfer of goods from one country to another. Such services include tourism, insurance, revenue from foreign investments, government transactions, medical and educational services, loan interest, banking services, transport services, consultancy services,
– International trade also involves balance of trade and balance of payment
– Balance of Trade- refers to the difference in value between a country’s visible exports and imports. This could be favorable or adverse depending on the value of exports relative to imports.
– Balance of payment – in the balance of all transactions involving both visible and invisible trade of a country with foreign countries.
Factors influencing Trade
Differences in resource endowment such that no country is self-sufficient. This creates the need for external sourcing of goods and services that a country doesn’t produce.
Presence of capital for stocking various goods needed by consumers by traders and to enable buyers purchase.
Demand for goods and services that push the buyers to purchase the same.
Security: – places with relative peace enjoy greater trading opportunities since traders are sure of their security and of their goods, they thence invest more
Stage of economic development – There are differences in technological capabilities among countries which result in regional differences based on industrial productivity. Level of industrialization dictates the type of goods to be imported and those to be exported.
Transport and communication links – efficient links are essential for successful trade.
Government policies determine the trading partners and also the trading blocs to join. Political hostilities limit trade. Protectionist policies substantially influence volume of trade.
International market agreements such as quotas also affect trade
Use of different currencies and language.
Extent of foreign investment especially in developing countries can significantly affect the volume, type and pattern of world trade.
Major Exports and Imports of Kenya
Exports
– Exports are goods and services sold to other countries
– Most exports from Kenya are agricultural products
– Some are exported while raw e.g. coffee/tobacco while others such as pyrethrum undergo some processing before exportation
– Includes the following tea, horticultural produce, soda ash, cigarettes/tobacco, fish, livestock products, tourism, sisal products, footwear, pyrethrum extract, textiles, petroleum products, scrap metal, fluorspar, insecticides, timber/timber products, etc
Imports
– Are goods and services that are bought/brought into a country from other countries
– The major imports include petroleum, machinery, electronics, motor vehicle, pharmaceuticals, skilled labour and foodstuffs
Why countries institute measures to limit imports
To encourage and stimulate the growth of domestic industries.
To protect local industries from competition posed by foreign firms
To create more job opportunities locally.
To encourage self-sufficiency.
Imports restriction prevents cases of dumping by foreign manufacturers.
Protection helps check on quality of incoming goods.
Ways in which the government may restrict external trade
By imposing import duties/tariffs.
Fixing import quotas.
Imposing total ban.
Price control.
Issue license or permits for importation/exportation.
Offer subsidies.
Enter into economic
Significance of Trade
Trade encourages specialization based on a country’s comparative advantage which in turn leads to higher production.
Development of settlement centres/urbanization as major trading towns attract settlements.
Trade stimulates industrial growth through a high demand for goods locally and abroad.
Availability of imported raw materials also stimulates the establishment of import substitution industries for local market.
Expansion of agriculture as most of the trade items are agro based.
Earning of foreign exchange – exports earn foreign currency which is used to buy imports.
Creation of employment opportunities as wholesale/retail traders, customs official etc.
Leads to development of infrastructure in abide to create transport and communication links for more trade.
Trading blocs create a competitive environment for business. This helps in eliminating wasteful monopolies as well as leads to production of high quality products at reasonable prices.
Source of revenue through licence fees and taxation of goods and services rendered.
Regional cooperation enhances international peace and understanding
Problems facing Trade in Kenya
(a) Nature of imports and exports
– Kenya mainly exports agricultural and mineral commodities of low value. It also imports machinery and finished products of higher values resulting to an adverse balance of trade hence trade deficit
(b) Scarcity of goods
– Some goods required by consumers in given places may be lacking may be due to adverse weather conditions e.g. prolonged drought or exhaustion of mines. This makes them to be expensive and unavailable
(c) Poor infrastructure
– Most parts of the country have poor transport network making it difficult to transport goods to various markets.
– This makes the transport expensive leading to marginal profits
(d) High charges/tariffs
– The charges levied by the government in terms of taxes and councils inform of levies to conduct businesses are very high making the traders to earn little profits and discourages importation
(e) Inadequate Capital
– Most traders operate in small scale and have to rely on banks and micro-finance institutions to expand their trading activities.
– The interests charged by the banks are very high limiting the profits.
(f) Insecurity
– In some areas traders may be attacked by thugs and lose their goods/proceeds. They therefore have to invest in heavy and expensive security system that eats into their profits.
(g) Trade restrictions/barriers
– The government may impose restrictions on goods to be imported or exported. Other countries/trading blocs may also impose bans on importation of some commodities from Kenya
(h) Smuggling
– Some unscrupulous traders may import goods into the country without following the correct procedures. Such goods evade taxes thus denying the country revenue and also impose unfair competition from traders who have imported correctly
(i) Dumping of goods
– This refers to the selling of goods in an external market at a price cheaper than that charged in the exporting country. It may lead to a decline in market for local goods due to the cheap imports.
Future of International Trade in Kenya
– International trade in Kenya is likely to improve because of the following reasons
Improvement of balance of trade through the following
Establishment of import substitution industries to reduce importation of commodities.
Development of alternative sources of energy (H.E.P, solar, biogas) to reduce expenditure on oil importation.
Encouraging local assembling of machines since importation of parts is cheaper.
Finding new markets for exports to avoid dependence on a few trading partners.
Diversification of exports.
Encouraging use of appropriate/local technology that does not require heavy machinery.
Encouraging exportation of locally manufacturing goods.
Increasing invisible trade e.g. shipping, tourism, insurance.
Restricting the importation of luxury items through higher taxation.
Encouraging the production of high quality/manufactured goods for export in order to earn higher income.
Setting up industries in the neighbouring countries/within COMESA/EAC regions
Improvement of infrastructure connecting/linking neighbouring countries to facilitate easy movement of goods and people along the borders.
Expansion of other markets e.g. in Europe and Middle East.
Holding trade exhibitions/fares in partner countries to enlighten Kenya’s trade potential thus increasing trade.
Use of conditions of AGOA e.g. various countries are allocated quotas to export textile to overseas especially USA.
Reduction of import duties through EAC agreeing on a common customs unions
Economic integration
Refers to the agreement between two/more countries tocooperate with each other in order to promote mutual trade. Such cooperating countries are collectively referred to as an Economic/Trading bloc.
Regional trading blocs
– These are trade and economic organizations formed by countries in different continents
– The regional trading blocs in Africa include COMESA, SADC, ECOWAS and EAC.
(a) COMESA
– Common market for Eastern and Southern Africa
– Has headquarters in Lusaka, Zambia
– Membership include Kenya, Burundi, Uganda, Ethiopia, Eritrea, Sudan, Djibouti, Angola, Namibia, Zimbabwe, Lesotho, DRC, Madagascar, Mauritius, Swaziland, Zambia, Comoros, Seychelles, Egypt, Malawi, and Rwanda.
Objectives of COMESA
To eliminate taxes on goods produced within the member states.
To create a common market for goods produced in the member countries.
To enable member states to increase the use of their raw materials.
To promote transport and communication between the member countries.
To promote joint development in all fields of economic activity through establishment of a common bank to aid in economic and social development.
To raise the standards of living of its people.
To foster closer relations among its members states.
To cooperate in the promotion of peace, security and stability among the member states.
To strengthen the relationship between member states and the rest of the world.
– COMESA has established a bank, COMESA bank in Bujumbura, Burundi to promote trade among the member states
– This enables the traders to pay for the goods and services from member countries
– Other established institutions other than COMESA bank include Reinsurance
Company, Clearing House and Court of Justice
(b) ECOWAS
– Economic Community of West African States
– Found in West Africa
– Member countries include Benin, Burkina Faso, Ivory Coast, Gambia, Ghana, Guinea, Guinea Bissau, Liberia, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone, Togo and Cape Verde
– It has its headquarters at Lagos, Nigeria
Objectives of ECOWAS
To encourage trade among the member states.
To eliminate trade barriers on locally produced goods in the region.
To encourage industrial and agricultural development among the member states.
To promote free movement of goods and people in the region.
To encourage the improvement of transport and communication in member states so as to facilitate trade
(c) SADC
– Southern African Development Cooperation – Established in 1992
– Members – Angola, Botswana, Dr. Congo, Lesotho, Malawi, Mozambique, Namibia, Mauritius, Tanzania, Swaziland, South Africa, Zambia, Zimbabwe.
– Has its headquarters at Gaborone – Botswana
Aims of SADC
– To promote and co-ordinate regional integration
– To foster international cooperation
– To facilitate trade and economic liberalization.
Benefits of regional trading blocs
– Create a large market for goods and services to be bought and/or sold
– They have helped to create harmony and cooperation among the member states
– Reduction of tariffs making the goods cheaper in the region
– Expanded markets
General Factors that favour regional trade
Political willingness.
Common language e.g Kiswahili for EAC.
Diversified resources.
Specialization in production according to resource endowments.
Similarly in economic system/ideology i.e. common currency or easy currency convertibility.
Common cultural, religious characteristics.
Accessibility to one another e.g. sharing of common transport system – railway of same gangs.
Benefits of Economic Integration
It creates a wider market for goods and services from member countries.
It encourages specialization in production in line with a country’s comparative advantages. This enhances efficiency in production and better resources allocation.
Infrastructural facilities may be jointly financed. This significantly spreads out to cost born by each country.
Increased employment opportunities owing to increased demand for raw materials in line with the expanded market as well as labour mobility.
Expanded market will attract foreign and domestic investment in industries hence lead to industrialization.
It enhances exchange of technology as well as jointly funded research findings.
It promotes peace and international understanding as countries are likely to pursue policies that are mutually beneficial in an atmosphere free of friction.
It avails better quality goods and services to the citizen at fair prices due to the removal of restrictive trade practices that distort prices.
Factors/ problems that limit trade among East African countries
The East African countries product similar agricultural/primary goods this limits exchange.
Differences in political ideology and economic systems e.g. socialism in Tanzania, while Kenya pursues a capitalization economic system.
Different currencies i.e. different value of the shilling discourages the flow of trade.
Un-equal levels of economic and industrial development. Argument that Kenya takes a bigger share of the inter community trade.
Different taxation policies i.e. Tanzania still insists on charging tariffs on Kenya’s exports.
Poor transport and communication linkages.
Lack of adequate information of what’s available in other countries.
Language barrier particularly the ban on use of Swahili in Uganda.
Restriction on movement of labour/people has limited the degree of movement of people and goods.
Note
Candidates can also be asked to suggest ways in which trade between the East African countries may be improved. Such a question seeks an understanding of how the above problem can be overcome. Diversification of goods Creation of East African Federation – Uniform currency introduction –synchronization of taxation – harmonization of economic policies – mobilization of domestic savings for capital formation
Reasons why Kenya imports some goods that she is also producing e.g maize, sugar, wheat
Kenya is not self-sufficient in these commodities because of high population.
Cane sugar produced in Kenya is sold at higher price than beet sugar hence Kenya makes a profit by importing beet sugar.
Crop failure (Unreliable rainfall) leads to shortages hence imports supplement the locally produced food crops.
Pressure on land has led to reduction in production thus necessitating importation.
Increased cost of farm inputs leads to low production, hence need to import the commodities.
Liberalization of trade encourages trade especially in sugar from COMESA member states.
Delayed payments and low prices of sugarcane have discouraged small scale farmers thus lowering production hence need to import.
Mismanagement of the sugar factories leads to their collapse hence need to supplement local supplies.
Pests and diseases reduce amount of wheat hence need to
Discuss five problems associated with international trade
Smuggling – involves importation and exportation of goods through black market, this denies the country the much need foreign tax earnings.
Dumping – this refers to the selling of goods in an external market at a price cheaper than that charged in the exporting country. It may lead to a decline in market for local goods due to the cheap imports.
Liberalization has led to the collapse of many local industries e.g Textile
Kenya’s exports are mainly agricultural and primary productswhich face quota restrictions.
The semi processed/raw material exported fetch low prices and are prone to acute price fluctuation as they face inelastic demand.
Unfavourable balance of tradedue to high import values against low export values.
Favorable and Unfavorable balance of Trade
Balance of trade refers to the difference in the value of a country’s visible exports relative to her visible import values.
Unfavourable balance to trade occurs when a country earns low export returns relative to high expenditure on expensive imports.
Measures to correct unfavourable balance of trade
Establishment of import substitution industries to reduce importation of commodities.
Development of alternative sources of energy (H.E.P, solar, biogas) to reduce expenditure on oil importation.
Encouraging local assembling of machines since importation of parts is cheaper.
Finding new markets for exports to avoid dependence on a few trading partners.
Diversification of exports.
Encouraging use of appropriate/local technology that does not require heavy machinery.
Encouraging exportation of locally manufacturing goods.
Increasing invisible trade e.g. shipping, tourism, insurance.
Restricting the importation of luxury items through higher taxation.
