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Responding to Threats » Technology and Water Shortages

What you'll learn this session

Study time: 30 minutes

Edexcel spec: 7.3 The responses to desertification, deforestation and climate change (a)

Why water shortages are the big problem in dry fragile environments
How drip irrigation, water harvesting, wells and pumps, and desalination work
The advantages and limits of each type of technology
How to write a clear "explain how technology helps" answer

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Why technology is needed

In Impacts of Desertification you saw that dry land loses its soil and crops, and people suffer. Fragile environments under threat from desertification often have too little water. Rain is low and unreliable, and wells and rivers can dry up. Technology can help people get more water, or use the water they have more carefully. This lesson looks at four examples: drip irrigation, water harvesting, wells and pumps, and desalination.

Key terms:

Technology: tools, machines and methods that people use to solve a problem.
Water shortage: when there is not enough water for people, farming and wildlife to meet their needs.
Irrigation: giving water to crops using pipes, channels or sprays instead of waiting for rain.
Desalination: removing salt from sea water to make fresh water.

Four ways technology helps

💧 Drip irrigation

Pipes with tiny holes drip water slowly onto the soil right next to each plant's roots. Very little water is lost to evaporation or runs off, so the same water grows more crops. This keeps farmland working and helps stop the soil turning to desert.

🌧 Water harvesting

Rain is collected when it falls and stored for the dry months. Examples are small earth banks or stone lines that slow runoff so water soaks in, and tanks or ponds that store rainwater. Water harvesting is cheap and can be built by local people.

⛱ Wells and pumps

A well is a hole dug or drilled down to underground water. A pump lifts the water to the surface, powered by hand, by the wind or by solar panels. This gives villages a safe supply close to home, and water for animals and crops.

🌊 Desalination

Sea water is treated so that the salt is removed, leaving fresh water. This works for places on the coast with little rain. It is the most expensive of the four and needs a lot of energy.

Weighing up each technology

No technology is perfect. Each one solves part of the problem, and each has limits.

Drip irrigation: saves water and boosts crop yields. Equipment costs money, and farmers need training and spare parts.
Water harvesting: low cost and uses local materials. It only works if it rains, so stores can run out in a long drought.
Wells and pumps: give a steady supply. If too much water is pumped out, the underground supply can run low and wells can dry up. Pumps can break and need people, wind or sun to run them.
Desalination: gives a supply that does not depend on rain. High cost and high energy use mean it suits wealthy places near the sea better than poor, inland villages.

Learn this

Matching the technology to the place is the key. Simple, low-cost methods such as water harvesting and hand pumps suit poor rural villages. Expensive methods such as desalination suit richer coastal places.

How technology fits the problem

Desertification is helped when water is used well. If crops can be watered, plants hold the soil together and the land stays useful. If people have a reliable well, they are less likely to move away, and animals are not crowded onto one patch of ground until it is bare. Technology can therefore help people stay and farm, and slow the spread of desert.

Worked example

Question: Explain how drip irrigation can help a dry area. [3 marks]

Answer: Drip irrigation delivers water slowly to the roots of each plant (1), so less water is lost by evaporation than if it was sprayed or left to flood the field (1). Farmers can grow more crops with the same water, so the land stays covered and productive (1).

Common mistakes

Naming the technology without saying how it works. "Wells help" is not enough. Say that wells reach underground water and pumps lift it.
Saying technology solves everything. Mention a limit such as cost, energy or a need for rain.
Mixing up water harvesting and desalination. Harvesting collects rain. Desalination removes salt from sea water.
Writing about the causes or impacts of desertification. This lesson is about solving water shortages.

Exam-style question

A village in a dry fragile environment has little rain and its well often runs dry.

(a) State one way technology can give the village more water. [1 mark]

(b) Explain how water harvesting can reduce water shortages. [3 marks]

Model answer

(a) A pump and a deeper well to reach underground water (1).

(b) Rain is collected when it falls, for example in tanks or behind small earth banks (1). It is stored, or soaks into the ground, instead of running away (1). The village can then use this water in the dry months (1).

(c) Desalination is very expensive to build and run (1), and it needs a lot of energy, which a poor village may not have (1).

Exam tip

In an "explain" question, write how the technology works, then what difference it makes. Adding one limit, such as cost, shows you have weighed it up.

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