S.S.2.

THIRD TERM NOTE

WEEK ONE

GLACIER ACTION

The action of glacier as an important agent of erosion, transportation and deposition of materials is
confined to mountainous and temperate regions of the world.

Terms Associated with Glaciers

(i) Ice: This refers to the solid form of water, resulting from freezing when the temperature is
persistently below 0°C.

(ii) Glacier: It means moving ice, referring to a very large accumulation of ice (frozen sea or river) in
motion.

(iii) Glaciation: This refers to the wearing away of the earth's surface by glaciers.

(iv) Snow: This refers to frozen water vapour which falls in the form of crystals through the atmosphere.

(v) Snow-line: This is the lower limit of per- petual snow cover on a mountain.

(vi) Snow field: This refers to the region or area permanently under snow cover.

Action of Glacier Erosion: Glacier erosion is carried out in the following ways:

(1) Sapping: This is the breaking up of rocks of alternate freezing and thawing of water at the bottom of
cracks between a mass of ice and the sides and floor of a valley or the sides of a mountain.

(2) Plucking: This is the tearing away of blocks of rocks which have become frozen on the sides or
bottom of a glacier.

(3) Abrasion: This is the wearing away of rocks beneath a glacier by the scouring action of the rocks
embedded in the glacier.
Features of Glacier Erosion in the Highland Areas

(1) Striations: These are scratches or marks left on rocks over which glacier passes. Rock fragments or
mountains embedded in the glacier affect the striation of rocks.
(2) Corries or cirque: A corrie (Fig. 23.23) is a deep and rounded hollow or depression with steep sides,
formed through erosion by ice. They are arm- chair-shaped hollows, resulting from the plucking of rock
materials down the slope. After the ice has moved, it later forms corrie lake.

(3) Arete: This occurs when two corries cut back opposite sides of the same mountain, resulting in a
knife-edged ridge called Arete. Arete (Fig. 23.23) is therefore a wall ridge-like structure separating two
corries.

(4) Pyramidal peak: This occurs where three or more corries cut back on the same mountain. A pinnacle
shape like a pyramid develops and is called pyramidal peak

Glacier Erosion in Lowland

Erosional features of glaciers which occurs in Lowland areas includes

(1) Roche moutonnee: This is a resistant residual rock structure. The surface is striated by ice
movement. Its upstream side is smooth due to abrasion while the downstream is rough due to plucking.
The surface is also rough.

2) Crag and tail: Crag is a mass of hard rock which slopes on the upstream side that protects the softer
leeward slope from erosion and later develops to form the tail.

1) Roche moutonnee: This is a resistant residual rock structure. The surface is striated by ice movement.
Its upstream side is smooth due to abrasion while the downstream is rough due to plucking. The surface
is also rough.
(2) Crag and tail: Crag is a mass of hard rock which slopes on the upstream side that protects the softer
leeward slope from erosion and later develops to form the tail

Features of Glacier Deposition in Lowlands

(1) Boulder clay: Boulder clay is the ground moraine of the glaciers. It generally consists of stones of
various sizes and shapes in a mass of sand and clay.

(2) Erractics: Erractics are transported rock fragments which are composed of materials entirely different
from the bedrock or rock fragments of the region in which they are deposited. They are deposited when
the ice carrying them nomelts into water.
(3) Drumlins: These are swarms of oval, elongated whale-back hummocks composed mainly of boulder
clay with their elongation in the direction of the ice flow. The shape of drumlins are better described as
basket of eggs.
4) Eskers: Eskers are long, narrow and winding ridges of sand and gravel deposited by melt-water
streams. They are porous and numerous.
5) Terminal moraines: They are made up of boulders which are deposited at the edge of the ice-sheet.
They usually form a large debris deposited at the edge of the ice sheet.
WEEK 2

ACTION OF WIND

The action of wind is dominant in deserts and other semi-arid regions of the world.
Deserts which are associated with aridity (dryness) are caused by low rainfall, high temperature, cold
currents and high evaporation rate. About ⅕ of the world's land is made up of deserts which are
confined within 15° to 30° north and south of the equator. These deserts are blown by cold currents.

Examples of Deserts

(1) Sahara Desert (West Africa) - the largest desert.

(ii) Kalahari and Namib deserts (South Africa).

(iii) Arabian, Iranian and Thar deserts (Middle East).

(iv) Australian Desert (Australia).

(v) Atacama Desert (South America)

(vi) Mohave Desert (USA)

Characteristics of Deserts
(1) Extremes of temperature: Deserts do experience extreme high temperature during the day and
extreme low temperature at night.

(ii) Low rainfall: Deserts do experience low rainfall due to cold currents blowing them.

(iii) Absence of vegetation cover: There is lack of dense vegetation cover in deserts because of low
rainfall.

(iv) High evaporation rate: As a result of high temperature, there is a high rate of evaporation.

V) Wind action is dominant: As a result of the above charateristics, the action of wind tends to be
dominant in deserts.

(vi) Presence of cold currents: Cold currents are known to be responsible for buive the causes of deserts.

Types of Desert

There are five distinct kinds of desert landscape. These are:

(1) Erg or sandy deserts: These are made up of sand and sand dunes or sheets.

(2) Hamada or rocky deserts: These are made up of mainly rocks.

(3) Reg or stony deserts: These are made up of mainly pebbles and gravel.