Encouraging the production of high quality/manufactured goods for export in order to earn higher income.
Ways in which the Kenya government is promoting export trade
The government encourages the production of high quality export goods and controls the quality of export goods.
The government offers customs draw-backs.
The government has established export processing zone.
The government has reduced import duty/tariffs on raw materials meant for export products.
Improved communication and transport network has enabled accessibility to export markets.
The government conducts overseas trade fair promotion to create awareness about Kenyan goods.
Removal of trade barriers and issuing of export license.
The government has introduced export compensation on export of traditional goods.
The government is allowing the exporters to retain foreign exchange earned through exportation of goods/export retentions account.
The government is encouraging foreign investors to establish industries in the country for production of export goods.
Signing of international trade agreements with COMESA, EAC with the aim of boosting export trade.
Ways in which Kenya can control dumping of goods.
Banning importation of substandard goods and counterfeit products.
Strict supervision on all imported goods.
Raising the import duties on all second hand or reconditioned goods.
Heavy penalties for those found floating the importation rules.
State four reasons why Kenya’s agricultural export earnings are generally low
Agricultural production depends more on the climatic conditions as well as incidences of pests and diseases. This leads to crop failures hence lo export earnings.
Kenya’s agricultural exports face quota restriction as well as strict health standards.
The exports are mainly in raw or semi processed hence of law value.
The exports also face stiff competition from those produced in other countries. This may further lower the prices due to overproduction.
Much of our exports face inelastic demand hence less in demand by the high income earners of the developed countries.
The agricultural exports are also bulky and attract high transport and overhead costs. This further reduced the export earnings.
The fluctuation in the world commodity prices is further worsened by Kenya’s inability to influence the prices in the world market.
Outline three negative effects of liberalization of trade in Kenya
Dumping of cheap, low quality goods in the local market.
It has limited the marker for locally produced goods.
It has led to unfair competition that has resulted in closure of home industries
It has encouraged smuggling of goods as well as black market trade in counterfeit goods.
Describe four ways in which Kenya benefits from the African Growth and Opportunity at (AGOA).
This is an initiative by the US government to promote the export business of the developing countries.
Offers employment opportunities to Kenyans who are engaged in the production of goods for export under the Act.
The increased volume of export trade generated foreign exchange.
The increased access to the US market has improved Kenya’s Balance of Trade
It has stimulated cotton growing in the country.
It offers guaranteed markets for Kenya textiles products
It has improved the standards of living through the income earnings
Past KCSE Questions on the topic
1. (a) State five reasons why the common market for Eastern and Southern
Africawas formed. 5mks
2. (a) What is international trade? 5mks
(b) Name major imports from Europe to Kenya 2 mks
(c) List factors that influence the import and export of goods in Kenya. 4 mks
(d) Explain ways through which Kenya will I benefit from the renewed East African co-operation. 6 mks
(e) Explain negative effects of international trade. 6 mks
3. (a) Explain four measures which Kenya may take to reduce the unfavourable
Balance of trade. 8 mks
(b) Explain four benefits that Kenya derives from international trade. 8 mks
4. (a) What is Trade? 2 mks
(b) Identify the two types of internal trade. 2 mks
5. State the factors influencing trade. 4 mks
6. (a) Differentiate between visible and invisible exports. 4 mks
(b) Draw a table showing the major visible export and imports of Kenya. 8 mks
7. Explain the significance of trade to Kenya. 5 mks
8. State the future on international trade in Kenya. 3mks
9. (a) What is a regional trading bloc? 2 mks
(b) Apart from the European Union, name three other regional trading blocs.
3 mks
(c) Outline the role played by the European Union in the economy of Europe.
4 mks
10. Explain why the Kenya’s exports are more to the outside world than her neighbors. 6 mks
CHAPTER TWELVE
Specific Objectives
By the end of the topic the learner should be able to:
(a) Define transport and communication;
(b) Identify modes of transport and types of communication;
(c) Locate the major lines of transport in Africa;
(d) Outline the role of transport and communication in the economic development of Africa;
(e) Discuss the problems facing transport and communication in Africa and the efforts being made to solve them;
(f) Explain the role of the Great lakes and the St. Lawrence Seaway in the economies of the USA and Canada.
Content
Definition of, and distinction between transport and communications.
Modes of transport and types of communication.
Distribution of major lines of transport in Africa.
The role of transport and communication in the economic development of Africa.
Problems facing transport and communications in Africa and the efforts being made to solve them.
A study of the Great Lakes and the St. Lawrence Seaway.
Definition
Transport is defined as the physical carriage and movement of goods and people from one place to another while communicationis the process of transmitting/ exchanging information between persons.
Modes of transport
Mode refers to the manner in which transport is carried out. There are three modes of transport namely;
Land transport
Water transport
Air transport
Land transport
This mode of transport involves movement of goods and people using units of carriage that move on dry land. The various means here include:
Human porter age
This involves human being carrying goods on their shoulders, heads or backs
Advantages of Human Porterage
Compliments other means of transport
Flexible as it has no fixed time table or routes.
May be a cheap means compared to other means of transport.
Readily available when required
Convenient over short distances.
Disadvantages of human porterage
Not suitable for long distances.
Add on congestions on the roads.
It is relatively slow.
Relies on human energy which is exhaustible.
Carts
Carts are opened vessels usually on two or four wheels that are pushed or pulled by either human beings or animals such as donkeys and oxen.
Advantages of Carts
Compliments other means of transport.
Relatively cheap to hire.
Initial buying and maintenance cost is low.
Appropriate in remote areas where other means are not available.
Readily available for hire.
Can carry fairly heavier and bulky goods.
Convenient for transporting goods over short distances.
Disadvantages of carts
May not be suitable for transporting heavy and bulky goods.
Cause traffic jams on roads leading to congestion and accidents.
Not suitable for transporting goods over long distances.
Vehicle
These are means of transport that ferry goods and people on roads. Matatus are the most commonly used in transportation.
Advantages of matatus
They supplement regular bus companies.
They fill up faster than buses hence save time.
They are more flexible since they can change routes easily depending on demand.
They reach out into the interior of rural areas where big buses cannot access.
They are more flexible with the fares they charge.
They are easier to hire as most of them are readily available.
They are cheaper to acquire as compared to buses.
Disadvantages of Matatus
Some matatus are poorly maintained to the extent of being unroad worthy.
Most drivers are reckless as they rush to compete for customers.
In some cases, touts use impolite language when dealing with passengers.
They may cause noise pollution such as unnecessary hooting and loud music.
They may cause congestion in towns unnecessarily because of careless driving and parking.
Uncalled for sudden increase in fares at peak hours, during the night and on public holidays.
Their operation is concentrated on peak hours, rarely operating at night.
They at times unexpectedly change their route hence causing breach of contract.
Advantages of Vehicles
Most readily available means of transport.
Relatively fast compared to carts and human porterage.
Relatively cheaper over short distances.
Flexible as it can offer door to door service.
Vehicles may be available for transporting special goods.
Roads are widely spread thereby making many areas accessible.
Transnational highways in Africa.
-The great North road – Cape Town, Zimbabwe, Zambia, Kenya (Nairobi), Tanzania, Uganda (Tororo), Sudan (Juba, Khartoum), Egypt (Atbara, Cairo).
-The Trans-Africa Highway – Mombasa, Uganda, Zaire, Cameroon, Central African Republic, Nigeria (Lagos)
Reasons for Establishment.
-To stimulate local, regional, international trade.
-Reduce remoteness.
-Reduce problems for land locked countries.
-Assist in transporting bulky goods.
-Stimulate contracts among African countries. 5
Benefits
-Have led to the growth of towns, ports.
-Enhanced International cooperation.
-Opened up remote areas.
-Provide employment of people.
-Facilitate international trade.
-Sources of revenue to governments (Toll fees).
Trains
Trains are vessels that transport goods and people on rails.
Advantages of Trains
Relatively secure as cases of theft and accidents are rare.
Enables a transporter to plan for the transport of his/her goods as trains follow a fixed time table.
Economical for transporting heavy and bulky goods over a long distance.
Trains may have facilities for carrying special type of goods. e.g. gas, petrol and vehicles.
Where shunting facilities are available trains may deliver goods up to or from the owners’ premises.
Disadvantages of Trains
Not flexible as trains follow a strict time table.
Railway lines are expensive to construct and maintain.
Not all areas are served by railway lines.
Not suitable for transporting urgently required or perishable goods as it is slow.
Unsuitable for transporting goods over short distances.
Trains are expensive to acquire and maintain.
Pipeline Transport
Pipeline transport is the movement of liquids and gases from one place to another through a pipe. Products transported through pipes included:
Water
Gases
Petrol
Diesel
Advantages of pipeline transport/advantages of transporting oil through pipeline.
Road accidents have reduced due to reduced congestion of tankers on the road.
Environmental pollution have been reduced as smoke from tankers has reduced/pipes do not emit smoke Polluters.
Road damage has reduced due to reduced heavy tankers on roads.
Reduced cost of handling oil due to few workers/employed /pipeline use machine mainly.
Pilferage of oil has reduced as it’s difficult to steal oil from the hard pipes that area underground.
Large volume of oil will be transported within a short time.
Ensure regular supply of oil hence reducing oil shortages.
Not easily affected by poor weather as pipes can be underground/permanently fixed.
Disadvantages of pipeline transport.
Not economical for small quantities.
Solid products are not transported through pipeline.
Can be easily targeted for sabotage.
A variety of product cannot be transported the same time.
Very expensive to put up.
Providing security has high costs
Monitoring pipeline is expensive
Heavy loses may be incurred if damaged is not discovered within a short time
May result in environmental degradation in case of damage
Reasons for a few railway links among African countries.
-Differences in rail gauges complicate connectivity.
-The countries were colonized by different European powers who constructed railway lines to transport raw materials from the interior to ports in their own colonies
-Political difference/political instability in some African countries hinder efforts to construct rail links.
-Lack of adequate capital for rail construction.
-Stiff competition from other means of transport which are cheaper, faster, flexible and have a wide coverage.
-They produce similar goods, this limits inter community trade.
-Parts of Africa are unproductive hence uneconomical to construct rail.
-Most of Africa is covered by a high plateau/mountainous which it expensive to construct rail.
Reasons why Road Transport in Africa is better developed than Railway transport.
-Roads are more flexible- door-to-door delivery.
-Cheaper to construct.
-Roads can be of different grades -loose surface, tarmac. Railways are built on specific gauges
-Road transport is faster.
-Roads carry small quantity of load, thus ideal for small-scale business. Railway requires bulky goods.
Water transport
This a mode of transport where the units of carriage, transport goods and people on water. The vessels using this mode include:
Ships
Dhows
Boats
Steamers
Ferries.
Water transport is divided into two
Inland water ways
Sea transport.
Inland waterways
This is a transport carried out on lakess,rivers and inland canals.Most rivers in Kenya are not navigable due to the following reasons:
Too small
Presence of rapids and waterfalls
Too shallow
Most are seasonal
High gradient.
Navigable rivers in Africa.
River Nile.
River Zambezi.
River Congo.
River Tana.
River Niger.
Reasons why river transport is less developed in Africa.
Most rivers are seasonal and therefore the water levels fluctuate making it difficult to sail.
Some of the rivers contain huge rocks/boulders/rock outcrops on their courses that reduce the navigable distance.
High siltation in the lower courses of some rivers makes their channels shallow to suffice river transportation.
Most rivers have short and shallow navigable stretches thus discouraging development of transport in them.
Some rivers flow in areas of low economic value/sparsely populated areas that have limited human activities.
Presence of waterfalls and rapids along the courses of some of the rivers hinder development of river transport as they have increased velocity of river water/very steep.
Reasons why inland water transport is not well developed in Africa.
Some miners are interrupted by waterfalls and rapids so are not navigable throughout.
Some rivers are seasonal and fluctuate in volume during the dry season.
Some rivers flow through climatically hostile areas for example river Congo.
Most of the rivers flow through shallow or too short therefore unsuitable for navigation.
Some of the rivers flow through climatically hostile areas which are eg little economic significance.
Many rivers tend to meander especially on the flood plain making distances longer than on land.
Season Transport
This is where goods and people are transported in seas and oceans.
Types of water vessels
Ships
Ships may be classified as either liners or tramps.
Liners
These are ships that are owned and operated by shipping companies called conferences.
Characteristics of liners
Have fixed routes.
Follow a fixed time table.
Charges are fixed.
Call at specified ports along the route at specified intervals.
Travel at regular intervals.
Tramps
These are ships that do not follow a regular route or time table.
Characteristics of tramps
Do not have a fixed rate.
Have no set time tables.
Their fares change according to demand.
Their travelling patterns are irregular and therefore cannot be relied upon.
Boats and ferries
These are water vessels used in transporting goods and people over short distance.
Advantages of water transport.
Sea transport is economical to the owner as the number of employees to carriage volume ratio is less compared to road transport.
