Lake Chad

lake Chad is large Lake not very deep of Africa whose water is soft, which is rare for a endoreic lake , i.e. whose water does not join the ocean. Its economic role is very important, because it must provide water to more than 20 million people of the four countries bordering: the Chad, the Cameroun, the Niger and the Nigeria.

The catchment area of the lake is theoretically of 2 380 000 km ², but the active basin is in fact only of 967 000 km ². The principal contribution, for 90%, comes from the river Chari and its affluent Logone, both resulting from the mountains of the Central African Republic. Komadugu-Yobé, resulting from Nigeria, is weakened by the presence of two stoppings.

Formerly one of the more big lakes of the world, the lake was reduced considerably during the four last decades. In the Years 1960, it covered a sector of more than 26 000 km ². In 2000, it had fallen to less 1 500 km ². The deficit of rainfall combined with a greater use of water of the lake and rivers for the irrigation explain this dramatic retreat. Its low depth, to the maximum of 7 meters, makes it fragile and very depend on the seasonal fluctuations. Navigation is from now on impossible there.

The retreat of the lake in the years 1970-80 had only disadvantages. The new emerged grounds, still wet, made it possible to especially undertake very productive cultures in the south of the lake, Chadian side. These banks became a true kitchen garden for Ndjamena (fruits, vegetables but also cereals, rice, corn…). The agriculture of fall made live comfortably approximately 40 000 Chadians.

NASA financed a study on the lake Chad within the framework of its system of observation of the Earth. The variations are followed by Artificial satellite, in order to prevent the residents of the awaited modifications. However, the specialists are very pessimistic as for the future of the lake.

Commission of the Basin of the Lake Chad (CBLT)

History of its evolution

During the postglacial periods, the the Sahara profited from climatic conditions much more lenient than nowadays and the real desert was very restricted. The Sahara in major part was covered of a wooded vegetation of Mediterranean type, particularly in the Massif Centrals with around them of many lakes and the dry meadows, situation favorable to a giboyeuse fauna.

According to alternations of the wet phases and dry periods the lake Chad extends or retracts, but starting from 4.000 front J. - C., until our days, the fall of water is fast corresponding to the installation of the aridity and the inexorable projection of the immense desert.

The variations of the lake Chad testify to many changes:

Towards 20.000 front J. - C., the lake disappeared completely because of the consecutive aridity of the tropics to the apogee of the glaciation.
Towards 9 500 av. J. - C., grown bigger by the rains which fell in abundance on the Tibesti, it has a 15 m depth, before returning about to the current location towards 9.000 front J. - C..
Towards 7.000 front J. - C., it has a 38 m depth, before returning about to the current location towards 5 500 av. J. - C..
Towards 4.000 front J. - C., it has a 65 m depth, and ends up covering a surface of more than one million km ², that is to say several hundreds of times its current surface, before returning about to the current location towards 2.000 front J. - C.. The lake was then a true inland sea of central Africa which was drained and the basin filled of sand.
Towards 1.000 front J. - C., it has a 17 m depth, before going down again to the current location.
Today, dimensions of the lake are modest: 30 km out of 40 with the mouth of the river Chari - (Logone).

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