River Basins

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River Basins

For thousands of years, rivers have been the focal point of people's activities. Some of these are listed below:

  • Rivers provide a source of fresh drinking water, a source of food (fishing) and a transport route, all of which were very important to the location of early settlements.
  • Flood plains provide areas of rich, fertile alluvial soil. Hence areas like the Canterbury plains in New Zealand are intensively farmed.
  • Rivers can act as a very effective power source. Initially waterwheels were used to power factories during the Industrial revolution. Latterly the development of hydroelectric power has meant a great increase in the building of dams to trap the water of a river and its drainage basin.
  • Rivers have always been seen as a convenient way of waste removal. This has led to many rivers becoming very polluted and in some cases, dangerous.
  • Estuaries commonly have been used for industry, which has been able to build its factories on the flat flood plain land. This location is ideal for many industries, such as oil refineries, as they then have easy access to the sea for transporting their goods. The land is flat, cheap and easy to reclaim. Usually a local labour source is not too far away. The ship building industry used also to be found in the estuaries of many of the great rivers around Britain, such as the Clyde and the Mersey. Now only a few remain.

As humans have increasingly used and abused river basins so management and planning of them has become increasingly important.

  • Flooding is the most common thing to have to plan around. In many cities the flood plain has not really been built on. Oxford, Exeter and Salisbury are all good examples of where this is the case.
  • To prevent the impact of flooding schemes have been introduced in many of these places. These methods can be very successful, or can cause greater problems further downstream. In Exeter, flood relief channels and raised riverbanks have been used to diminish the flood risk. The scheme in place is aimed at countering a "once in one hundred years" flood, and has been severely tested a couple of times.
  • Building dams across rivers can also cause problems. Obviously there are the advantages of creating a large reservoir, which can be used for drinking water or as the source of water for a hydroelectric power scheme. The reservoir will often also be used for recreational purposes. However the building of a large dam can also cause problems by affecting the flow of water further down the river, by flooding areas of farmland and even towns or villages,and by affecting entire ecosystems.
Tucurui Dam
  • The Tucurui Dam in the Northern Brazilian rainforest did just this, flooding an area of 2875 square kilometres. It was built to provide power for local industries, but at quite a price. The lake it created displaced 40,000people, and is estimated to have destroyed hundreds of species of animals and plants, some of which may never have been actually known about.
  • Rivers are used for the dumping of waste, such as sewage, agricultural waste, chemicals and oil. All will greatly harm the wildlife of the river as well as causing potential problems for humans when they drink the water. Schemes and by-laws have been introduced to try to prevent the pollution of our rivers.