Best for transporting heavy and bulky goods.
It is cheap as the way is natural and free.
Connects countries of the world which border the sea.
Special types of ships are available for transporting goods.
Large volumes can be carried thereby reducing cost per unit.
Disadvantages of water Transport
Sea-sickness, sea-pirates and storms may occur.
Not suitable for transporting perishable and urgently required goods.
It is expensive to construct and maintain artificial harbors.
Unfavourable weather conditions may affect water transportation.
Sea –transport is not accessible to land locked countries.
Lack of loading and off loading facilities may lead to delay.
Cost of acquiring and maintaining chips is high.
Distinguish between a Hinterland and an Entreport.
-Hinterland is an area served by a port or a ports sphere of influence i.e. where it draws its exports and distributes its imports.
-Entreport is a port where goods on transit are brought for temporary storage before being re-exported to another country.
Factors that led to growth of Rotterdam as a major sea port in Europe.
-Hinterland rich in minerals and heavy industries.
-Extensive hinterland such as France Germany, Switzerland, Australia, Czechoslovakia.
-Its location on the river mouths of Rhine & Meuse/deep harbours.
-The warm North Atlantic drift keeps the port ice free all year.
-It’s a major industrial town- engineering, oil refining, petrol-chemicals, food processing.
-Strategic location connects sea routes to and from America, Africa and other parts of Europe.
-Provision of modern port facilities i.e. container terminal, berths, canals, coal & oil terminals.
Differences between Rotterdam & Mombasa ports.
Mombasa Rotterdam
Is on an island -At the mouth of river Rhine, biggest in Europe.
Serves a developing & agricultural
hinterland -Serves a developed, highly industrialized
hinterland
Export cargo mainly agricultural & minerals. -Often manufactured, chemicals.
Imports manufactured goods, chemicals -Fuel, mineral raw materials, agricultural commodities.
Served by roads & railways. -Served by rivers. .
Limited volume of cargo. -Handles large volumes of cargo.
Factors that have favoured the growth of Kisumu as a port town.
-Being a terminus of Kenya-Uganda railway.
-Converging point of all roads of Western Kenya e.g. Kisumu-Busia; Kisumu-Homabay: Kisumu Kakamega.
-High population density of surrounding districts.
-Rich agricultural hinterland.
-As an administrative centre.
-Location on Lake Victoria easily connects E.African countries.
-Development of industries -Wicomico breweries, fishing attracts trade, employment.
Economic uses of rivers in Africa.
-Fishing ground.
– Transportation
-Provide water for irrigation, domestic use and industrial purposes.
-H.E.P. generation.
-Source of sand for construction.
-Source of minerals.
-Source of alluvial soils for Agriculture.
-Tourist attraction.
Factors that have hindered the development of river transport in Africa.
-Seasonality.
-Presence of rapids and waterfalls.
-Many are too short, shallow, and too swift/narrow.
-Silting at the river mouths hinders port development.
-Most rivers pass through unproductive areas hence its uneconomical to develop river transport.
– Inadequate technology.
-Presence of floating vegetation and dense vegetation along the riverbanks.
-Inadequate capital.
-Differences in political ideologies of countries through which rivers pass calls for negotiation.
Air transport
This is a mode of transport in which aeroplanes are used.
Advantages of Air Transport
There is less handling of goods on the way since aeroplanes may move direct to the final destination.
The way does not require construction or maintain as it is natural and free.
Planes can move though places where other means cannot.
Have efficient interconnections between airlines all over the world which makes it convenient.
Suitable for long distance travelers especially from one continent to another.
Suitable for transporting perishable and urgently required goods.
Disadvantages of Air Transport
Causes noise pollution.
Air fields are not available in all places.
Cannot be conveniently used to carry heavy and bulky goods.
Expensive to acquire and maintain aircrafts.
Requires highly trained manpower.
Unfavorable weather conditions may cause delay.
In case of accidents results are catastrophic.
It is expensive to construct and maintain airfields
It is an expensive means of transport in terms of freight charges.
Ways through which Kenya has benefited from her international air links.
-Promoted tourism.
-Promoted international trade.
-Creation of employment opportunities.
-Helps to generate revenue through taxation of goods & passengers at airports.
-Facilitates relief & emergency assistance (drugs, medical staff).
-Promoted international understanding by enabling Kenyans interact with people from other parts of the world.
-Promotes horticultural industry.
-Enables cultural exchange.
Containerization
It involves transporting goods packed in standard box like containers.
Advantages of containerization
Can carry large quantities of goods if properly arranged.
Minimal damage to goods as they are protected against weather conditions by the metallic container.
Goods are safe from theft and pilferage as containers remain sealed up to the point of destination.
Low insurance premiums due to reduced risks of theft and damage.
Easy of loading and off-loading due to use of handling equipment such as cranes.
Handing cost may be minimized due to use of modern technology.
Containers can be easily moved as they are fitted with appropriate handling devices.
it is possible to transport specialized goods using specialized designed containers
Disadvantages of containerization
Containers are expensive and this increases the cost of transporting goods.
Contributes to unemployment since it is capital intensive.
Not suitable for transporting small quantities.
Requires special handling equipment which may be expensive.
May not be suitable for goods with irregular shapes.
Problems faced by African states in trying to improve the transport system in the continent.
-Lack of adequate funds.
-Lack of adequate skilled man power and technical know how.
-Political differences.
-Civil wars destroy existing transport networks.
-Seasonality of rivers.
-Poor terrain (plateau, Rift Valley and thick vegetation.)
-Limited interstate trade.
-Mismanagement of funds for transport project
Use the diagram below to answer the questions that follow.
Name the canals marked S&M
S- Soo canal.
M- Weiland canal
C- River St. Clair
N- Quebec (port)
Lakes that make up St. Lawrence Seaway.
Superior
Michigan
Huron
Erie
Ontorio
List four obstacles that faced the navigation at the St. Lawrence Seaway.
-Existence of rapids and waterfalls.
-Existence of both shallow and narrow sections.
-Existence of different water levels.
-Existence of rocky Island with river channel.
-Freezing of the waterway in winter
-Frequent fog/ mist at the month of St. Lawrence were a great hindrance to shipping.
Describe four ways in which navigation was improved at the sea way.
-Constructions of canals to avoid rapids and waterfalls.
-Deepening/ dredging of the canals and channels to accommodate larger ships.
-Blasting of the rocky Islands.
-Use of ice breakers during winter when water is frozen.
-Locks were constructed along the seaway to regulate the flow of water as well as the movement of vessels.
-Installation of radars and fog lights on ships.
Explain three ways in which the Great Lakes – St. Lawrence Sea way has Contributed to the economy of Canada and U.S.A.
-It provides cheap means of transport for both imports and exports, thus encouraging internal/ international trade.
-Industrialization of the area such as pulp and paper, steel manufacturing, agricultural processing, engineering. (Due to accessibility of raw materials.)
-Increased trade between U.S.A. & Canada and the rest of the world.
-Niagara Tourist attraction -The Niagara Falls is the world’s spectacular waterfall.
-Source of employment in the transport industry.
-Has led to development of sea ports and towns which have become focal points for various economic activities. (Toronto, Montreal, Detroit.)
-The dams along the route provide H.E.P.
-Tariffs charged earn the countries income.
Canals found along St. Lawrence seaway.
– Soo canal
– Welland canal.
– Newyork State berge canal
– Sault St. Marle canal.
– Nipssing canal.
– Rudan canal
Reasons why the St. Lawrence seaway project was set up
To remove rock shoals, rapids and several islands in the river channel that hindered navigation.
To deepen the river channel and regulate the difference in the lake level.
To construct dams to generate H.E.P and regulate the flow of the river.
To construct locks among the route to regulate the flow water as well as movement of the vessels.
To construct canals by-passing the sections with rapids and waterfalls along river St. Lawrence.
Principal products\ cargo handled at the sea way.
– Grain, Petroleum, Iron Ore, timber, Coal; Iron and Steel; Textile
Recent developments that have taken place in Kenya to improve communication of information.
-Liberalization of air waves\ licensing of more private radio\ TV stations.
-Introduction of E-mail\ Internet, Telefax.
-Introduction of cell phones\ pagers\ wireless phones.
-Liberalization of the press.
-Expansion of telephone facilities\VSAT.
-Liberalization of postal services.
-Cable network connections.
Communication
Means of communication used in Kenya.
– Cell phone / mobile phone / telephone.
– Fax
– Telex
– Telegram
– Email
– Internet. (2 x 1
Explain three problems facing telephone as a means of communication in Kenya.
-Development of other faster and more efficient means of communication e.g. E-mail has led to reduced use of telephones.
-High cost of installation and maintenance of telephone lines limits the number of subscribers.
-Vandalism of telephone equipment renders most of telephone services unavailable to would be users.
-Lack of modernization of telephones/ obsolete telecommunication equipment.
-Poor reception/ network congestion.
Problems facing communication in Kenya.
Inadequate capital to install communication equipment.
Language barriers due to diverse ethnic backgrounds / low levels of education.
Inadequate communication facilities.
Vandalism of communication equipment / wars.
Inefficient communication systems /Networks failure.
Examples
Use the map of Africa below to answer the following questions.
Name the highways marked X and Y.
Name the port marked M.
Name the country marked S.
Solution
Highways
X –Trans-Saharan highway
Y – Trans Africa highway
M – Dakar
S – Chad
Reason for difficulties in transporting goods from Mombasa to Lagos.
Traffic charged at border points increase transportation costs.
There is long distance between the two parts which would take a long time.
Some parts of the highway are impassable during wet seasons.
There are civil wars / banditry along the way e.g. DRC
There are political differences and hostilities between some countries through which the highway passes. (2 x 1 = (2mks)
Four ways in which road transport has been improved in Kenya.
– Construction of highways to accommodate more traffic and improve traffic flow e.g. Nairobi – Mombasa highway, Thika Superhighway.
– Construction of by-passes, flyovers in Nairobi and along Thika Super Highways to reduce congestion and improve traffic flow.
– Rehabilitation and maintenance of major roads to reduce road accidents and improve traffic flow.
– Control of loads carried by trailers and large lorries by traffic police to reduce damage on road surface.
– Educating road users on road safety precautions and discipline on roads to ease traffic and to reduce road/accidents.
– Enforcing traffic rules to reduce road accidents and regular traffic flow.
Four reasons why motorcycle transport has become common in most parts in Kenya.
– Motorcycle offer services into areas than the inaccessible by motor cycle.
– Motorcycles are more affordable than vehicles.
– Motorcycle are cheaper to maintain than vehicles.
– Most roads to the interior of some parts of the country are narrow making motorcycles the most suitable means of transport.
– Motorcycle require minimal skills to ride so many people are able to use them
A Road By-pass is a road / highway which avoid a town or residential areas to avoid traffic jam.
Roles of transport and communication in Africa.
Opens up large areas creating large markets for goods and services.
Creates employment opportunities.
Promotes tourism.
Helps in exploitation of natural resources.
Promotes regional cooperation and specialization.
Promotes urbanization.
Adds value to goods and services.
Earns the country revenue through taxes
Past KCSE Questions on the topic
TRANSPORT AND COMMUNICATION.
1. State the causes of the decline in the use of letter writing as a means of communication in Kenya. 5 mks
2. (a) Give three advantages of railway over road transport. 3 mks
(b) The map below shows the extent of the oil pipeline in Kenya. Use it to answer question (b).
Name the towns marked X and Y which are served by the pipeline. 2 mks
(c) State two disadvantages of using pipelines as means of transporting oil.
(d) Use the map drawn below of St. Lawrence sea way to answer the questions that follow.
(i) Name the towns A and B
(ii) Name lakes X, Y, Z
(iii) Name canal marked V 3.
3. Use the sketch map of Lake Victoria below to answer question (a).
(a) Name the lake ports marked P, Q, and R 3 mks
(b) Outline two advantages of using containers while handling goods at the port of Kisumu. 2 mks
4. (a) Give three reasons why road transport is used more than air transport in
East Africa. 3 mks
(b) In what three ways does Kenya benefit from air links with the rest of the world? 3 mks
5.Use the map of East Africa below to answer question (a).
(a) Name the railway terminuses marked P, Q and R. 3 mks
(b) Give the main commodities transported by the railway lines marked Sand T. 2 mks
(c) Name the port marked U and the lake marked V. 2 mks
(d) State four reasons why road network is more widespread than railway network in East Africa. 4 mks
(e) One of the problems facing road transport is the high frequency of accidents. Explain four conditions of roads in Kenya that may lead to accident. 8 rnks
6. Give four benefits of the efforts the government is data in streamlining pubic transport sector. 4 mks
7. Outline two major problems affecting the development of trans- African highway in Africa. 2 mks
8. State two major problems hindering river transport in Kenya. 2 mks
9. Suggest three benefits of the proposed Southern bypasses to be constructed in Kenya. 3 mks
10. (a) Define containerization.