(4) Badlands: These are deserts highly eroded by wind.

(5) Mountain deserts: These deserts are associated with highland areas.

In deserts, mechanical (exfoliation) and chemical weathering are more active in breaking rocks to sand
than wind erosion. However, wind transportation and deposition are more active in deserts.

Action of Wind Erosion

Wind erosion is carried out in the following ways:

(1) Deflation: This is the lifting and blowing away of loose sand and pebbles by wind. Deflation results in
the lowering of the land surface to form large depression called deflation hollows.

2) Abrasion: This is the process whereby sand particles carried by wind are used to blast or wear away
rock surfaces as in rock pedestals, zeugens and yandangs.
(3) Attrition: This is the process whereby wind-borne particles collide with one another, resulting in the
wearing away of each other. This results in reduced and rounded sizes of the particles.

Features of Wind Erosion in the Desert

(1) Rock Pedestals

Characteristics or Appearance

(i) It consists of horizontal layers of hard and soft rocks

(11) It looks like a pillar in structure.

(iii) It is narrow at the base and broader at the top.

(iv) It may range from 10 - 15 metres high.

(v) It has a flat or dome shape.

(vi) It has an irregular surface.

Formation

(1) Alternate bands of soft and hard horizontal rocks lying at right angles to the prevailing wind.

(ii) It is formed by wind abrasion.bins

(iii) Abrasive action attacks alternate horizontal layers of hard and soft rocks.

(iv) Soft rocks are removed (eroded) faster than the hard rocks.
(v) Abrasion is stronger at ground level, resulting in serious undercutting.

(vi) An irregular-shaped feature called rock pedestal is produced.

(vii) Found in desert, e.g. Sahara Desert.

(2) Zeugen

Characteristics

(i) These are tabular masses with a layer of soft rocks lying beneath a surface layer of hard rock.

(ii) It has a long ridge and furrow landscape with a length of 10 - 30 meters.

(iii) They are also formed by wind abrasion in deserts.

Mode of formation: Zeugen is formed when a tabular mass of rock which has a layer of soft rocks lies
under a layer of a more resistant hard rock. It is lying horizontally to the direction of wind. The mass of
rock is then attacked by wind abrasion. This wind abrasion wears the mass into a ridge and furrow
landscape, leading to the formation of zeugen. Mechanical weathering starts the formation by opening
up joints of the surface of hard rocks.
(3) Yardangs

Characteristics

(i) Yardangs have vertical bands of hard and soft rocks, ridge and furrow of landscape of about 10 - 15
metres long.

(11) They are formed in the deserts, e.g. Atacama deserts.

Mode of formation: Yardangs are formed when hard and soft rocks in vertical bands are aligned in the
direction of prevailing winds. Wind abrasion wears the softer rocks into long narrow corridors which
separate the steep-sided ridges of the hard rocks. These hard rocks are called Yardangs.

Differences between Zeugen and Yardang

(1) In Zeugen, the hard and soft rocks are arranged in horizontal bands while those of Yardangs are
arranged in vertical bands.
(ii) In Zeugen, there must be lines of fissure in order for wind abrasion to perform its work but in
Yardang, there will be no lines of fissure.

(iii) Yardangs are easier to form than Zeugen.

Mesas and Buttes

Characteristics: Mesa is a flat, table-like landmass. It has a resistant horizontal top layers with steep
sides and it is made up of soft and hard layers.

Mode of formation: As a result of the action of denudation, the hard top layer of rock resists agents of
denudation and protects the softer layers of rocks below from being eroded.

At times, mesas may be formed in canyon regions. Canyon develops in the space between mesas and
butte. Denudation, sometimes, may reduce mesas in areas to become isolated flat- topped hills called
buttes.
(5) Inselberg

Characteristics: Inselberg is an arid land form. It is an isolated rocky outcrop having steep sides, round
top and composed of granite. It may rise up to a height of over 500 metres and may occur singly or in
group. Examples are found in Northern Nigeria, Kalahari Desert, and Western Australia.

Mode of formation: Inselberg is formed from the existence of extensive old plateau. It is caused as a
result of weathering and removal of weathered materials by water and wind. It is an exposure of rock
outcrop.
WEEK THREE AND FOUR

ENVIRONMENTAL RESOURCES
"Environmental resources" refers to any useful item in the environment, or materials and substances
that are useful to man. In other words, environmental resources are useful things (both living and non-
living) occurring naturally within a particular geographical location which are of benefit to man, animals
and plants. Any useful thing we can find in water, atmosphere, vegetation and land are all examples of
environmental resources.
Types of Environmental Resources: There are five main environmental resources and these are:

(i) Atmospheric resources.

(ii) Water resources.

(iii) Vegetation resources.

(iv) Human resources.

(v) Mineral resources.

ATMOSPHERIC RESOURCES
Meaning: Atmospheric resources are those elements found in the atmosphere which are of benefit to
man, animals and plants.

Types of Atmospheric Resources

(i) Atmospheric gases, e.g. oxygen, nitrogen, carbon dioxide, water vapour, ozone layer and some inert
gases like neon, argon and helium.

(ii) Wind,

(Ⅲ) Rain

(iv) Solar energy

The percentage composition of these gases in the atmosphere includes oxygen (21%), nitrogen (78%),
inert gases like argon and neon (0.93%), carbon dioxide (0.03%), water vapour including some impurities
like smoke and dust is negligible.
Importance of Atmospheric Resources

(1) Gases

(a) Oxygen

(1) Oxygen is used by plants and animals for respiration.

