THE DRAINAGE SYSTEM OF AFRICA
Drainage is the water ground system of an area.
-The following are the main features of drainage features:
- Drainage basins
- A river is a mass of flowing water
- Tributary is a small river that flows into the main river.
- Distributary is a small river that flows away from the main river.
- Source is where a river starts flowing.
- Mouth is where a river pours its water.
- Confluence is where two or more rivers meet.
- Course is the direction a river moves in.
- Watershed is a line of highland separating two streams which flow into different rivers.
- River bank is a side of a river.
- Estuary is where a river widens as it reaches its mouth.
- Delta is where a river forms several streams as it ends its course.
Rivers of Africa:
Africa is drained by many rivers.
The rivers are in two types.
- Perennial or permanent rivers
- Seasonal rivers
-Perennial rivers: are rivers that flow throughout the year.
-Seasonal rivers: are rivers that flow mainly during the rainy season.
Examples of seasonal rivers:
- i) R. Agago – Uganda
- ii) R. Turkwel – Kenya Major rivers in Africa:
Major rivers in Africa:
-Rivers originate from the following features;
- i) Lakes
- ii) Highlands
- iii) Melting snow / Glaciers
- iv) Springs
Stages of a river:
- A river has three stages / courses
- Upper course / Youth stage
- Middle course
- Lower course / old stage
Characteristics of Upper course:
- -Waterfalls and rapids are formed.
- -The river is narrow.
- -The river is so destructive with gorges formed.
- -The river forms steep slopes.
- -The river erodes down wards.
- -The river flows zig zag course.
Characteristics of the middle course: –
- -The river is wide.
- -It carries many objects.
- -It erodes its sides.
- -It begins to form meanders.
- -It has large amount of water.
Characteristics of the lower course:
- -Ox-bow lakes are formed.
- -The rivers form deltas.
- -Waterfall is where flowing water in a river falls from high altitude to low altitude.
- -Waterfalls are formed when water flows over a cliff (steep slope) or hard rock.
Importance of waterfalls:
- -They are used to generate hydro electricity.
- -They attract tourists who bring income
- -They are used for rafting
Economic importance of rivers
- -They attract tourist for income.
- -They help to generate hydro electricity power.
- -They provide fish to people.
- -They provide water for industrial use.
- -They provide water for irrigation.
- -Some rivers are used for transport. Other uses of rivers
- -They help in the formation of rainfall.
- -They are used for recreation.
- -They provide materials for craft work.
- -They have fertile soils for farming.
- -They provide water for domestic use.
- Why do many rivers in East Africa flow towards Indian Ocean?
- Give two reasons why most rivers have their source in mountain areas.
- In which way do rivers influence human settlement?
- Give two reasons why R.Congo drains a lot of water into Atlantic Ocean.
- In which way can rivers be a disadvantage to people?
- Give three reasons why some rivers are not used for transport?
- Give two reasons why it is believed that early civilization started along river valleys.
- Mention three problems faced by rivers in Africa.
- In which way do rivers influence the way of living of:
10. How do rivers promote industrial development?