(b) Outline three merits of using containerization as a method of transportation. 3mks
11. (a) State three problems facing railway transport in Kenya. 3 mks
(b) Identify importance of railway transport in a country. 4 mks
12. Differentiate between ‘transport’ and communication. 4 mks
13. Apart from cell phones, mention other two modern methods of communication.
2 mks
14. State advantages of using cell phones communication. 3 mks
15. State reasons why St. Lawrence sea way was set up by the government of USA.
4 mks
16. (a) Define:
(i) Transport
(ii) Communication 4 mks
(b) Apart from water transport, list the other modes of transport. 2 mks
(c) Name the two types of waterways used in transportation. 2 mks
17. (a) Give three reasons why river transportation in Africa is poorly developed.
3 mks
(b) Name the major ocean routes of the world. 3 mks
(c) State the advantages of water transport. 6 mks
18. (a) Account for the poor rail linkages j, between the African countries. 2 mks
(b) Name three trans-continental rail lines in Africa. 3 mks
(c) What are the advantages and disadvantages of transporting goods by rail?
6 mks
19. (a) Why is railway transport less used in Africa? 4 mks
(b) Name two railway systems in Africa. 2 mks
(c) Discuss the advantages and disadvantages of railway transport. 4 mks
20. State the advantages of road transport. 4 mks
21. (a) What is containerization? 2 mks
(b) Discuss advantages and disadvantages of containerization. 6 mks
(c) State advantages and disadvantages of air transport. 6 mks
22. Identify the main types of communication. 4 mks
23. (a) Name two trans-African highways 2 mks
(b) What are the benefits of trans-African highways? 2 mks
(c) Explain the problems facing the trans-African highways. 4 mks
24. Discuss the role of transport and communication in economic development of Africa. 4 mks
25. (a) State the problems facing transport and communication in Africa. 4 mks
(b) Outline the efforts being made to solve these problems. 4 mks
26. (a) (i) Identify the obstacles that face navigation along the St Lawrence
seaways. 3 mks
(ii) State ways in which navigation on the seaway was improved. 4 mks
(b) Explain the benefits of the St. Lawrence seaway on the economies of the United States of America and Canada. 6 mks
26. Below is a map of Africa showing major trans-continental highways in Africa.
(i) Name the highway marked A and B (2mk)
(ii) Name the towns marked C,D and E (3mks)
CHAPTER THIRTEEN
Specific Objectives
By the end of the topic the learner should be able to:
(a) Define population;
(b) Explain the factors influencing the distribution of population is East Africa;
(c) Explain the factors influencing population growth;
(d) Describe population structure;
(e) Analyses the consequences of population growth and structure;
(f) Compare and contrast population trends between Kenya and Sweden;
(g) Present population data using relevant statistical graphs.
Content
Definition of population
Factors influencing the distribution of population in East Africa.
Factors influencing population growth with specific reference to the fertility, mortality and migration.
Population structure.
Consequences of population growth and structure.
Comparative studies of the populations of Kenya and Sweden.
Definition:
Human population refers to the total number of people living in a given area e.g. district,province or a country.
– This number is determined by taking population census.
– The study of population is termed Demography.
Sources of population data
– Data on population can be obtained both from primary as well as secondary sources.
Primary sources of population data
Registration of persons (births, deaths, marriages) helps determine birth and death rates, infantmortality, refugees.
Sample surveys – are based on representative samples of the total population to secure desired information such as fertility rates, people attitudes towards family planning, breast feeding etc.
Censuses – Refers to the total process of collecting, compiling and publishing demographic data at a particular time. It involves physical enumeration of the entire population in an area. Census gathers wide variety of information relating to the;
Physical characteristics in terms of sex, race, birthplace and tribe.
Social characteristics such as marital status, religion, education, housing, language.
Economic characteristics- occupation and income.
Secondary sources of population data
– Secondary sources include Statistical abstracts, Published/ unpublished reports and tally tapes.
Factors influencing population distribution in East Africa
Climate
– Areas with extremely low and extremely high temperatures discourage settlement and influence population pattern since the cannot support the growth and development of various agricultural activities
– High rainfall areas (of above 1000mm) have high population density/densely populated because the high rainfall favour the growth of a variety of food crops. Plenty of food grown support a large population while cash crops attract a large labour force
ii. Relief
– High altitude areas of above 2500m above the sea level have low population due to the extremely low temperatures that do not favour settlement and growth of crops
– Very steep areas e.g. around escarpments have low population density due to the difficulty in putting up buildings. Farming is also difficult due to impacts of soil erosion and landslides
– Flat areas and depressions are less attractive for settlement because they exhibit poor drainage leading to swampy conditions and flooding – prone to water borne diseases that attack human beings
iii. Soils
– Areas with fertile, well drained volcanic soils that allow arable farming e.g. the Kenya highlands are densely populated because the soils encourage the growing of a variety of crops that attract large populations
– Areas with fertile alluvial soils have attracted dense settlement e.g. around Lake Victoria
iv. Drainage
– Well drained areas attract settlements hence have high population density because they are free from water borne diseases
– Swampy and waterlogged areas are uninhabited since they cannot support farming and settlement
– Areas prone to flooding are less settled/have low population densities since floods displace people and destroy property and life
v. Incidences of pests and diseases
– Areas prone to pests such as mosquitoes and tse tse flies that cause diseases e.g. malaria and sleeping sickness respectively have few people settled there because such diseases may weaken and kill human beings and livestock.
vi. Government policy
– A government can influence the distribution of its population by creating settlement schemes to settle the landless or resettling people from areas of dense population concentration.
Vii. Land ownership
– Places where people own large tracts/parcels of land area sparsely populated compared to places where land is owned communally that has dense population
viii. Urbanization
– Urban areas are densely populated due to presence of employment opportunities and improved social amenities compared to the rural areas.
Population growth
– This refers to the change that occurs in the number of people in a population over a given period of time.
– It can be negative by having a decrease in the population or positive by having an increase
– It is detected after comparing successive census reports
– Census refers to the enumeration or physical counting of the whole population of an area taking care of demographic, social and economic factors at a given time and place.
– Census may be conducted after 5 to 10 years; in Kenya it is conducted after 10 years
Importance of conducting a population census
– It gives the characteristic features of a population in terms of age, sex, ethnicity, education and occupation
– Provides information on trends and levels of fertility and mortality thus helping the government in the provision of basic amenities
– Helps the government in division of administrative units
Problems of population census
– Expensive to conduct
– May be inaccurate/unreliable especially when informants give false information to the enumerators
– Some people may be counted more than once or omitted during the exercise
– Population growth can be calculated in two ways namely
(a) Natural population growth
(b) Numerical population growth
(a) Natural population growth
CBR
– This refers to the number of births per 1000 persons in a population
CBR = (Total Number of Births in a year)/(Total Population recorded in the year) x 100
CDR
– This refers to the number of deaths in an year against 1000 by the total population
CDR = (Total Number of Deaths in a year)/(Total Population recorded in the year) x 100
– CBR and CDR are referred to as crude because all other characteristics of the population e.g. age and sex are not considered
– Natural population growth is given by
Natural Population Growth =(CBR-CDR )/1000 X 100
(b) Numerical Population Growth
– This is the absolute or actual increase in the number
– This is the absolute or actual increase in the number of people in an area within a given period of time
– It is calculated every 10 years by getting the difference between two census/can also be expressed as a percentage
Factors influencing population growth
Fertility
– Refers to the number of live births a woman has during her reproductive period
– The ability to conceive and give birth to a child whether or not live birth or still born is called fecundity. Inability of the same is infecundity/sterility
– Infertility is the inability of a woman to bear a child. (can be primary or secondary)
– Fertility is influenced by factors such as
Level of education of women.
Urbanization
Career prospects.
Birth control/family planning measures
– Fertility rate is the ratio of live births in an area to the population of that area expressed per 1000 population in a given year/total number of births/children a woman would have during her reproductive period (15 – 49years)
– Kenya experiences a high fertility rate because of
Improved health and nutrition services.
Weakening of some traditional values.
Cultural factors e.g. sex preference, polygamy, early marriages, naming of relatives, need for more children for prestige, leads to high child bearing period.
Economic factors e.g. need for a large pool of family labour and security in old age.
Lack of effective family planning practices due to ignorance/inaccessibility/use of traditional ineffective birth control methods.
High mortality rates therefore need to reproduce for replacement
Causes of decline in Kenya’s fertility rate due to
More girls are attending school leading to reduced early marriages.
Urbanization has led to high cost of living; people thus prefer smaller families.
Modern career opportunities.
Increased use of birth control measures.
Increase in the number of women opting to remain single
Mortality
– Refers to the death among members of a population
– It reduces the population and affects its structure and composition in terms of age and sex
– May be caused by
Outbreak of war/warfare.
Famine.
Floods.
Diseases/epidemics
– Death rate is the average number of deaths per 1000 persons in a population
– Death rate in many countries, Kenya’s inclusive is declining because
Improved health care provision.
Improved diet
Migration
– Definition: – this is the movement of people from one place/region to another resulting in a change of residence temporarily or permanently
– Can be voluntary or forced
– Can be within a country – internal migration or across countries – external/international
– International migration may involve emigration (from your country to another) or immigration (from other countries into a country).
General reasons/causes of migration
Pressure on land – has pushed people to other areas in search of land.
Availability of employment opportunities has led to rural – urban influx.
Religious conflicts/ persecution of specific religions / sect groups force the members to migrate to safe place where they can practice their religion without interference.
Political unrest, persecution, wars etc. This accounts for influx of refugees and increasing numbers of internally displaced people.
Natural calamities – floods, disease, earthquakes, famine, drought, lightning etc.
Government Policy – relocation of people to create room for projects such as schools,irrigation schemes, forest/ games reserves.
Types of migration
(a) Internal migration
– Refers to the movement of people within a country
– Include
Rural to urban
– Involves the movement of people from rural areas to urban areas/centres
– Mainly involves the youth
– Reasons for rural to urban Can be push or pull factors.
Pull factors Push factors
Transfers Insecurity
Better living standards High incidences of disease.
Opportunities for better education and health.
Lack of adequate land.
Recreation Unemployment.
Attractions of Urban life Diminishing returns on land.
Better paying white collar jobs Rural hard living conditions.
Industrial centralization in towns Low wages/ low prices of farm produce force some people to abandon farm work and seek alternative sources of income in the towns
Push factors
Insecurity.
High incidences of diseases.
Lack of adequate land.
Unemployment.
Diminishing returns on land.
Rural hard living conditions.
Low wages/ low prices of farm produce force some people to abandon farm work and seek alternative sources of income in the towns.
Inadequate social services – hospitals, schools,sporting facilities
Urban to rural
– Involves movement of people from urban areas to settle in rural areas due to
– Involves movement of people from urban areas to settle in rural areas due to
Transfer from urban places of work to rural areas.
Search of employment if industries are established in rural areas.
After retiring/retrenchment from service.
To avoid unbearable life in the urban areas/unemployment.
Urban to urban
– Involves movement of people between towns/urban centres – from one town to another due to the following
Change of profession
Job transfers.
Leisure.
Investment in a new town.
Search of higher education and better healthcare.
Rural to rural
– Involves movements within people from one part of a country to another within the rural –side.
Reasons: –
Population pressure which leads to land fragmentation has led to migration of people to settlement schemes and less populated rural areas in search of land.
Insecurity in areas such as North Eastern, Mt. Elgon has forced people to move to safer areas.
Establishment of large plantations (Mwea, Ahero) attracts people from the neighborhood as they search for employment.
Pastoral communities ( Maasai, Borana, Samburu) migrate from one rural area to another in search of pasture and water for their livestock.
Inheritance of land /land disputes cause people to move and settle elsewhere..
Natural catastrophes – floods, disease, famine in Kano and lower Tana cause people to move to more secure higher grounds.
Government policy of moving people from one rural area to another to create room for government projects
(b) External migration
– Also known international migration involves the movement of people across international borders so as:
Pursuit of higher education.
International job offers.
Warfare/Refugees/political unrest.
Tourism.
Visiting relatives overseas/attending international conferences.
Political persecution/political asylum
Effects of migration
(a) On the origin
Shortage of labour on the farms leading to reduced food production hence food shortage.
Imbalance in the male to female ratio as most migrants are males. This may result to family break ups.
Under development in the rural areas.
Depopulation especially if the migration is forced
(b) On the destination
Increase in population.
Economic development in an area especially if the migrants are engaged in meaningful income generating activities.
Increased cases of crime from migrants who fail to secure employment.
Pressure on existing social amenities.
Presence of refugees would drain the resources of a country/insecurity as some refugees may engage in unlawful practices
Problems which result from the high population growth rates in East Africa
High dependency ratios as the youth outnumber the working population. This slow down economic growth due to greater consumption expenditure.
Unemployment since population growth surpasses the rate of employment creation.
