WAEC SSCE - Geography - 2010 (Essay)

(a) What is water pollution?

Water pollution is the contamination of water bodies (rivers, lakes, seas and underground water) with harmful substances that make the water dirty, unsafe and unfit for drinking, farming, aquatic life or other uses.

(b) Three causes of water pollution

• Discharge of untreated sewage and domestic waste into water bodies.
• Release of industrial effluents and chemicals from factories.
• Oil spillage from tankers, pipelines and oil fields.
• Run-off of agricultural fertilisers and pesticides, and dumping of refuse in water.

(c) Three effects of water pollution

• It causes water-borne diseases such as cholera, typhoid and dysentery in humans.
• It kills fish and other aquatic organisms, reducing the fishing industry.
• It makes water unfit for drinking, irrigation and domestic use, raising the cost of water treatment.
• It damages the ecosystem and can cause loss of biodiversity.

(d) Two control measures

• Treat sewage and industrial effluent before it is released into water bodies.
• Enforce anti-pollution laws and penalise offenders.
• Prevent and quickly clean up oil spills, and provide proper waste-disposal systems, plus public enlightenment.

(a) Distance from Agbeyangi to Marafa "as the crow flies"

Join the two places with a straight line and measure it on the map. The straight-line distance measures 20.6 cm. On a scale of 1:50,000, 1 cm represents 50,000 cm on the ground, so

\[ \text{Actual distance} = \frac{20.6 \times 50{,}000}{100{,}000}\ \text{km} = 10.3\ \text{km}. \]

The distance from Agbeyangi to Marafa is 10.3 km.

(b) Drainage of the mapped area

• The area is well drained, being covered by a network of well-defined stream channels.
• The major river is the River Oshin, which flows in a north-easterly direction and has many tributaries.
• The general drainage pattern is dendritic.
• The central ridge is the main watershed from which many rivers take their source.
• The rivers are at an early (youthful) stage of development, shown by the V-shaped valleys and the dissected highlands produced by active downward cutting.
• The smaller ridge at the north-eastern corner has rivers radiating from it, while the rivers in the north-west flow northwards.

(c) Relationship between the relief and the road network

• The main road takes advantage of the lowland and runs between the two major ridges, avoiding the highland.
• The road keeps to the valley floors, running parallel to Igporin hill rather than climbing it.
• The secondary roads, minor roads and footpaths are built along the spurs.
• The roads avoid steep slopes and pass through gaps such as passes, cols and saddles where the gradient is gentle.

(d) Two land-use types

1. Agricultural land use, shown by areas of scattered cultivation.
2. Transportational land use, shown by the roads, paths and tracks (educational land use is also evident from the schools).

(a) Definition of soil

Soil is the thin, loose upper layer of the earth's surface made up of weathered rock particles (mineral matter), organic matter (humus), water, air and living organisms, in which plants grow.

(b) Three functions of soil

• It anchors plant roots and holds plants firmly in place.
• It supplies plants with water, air and mineral nutrients.
• It provides a habitat for micro-organisms and small animals that recycle nutrients.
• It serves as a medium for farming and a base for building.

(c) Two negative effects of man's activities on soil

• Soil erosion: deforestation, overgrazing and bad farming expose the soil so that water and wind wash or blow away the fertile topsoil.
• Loss of fertility/degradation: continuous cropping without rest, and burning, exhaust the nutrients and destroy the soil structure.
• Pollution of soil by chemicals, refuse and oil spillage.

(d) Two methods of conserving soil

• Contour ploughing/terracing: ploughing across the slope and building terraces to slow run-off and check erosion.
• Crop rotation and fallowing: alternating crops and resting the land, plus adding manure/fertiliser, to restore fertility.
• Afforestation and cover cropping to bind and shade the soil, and mulching to protect the surface.

(a) Formation of clouds

Clouds are masses of tiny water droplets or ice crystals floating in the sky. They form when warm, moist air rises and cools. As the air rises it expands and its temperature falls; when it cools to the dew point the water vapour it carries can no longer stay as a gas, so it condenses around tiny dust particles (condensation nuclei) in the atmosphere. Countless tiny droplets so formed collect together to become a visible cloud. The air may be forced to rise by heating of the ground (convection), by being pushed over mountains (relief), or where warm and cold air meet (frontal uplift).