(ii) It also supports burning of materials (i.e. combustion).

(iii) Oxygen supports animal life.

(iv) Oxygen combines with water vapour (oxidation) for chemical weathering.

(v) Oxygen is also used for industrial purposes.

(b) Carbon dioxide

(1) It is required by plants for photosynthesis.

(ii) Carbon dioxide combines with water to produce chemical weathering (carbonation).
(iii) Green plants take in carbon dioxide.

(c) Nitrogen:

(1) Nitrogen is required by plants for the manufacture of proteins.

(ii) It combines with water to provide food for plant growth.

(iii) Nitrogen in soil can be converted to nitrate in the soil.

(iv) Nitrogen gas is used in electrical industry.

d) Ozone: The ozone layer acts as a blanket to the earth. It protects the earth and its living things against
the burning effects of ultraviolet rays of the sun.

(e) Water vapour:

(i) It is important for rain formation.

(ii) The resultant rain is used by plants and animals in the process of chemical weathering.

(iii) Water vapour moderates atmospheric temperature.

Wind

(1) Wind can be harnessed for wind mills and used for pumping water.

(ii) It aids drying of clothes and crops.

(111) It is used in meteorological studies.

(iv) It aids sailing of ships and aviation.

(v) It is useful in winnowing and pollination.

(vi) It is used for sporting, e.g. yatching.

(vii) It is used for dispersal of seeds.

Ways in which Human Activities Affect the Composition of the Atmosphere

These include:
(1) Emission of carbon dioxide through burning fossil fuel such as coal, petrol and gas.

(ii) Deforestation.

(iii) Use of chemicals, biological and nuclear warfare.

(iv) Release of toxic waste.

(v) Bush burning.

WATER RESOURCES

Meaning: 'Water resources' refers to any useful material (living or non-living) inside water which are of
benefit to man, animals and plants. Water resources are some of the most important environmental
resources of man.
Importance of Water Resources to Man

Ways in which water resources can be used include:

(1) Sources of food supply: Fishing in oceans, lakes and rivers is known to provide food for man in the
form of fish, prawns, crayfish, crabs, etc.

(2) Generation of hydro-electric power (H.E.P): Many rivers are dammed in areas of waterfalls and
rapids for the purpose of generating electricity, e.g. Kainji and Shiroro dams.

(3) Agricultural purposes: Water from rivers, lakes, wells, boreholes, etc. is used for irrigation purposes,
especially in areas of low rainfall, to aid crop cultivation.

(4) Medium of transportation: Rivers, e.g. Rivers Benue and Niger, lakes and oceans provide a useful
medium by which people and goods are transported from one place to another.

(5) Domestic use: Water from lakes, rain, rivers and boreholes is used for cooking, washing, bathing and
drinking.

(6) Industrial use: Water from rivers, lakes and boreholes is used by textile, brewery and chemical
industries for production.

(7) Provision of employment: Oceans, lakes and rivers also provide people with jobs, e.g. fishermen,
canoe and ship builders, etc.

(8) Recreation/Tourism: Water in lakes, oceans and rivers is used by people for sports, e.g. swimming,
diving for relaxation and tourism, e.g. Bar Beach and Lekki Beach in Lagos, Nigeria.

Problems of Degradation of Water Resources

(1) Destruction of aquatic life.

(ii) Water poisoning.

(iii) Inadequate fresh and pure water for domestic purpose.

(iv) Inadequate fresh and pure water for industrial use.

(v) Unemployment among fishermen

(vi) Scarcity of sea foods

(vii) High cost of water treatment.

Ways by which Man's Activities Limit the Use of Water Resources

(i) Discharge of industrial waste into water bodies

(ii) Fishing with chemicals

(iii) Oil spillage

(iv) Mining activities

(v) Waste disposals

(vi) Application of chemical fertilisers.

(vii) Discharge of toxic substances into water bodies.

(viii) Sharing of the same water source with animals.

(ix) Damming of rivers up stream.

(x) Dumping untreated sewage inside water bodies.

(xi) Discharge of effluent from ships inside water.

VEGETATION RESOURCES

Meaning: Vegetation resources include all the resources one can get from the forest and savanna for the
benefit of man, animals and plants. Vegetation resources include timber, roots, leaves, barks of trees,
latex, fruits, fibre, firewood and wild animals.
Importance of Vegetation Resources to man
(1) Source of food supply: Resources like fruits (mango, orange), leaves in the form of vegetables and
bush meat from wild animals provide food for man.

(2) Source of timber: Timber like Iroko, Obeche, Mahogany, etc. are sources of planks and plywood used
for building and furniture. Timber also provides foreign exchange for the nation.

(3) Medicinal herbs: Leaves, roots and barks of some trees are used to prepare medicine for curing
various diseases. For example, the neem plant is used to provide medicine for curing malaria fever.

(4) Source of firewood: Firewood or fuelwood is used to provide fuel for the cooking food, warming the
body during cold weather, for drying fish, etc.

(5) Development of game reserves: Forest and savanna are the home of wildlife which can serve as
game reserves, e.g. Yankari Game Reserve.

(6) Employment: Forest provides employment to some people, e.g. forest guards, lumbermen,
sawmillers and hunters.