High population exerts pressure on land this leads to environmental degradation such as soil erosion, cultivating wetlands/ water catchments, land fragmentation and landlessness.
High population growth leads to pressure on basic facilities/social amenities e.g. schools,health facilities, recreational facilities, power rationing and perennial water shortages.
High population growth creates market for goods and services.
Leads to importation of food stuffs due to food shortage thus draining foreign exchange earnings.
High population growth may lead to unemployment forcing many people to turn to crime and other social delinquent behaviors (immoral practices).
High rates of migration.
Congestion in towns and cities leading to traffic congestion and mush rooming of slums.
Discuss six measures that the government may use to control high rate of population increase.
The family planning association of Kenya (FPAK) had been established to coordinate family planning programmes.
Effective family planning campaign. To this end family planning programmes and clinics have been set up to provide information to families.
Use of mass media to create public awareness about the demerits of a large family.
Advocating for late marriage particularly in some communities which practice early marriages.
Effective birth control measures and facilities have been introduced e.g. provision of free contraceptives.
In corporation of family life education in the formal school curriculum to sensitize youth on dangers of premarital sex.
Seminars Barazas are help to disseminate information on the need to plan facilities.
Establishment of National Council for population Development to co-ordinate population studies activities..
Causes of high death rates in Kenya.
Poor diets mean there is less immunity to disease.
Inadequate medical facilities reduce the ability to treat sick patients.
Congestion and poor living conditions cause the spread of disease.
High prevalence of malaria and HIV and Aids.
Tribal clashes, road carnage etc
Describe the measures that have been taken in Kenya to reduce infant mortality rate
Infant mortality refers to the number of deaths of children below age one year per 1000 of the population.
Measures
Improving medical facilities and immunization of children to control diseases. This has enhanced child survival rates.
Providing free malaria control drugs and distribution of free treated mosquito nets to expectant mothers and children below 5 years of age.
Intensified research on infant related diseases to come up with ways of controlling them ensures higher chances of survival.
Providing education for parents on better child care practices.
Introduction of family planning programmes has led to emergence of manageable sizes of families which promote higher chances of children survival.
Improved diet to children through the Malezi Bora campaigns.
Effective control of mother to child transmission of HIV /Aids virus has enhanced child survival.
Free pre-natal clinic has led to more births attended to by trained health care providers.
Population trend
– Refers to the various changes that take place in a population of a given country and their impact on socio – economic environment
– These changes go through demographic transition i.e. historical changes in birth rate and death rate from high to low
– There are four phases of demographic transition face i.e.
a.) Stage 1 – involves little or no increase in population
b.) Stage 2 – characterized by high birth rate, decline in death rate and high population growth rate – Kenya is at this stage
c.) Stage 3 – decline in birth rate, low death rate and moderate population growth
d.) Stage 4 – low birth rate and low death rate, population growth rate is low leading to population replacement. The population becomes static and can only produce to replace dying one.
Factors leading to slow population growth
– Warfare that leads to death among members of a population/migration
– Epidemics/outbreak of diseases
– Famine as a result of prolonged drought
– Family planning practices/late marriages
– Emigration
– Natural calamities
– Socio – cultural factors.
Under population is a situation where the population is too small for the full utilization of the available resources. In this circumstance, a higher population could be supported without a fall in living standards.
Causes of under populations
– Strict birth control measures.
– legalized abortion
– Late marriages
– High cost of living
– Preference for a smaller family size
– Government policy
– Proper family planning programmed/ fully embraced
– High levels of female literacy
– People are busy pursuing education and careers
– There is a high rate of emancipated women
– There is low rate death and infant mortality.
Problems resulting from under population
– Small labour force may lead to importation of foreign expatriates.
– Underutilization of existing resources such as schools, hospitals
– Slow growth of industries due to the small market and shortage of labour force.
– Un-even distribution of population causes regional imbalance in a country.
– Rural depopulation caused by high influx to urban areas lead to abandonment of same areas of farms. This creates remoteness as it becomes uneconomical to lay infrastructure in such sparsely populated areas.
– Urbanization – Urban sprawl has engulfed land which would otherwise be suitable for agriculture.
Optimum population
Refers to the size of population which is considered to be the most desirable for the full utilization of its natural resources and which yields the highest standard of living.
Over population– refers to a situation where an area has a higher population than its available resources can support.
Problems of over – population in developing countries
– Mass unemployment
– Poor housing hence emergence of slum and gather settlements
– Poor health care, malnutrition spread of diseases
– Slow growth of industries consequent upon prevalence of unskilled labor, poverty.
– High dependency ratio
– Erosion of social/moral fabric and values.
– Strain on infrastructural facilities/existing social amenities (perennial water and power rationing).
Population Density
Refers to the ratio between the size of an area of land and the number of people living there usually expressed as the average number of people per square kilometer.
Average population density = (Total population)/(Total area)
Factors influencing population distribution
These factors can be grouped as climatic, soil, historical, economic and strategy/ government policy.
High rainfall areas have high population density while areas of extreme temperatures area are avoided.
Vegetation.
Topography and relief. Gentle slopes are preferred for ease of movement.
Drainage- availability of surface water..
Areas prone to diseases are avoided.
Development of industries attracts more people due to the employment opportunities.
Area prone to insecurity are largely avoided.
Transport and communication.
Mining areas and towns attract more settlements.
Historical factors e.g. early settlements encouraged growth of towns which became focus for migration.
Factors influencing population growth
Population growth is largely a factor of Fertility, Mortality and Migration.
Fertility refers to the ability a woman to give birth to a live child.
Fecundity – is the physiological capacity of a woman to conceive and give birth to a child regardless of whether it’s a live or still birth.
Fertility rate– is the total number of births that a woman would have during her productive age (15- 49 years)
Causes of high fertility rates and birthrates
a.) Cultural factors.
– Sex preference
– Polygamy
– Early marriages give longer child bearing span of life
– Need for more children for prestige
– Naming of relatives.
– Religions encourage natural procreation and oppose family planning.
b.) Economic factors
– need for a large pool of family labour
– Security in old age and defense
c.) Lack of effective family planning practices due to ignorance/inaccessibility/Use of traditional ineffective birth control methods.
d.) High mortality rates therefore need to reproduce for replacement
f.) Increased longevity i.e. the average age to which people of a country expects to live
g.) Improved medical facilities / health care reduce mortality rates.
h.) Improved nutrition/ diet.
Population Structure
– This refers to the characteristics and composition of a given population in terms of age and sex at a given time
– It is graphically represented using an age sex pyramid
– Population pyramids have different shapes depending on the population structure and the demographic stage of the country.
The importance of Age – Sex pyramid
It reveals the composition of the population by age .This information is useful in planning for provision of amenities for different age groups.
Reveals the dependency ratio .This is vital in determining tax relief.
May reveal population growth rate which could help determine future population trends for policy planning.
Can also be used in the attempt to understand historical events that may have affected the country in the past.
It reveals sex ratio i.e. number of males per 1000 females which could help to understand the social and cultural behavior of people e.g. polygamy.
The following information can be obtained from a population pyramid.
– Different age – group
– Proportion of male to female
– Proportion of depending ratio = Children + old people / working population.
– Size of the population.
– Composition of the sex.
– Proportion of the young
– Ageing population.
Characteristics of the Age-Sex pyramid for a developing country.
The Age –sex pyramid has a broad base which tapers off with increasing age. The broad base implies a large number of young populations. Partly due to the high birth rate.
The tapering off the population pyramid towards the top shows a relatively high death rate throughout the age groups with a much higher one at the early age of below 15yrs.
Characteristics of population in a developing country
High birth rate and high mortality rate.
Low life expectancy (51 yrs).
The population of old people is very low 0.75% – 80 yrs).
A high percentage of population comprise of young people below 15 yrs.
High dependency ratio 47.3 % depends on 52.7%.
High infant mortality rate
Characteristics of Age sex pyramid for a developed country.
The pyramid has a narrow bottom bulges out in the middle and a bit wide at the top.
The narrow base implies low birth rate.
A broad bulge in the older age group reflects a high life expectancy – over 80 yrs.
A large percentage comprises older age group over 64 yrs 17%, over 80 yrs 5.3%.
Characterized by a low mortality rate.
There is a low population growth rate.
There is low dependency ratio 37% depending on 63% working population
Example
The pyramid below represents the population structure of country X.
Describe the characteristic of the population represented by the pyramid.
The number of male and female population is almost equal at all levels.
From 0-14 yearrs, the population is low.
From 15-44 years the population is high.
The ageing population is low i.e. 60 years and above.
The population has a high longevity above 80 years.
The dependency ratio is low.
The population has a low birth and death rates.
45-59 middle age is low.
Kenya’s population pyramid
– Over 60% of the population comprises of youth below 20 years old – this depicts a high birth rate.
– About 5% comprises of older people over 65years old this depicts high death rate/low life expectancy/High infant mortality rate.
– The population has high dependency ratio i.e. proportion of unproductive population (below 20 years and above 65 years) in relation to productive age
Dr = (C-OP)/WP
Dr = Dependency Ratio
C = Children
Op = Old Population
Wp = Working Population
– Females comprises of 60% while males about 40%
Implications of a young population
1. High demands for unproductive goods e.g. Toys, Sweets.
2. Increases demands for social amenities e.g. maternity facilities.
3. High dependency ratio because of the unproductive group being very high.
4. High causes of juvenile delinquency – street children pick pocketing.
5. Increase in large numbers of unemployed people.
Population of Sweden
– Sweden has a low population density of 20 people per square km.
– Swedish population mainly lives in the urban areas
Factors influencing population distribution in Sweden
Relief- a large proportion of the country is mountainous, steep slopes with thin soils, the subsoil is permafrost. Population in the highlands is low and scattered.
Climate– 60% of the population is found in the warmer southern part with fertile soils the north is avoided due to chilly climate cold winters and snow covering most of the areas.
Forests account from 55% of the land especially steeps slopes.
Drainage- Sweden has a dense drainage e.g. small numerous lakes/rivers such areas are avoided.
Mining centre – have high densities due to immigrants who provide labour.
Urbanization– Urban centers form nucleated settlement e.g. Stockholm, Gutenberg and Norrkoping and most of population live in urban areas
Population growth of Sweden
– Sweden is in the final/fourth stage of demographic transition i.e. the birth rates equal the death rates
– It experiences a slow population growth rate because
Move towards smaller families due to high costs of living.
Introduction of birth control measures.
Improved health/medical care facilities.
Urbanized population thus the need for fewer children to maintain a high living standard
Population Structure of Sweden
– Draw the age sex pyramid for Sweden on Certificate Geography Bk 4 pp 214
– It is a developing country and its population is characteristic of the following
The pyramid has a narrow bottom bulges out in the middle and a bit wide at the top.
The narrow base implies low birth rate.
A broad bulge in the older age group reflects a high life expectancy – over 80 yrs.
Characterized by a low mortality rate.
There is a low population growth rate.
There is low dependency ratio 37% depending on 63% working population
Comparison between population in Kenya and Sweden
Kenya Sweden
Consists of young people below 20yrs of age has an ageing population.
Has low life expectancy has high life expectancy
A high percentage population lives in rural areas most people live in urban centers
Experiences a high population growth rate Experiences a slow population growth rate
High fertility/birth rate Low fertility/birth rate
High dependency ratio Low dependency ratio
High death/mortality rate Low death/mortality rate
Effects of ageing population
Ageing population has a large number of old people aged 65 years and over which may have the following effects.
Increased dependency ratio.
Increased cost of health care for the aged who are prone to ill health..
Shortages of man power/ labour in some professions.
Underutilization of already set up social facilities for the young people
Provision of pension poses financial problems.
High degree of occupational and geographical immobility amongst the aged.
Older people many resist social – economic and scientific changes.
There is a heavy burden on the community i.e. they demand more sick leaves.
Production will be turned towards goods used by the old.
Lack of natural regeneration of population
Problems rendering population census data unreliable
– Shortages of funds make it difficult to employ enough personnel and acquire other necessary equipment.
– Insufficient and inaccurate census area maps and questionnaires.
– Fear/ Suspicion/ Superstition etc all of which may lead to falsification of information regarding the number of children
– Illiteracy may lead to wrong information being given relating to age of children.
– Problem of double counting.
– Lack of documents on vital data like birth and death certificates which could enable enumerators to verify the information given.
– Problems of language barrier / accessibility that may lead to omission.
– Political maneuverings.
– Inadequacies of enumerators – poor training
Past KCSE Questions on the topic
1. (a) State four reasons why the northern parts of Kenya are sparsely populated.
4 mks
(b) Give two primary sources of population data 2 mks
(c) What information can be derived from a population pyramid? 4 mks
(d) Describe three ways in which the population of Kenya differ from those of Sweden. 6 mks
(e) Explain four causes of rural-urban migration in Kenya. 8 mks
2. Explain three problems which result from the high population growth rate in the East African countries. 6 mks
2005:
3. List three factors that have contributed to a decline in infant mortality in Kenya. 3 mks
4. Explain two reasons why Thika District has a higher population than Murang’a district. 4 mks
5. (a) State the reasons for carrying out population census. 5 mks
(b) How the following factors lead to population increase in Kenya.
