Extreme Environments Rivers
The world''s lakes and flowing rivers constitute only one percent of the Earth''s water. However the fresh water in rivers is vital to all land-based life. Population pressures are putting all major waterways under stress. Rivers provide drinking water, and water for agricultural purposes. Since the beginning of civilization, they have also been used for transport, and cities have grown on their banks. An example, the river Nile is the longest in the world, providing animals and the people of Africa – in particular, Egypt - with their principle water source.