Lake Chad is a large, shallow lake in Africa. It is economically very important, providing water to more than 20 million people living in the countries which surround it - Chad, Cameroon, Niger and Nigeria.
Once one of the largest lakes in the world, it has shrunk considerably over the last 40 years. In the 1960s it had an area of more than 26,000 km². By 2000 it had fallen to less than 1,500 km². This is due to reduced rainfall combined with greatly increased amounts of irrigation water being drawn from the lake and the rivers which feed it, the largest being the Chari/Logon system. Because it is very shallow - only 7 metres at its deepest - its area is particularly sensitive to small changes in average depth, and it consequently also shows seasonal fluctuations in size.