(i) Early marriages
(ii) Improved medical facilities
(iii) Cultural beliefs. 6 mks
6. The pyramid below represents the population of country X. Use it to answer question (a).
(a) Describe the characteristics of the population represented by the pyramid.
4 mks
(b) Explain three problems which may result from a high population growth rate. 6 mks
(c) Describe THREE measures that have been taken in Kenya to reduce infant mortality. 6 mks
(d) Explain four factors that have led to a high population density in Lake Victoria basin. 8 mks
7. a) Define the term population. 2 mks
(b) Explain factors influencing population distribution. 6 mks
8. (a) Explain factors influencing population growth. 8 mks
(b) Describe the main features of population structure of a developing country. 4 mks
9. Explain the factors leading to high fertility levels in a population. 6 mks
10. Compare and contrast population trends between Kenya and Sweden. 8 mks
11. The table below shows population distribution in Kenya by province in 1999. Use it to answer the questions below.
Province Population Area in Sq Kms
Nairobi 2,143,254 696
Central 3,724,159 13,220
Rift Valley 6,987,036 182,539
Western 3,358,776 8,264
Nyanza 4,392,264 12,547
Coast 2,487,264 82,816
Eastern 4,634,779 153,473
N. Eastern 962,143 128,124
Table 9.3 Population of Kenya by Provinces
(a) Calculate the population density of each province. 2 mks
(b) Give reasons why there is a high population density in Central Province of Kenya. 3 mks
CHAPTER FOURTEEN
Specific Objectives
By the end of the topic the learner should be able to:
(a) Define settlement and urbanization;
(b) Explain the factors that influence settlements and settlement patterns;
(c) Account for the distribution of major urban centers in East Africa;
(d) Explain the growth and functions of selected towns in Kenya;
(e) compare and contrast selected urban centres in Kenya with those of other parts of the world;
(f) Discuss the effects of urbanization.
Content
Definition settlement and urbanization.
Factors that influence settlement and settlement patterns.
Distribution of major urban centres in East Africa.
Factors influencing the growth of major urban centres in East Africa.
A study of an industrial town in Kenya (Thika), a lake port (Kisumu) and an agricultural collection centre (Eldoret).
Comparative studies of (a) Nairobi and New York and (b) Mombasa and Rotterdam ports.
Effects of urbanization.
Definition;
Settlement refers to a place housing units where a group of people live.
– Involves villages and towns/urban centres and the infrastructure and the human activities that take place in them
– Can be rural or urban
(a) Rural Settlements
– Are built in the countryside.
– Include farmsteads, villages and all the activities in them
– Are occupied with primary production activities e.g. mining, lumbering, fishing, livestock keeping, crop production, etc
– Their main function is to house agricultural & fishing population (in case sited along fishing grounds e.g. rivers, lakes, oceans
(b) Urban Settlements
– Urbanization is the growth and spread of towns and town life
– Are occupied with industrial and commercial activities
– Have dense population
– Trading is the main activity
Factors influencing location and pattern of settlements
– Are physical and human
(a) Physical Factors
Climate
– Rainfall and temperature are the major climatic elements that influence the distribution and patterns of settlement because they determine people’s economic activities
– Areas with high, reliable and well distributed rainfall e.g. the Kenya Highlands/Central province have high concentrations of settlements because they support the production of a variety of food and cash crops
– Hot and dry areas e.g. northern/north eastern Kenya have low densities of settlement as they receive low and unreliable rainfall and high average temperatures that cannot support production of cash/food crops
Relief/topography
– Areas with rugged terrain i.e. steep slopes/mountain tops have low densities of settlement because they have thin soils to support growth of crops. It is also difficult and expensive to put up housing units. They are also cold/experience low temperature
– Gentle slopes e.g. plateaus and lowlands are heavily settled because they are suitable for farming and construction of housing/infrastructure
– Landforms such as mountains create a rain shadow effect. Windward sides receive high rainfall thus have more settlement compared to the leeward sides
Soil fertility
– Areas with fertile, well drained alluvial/volcanic coils attract high densities of settlement because they allow production of a variety of food and cash crops
iv. Environmental diseases
– Regions infested with environmental diseases e.g. sleeping sickness have low concentration of settlements as they are avoided by people due to fear of contracting diseases
v. Vegetation
– Thick vegetation e.g. forest may discourage establishment of settlements as they may not be easily accessible and can be habitats to disease causing organisms and dangerous animals
vi. Drainage/presence of water bodies
– Rivers and springs with clean water may attract settlement as they provide water for domestic uses
– Swampy and marshy areas discourage settlement as they are hosts to disease causing organism and it’s also difficult/expensive to put up housing units
(b) Human Factors
Political factors
– Tribal wars/civil strife may displace people from their original homes/places of residence and be settled in other areas e.g. refugee/IDP camps
ii. Historical factors
– In the historical times, many communities settled in areas that were safe/secure from hostile communities.
– They also lived in groups
iii. Economic factors
– Settlement of nomadic pastoralists are temporary, scattered and at times moveable
– Permanent settlements are found in areas where people are engaged in arable farming and formspecific pattern
– Concentrated settlements are found in mining and fishing areas as people settle around to provide labour
– Establishment of manufacturing/processing industries lead to growth of settlement to provide labour to the industries
iv. Government policy
– A government of a country may create new schemes of settlements to its population for reasons such as giving land to establish a plant/scheme, ease pressure on existing social amenities, etc
Settlement Patterns
– These are layout/arrangement of dwellings/housing units in a particular place.
– Major settlement patterns include; nucleated, dispersed and linear
(a) Nucleated settlement pattern
– This consists of a cluster of dwellings, shops and other buildings in one place
– The buildings are close to one another forming a cluster/nucleus that can either be a mining centre, oasis, water pan or a water reservoir
– The buildings may be permanent of semi permanent.
Reasons for development of a nucleated settlement pattern
Security especially in banditry/cattle rustling prone areas.
Presence of social amenities e.g. schools, health care facilities, etc.
Inadequate/insufficient land for expansion leading to clustering.
Existence of an industrial plant and/or natural resources e.g. mineral works, rich agricultural soils, etc
(b) Dispersed settlement pattern
– Consists of scattered, widely set and randomly distributed housing units especially in the countryside/rural areas
– The housing units are separated by physical features e.g. rivers, valleys and ridges
– They occur in areas with large land parcels and even or rolling landscape
– The can also be permanent or semi permanent
Reasons for the development of a dispersed settlement pattern
Presence of adequate land for expansion and settlement.
Good/improved security over a wide area.
Presence of evenly distributed water points/resources.
Areas with even/rolling landscape e.g. plains/plateaus experience a uniform soil fertility across the region, people will settle anywhere without being limited to relief features
(c) Linear Settlement Pattern
– Formed when people build housing units along communication lines such as roads, railway lines, water pipeline or along specific physical features e.g. a river, a canal or along a coastline
– The housing units appear to be arranged in a line along the communication infrastructure
Reasons for the development of a linear settlement pattern
Ease of means of transport.
Coastline/lake shore provide favourable fishing ground.
Water body provides water for domestic uses
Urbanization.
The process by which a population is transformed from rural based agricultural lifestyle to urban based non-agricultural lifestyle.
Process whereby an increasing population of the total population in a country settles in towns.
Process through which towns and cities grow in number and size.
Distribution of major urban centers in East Africa
Nature/Functions of Urban centres Description Examples
Capital Towns/Cities
Administrative Towns
Cities
– Main seat of the governments
– Houses the national assemblies
– Administrative headquarters
– Headquarters of government
ministries, organizations and
agencies
Have city council status
– Houses diplomatic missions
and international
organizations, referral
hospitals
– Offer specific services – Nairobi – Kenya
– Kampala – Uganda
– Dodoma – Tanzania
– All provincial and district
headquarters in Kenya
– Dodoma, Morogoro – Tanzania
– Fort Portal – Uganda
– Nairobi
– Dar es Salaam
– Kampala
Nature or function of urban centres. Description Examples
Sea ports
Lake Ports
Industrial Towns
Mining Towns – Located along the Indian
Ocean shores of East Africa
– Assists in sea/water transport
Located along the shores of
Lake Victoria
– Assist in water transport
– Processes raw materials into finished products.
-Involved with mining
activities/mineral extraction – Mombasa and Malindi – Kenya
– Dar es Salaam, Tanga, Lindi, -Tanzania
– Non in Uganda – landlocked
– Kisumu – Kenya
– Mwanza, Kigoma, Musoma –
Tanzania
– Bukoba, Jinja, Masindi -Uganda
-Thika, Athi River – Kenya
– Tororo, Jinja – Uganda
– Tanga – Tanzania
– Magadi, Kakamega – Kenya
– Shinyanga – Tanzania
– Kilembe, Tororo – Uganda
Factors favouring the growth of major urban centres in East Africa
Rural – urban migration:- many youth upon completion of secondary and tertiary education migrate to the major towns of East Africa in search of employment opportunities. This leads to the expansion of the facilities in the urban areas to carter for the increased population
Industrialization:- establishment of industries in the urban centres attract people as they offer employment opportunities. As industries expand, people move closer and settle near them to provide labour.
Natural population growth:- this is due to high birth rates and relatively low death rates in most of the East African countries. This because most of the migrants are in their reproductive age.
Infrastructural development:- most urban centres in East Africa tend to grow due to development and improvement of transport and communication network i.e. most are accessible by good roads, railway lines, airports and waterways. This enables import/export trade, accelerates migration and avail social amenities and recreational facilities.
Administration:- regional, district and provincial headquarters lead to the development of urban centres as government employees are posted to provide services. Also administration offices and workers’ houses are built leading to expansion of the towns.
Agriculture:- makes a town to grow in the following ways:
Provide market for the industrial products from the urban centres.
Provide food for the urban residents.
Provide the raw materials for the industries established in urban areas
As such urban centres located in rich agricultural lands grow faster
Mining: – attracts workers who move and settle near the mineral works. The mining company takes up the responsibility of providing the workers with social facilities leading to expansion of towns e.g. Magadi Town (soda ash mining).
Tourism:- the influx of tourists in a town may lead to its growth/expansion because of high demand for hotels, social and recreational facilities
Ways in which a country benefits from urbanization.
• It encourages national unity as people of various nationalities/ethnic backgrounds come together.
• Creates employment opportunities through the establishment of commercial and industrial activities.
• Leads to development of infrastructure both within and the surrounding rural areas.
• Encourages the provision of social amenities (recreational, water, power).
• Provides market for agricultural and industrial goods produced within a country.
Urban Morphology
• It refers to the internal structure and arrangement of towns. It is concerned with the physical shape of towns, their history of development, variations in land uses and functions within tons.
Internal Structure of an ideal urban centre/urban zoning
– This is based on functions of the urban centre, governing urban policies, physical conditions of the site and historical background of the urban centre.
– Involves zoning i.e. classifying urban centres on the basis of land use within them.
– Urban centres are zoned into
(a) Central Business District
– Also known as the town centre/downtown
– It is centrally located in the urban centre
– Has the highest concentrations of the tallest buildings/vertically extended buildings
– Has high rental values
– House are mainly income generating
(b) Transition Zone
– Surround the CBD
– Has older buildings – may be replaced by expansion of the CBD
– Suitable for activities requiring proximity to the CBD
– Land values are slightly low
– Include shopping malls, government offices and wholesale outlets
(c) Industrial Zone
– Border transition zone
– Forms the industrial centre
– Located next to railways/ports to ease transport of raw materials and finished products
(d) Residential Zone
– Houses workers hence located close to industrial zones
– Starts with low class residential estates to middle and high class
(e) Commuter Zone
– Emerges into the surrounding rural areas
Case Studies of Sample Towns in Kenya
A. Thika
– This is an industrial town
– Has many industries e.g. processing & canning of pineapples, Fabrication of metal containers, Motor Vehicle Assembly, cooking fat making and coffee processing amongst others
Factors favouring the growth and development of Thika as an industrial town
– Excellent road networkthat connects Thika to Nairobi, Mombasa, Mwingi, Garissa, Murang’a, Nyeri and Nanyuki enables the movement of raw materials and finished products to and out of the industries. Thika is also linked to Nairobi by railway
– Strategic location:- Thika enjoys proximity to the capital city – Nairobi. Many investors from Nairobi find it cheaper and more convenient to invest in Thika because the land rates are low and it is also surrounded by economically rich hinterland of Kiambu, Murang’a and Maragua.