(7) Prevention of erosion: Leaves of plants and grasses help to prevent water and wind erosion.

(8) Provision of furniture: Timber derived from the forest is sawn into planks and plywoods used in
making chairs , tables, doors and windows.

Problems Resulting from Exploitation of Vegetation Resources

The exploitation of vegetation resources can lead to the following problems:

(1) Soil erosion: The exploitation of vegetation resources such as timber can lead to soil erosion.

(2) Depletion of natural forest products: The continuous exploitation of vegetation resources also leads
to the depletion of natural forest products.

(3) High cost of exploitation: Huge amount of money is involved in the exploitation of vegetation
resources especially timber.

(4) Soil leaching: Due to the depletion of vegetation cover, the soil is now exposed to heavy leaching of
soil nutrients.

(5) Flooding: Continuous removal of vegetation can also expose the soil to flooding.

(6) Transportation problems: The cost of transportation of most forest resources like timber is always
very high from the forest to the cities.

Solutions to the Problems Resulting From Exploitation of Vegetation Resources

(i) Forest guards should be employed to check illegal felling and ensure planting of new trees.
(ii) Roads should be constructed round lumbering areas for easy transportation of logs.

(iii) Afforestation, i.e. the policy of planting of two trees in an area where one tree is cut, should be
encouraged.

(iv) Re-afforestation, i.e. the practice of clearing the bush of bad trees and planting valuable ones to
replace them, should also be encouraged.

(v) Bush fallowing should be discouraged.

(vi) Bush burning should also be discouraged.

HUMAN RESOURCES

All resources of the environment are usually organised by man for optimum use. The ability of man to
make the best use of these resources depends on his level of education, technology and culture.

Factors which Determine the Size of Human Resources

Factors which can determine the size of human resources are:

(1) Birth rate or natality: A high birth rate generally leads to high population or human resources.

2) Death rate or mortality: A low death rate leads to increase in human population while a high death
rate reduces it.

(3) Migration: While migration (movement out of a country) reduces population, immigration
(movement into a country) increases human resources.

(4) Level of fertility: Ahigh level of fertility of the population leads to increase in human population.

(5) Medical facilities: Improved medical facilities in a country leads to increase in human population.

(6) Education: The higher the level of education, the lesser the growth of human population. In other
words, illiteracy leads to increase in human population, because of indiscriminate rate of child bearing.

(7) Technology: A high level of technology leads to reduction in human population and vice versa.

Importance of Human Resources

(1) Labour supply: Labour is necessary for the economic growth and development of all nations.
(2) Control over other resources: Human beings, because of their intelligence, can control other
resources for maximum benefit.

(3)Defence: Large population does provide the required armed forces for defence purposes.

(4) Development: Development is only possible through the contribution of individuals who are healthy
and educated.

(5) Power: Countries known to have large, educated population with scientists, etc. are known to control
world power more than others, e.g. USA.

MINERAL RESOURCES

Minerals, unlike other resources, are non- renewable resources because once they are exhausted, they
cannot be replaced. Mineral resources are grouped into the following:

(1) Mineral fuels such as petroleum, coal and natural gas.

(2) Ferrous and non-ferrous metals such as iron, copper, tin, aluminium, lead and zinc.

(3) Industrial metal, e.g. gold, mercury, diamond, silver, graphite and limestone.

4) Ornamental minerals, e.g. gold, silver and diamond.

Importance of Mineral Resources

(1) Sources of fuel: These include coal, petroleum and natural gas. They provide power and energy for
domestic and industrial use. Petrol, from petroleum, is used as fuel for vehicles, and natural gas for
cooking.

(2) Construction purposes: Some minerals like iron, aluminium and zinc are used for construction. For
example, iron ore is the basis of industrial development and construction of bridges and houses. Zinc is
required for roofing sheets and lead for water and oil pipes.

(3) Industrial development: Diamond, iron, copper, silver and graphite are useful for industrial
development. For example, diamond, the hardest known metal, is used in cutting other metals, and
graphite is used in making pencils.

(4) Sources of ornamentals: Some minerals like gold, silver and bronze are used as ornamental wares or
jewellery. Gold is said to be the queen of metals because it is the most valuable metal used in making
wristwatches, chains, etc.

(5) Sources of foreign exchange: Most minerals sold to other countries provide foreign exchange for
development, e.g. petroleum in Nigeria.
(6) Provision of employment: People engaged in the mining of these minerals get jobs as miners, drillers,
engineers, etc.

(7) Provision of basic amenities: Amenities and infrastructures like electricity, pipe-borne water, roads
and 199100 telephone are provided in areas where mining takes place, thereby promoting the
development of such places.

(8) Provision of raw materials for industries: Various minerals are supplied to industries for the
production.

WEEK FIVE and SIX

ENVIRONMENTAL PROBLEMS

Environmental harzards or problems can be refered to as any natural or human-induced event which
poses a serious danger or risk to the lives and property of people in their environment. In other words,
environmental hazards are disasters caused by nature or man which pose a serious danger or risk to
lives and property of people in their environment.
Types of Environmental Problems

(i) Volcanic eruptions

(ii) Drought

(iii) Pollution

(iv) Earthquakes

(v) Desert encroachment

(vi) Deforestation

(vii) Soil erosion

(viii) Coastal erosion

(ix) Flooding

(x) Tornadoes

(xi) Hurricanes

(xii) Blizzards.

