Africa: Relief and Drainage – SS2 Geography Lesson Note (Third Term)

Africa’s relief is grouped into four regions: mountains in the east, highlands in the west, plateaux in the south and ranges in the north. Lowlands lie mainly along the coasts and in the East African Rift Valley. Drainage is carried by many rivers, of which the Nile, Niger, Zambezi and Orange are outstanding, and by natural and man-made lakes.

Behavioural objectives

By the end of the lesson, students should be able to:

• Name the four relief regions of Africa and give examples of the highlands, mountains and plateaux in each.
• State the location, origin and importance of the East African Rift Valley.
• Name the four outstanding rivers of Africa and their lengths.
• Give examples of natural and man-made lakes in Africa.

What are the relief regions of Africa?

Africa can be grouped into the following relief regions:

1. The east (made up partly of mountains)
2. The west (made up partly of highlands)
3. The south (made up mainly of plateaux)
4. The north (made up mainly of ranges)

East Africa

There are many mountains in this part of Africa. They include Mount Kilimanjaro (5,895 m), which is the highest mountain in Africa, Cameroon Mountain, Ethiopia Mountain, Mount Elgon, Mount Rwenzori and Mount Kenya.

West Africa

The highlands in this area include the Fouta Djallon, Guinea, Adamawa highland and Jos Plateau.

South Africa

This area is mainly made up of plateaux. There is a continuous escarpment, highest in the Drakensberg Mountains in South Africa.

North Africa

The ranges include Ahagger, Tasilli, Tibesti, Darfur and the Atlas Mountains.

Where are the areas of lowland in Africa?

The areas of lowland are restricted mainly to the coasts of Africa and the Rift Valley of East Africa.

What is the East African Rift Valley system?

1. Location: It stretches from the Red Sea to the River Zambezi in Zambia, through Ethiopia, Kenya, Uganda, Tanzania and Malawi. It is about 5,000 to 6,000 km long.
2. Origin / formation: Due to block faulting, there was subsidence of land between two parallel faults caused by tension.
3. Nature of the floor / depth: It has a narrow flat floor with lakes, some of which fall below sea level. The valley has steep walls. It contains lakes such as Tanganyika (the second deepest lake in the world) and Lake Malawi.
4. Importance: The Rift Valley system is important for the following:
   • Tourism
   • Fishing
   • Salt mining
   • Rich agricultural land

What are the main rivers of Africa?

Africa has a large number of important rivers. Out of all the rivers, only four are outstanding because of their length and volume. These are:

1. River Nile (6,600 km), the longest
2. River Niger (4,200 km)
3. River Zambezi (2,400 km)
4. River Orange (1,600 km)

What are the main lakes of Africa?

1. Natural lakes: These include Lake Victoria, Chad, Tanganyika, Malawi and Turkana.
2. Artificial / man-made lakes: These include Lake Nasser on the Nile, Lake Volta on the River Volta, Lake Kainji on the Niger and Lake Kariba (the largest man-made lake in Africa) on the Zambezi River.

Evaluation

1. Name the four relief regions of Africa.
2. What is the highest mountain in Africa, and how high is it?
3. Explain how the East African Rift Valley was formed.
4. State four ways in which the Rift Valley system is important.
5. Name the four outstanding rivers of Africa, starting with the longest.

Assignment

Draw an outline map of Africa. On it, show the following rivers:

• (a) River Nile
• (b) River Niger
• (c) River Orange
• (d) River Zambezi