Lake Chad - History

History

Lake Chad gave its name to the country of Chad. The name Chad is a local word meaning "large expanse of water", in other words, a "lake".

Lake Chad is the remnant of a former inland sea, palaeolake Mega-Chad. At its largest, sometime before 5000 BC, Lake Mega-Chad was the largest of four Saharan palaeolakes, and is estimated to have covered an area of 400,000 km2 (150,000 sq mi), larger than the Caspian Sea is today, and may have extended as far northeast as within 100 km (62 mi) of Faya-Largeau.

Closer to the present, Lake Chad was first surveyed by Europeans in 1823, and it was considered to be one of the largest lakes in the world then. 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.

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 km2 (3,900 to 9,700 sq mi), had a maximum depth of 11 metres (36 ft), and a volume of 72 km3 (17 cu mi).

By 2000, its extent had fallen to less than 1,500 km2 (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. Some consider it likely the lake will shrink further and perhaps even disappear in the course of the 21st century.

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.

Lake Chad's volume of 72 km3 (17 cu mi) is very small relative to that of Lake Tanganyika (18,900 km3 (4,500 cu mi)) and Lake Victoria (2,750 km3 (660 cu mi)), African lakes with similar surface areas.