(xiii) Lightning

(xiv) Oil spilage

(xv) Hail

(xvi) Mass wasting

(xvii) Mining.

The causes, effects and control measures of some popular environmental hazards common in West
Africa are discussed in this note.

Natural Hazards

Definition: Natural hazards can be referred to as any natural event which poses a serious danger or risk
to the lives and property of people in their environment.

Examples are flood, drought, volcanic eruption, earthquake, soil erosion, desert enchroachment,
hurricane, landslide, ozone layer depletion, global warming, tornado, mass wasting, etc.

SOIL EROSION
Definition: Soil erosion may be defined as a process whereby the top soil is gradually removed, that is,
transported away by erosional water, wind and ice. In other words, it can also be defined as the gradual
removal of the top layer of the soil through the action of wind and water. Soil erosion including the
types, agents and areas where they occur in Nigeria.

Agents Responsible for Modifying Landforms

- Surface running water

- Underground water

- Volcanism

- Earthquake

- Glacier/ice

- Waves/seas

- Wind

- Living organisms

- Wariation in temperature

- Rainfall

Causes of Soil Erosion

(i) Deforestation: This is the removal of vegetation, thereby allowing erosion to take place.

(ii) Bush burning: This also exposes the soil to erosion.

(iii) Overgrazing: This is the excessive removal of grasses by animals that feed on them, thereby exposing
the soil to erosion.

(iv) Cultivation along the slope: This speeds up the rate of erosion when ridges are constructed along the
slope instead of across the slope.

(v) Excessive rainfall/wind: This increases the rate of soil erosion.

(vi) Shifting cultivation: This also exposes the soil to erosion.

vii) Population pressure on land: Continuous cultivation of the land due to high population eventually
exposes the soil to erosion.
Control

(1) Afforestation: This is the planting of trees to control erosion.

(ii) Re-afforestation: This is the replanting of trees in areas which do not contain plants before in order
to check erosion.

(iii) Controlled grazing: Few animals should be allowed to graze on an area to avoid soil erosion.

(iv) Contour ploughing: This is the making of ridges across the slope to control erosion.DO
(V) Cover cropping: This is the planting of legumes to cover the soil so as to prevent erosion.

(vi) Terracing: This is the method of cutting steps on hill sides to reduce the speed of running water
down the hill.

(vii) Improved farming methods: The practice of mixed farming, strip cropping and crop rotation helps to
control erosion.

DESERT ENCROACHMENT

Meaning: Desert encroachment is the extension or spread of the desert to areas which were originally
not deserts before.

Causes

(i) Overgrazing: The excessive removal of the grasses by animals leaves the soil bare to desert
encroachment.

(ii) Changes in climate: Desert encroach- ment may also occur when there are changes in the climate of
a place from a partial wet climate to a dry one.

(iii) Bush burning: This exposes the soil, thereby encouraging desert encroachment.

(iv) High speed of winds: High speed of winds across the desert carries sand and deposits them on the
land, e.g. harmattan wind.

(v) Shift in climatic belt: The shifting of the climatic belt from one place to another may encourage desert
encroachment.

(vi) Deforestation: The cutting down of trees can also encourage desert encroachment.

FLOODING

Definition: Flooding is defined as the occurrence of excessive volume of water in areas not usually
waterlogged. Flooding is also defined as the accumulation of an abnormal large volume of water in an
area which has refused to percolate or flow away.

It usually occurs mostly when there is heavy rainfall in an area and all the water refuses to sink into the
soil but flows on the earth's surface as floods. When such floods occur in the cities, it is referred to as
urban flooding.
Areas of Occurence of Flooding

(1) Flood plains of big rivers, e.g. Rivers Nile, Niger and Benue.

(ii) Collapsed dam sites

(iii) Low coastal areas

(iv) Poorly drained areas

(v) Regions where water table is close to the surface cititu

(vi) Specific places, e.g. the lower coastal areas of Rivers State of Nigeria, etc.

(vii) Deltaic areas

(viii) Areas of heavy rainfall

Causes

(i) Excessive rainfall

(ii) Refuse dumping into drains

(iii) Poor engineering/construction of drainage system

(iv) Settlements along river channels

(v) Volcanic eruption

(vi) Tsunamis

(vii) Wind storms, e.g. hurricane, tornadoes.

(viii) Non-enforcement of environmental laws

(ix) Strong tidal waves along the coast

(x) Erecting structures along waterways

(xi) Bursting of weak dams

(xii) Inadequate urban planning

(xiii) Extensive cementing of compounds in urban areas

(ix) Overpopulation and increased solid waste generation

Control:

(i) Enforcement of legislation against indiscriminate waste disposal

(ii) Efficient urban planning

(iii) Construction of wider culverts and drains

(iv) Frequent cleaning of drains

(v) Re-channelling of flood water from city centres

(vi) Public enlightenment

(vii) The use of water pumps to suck away flood water

(viii) Construction of dams to create reservoirs

(ix) Strengthening old dams

(x) Building/construction of artificial levees or gronnes or embankments along river banks

(xi) Provision of more refuse bins in urban centres

(xi) Organised communal efforts at cleaning drainage channels

(xii) Environmental education in schools

(xiii) Creation of lanes and lawns in urban areas

( xiv) Establishment of disaster management agencies

DROUGHT

Meaning: Drought can be defined as a state of prolonged and abnormal moisture deficiency and a
general state of dryness. In other words, it refers to the absence of rainfall which is long enough to
cause total dryness in an area.