(b) Relief (orographic) rainfall

Relief rainfall forms when moist air from the sea is forced to rise over a highland or mountain barrier. As the air climbs the windward slope it cools, its vapour condenses into cloud and heavy rain falls on that side of the mountain. Having lost most of its moisture, the air descends the far (leeward) slope, where it warms and dries; this drier side receives little rain and is called the rain shadow. Relief rainfall therefore gives heavy rain on the windward slope and a dry rain shadow on the leeward slope.

(a) Four irrigation areas in the Nile Valley

• The Nile Delta (Lower Egypt, around Cairo/Damietta/Rosetta branches).
• The Faiyum (Fayoum) Depression.
• The Gezira Scheme in the Sudan (between the Blue and White Nile).
• Upper Egypt around Aswan and the area behind the Aswan High Dam (Lake Nasser).

(Other acceptable areas: the Middle Egypt reaches around Asyut; the New Halfa scheme.)

(b) The perennial method of irrigation in the Nile Valley

Perennial (all-year) irrigation is the modern system in which water is stored and supplied to the land throughout the year, so that two or three crops can be grown annually instead of one.

• Large dams and barrages (for example the Aswan High Dam) are built across the Nile to hold back the flood water in a reservoir such as Lake Nasser.
• The stored water is released steadily and led away by a network of main and branch canals which distribute it to the fields all through the year.
• Water is lifted to the fields where necessary by devices such as the shaduf, sakia (water-wheel) and Archimedean screw, or by mechanical pumps.
• Because water is available at all seasons, the farmer no longer depends on the natural annual flood, and the land is cropped continuously.

(c) Four problems created by irrigation in the Nile Valley

• Salinity (salinisation): constant watering without natural flushing leaves salts in the soil as the water evaporates, reducing fertility.
• Waterlogging and rising water table: excessive irrigation raises the water table and floods the root zone, harming crops.
• Loss of natural silt/fertility: the dam traps the fertile silt behind it, so farmers must now buy expensive artificial fertilisers to replace it.
• Spread of water-borne diseases: permanent standing water in canals encourages bilharzia (schistosomiasis) and malaria, and also allows aquatic weeds to choke the canals.

(a)(i) What is internal trade?

Internal trade (domestic or home trade) is the buying and selling of goods and services within the boundaries of a single country, using the country's own currency and moving goods from areas of surplus to areas of demand.

(a)(ii) Four commodities involved in internal trade in Nigeria

• Foodstuffs such as yam, rice, beans and garri.
• Livestock and animal products such as cattle, goats and hides.
• Manufactured/consumer goods such as textiles, soap and cement.
• Cash and forest products such as kola nut, palm oil, timber and vegetables.

(b) Four factors that encourage internal trade in Nigeria

• Regional differences in resources and production: the north produces grains and livestock while the south produces roots, palm produce and manufactures, encouraging exchange between zones.
• Improved transport network: roads, railways and waterways link producing and consuming areas, allowing goods to move cheaply.
• Large population and market: a big and growing population creates high demand for goods and services.
• Common currency and language of trade, and a single political unit: the naira and shared trading languages (Hausa, Yoruba, Igbo, English) ease transactions and remove internal tariff barriers.

Other valid points: presence of markets and middlemen, banking and credit facilities, division of labour/specialisation.

(c) Three problems limiting internal trade in Nigeria

• Poor transport and infrastructure: bad roads, few railways and poor storage raise costs and cause spoilage of perishable goods.
• Inadequate capital and credit facilities: many traders operate on a small scale and cannot expand.
• Insecurity and multiple taxation/levies: armed robbery, unrest and illegal tolls on highways discourage the movement of goods.

Other valid points: seasonal fluctuation and price instability, lack of market information, poor storage/preservation.

Explanatory notes on drought

Drought is a long period of abnormally low or no rainfall which causes a serious shortage of water for people, plants and animals.

(a) Causes

• Prolonged failure or lateness of the rains and general low, unreliable rainfall.
• Deforestation and removal of vegetation, which reduce local moisture and rainfall.
• Southward advance of dry desert conditions (desertification) and dry, dust-laden winds such as the harmattan.
• Climatic change and shifting of the rain-belts, and over-grazing/over-cultivation that dry out the land.

