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, rivers have also been used for transport, and cities have grown on their banks. The River Nile, for example, is the longest in the world and, since ancient times, has provided animals and the people of Africa – in particular, Egypt – with their principle water source.