Areas affected by drought: the Sahara Desert. - Northern Nigeria. - Senegambia. - Northern Ghana. Mali
Mauritania. - - Burkina Faso. - Somalia. -Niger Republic. - Northern Benin Republic, etc. - Sahelian region.
- Sudan savanna region. - Ethiopia-Eritrea.

Causes

(i) Prolonged break in ranfall.

(ii) Presence of high daily temperature.

(iii) High rate of evapotranspiration.

(iv) Climate change.

(v) Little or no cloud cover.

(vi) Presence of green house gases.

Control

(i) Afforestation: The planting of trees does encourage formation of rain.

(ii) Irrigation: The artificial application of water to soil encourages the growth of plants. Ato stu

(iii) Planting of cover crops: This will reduce evaporation and retain water in the soil.

(iv) Avoidance of over-grazing.

(v) Drought-resistant trees and crops should be planted.

(vi) Legumes and grasses can be planted.

(vii) There should be artificial stimulation or cloud seeding

DEFORESTATION

Definition: Deforestation is defined as the indiscriminate destruction of forest or felling of trees.

Causes

Deforestation is caused when:

(1) Trees are cut for timber.

(ii) Trees are cut for cultivation of crops.

(iii) Bush is cleared for grazing purposes.

(iv) The leaves of plants are required for feeding livestock and other purposes.

(v) Trees are used for fuel or firewood.

Control

(1) Afforestation. This is the planting of trees which help to check deforestation. This underscores the
ongoing campaign of planting of two trees where one is cut.

(ii) Legislation against indiscriminate felling of trees.

(iii) Issuance of licences to authorised persons to fell trees.

(iv) Public awareness campaigns on the effects of deforestation.

(v) Development of other sources of fuel, e.g. gas and kerosene.

COASTAL EROSION

Definition: Coastal erosion refers to the gradual removal of land along the coast.

Causes: Coastal erosion is mainly caused by the action of wave, resulting from the movement of water
over the ocean waters.

Effects

(i) It causes the destruction of lives and property.

(ii) It leads to the formation of cave, bay and cliff.

(iii) It causes reduction in the size of areas to be used for recreation and relaxation. (m)

(iv) It leads to loss of revenue to government.

Control

(1) Regular sand-filling of beaches or coasts.

(ii) Erection of materials that can reduce the power of wave along the coasts.

(iii) Regular dredging of deposited materials along the coasts.

(iv) Partial planting of shrubs along the coasts.

(v) Construction/building of permanent embankment on the coasts.

ENVIRONMENTAL POLLUTION

Meaning: Pollution is the release of substances into the environment, i.e. air, water or land in quantities
or to the level that is harmful to man, animals and plants.

The susbtances that cause pollution in the environment are called pollutants.

Types of Environmental Pollution

There are three main types of pollution. These are:

(i) Air pollution

(ii) Land pollution

Water pollution.

(a) Air pollution

Definition: Air pollution refers to the release or injection of substances into the air in quantities or to the
level that is harmful to man, animals and plants.

Causes
(1) Discharge of solid substances like smoke, dust and soot from industries, machines and coal into the
air.

(ii) Fumes from industrial processes such as sulphuric acid, mist from coal mining and cement factories.

(Ⅲ) Gases such as sulphur dioxide and carbon monoxide from the exhaust pipes of motor vehicles and
aeroplanes.

(iv) Radioactive rays from industrial processes such as electric plants that use radioactive susbtances.

(v) Spray of liquid (vapour) and gaseous herbicides and pesticides.

(vi) Noise from loudspeakers, cars, sirens, aeroplanes, horn blarring, construction and mining sites.
Control

(I) Use of environmental-friendly energy source, e.g. solar and wind energy.

(ii) Waste recycling instead of burning.

(iii) Afforestation.

(iv) Legislation against uncontrolled emission.

(v) Bush burning should be minimised.

(vi) Vehicles with bad exhausts should not be allowed on the highways.

(vii) Siting of industries far away from residential areas.

(viii) International co-operation on control of air pollution

(ix) Fumes from industries must be treated to make them environmentally friendly.

(b) Land Pollution

Definition: Land pollution is defined as the release or injection of substances into the land in quantities
or level that is harmful to man, animals and plants.

Causes: Land pollution is caused by dumping of refuse, sewage, metal scraps, plastic waste, chemicals,
oil spillage, toxic wastes, pesticides and fertilisers in an area or place.

Effects

(1) Land pollution causes offensive odour.

(ii) Some are poisonous to man and animals.

(iii) Some can kill useful soil organisms.

(iv) Some can render soil infertile.

Control

(i) Refuse should be burnt in an incinerator.

(ii) Urban waste should be buried.

(iii) Proper disposal of sewage.

(iv) Legislation by government against dumping of harmful or toxic wastes at any place.

(v) Pesticides, fertilisers, etc. should be applied as instructed.