– Thika is surrounded by agriculturally productive districts that supply the residents food and raw materials for some industries
– The town is sited near rivers Chania and Thika that readily supply water for irrigation, industrial and domestic uses
– Existence of expansive land for industrial growth – Thika is located in an open place that is sparsely settled giving room for expansion of industries
– Nairobi’s industrial area is already congested and many investors therefore prefer to establish industries in Thika as an alternative to Nairobi
– Existence of cheap local labour as Thika is surrounded by regions of high population densities that provide a large pool of cheap local labour to the industries
– Hydro electric power from the Seven Forks Dam on River Tana provide electricity for industrial and domestic uses
– Adequate social amenities e.g. hospitals, schools, colleges etc attract people to settle there
Other functions of Thika are administrative, educational, tourism, religion, recreational and residential
B. Kisumu
– This is third largest town in Kenya
– The largest lake port in East Africa
Factors favoring the growth and development of Kisumu as a lake port
– Strategic location at the shores of Lake Victoria making it the main commercial and industrial focus of western Kenya and gateway to Uganda
– Location at the shores of Lake Victoria ensures adequate water supply for domestic and industrial uses
– Presence of many industries e.g. fish processing, textiles, breweries, soft drink making, boat making and repair etc have made people to settle around the industries to provide labour
– It is the terminus of the railroad from Indian Ocean to Lake Victoria thus supporting large volumes of trade in western Kenya and the landlocked Uganda etc
– The port is surrounded by densely populated areas providing ready labour for the industries
– It is surrounded by a rich agricultural hinterland that provide raw materials for the development of industries
Other functions of Kisumu include:- education, administration, tourism, recreation, religion, residential, and industrial
C. Eldoret
– This is an agricultural collection centre
– Located in the highlands on the western side of the rift valley
– Originally it was a centre for collecting agricultural produce from the surrounding farms in Trans Nzoia and Uasin Gishu
Factors for the development of Eldoret Town as an agricultural collection centre
– Strategic location along the Nairobi Kampala international trunk road through Malaba border and proximity to Southern Sudan & Uganda has made it a major export town
– It is located in a rich agricultural hinterland that is well served with road, railway and airport making transportation of agricultural produce faster
– Key collection and export facilities e.g. inland container depot has enhanced the capacity of Eldoret as key agricultural collection centre
– Availability of H.E.P encouraged establishment of industries-tanning, textile, milk processing, soft drinks, plywood making.
– The high population in surrounding areas provides a pool of labour and ready market.
– The presence of river Sosiani provides reliable water supply.
– Presence of educational institutions-Moi university, Eldoret polytechnic, Baraton University.
– There was plenty of land for expansion of the town and industries.
– Some industries were established as art of government’s decentralization policy.
– The establishment of service industries (banks, insurance)
Other functions of Eldoret include education, recreation, tourism and industrial
Related Studies of Nairobi and New York Cities
Nairobi
– This is the capital city of Kenya and the largest urban centre in East Africa
– It grew from a railway camp established in 1899 during construction of the Mombasa Railway
– It gained city status in 1962 and today it is one of the most metropolitan cities with international reputation
– It is the headquarters of many international organizations e.g. UNEP, ILRI, ICIPE, ICRAF,
HABITAT, etc
Factors that influenced the growth of Nairobi City
– Nairobi is the leading industrial city in Eastern Africa. It has many industries that attract many people for employment opportunities
– Nairobi is linked to East Africa by efficient transport and communication network e.g. JKIA that
connects it to the rest of the world; Wilson Airport for domestic and regional flight. Also roads,railway lines, inland container depot and a pipeline terminus
– Administration centre: – Nairobi is the capital city and the main seat of the government of the Republic of Kenya, houses the parliament and headquarters of Nairobi County (Province)
– Internationally recognized centre: – has conference centre KICC that hosts international meetings and headquarters of many international organizations e.g. UN, ICRAF, ICIPE
– Education Centre: – hosts many educational institutions e.g. schools, universities, tertiary educational institutions and draws students from Eastern Africa and beyond
– Immigration: – Nairobi is a major destination for local and international immigrants who come into Nairobi to seek employment and invest/trade
– Tourism: – Nairobi is attractive to tourists because of its central position within East African air transport network and also has good tourist facilities e.g. hotels and recreational centres Problems facing Nairobi City
– Traffic congestion leading to traffic jam during rush hours leading to loss of time
– Unemployment due to large number of employees against few job opportunities
– Inadequate housing due to rapid population growth results to increased rents/development of slums
– Uncontrolled disposal of liquid/solid wastes lead to water and land pollution
– Lack of/few public utilities/social amenities e.g. acute water shortage; their provision doesn’t match population increase
– Criminal activities e.g. mugging, prostitution, drug trafficking, etc due to high rates of unemployment and slow economic growth
New York City
– This is the largest and most cosmopolitan (contains people of different types from different countries, and influenced by their culture) urban centre in North America
– Situated at the estuary of Hudson River on the islands in Atlantic Ocean
– Has a population of over 10million people
Factors favouring the growth of New York City
– Great Sea Port: – New York is the world’s most known sea port handling about 30% of all trade in North America
– Transport & Communication: – New York is connected to all parts of the world by sea routes, canals,international airports and railways. It also handle the greatest import-export trade in North America
– International Centre: – New York is the headquarters of several international organizations e.g. UN, IMF and World Bank
– Well planned internal city structure: – New York City has a unique street pattern i.e. shorter distances between any two places in a series of right angled segments that enables fast movement of traffic and pedestrian into, out of and within the city. There are also subways and electric trains that are popular and cheapest transport means
– Industrial centre: – New York is the leading industrial centre in North America
Functions of New York City
– Finance and Trade – New York Stock Exchange
– Cultural and recreational – clubs, pubs, national park
– Transport and communication
– International centre
– Industrial centre – ship building, oil refinery, publishing, etc
Problems facing New York City
– Inadequate space for expansion because the city is mostly located on islands
– Unemployment and underemployment since most immigrants are unskilled/employment opportunities less than the available labour force
– Pollution due to heavy industrial wastes and exhumes from several motor vehicles
– Development of slums/ghettos due to inadequate housing
– Traffic congestions
– Terrorist attacks
– High crime rates especially drug trafficking/abuse due to higher rates of unemployment
Similarities between Nairobi and New York Cities
– Both are international centres
– Both are industrial centres
– Both are transport and communication centres
– Both are financial/commercial centres
– Both experience similar problems
Differences between Nairobi and New York Cities
Nairobi City New York
It is an inland/dry port
It is a national capital.
Leading industrial town in Eastern Africa It is a seaport
It is a state capital.
Leading industrial centre in North America
Related Studies of the ports of Mombasa and Rotterdam
Mombasa
– This is the largest sea port in the coast of East Africa and the second largest town in Kenya.
– It is partially situated on the mainland and partially on Mombasa Island.
– It started as a small settlement during the slave trade era – as a resting place and a calling port for the long distance traders
– The growth and development of modern Mombasa was influenced by the beginning and eventual construction of the Kenya – Uganda Railway in 1896
– Today, Mombasa is one of the best ports in East Africa with modern port facilities for handling import – export trade
Factors influencing the growth of Mombasa Port
(a) Deep and well sheltered harbour:- The deep water on Mombasa and Kilindini creeks provides a good, well-sheltered natural harbour with large berths for docking and anchoring large vessels. The berth area is also free from coral reefs
(b) Strategic location:- Mombasa is centrally located in the Eastern Africa and connected to the major sea routes of the world. This has made it an important port of call – ships serviced/service crew rest
(c) Large hinterland:- a hinterland is an area served by a port; from which it derives its exports and within which it distributes its imports. Mombasa’s hinterland is large and rich covering Kenya, Eastern and Central Africa. The hinterland is rich in agricultural produce and mineral wealth exported through it and crude oil/finished products for imports making it an entreport
(d) Establishment of oil refinery and other industries:- port of Mombasa handles more crude oil from Middle East due to the establishment of oil refineries at Changamwe and Kilindini
(e) Modern Port Handling Equipment:- Kilindini Harbor and the port of Mombasa are well equipped with modern facilities for handling bulk cargo
(f) Tourist and cultural centre:- Mombasa boasts of many features of tourist attraction ranging from historical sites, sunny and sandy beaches, warm weather, scenic beauty and rich cultural and architectural origin
Rotterdam
– Rotterdam, city in the south-west Netherlands, a port on the Maas River near The Hague, 30 km (19 mi) from the North Sea.
– Rotterdam is one of the major seaports of the world. It is directly linked to River Rhine and to the Waal and Meuse rivers, which extend inland into Belgium and Germany.
– Rotterdam is the principal centre of overseas trade for the Netherlands and for the industrial Ruhr district of Germany.
– This is the largest port in the world and the most important entreport in Europe
Factors for the growth and development of Rotterdam as an international entreport
(a) Large and rich hinterland: – the port of Rotterdam covers a large hinterland from Luxembourg, Netherlands, Germany, Belgium, Switzerland, France and Austria. It is also connected to many parts of interior Europe through navigable rivers e.g. Rhine, Rhone. It therefore handles to and from the wide hinterland
(b) Suitable location: – Rotterdam is centrally located at the point of sea routes to and from Europe, Asia and the Americas. This has made it an important port of call
(c) Warm weather:- the coast of Rotterdam is washed by the warm North Atlantic Drift Current making it free from ice TOTY thus allowing port operations even during the winter
(d) Modern port handling facilities: – new and modern port handling facilities have been put at the port of Rotterdam. These include container terminals, loading off equipment. These make it handle large cargo volumes and serve many ships at a time
(e) Deep harbor and canals:- several canals have been constructed as early as 1872 that are deep and free from silt. Over the years, the canals have been dredged and widened to accommodate larger/wider vessels. Also a new out port – Euro port that is deep and large has been established at the Rotterdam.This improved its capacity to handle larger volumes of trade.
Comparison between ports of Mombasa and Rotterdam
Mombasa Rotterdam
Exists on an island
Port operations are less mechanized
Relies on road, railway, air and pipeline transport
Exists on mainland
Port operations are highly mechanized
Relies on road, railway, air and pipeline transport in addition to canals of Rhine River
Mombasa Rotterdam
Exports mainly agricultural/unprocessed goods.
Imports manufactured/finished products
Has limited space for expansion
Serves a developing agricultural hinterland Exports mainly manufactured products.
Imports fuels, minerals and agricultural commodities.
Still expanding – has a Euro port.
Serves a developing and highly industrial hinterland
Effects of Urbanization
Environmental degradation
– Urban centres have many industries, motor vehicles and other activities that lead to pollution e.g.
a.) Land pollution:- garbage from institutions, households and open markets deposited on land
b.) Air pollution:- smoke emitted from motor vehicles and industries
c.) Water pollution:- dumping of solid/liquid wastes into water bodies
Solution: Recycle, treat, proper waste disposal, creation of public awareness, develop national environmental standards
Unemployment
– Rural – urban migration leads to the influx of job seeking youths to urban centre against fewer job opportunities leading to unemployment and increase in dependency ratio.
Solution: – decentralization of industries, develop rural areas, encourage self employment, jua kali industries.
Increased crime
– Many of the unemployed youth end up engaging in criminal activities e.g. prostitution, thuggery,drug abuse/trafficking, impersonation to earn a living
Solution:Increased police surveillance, encourage use of security devices e.g. CCTV camera, stiff penalty for the offenders
Traffic congestion
– Most urban centres in developing countries have poorly planned roads and traffic control systems. They also have many motor vehicles that lead to congestion in most of the roads especially during rains and state of emergency
Solution: – encourage use of public transport, installation of traffic lights, control of tunnels, bypasses, flyovers, use of electric trains
Breakdown of family units
– Most urban centres have larger concentration of males compared to females as many males migrate to the urban centres in search of job opportunities leading to separation of family units
Strain/pressure on social amenities
– Due to the high population growth rate in many urban centres in developing countries, there has been a strain on the existing social amenities e.g. health care facilities, schools due to overusing.
Inadequate housing facilities
– Rural – urban migration has caused a shortage in housing. This has this has led to a sharp increase in house rents and the development and establishment of slums and squatter settlements that lack basic facilities, they are congested and prone to diseases
Solution: – funding for high-rise, multi storey flats, building of low cost housing for the urban poor, expansion of urban boundaries into suburbs, establishment of housing finance institutions
Past KCSE Questions on the topic
The diagram below represents the functional zones of urban centre. Use it to answer question (a)
(a) (i) Name the zones marked X and Y. 2 mks
(ii) List three functions of the Central Business District. 3 mks
2. (a) Name two types of human settlements. 2 mks
Use the sketch below to answer question (b)
(b) Settlement patterns marked Q A R. 2 mks
3. (a) Name two types of rural settlement patterns. 2 mks
(b) Apart from urban-rural migration, name two other types of migration.
2 mks
(c) State three factors that may lead to urban-rural migration. 3 mks
4. State three factors which led to the development of Mombasa into a major sea port in the region. 3 mks
5. (a) What is urbanization? 2 mks
(b) Give two differences in the functions of New York and Nairobi cities.
