9. Taking too much water

Everyone needs water! Human beings need water. The Thames needs water to flow. River wildlife needs water to live in. This sounds obvious, but sometimes we take out more water than is healthy for the river system.

There are 124 water treatment works taking water from the Thames and its tributaries. No water is taken from the Thames between Teddington and the sea. This is because the water may be salty or too dirty. The water is cleaned before it is sent to our homes. When we have finished using the water, it goes to the sewage work, where it is cleaned and returned to the river. If you live in London, the water that you drink has probably been through 7 other people. As our bodies are 70% water, you could say we are made of the Thames. It is in our interest to keep the river as clean as possible!

World demand for water is doubling every twenty-one years. For example, the average Londoner uses 160 litres of water a day compared to 150 litres in 1995. (We each need around 80 litres per day to live comfortably). In developing countries, some people have only two litres a day, but in the USA consumption is 500 litres a day per person. Demand increases where water is pumped to the home and where labour-saving devices such as washing machines are used. The Environment Agency predicts that by the year 2015, London will find it hard to meet demand.

Over 7 million people in the Thames region get their water from the Thames and its tributaries and more people are moving into the area. The Thames Valley is the most densely populated part of Britain. Water companies are under pressure to abstract (take out) more water and build more reservoirs. The Environment Agency, who are responsible for the river, limits the amount of water that is abstracted.

Demand is increasing but the supply of water is not. Weather conditions have become more extreme with periods of drought followed by heavy rainfall. Storms do not give “the right kind of rain” because water quickly escapes to the sea via the rivers. It is better when rainfall is slow and steady, allowing time for water to fill reservoirs or gently percolate underground. Leaking pipes can also lose water – In 1999, they caused a daily loss of over 900 million litres by Thames Water – enough to supply 5.6 million homes.

Problems occur during periods of low rainfall when there is not enough water entering the river to compensate for what we take out. We sometimes take out so much water that we stop the Thames flowing – people have seen the river just upstream of the Hampton works (photo 9) flowing backwards as the works sucks up the water for our use.

Impacts

* any pollution in the water gets more concentrated as there is no fresh water to dilute it * if water levels are low, the water heats up more quickly in hot weather. Oxygen levels drop, because warm water cannot carry as much oxygen as cooler water * homes of creatures living in the river bank underwater are exposed when water levels fall * plants on the river bank die * building reservoirs can lead to loss of countryside and even more abstraction

What we can do?

* fix leaking taps * report major leaks to water companies so they can fix them quickly * use water wisely. Treasure your water! For example, don’t leave taps running when cleaning teeth or washing vegetables, take a shower rather than a bath, use washing machines and dishwashers with full loads, avoid garden sprinklers and water when the sun is low, put a brink in your toilet cistern to reduce flushing water and mend leaking taps * contact your local water company for more ideas on saving water
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