(vi) Oil pipelines should be maintained and checked regularly to prevent oil spillage.
(c) Water Pollution

Definition: Water pollution is defined as the release or discharging of toxic substances into the water
bodies in quantities or level that is harmful to man, animals and plants.
Causes or Sources

(i) Herbicides

(ii) Pesticides

(iii) Industrial waste discharge bord

(iv) Heat from power and industrial plants

(v) Use of chemical fertilisers

(vi) Flooding coll no zaton stir

(vii) Acid rainfish

(viii) City drainage

(ix) Untreated sewage

(x) Cloud seeding

(xi) Mining

(xii) Discharge from ships

(xiii) Fishing with chemicals

(xiv) Dumping of refuse in water

(xv) Erosion materials

(xvi) Volcanic eruption

(xvii) Oil spillage

(xviii) Leakage from landfills

(xix) Washing of clothes in rivers with detergent

(xx) Animal dung in rivers

Effects or Problems of Water Pollution

(i) Rapid growth of water weeds.

(ii) It cannot be used for agricultural purposes.

iii) Extinction of aquatic plants and animal species.

Iv) Waterborne diseases, e.g. cholera.

(v) Migration of people and animals.

(vi) Ecological imbalance

(vii) Shortage of water for domestic purposes

(viii) Shortage of water for industrial purposes.

Measures to Control Water Pollution

(1) Controlled use of herbicides

(ii) Controlled use of pesticides

(iii) Control of floods

(iv) Control of air pollution

(v) Good drainage

(vi) Enforcement of legislation against improper disposal of toxic wastes

(vii) Good management of industrial effluents

(viii) Proper channelling of thermal fluids

(ix) Good management of sewage

(x) Use of organic manure

(xi) Good livestock management practices

(xii) Use of good fishing methods

(xiii) Formation of awareness clubs in schools

(xiv) Use of age grades and other voluntary agencies to control misuse of streams

(xv) Enlightenment programmes

(xvi) Erosion control measures

(xvii) Formation of environmental conservation organisations and agencies in communities.

WEEK SEVEN and EIGHT

ENVIRONMENTAL CONSERVATION
Definition: Conservation is defined as the planned, control exploitation or judicious use of natural
resources to ensure their continous availability and to preserve the quality or original nature of the
environment. In other words, conservation is the preservation of natural resources from loss, waste or
exploitation through rational use and to ensure their continued use or availability and preserve the
quality or original nature of the natural resources.
NEED OR REASONS FOR CONSERVATION
(1) To prevent destruction of natural environment or to allow for continued use of natural resources for
man's benefits.

(2) To preserve rare and valuable species of plants and animals for the future generation or to save them
from extinction or permanent destruction.

(3) To preserve naturally beautiful sceneries for their aesthetic values.

(4) To promote the recycling of some scarce mineral resources, e.g. water.

(5) To prevent the destruction of natural ecosystem; this will allow the organisms in the ecosystem to
survive.

NATURAL RESOURCES THAT NEED TO BE CONSERVED

Natural resources that need to be conserved include wildlife, water, forest, soil, air and mineral
resources.

METHODS OF CONSERVING WILDLIFE

(i) Establishment of game or forest reserves.

(ii) Establishment of zoological gardens.

(iii) Control of hunting to prevent extinction of some animal species.

(iv) Prohibition of killing or poaching of animals in game reserves.

(v) Prohibition of bush burning as this may lead to migration or displacement of wildlife.

(vi) Prohibition of deforestation and encouragement of afforestation or reafforestation.

METHODS OF CONSERVING WATER

(1) Trapping or storage of water in tanks or wells.

(ii) Damming of rivers to allow for more effective management of water.

(iii) Treatment and recycling of used water.

(iv) Saving of water by prompt repair of burst pipes or tuming off taps immediately afteruse.
(V) Tree planting which provides vegetation cover and reduces evaporation and promotes water
retention.

(vi) The existence of vegetation also brings about the formation of rainfall.

(vii) Prevention of water pollution by sewage and chemical from industries and homes.

METHODS OF CONSERVING FOREST

(i) Cutting of trees without destroying the undergrowth.

(ii) Reafforestation or encouraging the planting of trees.

(iii) Prevention of bush burning or careless forest fires.

(iv) Prevention of plant pests and diseases.

(v) Establishment of forest reserves.

(vi) Educating the public on the value of forests and the importance of conservation.

METHODS OF CONSERVING SOIL

(1) Prevention of over-grazing which may cause soil erosion.

(2)Prevention of indiscriminate felling of trees or deforestation which exposes the soil to erosion.

(iii) Adoption of better farming practices, e.g. crop rotation so as to prevent erosion, leaching, water
logging or acidity.

(iv) Prevention of pollution of land so as not to destroy useful soil organisms.

(v) Avoidance of clean clearing which may expose the soil to erosion.

(vi) Prevention of bush burning which may expose the soil to erosion.

METHODS OF CONSERVING AIR

(i) Prevention of effluents from factories or factory chimneys which may pollute the air or cause acid
rain.

(ii) Prevention of fumes from automobile or thermal plants which may affect aerial life or render air unfit
for organisms.
(iii) Proper treatment and disposal of sewage.

(iv) Proper burning of wastes so as to prevent smoke or soot from polluting the air.

(v) Proper disposal of dust from construction sites which may cause air pollution.

METHODS OF CONSERVING MINERAL RESOURCES

Mineral resources, unlike other resources, are non-renewable resources because once they are
exhausted, they cannot be replaced; hence, they need to be conserved. The methods of conserving
mineral resources are:

(i) There should be legislation against indiscriminate mining of mineral resources.

(ii) Effective and efficient extraction methods of mining should be adopted to prevent wastages.