4 mks
6. Apart from pollution, explain four problems experienced in urban centres. 8 mks
7. Explain similarities and differences between Nairobi and New York cities. 8 mks
8. State two main functions of rural settlements. 2 mks
9. Explain four problems that are experienced in Nairobi as one of the major urban centres in Kenya. 4 mks
10. List three factors that have led to rapid growth of Mombasa town. 3 mks
11. State ways through which the Kenyan government is using to solve problems of Nairobi city. 5 mks
12. (a) Differentiate between the terms settlement and urbanization. 4 mks
(b) Identify factors influencing settlement. 4 mks
(c) State the factors influencing patterns of settlement. 5 mks
13. (a) By use of relevant examples, explain the distribution of urban centres in
East Africa. 5 mks
(b) Explain 4 human factors which may lead to development of towns.
14. (a) Explain factors leading to the growth of Kisumu as a LakePort. 8 mks
(b) What are the functions of Thika town? 5 mks
15. Explain the problems facing New York City. 6 mks
16. (a) Outline the main differences between the cities of New York and Nairobi.
4 mks
(b) Compare the port of Mombasa to the port of Rotterdam. 8 mks
17. Discuss the effects of urbanization. 4 mks
CHAPTER FIFTEEN
Specific Objectives
By the end of the topic the learner should be able to:
(a) Define management and conservation;
(b) Explain the importance managing and conserving the environment;
(c) Name environmental hazards;
(d) Assess the impact of selected environmental hazards and suggest measures of combating them;
(e) Discuss measures taken in managing and conserving the environment.
Content
Definition of management and conservation.
The need for environmental management and conservation.
Environmental hazards.
Problems associated with, and measures of combating floods, lightning, windstorms, pests and diseases and environmental pollution.
Environmental management and conservation measures in Kenya.
Field work on any aspect of environmental pollution.
Definition of Environment
– Environment means the surrounding conditions that influence the behaviour and survival of living things
– It is divided into physical and human environments. The physical environment which includes the natural physical conditions of weather, climate, vegetation, animals, soil, landforms and drainage
– Human activities if not controlled may destroy the physical environment
Management
– Environmental management refers to the effective planning and control of the activities that could cause deterioration of the environment.
– It involves the wise and skillful utilization, maintenance and improvement of natural resources for the present and future generations
Conservation
– Environmental conservation refers to the protection, preservation and proper utilization of natural resources in the environment, guarding them from destruction, wastage or loss by careful use of the environment
Need for Environmental Management and Conservation
To sustain human life;- depend on environment for food, water, shelter, air and clothing.
To preserve genetic resources/protection of endangered species to ensure their sustainable utilization.
For future generation: – the resources will be able to regenerate and serve future populations.
For economic value:- a lot of natural resources in the environment are of economic importance e.g. minerals, soils, forests, etc. They should be exploited carefully so as to be preserved for future use.
For aesthetic value:- components of physical environment e.g. rivers, lakes, mountains, valleys, wildlife amongst others are beautiful to see. They should hence be managed and conserved so that they attract tourists hence a source of revenue to the governments
Environmental Hazards
– These are occurrences in the environment that cause disturbance in the equilibrium of the ecosystem
– They can be human induced or naturally occurring
– They may disrupt life in the environment, cause damage/loss to property and life
– They include the following
a.) Floods
– A flood is a covering with or an overflow of large amount of water over dry land.
Causes of floods include: –
When a river’s discharge exceeds the maximum capacity of its channel/when a river contains excess water which it cannot hold within its channel, the excess water and sediments spill over the river bank onto surrounding areas.
Rise in sea or lake levels due to increased rainfall, resulting in the water spilling and covering nearby lowlands.
Exceptionally heavy rainfall e.g. the El Niño results in excess water on land that collects in shallow basins/flat areas .
When a massive earthquake occurs at the sea bed, causing a tsunami that results into the flooding of coastal lands
– During floods people, animals, homes and the general infrastructure are drowned or killed. Many people get displaced in the process, the water resources are polluted through contamination by dirty flood waters. In some cases, floods may lead to landslides burying people and their property
– In Kenya, the following rivers are characteristic of floods Nyando, Nzoia, Tana, Kuja and Sondu – Miriu, Ewaso Nyiro, etc
Controlling/combating floods
Avoiding flood areas: – people living in flood prone areas area being encouraged to relocate to safer/higher grounds to prevent loss of life and property.
Diverting river channels: – some river channels have been diverted and meander loops cut off to control the flow of the rivers.
Land use zoning:- the government may evict people in flood prone areas leaving them for other developments e.g. setting up irrigation schemes, making bird sanctuaries, etc.
Afforestation: – planting more trees to increase vegetation growth especially in water catchment areas to reduce surface run offs and increase infiltration .
Building of artificial levees: – these consists of soil fill ups along the banks of some rivers to contain flood flow within the river channel.
Construction of dams: – these are built to create large water reservoirs that hold large amounts of water upstream preventing it from flooding. The dams can be multipurpose e.g. used for HEP generation, irrigation, fish farming, etc.
Building of dykes: – these are high walls made of concrete and built far from the river channel to protect the low lying areas from flooding by stopping the invasion of river water inland.
Dredging: – involves the removal of the deposited silt at the river bed and also widening the river channel artificially so as to increase its capacity
b.) Pollution:
– This is a state where foreign harmful substances interfere with the quality and composition of the environment hence endangering the survival and existence of humans, plants and animals
– the added impurities onto the environment are called impurities/pollutants and may be gaseous, liquid and solid
– The main types of pollution are air, water, land and sound
Air Pollution:- is the pollution of air in the atmosphere. This may involve industrial and natural activities. Examples include emission of toxic gases, dust and ash particles.during volcanic eruption. Industrial activities result in emission of harmful gases e.g. sulphur dioxide, carbon monoxide, nitrogen and hydrocarbons into the atmosphere through quarries, cement and paper factories. Motor vehicles also emit poisonous gases into the atmosphere
Water Pollution:- water in the rivers, lakes, oceans and seas may be contaminated through the following processes
Disposal of wastes from homes e.g. sewage/kitchen/solid wastes into the water bodies.
discharge of industrial effluents into water bodies.
Emission of hot water from industrial/HEP plants into the waters of a river or lake.
Oil spillage from motor vehicles/automobiles left to flow over land into water bodies or from water moving vessels e.g. ships
All these interfere with the aquatic life in the water bodies as well as making the water unfit for human consumption
The other sources of water pollution are; bathing/washing in rivers/lakes, agricultural fertilizers and sprays, acid rain, washing vehicles in lakes, abattoirs, etc
Land Pollution:- is the deterioration of the state of land by addition of harmful and poisonous wastes. It occurs when solid wastes e.g. polythenes, paper, glass, metal, plastics, vegetation and food remains are disposed carelessly on the ground. It also occurs through derelict land left after mining. These materials make the environment ugly, dirty and stinking
Sound/Noise Pollution:- occurs when some human activities results in the production of excessive and unwanted sound of disturbing nature. Sound pollution is caused by the following
Motor vehicles through hooting and roaring sounds of engines
Sound from steel rolling mills and metal fabrication e.g. welding.
High pitched music from discotheques, vehicles, dance halls, etc.
Blasts from mines and fireworks from celebrations e.g. Diwali Aircrafts landing and taking off in the airports
Measures of combating pollution
Creating public awareness among the people through mass media on the consequences of environmental pollution.
Encouraging people to use non motorized transport e.g. walking over short distances, use of bicycles, etc.
Imposing high import charges of high capacity vehicles to discourage the same.
Campaign on the use of unleaded fuel to promote cleaner environment.
Wearing of protective gears in areas prone to air and sound pollution.
Industries to conduct environmental impact assessment to establish the effects of their activities on the environment.
Encouraging recycling of wastes e.g. paper, cans, water and glass.
Prohibiting public smoking/setting up smoking areas in public places.
Encouraging use of alternative energy sources e.g. biogas, solar energy, etc that cause less pollution compared to petroleum.
Encouraging safe and hygienic disposal of solid wastes e.g. compost pits, man holes and incinerators.
Encouraging use of compost and organic manure in farming
Lightning:- a flash, or several flashes, of very bright light in the sky caused by electricity. It can lead to loss of life and property and even cause fire if it strikes. It can be controlled by installing lightning arresters in buildings found in lightning prone areas
Pests & Diseases:- pests are animals, birds or insects that are harmful to other plants and animals. Diseases affect plants, animals as well as people. Pests and diseases are environmental hazards because they destroy crops resulting to food shortage/famine. Pests include locusts, army worms, rodents, birds, weevils, mites, ticks, tse tse flies, mosquitoes and fleas. The major disease that is an environmental hazard is the HIV/AIDS scourge
Seismic disturbances/earthquakes: – include the trembling of the crustal rocks due to seismic waves. When they occur, they interfere with drainage, transport, communication and settlement. They may be associated with landslides that may bury people/property. They are also associated with tsunamis.
Tropical Cyclones/Windstorms:- are very strong winds that develop due to great differences in atmospheric pressure on the ground. They travel very fast/at very high speeds hence very dangerous. They include hurricanes (Caribbeans), Typhoons (Far East), Willy Willies (Australia) and Tornadoes (North America). They develop into storms which cause great destruction of property and even life.
Volcanic Eruptions:- volcanic activities are usually violent resulting to damage of property and loss of life especially if the volcanoes are active or dormant. The lava flow usually spread fast to nearby settlements burning and burying people. Some volcanoes emit poisonous gases into the environment that may lead to global warming.
Drought and Desertification:- drought is a situation whereby an area gets a rainfall deficient period followed by prolonged drought. Desertification is slow and steady encroachment of desert conditions on land that was once agriculturally productive. They lead to hunger and famine as a result of food shortage as the national food reserves are depleted.
Civil Strife/Ethnic Clashes:- ethnic conflicts e.g. cattle rustling and ethnic conflicts. These cause great damage to natural resources such as wildlife and biodiversity
Environmental Management and Conservation Measures in Kenya
Public awareness and education on the need for environmental management and conservation through school system and media.
Setting up laws/legislation against pollution e.g. the water act that ensures certain water catchment areas are protected by declaring them as reserves, factories act that requires factories to ensure wastes from them are free of dust and other emissions, effluents treated before being released into water bodies.
Setting up bodies e.g. NEMA through the Ministry of Environment to ensure environmental impact assessment is conducted by various factories and to control measure that may lead to pollution.
Afforestation and re-afforestation programme.
Protection of water catchment areas through gazetting forest reserves.
Agro- forestry is being encouraged.
Introducing environmental education component in the school curriculum to educate future generations.
Use of filters in the chimney to filter carbon soot.
•
Past KCSE Questions on the topic
1. (a) Why is it necessary to conserve water? 3 mks
(b) How does terracing help in water conservation? 2 mks
2. (a) Apart from desertification, name two other environmental hazards
experienced in Kenya. 2 mks
3. (a) Name three physical regions through which river Tana passes. 3 mks
(b) Name two rivers in Kenya to the West of the Rift Valley which causes large scale flooding. 2 mks
(c) Explain four problems caused by floods. 8 mks
4. (a) Define the term pollution. 2 mks
(b) Explain three effects of land pollution on the environment. 6 mks
(c) State four ways through which Sand pollution can be controlled. 8 mks
5. (a) State ways in which drought affects the agricultural sector in Kenya. 4 mks
(b) What is soil conservation? 2 mks
(c) State three farming methods that assist in soil conservation. 3 mks
6. State three factors contributing to occurrence of floods 3 mks
7. State five negative effects of floods. 5 mks
8. State measures currently undertaken by Kenyan government to control natural disasters. 5 mks
9. Explain five economic importance of controlling floods. 10 mks
10. Name five natural hazards. 5 mks
11. Name three human induced hazards. 3 mks
12. Define desertification. 2 mks
13. Name causes of desertification. 4 mks
14. List effects of desertification. 4 mks
15. Explain five types of environment. 10 mks
16. (a) Define:
(i) Environment
(ii) Management of the environment
(iii) Conservation of the environment 6 mks
(b) Why is it necessary to manage and conserve the environment? 4 mks
17. (a) Mention six environmental hazards. 6 mks
(b) Explain:
(i) The causes of floods.
(ii) The effects of floods. 4 mks
18. (a) (i) What is lightning? 2 mks
(ii) What causes lightning? 2 mks
(b) (i) What are the effects of lightning? 2 mks
(ii) How can lightning be controlled? 4 mks
19. (a) (i) Define pollution. 2 mks
(ii) Name the four types of pollution.
(b) (i) What is air pollution? 2 mks
(ii) State five causes of air pollution. 5 mks
(iii) How can pollution be controlled? 5 mks
20. (a) (i) Name four non -governmental organizations involved in the
management and conservation of environment in Kenya. 4 mks
(b) Explain how legislation in Kenya is used to manage and conserve the
environment. 8 mks
