Sustainable water supply

Sustainable water supplies

A water supply meets people's needs today without using up the water needed in the future.

using less, with water meters, low-flush toilets and efficient showers, fixing leaking pipes, and growing crops that need less water.
limiting how much is pumped from , so it isn't used faster than rain refills it.
Recycling: cleaning used water so it can be used again, for example by industry.
reusing water from sinks, baths and washing machines, for flushing toilets or watering gardens.

Key terms

The Wakel River Basin, India

The Wakel River Basin is in the hills of southern Rajasthan, in north-west India. Rain falls mainly in the summer , and for the rest of the year water is scarce. Most people are farmers, many of them from tribal communities, and over-pumping had made wells run dry.

A project helped villages to store monsoon rain, using simple, local methods:

taankas: underground tanks that collect rainwater from roofs;
johads: small earth dams that hold rainwater, so it soaks into the ground and refills the ;
across streams, which slow the water so more soaks in;
pats: channels that carry water to fields, shared in turn by farmers.

Key terms

How sustainable is it?

Benefits:

villages have water for more of the year, for drinking, animals and crops;
groundwater is refilled rather than used up;
the methods are traditional and cheap, using local materials, and villagers build and look after them;
communities share and manage the water together.

Limits:

the methods depend on the : if it fails, there is little to store;
structures need regular repair, and silt fills small dams;
outside help paid for the project, so it depends on villagers keeping it going.

Judgement: a sustainable scheme, because it works with the natural water cycle and is run by local people.

Exam practice

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

6 marks · about 6 minutes

Using an example, explain how a local scheme in an LIC or NEE can increase sustainable supplies of water.

Explain means: Give the reasons why something happens, developing each point with "because" or "so".

Link it

Use the facts from:

The Wakel River Basin (Southern Rajasthan, India, 2000s to 2010s)

Level 1 (Basic)· 2/6 marks (band 1–2)

In India, villages collect rainwater in tanks and small dams. This gives them more water.

Why this level: A relevant idea, but no named place and little explanation. To reach Level 2: name the scheme and explain how its methods work.

Level 2 (Clear)· 4/6 marks (band 3–4)

In the Wakel River Basin, in Rajasthan, over-pumping had made wells run dry. Villagers store monsoon rain: taankas collect it from roofs, and johads and check dams hold it so it soaks into the ground and refills the groundwater.

Why this level: Clear, named scheme with methods explained. To reach Level 3: explain why it is sustainable, and include its limits.

Level 3 (Detailed)· 6/6 marks (band 5–6)

The Wakel River Basin, in the hills of southern Rajasthan, gets rain mainly in the summer monsoon; outside it, water is scarce, and over-pumping had made wells run dry. Villagers store monsoon rain using traditional methods. Taankas are underground tanks that collect rainwater from roofs. Johads, small earth dams, and check dams across streams hold water back, so it soaks into the ground and refills the groundwater. Pats are channels that share water between fields in turn. The scheme is sustainable because the methods are cheap, use local materials, and are built and run by villagers, and they refill groundwater rather than using it up. However, they depend on the monsoon, and need regular repair.

Why this level: Detailed explanation of the methods, why the scheme is sustainable, and its limits. This is Level 3.

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