(iii) There should be effective and efficient utilisation of available mineral resources for man's use.

(iv) Over-dependence on a particular mineral resource should be discouraged as this can lead to the
depletion of such mineral resource.

(v) There should be proper pricing of mineral resources and their by-products to ensure maximum value
for the mineral products.

IMPORTANCE OR BENEFITS OF CONSERVATION OF THE ENVIRONMENT

Benefits of Wildlife Resources Conservation

(1) It provides food for human consumption, e.g. meat, fish and eggs.

(ii) It generates revenue for government.

(iii) It can serve as tourist centres for pleasure and relaxation.

(Iv) It provides research work for scientists.

(vi) It can generate employment for some people.

Benefits of Water Resources Conservation

(i) It serves as a source of food supply, e.g. fish, prawns and crayfish.
(ii) It is used for Hydro-Electric Power (H.E.P.) generation which provides electricity, e.g. Kainji Dam.

(iii) Water is useful for agricultural purposes, i.e. irrigation.

(iv) Water serves as a medium of transportation in rivers, lakes and oceans.

(v) Water is important for domestic and industrial uses, e.g. drinking, washing and cooking.

(vi) Water can be used for recreational and tourist purposes.

(vii) Water provides employment for people, e.g. fishermen and canoe or ship builders, etc.

Benefits of Forest Resources Conservation

(I) Forests are sources of food supply, e.g. fruits, vegetables and meat.

(ii) Forests are sources of timber for construction purposes.

(iii) Forests provide medicinal herbs.

(iv) They are sources of (fuel) firewood used for cooking.

(v) Forests are the homes or habitats of wild animals which can serve as game reserves.

(vi) Forests provide employment for some people, e.g. forest guards, lumbermen and hunters.

(vii) Forests provide raw materials for industries, e.g. cotton, rubber, ropes twine, latex and timber.

(viii) Forests can serve as centres of tourism.

(ix) Forests can also serve as windbreak.

Benefits of Soil Resources Conservation

1. Soil supports agricultural or farming activities.

(ii) Soil also supports forest and its resources.

(iii) Soil supports wildlife resources.

(iv) It is the home of some organisms.

(v) It supports the growth of valuable wood for building and furniture making.

(vi ) Buildings are erected on the soil.

(vii) Mineral resources are obtained from the soil.

Benefits of Air Resources Conservation

(i) Air provides oxygen used in respiration by plants and animals.

(ii) It provides carbon dioxide used by plants for photosynthesis.

111. Air also provides gaseous nitrogen used by plants to manufacture proteins.

(iv) Air is the habitat of most organisms, e.g. birds and insects.

(v) It makes life more meaningful and comfortable.

Benefits of Mineral Resources Conservation

(ⅰ) Mineral resources provide fuel, e.g. coal, petroleum and natural gas, for use.

(ii). They are used for construction purposes, e.g. iron, zinc and aluminium.

(Iii) Some are used for industrial development, e.g. diamond, iron, copper and silver.

(iv) Some are sources of ornamentals, e.g. gold, silver and bronze.

(v). Minerals are sources of foreign exchange.

(vi). They also provide employment, e.g. miners, drillers and marketers.

WAYS OF ENSURING THE CONSERVATION OF THE ENVIRONMENT

(1) Establishment of agencies for conservation: Agencies are established to ensure that these natural
resources are conserved, e.g. preservation of wildlife, forest resources, water resources, air, soil and
mineral resources.

Examples of agencies for conservation are:

(I). Nigerian Conservation Foundation,

(ii) Forest departments,

(!!!). Federal Environmental Protection Agency (FEPA),

(iv) River Basin Development Authorities (RBDA),

(v) Ministries of Agriculture,

(vi) Department of Wildlife Conservation.

(2) Establishment of game reserves or national parks: The game reserves or national parks serve for the
protection of wildlife, rare or endangered species and for recreational purposes as well as scientific
purposes.

Some game reserves in Nigeria are:

(I) Yankari Game Reserve in Bauchi State.

(ii) Borgu Game Reserve in Niger State.

(iii) Shasha River Forest in Ogun State.

(iv) Olomu Forest Reserve in Kwara State.

(v) Mamu River Forest Reserve in Anambra State.

(vi) Zamfara Forest Reserve in Zamfara State.

(3) Making of conservation laws, edicts or decrees: These laws, edicts or decrees are made by the
government to regulate the felling of trees, hunting or exploitation of endangered species or
indiscriminate exploitation of mineral resources. These laws must be obeyed.

(4) Conservation education: Conservation education serves to inform the populace about the need to
conserve natural resources and the consequences of extermination or exhaustion of such resources like
trees, wildlife and minerals.
(5) Setting standards for pollution control: These standards help to protect land, water and air resources
from a certain level of pollution from industries, vehicles, power plants and homes.

PROBLEMS AND DIFFICULTIES ASSOCIATED WITH CONSERVATION

The following problems or difficulties are encountered in the process of conserving natural resources:

(i) Soil erosion caused by natural wind, rainfall and run-offs.

(ii) Land, air and water pollution.

(ⅲ) Occurrence of natural disasters such as earthquakes and floods.

(iv) Overgrazing caused by domestic livestock.

(v) Indiscriminate hunting, leading to eradication of wildlife.

(vi) Indiscriminate bush burning and felling

WEEK NINE