<P> Lake Chad has shrunk considerably since the 1960s, when its shoreline had an elevation of about 286 metres (938 ft) above sea level and it had an area of more than 26,000 square kilometres (10,000 sq mi), making its surface the fourth largest in Africa . An increased demand on the lake's water from the local population has likely accelerated its shrinkage over the past 40 years . </P> <P> The size of Lake Chad greatly varies seasonally with the flooding of the wetlands areas . In 1983, Lake Chad was reported to have covered 10,000 to 25,000 km (3,900 to 9,700 sq mi), had a maximum depth of 11 metres (36 ft), and a volume of 72 km (17 cu mi). </P> <P> By 2000, its extent had fallen to less than 1,500 km (580 sq mi). A 2001 study published in the Journal of Geophysical Research blamed the lake's retreat largely on overgrazing in the area surrounding the lake, causing desertification and a decline in vegetation . The United Nations Environment Programme and the Lake Chad Basin Commission concur that at least half of the lake's decrease is attributable to shifting climate patterns . UNEP blames human water use, such as inefficient damming and irrigation methods, for the rest of the shrinkage . As late as December 2014, Lake Chad was still sufficient in size and volume such that boats could capsize or sink . The European Space Agency has recently presented data showing an actual increase in lake extent of Lake Chad between the years of 1985 to 2011 . </P> <P> Referring to the floodplain as a lake may be misleading, as less than half of Lake Chad is covered by water through an entire year . The remaining sections are wetlands . A wetland is an area of land with its soil saturated with moisture either permanently or seasonally . Such areas may also be covered partially or completely by shallow pools of water . Wetlands include swamps, marshes, and bogs, among others . </P>

Lake chad’s water level was lowest in