(b) Effects

• Crop failure, famine and food shortage.
• Death of livestock and wild animals from lack of water and pasture.
• Drying up of rivers, wells and reservoirs, causing acute water shortage.
• Migration of people and animals, and outbreaks of disease and poverty.

(c) Control

• Afforestation and reforestation to check desert advance and improve local rainfall.
• Building of dams, boreholes and irrigation schemes to store and provide water.
• Practising good land management (avoiding over-grazing and over-cultivation) and planting drought-resistant crops.
• Providing relief materials and early-warning weather forecasting to affected people.

(a)(i) Three commodities of world trade

• Crude petroleum (oil).
• Machinery and manufactured goods (vehicles, electronics).
• Agricultural products such as cocoa, coffee, wheat.

(a)(ii) Three sea routes in the world

• The North Atlantic route (between Western Europe and North America).
• The Suez Canal route (linking Europe with Asia via the Mediterranean and Red Sea).
• The Panama Canal route (linking the Atlantic and Pacific Oceans). (Also the Cape of Good Hope route.)

(b) Four conditions that promote trade among countries

• Differences in natural resources: countries exchange what they have in surplus for what they lack.
• Differences in climate and relief: allow production of different goods that can be exchanged.
• Differences in level of technology: industrial nations trade manufactured goods for raw materials.
• Good transport and communication: efficient shipping and ports ease the movement of goods.
• Peace, stable currencies and trade agreements between nations.

(c) Three reasons for the low volume of trade among African countries

• African countries produce similar raw materials, so they have little to exchange among themselves.
• Poor transport and communication links between the countries.
• Different currencies, languages and colonial ties that direct trade towards Europe rather than within Africa.
• Low level of industrialisation, so few manufactured goods are available to trade locally.

(a) What is a plateau?

A plateau is an extensive area of highland with a fairly level or gently undulating top and steep sides, standing well above the surrounding land. It is often called a tableland.

(b) Two types of plateaux

• Volcanic (lava) plateau.
• Dissected/tectonic (block) plateau. (Others: intermont plateau, continental plateau.)

(c) Formation of one type of plateau

Volcanic (lava) plateau: During quiet, fissure eruptions, very fluid basaltic lava wells up through long cracks in the earth's crust and spreads out over a wide area. As successive flows cool and solidify one on top of another, they build up thick, horizontal sheets of rock with a broad, flat surface. Over time this piled-up lava forms an extensive, level upland known as a lava or volcanic plateau (for example the Jos Plateau region and the Deccan of India).

(d) Three ways plateaux are important to man

• They are rich in minerals (tin, gold, coal), which are mined.
• Their cool climate favours settlement, health resorts and the growing of temperate crops.
• Their edges have waterfalls and rivers that are used to generate hydro-electric power.
• They provide grazing land for livestock and attract tourists with their scenery.

(a) Rural settlement explained

A rural settlement is a group of dwellings in the countryside where the population is small, sparsely spread and mainly engaged in primary activities such as farming, fishing, herding or lumbering, with few social amenities.

(b) Three types of rural settlement

• Nucleated (clustered) settlement: houses are grouped closely together around a central point such as a market, well or road junction.
• Dispersed (scattered) settlement: houses are spread far apart, each usually standing on its own farmland.
• Linear (ribbon) settlement: houses are strung out in a line along a road, river or valley.

(c) Five differences between rural and urban settlements

(a) Three features of local craft industry in Nigeria

• It uses simple, locally-made tools and local raw materials (clay, leather, cotton, wood, metal).
• It is small-scale, run by individuals or families using manual skill and little capital.
• The skills are traditional, often passed down within families, and the products (pots, cloth, mats, carvings) serve mainly the local market.

(b) Four factors affecting the location of manufacturing industries in Nigeria

• Availability of raw materials: industries locate near their raw materials, especially if bulky or perishable.
• Nearness to market: firms making consumer goods settle near the large centres of demand.
• Availability of power/energy: industries need reliable electricity or fuel.
• Transport facilities: good roads, rail and ports for moving materials and goods.
• Supply of labour and capital, and availability of water.

(c) Three ways industries have contributed to Nigeria's economy

• They provide employment and income for many people.
• They add value to local raw materials and reduce dependence on imported goods.
• They earn foreign exchange through the export of manufactured goods and generate revenue/taxes for government.
• They encourage the growth of towns and the development of infrastructure.