GCSE Revision

Increasing water supply

Ways to increase water supply

  • Diverting supplies: taking water from rivers by channels or pipes.
  • a across a river stores water in a reservoir, for use through dry seasons.
  • moving water, by pipes, tunnels or canals, from an area with a surplus to an area with a deficit.
  • removing salt from seawater to make fresh water. It is very expensive and uses a lot of energy, so it is used mainly in rich, dry countries, such as Saudi Arabia.

Key terms

The Lesotho Highlands Water Project

Lesotho is a small, mountainous country entirely surrounded by South Africa. Its highlands get plenty of rain and have little industry. South Africa's Gauteng region, around Johannesburg, is its economic heartland, with millions of people, mines and factories, but too little water.

The Lesotho Highlands Water Project is a :

  • in Lesotho's mountains, including Katse and Mohale, store water;
  • tunnels carry it to the Vaal River system, which supplies Gauteng;
  • about 780 million cubic metres a year are transferred, and Phase II, with the new Polihali Dam, aims to raise this to 1,260 million.

Key terms

Advantages and disadvantages

Advantages:

  • South Africa gets a reliable water supply for its people and industry.
  • Lesotho earns from South Africa for the water, an important income for a poor country.
  • The scheme's hydroelectric station supplies electricity to Lesotho, so it imports less.
  • Roads and other were built in the mountains.

Disadvantages:

  • Villages, farmland and grazing land were flooded by the reservoirs, and many people had to move.
  • The flow of rivers below the dams has changed, harming habitats downstream.
  • Some contractors were convicted of bribery over the project.
  • Many people in Lesotho itself still lack a reliable water supply.

Exam tip

Ask who gains and who loses, in each country.

Exam practice

Plan your own answer first, then open the model answers to see what each level looks like.

9 marks · about 9 minutes

To what extent does a large-scale water transfer scheme you have studied bring more advantages than disadvantages?

To what extent means: Weigh up how far something is true, with evidence on both sides, then give a clear judgement.

Link it

Use the facts from:

Level 1 (Basic)· 3/9 marks (band 1–3)
The Lesotho Highlands Water Project gives water to South Africa. But people had to move. It has more advantages.

Why this level: A named scheme with simple points and an unsupported judgement. To reach Level 2: use facts to explain the advantages and disadvantages.

Level 2 (Clear)· 5/9 marks (band 4–6)
The Lesotho Highlands Water Project uses dams such as Katse and Mohale to store water, which tunnels carry to Gauteng in South Africa. About 780 million cubic metres are transferred each year. Lesotho earns royalties and gets electricity from a hydroelectric station. However, villages and farmland were flooded, and many people had to move.

Why this level: Clear, accurate advantages and disadvantages. But they aren't weighed, and there's no judgement. To reach Level 3: compare who gains and who loses, then conclude.

Level 3 (Detailed)· 8/9 marks (band 7–9)
The Lesotho Highlands Water Project stores water behind dams in Lesotho's rainy mountains, such as Katse and Mohale, and tunnels carry it to the Vaal River system serving Gauteng, South Africa's economic heartland. About 780 million cubic metres are transferred each year, and Phase II aims to raise this to 1,260 million, giving South Africa's cities and industries a reliable supply. Lesotho also gains: South Africa pays royalties for the water, an important income for a poor country, and the scheme's hydroelectric station supplies Lesotho with electricity. However, there are disadvantages. Villages, farmland and grazing land were flooded by the reservoirs, and many people had to move, losing their homes and livelihoods. River flow below the dams changed, and some contractors were convicted of bribery. Overall, the scheme brings more advantages than disadvantages, but they are unevenly shared: South Africa gains most, while the costs fall mainly on rural people in Lesotho.

Why this level: Detailed, accurate evidence on both sides, with a judgement that considers who gains and who loses. This is Level 3.

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