CHAD, LAKE

French Lac Tchad, lake in west-central Africa at the conjunction of the countries of Chad, Cameroon, Nigeria, and Niger. The remnant of a much larger ancient sea, Lake Chad is the largest lake in western Africa and one of the largest lakes on the continent. In the northeast it is bounded by the dunes of the Kanem region. There the shores of the lake are sharp and clearly shaped into peninsulas and islands and underlain with channels that follow the lines of the dunes. The lake itself is composed of two pools (basins) partially separated by a ridge that impedes circulation between them. Lake Chad's surface averages about 6,875 square miles (17,800 square km), but it fluctuates seasonally with variations in local rainfall and drainage into the lake. The lake's main feeder source is the Chari-Logone river system flowing from the south. The mean area of the lake also tends to vary from year to year. The greatest variabilities of the 20th century occurred in the 1970s and '80s, with the area dropping to some 1,500 square miles (3,900 square km) in the mid-1980s. This change is apparently related to the desertification of the surrounding Sahel region. Wildlife populations were depleted in the 20th century, with especially notable losses among large carnivores and game animals. The area supports a mixed population including Yedina (Buduma), Kuri, Kanembu, Fulani, and Hausa peoples. The Niger and Sngal river basins and the Lake Chad basin and their drainage French Lac Tchad, freshwater lake located in the Sahelian zone of west-central Africa at the conjunction of Chad, Cameroon, Nigeria, and Niger. It is situated in an interior basin formerly occupied by a much larger ancient sea that is sometimes called Mega-Chad. Lake Chad ranks as the fourth largest lake in Africa, though its surface area varies greatly. When the surface of the lake is approximately 920 feet (280 metres) above sea level, the area is about 6,875 square miles (17,800 square kilometres). The hydrologic contributions and biological diversity of Lake Chad are important regional assets. The region is noteworthy for important archaeological discoveries, its role in trans-Saharan trade, and its association with historic African kingdoms. Additional reading A general overview of Lake Chad is contained in A.T. Grove, Lake Chad, The Geographical Magazine, 37(7):524537 (November 1964). Jean Maley, Histoire de la vgtation et du climat de l'Afrique nord-tropicale au Quaternaire rcent, Bothalia, 14(34):377389 (September 1983), presents a long-term view of climate change in the Chad basin. The annual vegetation of the region is discussed in H. Gillet, Essai d'valuation de la biomasse vgtale en zone Sahlienne (vgtation annuelle), Journal d'agriculture tropicale et botanique applique, 14(4-5):123158 (AprilMay 1967). J.-P. Carmouze, J.-R. Durand, and C. Lvque (eds.), Lake Chad: Ecology and Productivity of a Shallow Tropical Ecosystem (1983), is a lengthy study of the lake's environment and productivity. The fish of Lake Chad and its tributaries are described in J. Blache and F. Miton, Les Poissons du bassin du Tchad et du bassin adjacent du Mayo Kebbi (1964). A particularly useful study of the peoples of the Chad basin is Albert Le Rouvreur, Sahliens et Sahariens du Tchad (1962, reissued 1989). The more recently arrived Arab groups are discussed in J.C. Zeltner, Les Arabes dans la rgion du Lac Tchad: problmes d'origine et de chronologie (1977). Jeffrey Allman Gritzner Study and exploration For millennia settlement patterns of peoples of Mediterranean and sub-Saharan origin have overlapped in the Sahara, and there is emerging evidence of a long history of interaction between the Lake Chad region and other regions of northern Africa. There are essentially four periods during which the region was strongly affected by external influences. The first is expressed in hints of Egyptian contact with the region, in the sub-Saharan commerce of Carthage and the Garamantes, and in references in Greek, Roman, and Arabic literature. The second period was precipitated largely by the expansion of Islam in North Africa during the 7th century AD, when groups of Arabs and Berbers who resisted conversion sought refuge in the dry lands of the south. The third period emerged from trade between Kanem or Bornu and Mediterranean Africa, the penetration of Islam into sub-Saharan Africa, and increased Arab interest in geographic exploration. It is documented in the many Arabic works written in the 9th to 14th centuries and is also reflected in Abraham Cresque's Catalan Atlas (c. 1375). The fourth period emerged from growing interest in Africa within European academic and commercial circles and was a prelude to European colonization. Numerous descriptions of the Lake Chad region were written by 19th-century Europeans, and three scientific missions were mounted between 1898 and 1909. Since the 1960s the region has been the subject of long-term climatological studies. The people and economy Settlement history The Chad basin contains the earliest evidence of hominid occupation yet found in western Africa, and it appears that the Lake Chad region has been continuously settled since 500 BC. Among the major archaeological discoveries of the region has been the Sao civilization; it is believed that the modern Kotoko, a fishing people on the Chari near Lake Chad, are descendants of the Sao. During the medieval period (9th to 16th century) the Lake Chad region was both an important refuge and an area in which diverse populations were consolidated by the authority of powerful kingdoms. The modern Kanembu, for example, are composed of several groups consolidated by Kanem in the 9th century; similarly, the modern Kanuri emerged from the imposed authority of Kanem's successor state, Bornu, located southwest of Lake Chad. Some ethnic groups were not assimilated. The metallurgists of Kanem, for example, were apparently the Danoa (Haddad), who currently serve as blacksmiths among the Kanembu. Other groups resisted integration into the medieval kingdoms. The Yedina (Buduma) established themselves among the inaccessible islands and along the marshy northern shore of Lake Chad, and the Kuri did the same in inaccessible areas along the eastern margin of the lake. Other ethnic groups established themselves on the shores of Lake Chad in the more recent past. Arab settlement dates from the arrival of the Judam tribes in the 16th century. Some ethnic groups, such as Fulani pastoralists, now enter the Lake Chad lowlands on a seasonal basis; and Hausa agricultural communities can often be found along the lake. The economy of these modern peoples of the Lake Chad region is based primarily on fishing, subsistence and commercial agriculture, and animal husbandryoften in combination. Agriculture and forestry Subsistence crops include sorghum, corn (maize), African millet, beans, and vegetables. Bottle gourds are grown widely for making utensils. Polders near Bol, used to grow cash crops, are based on traditional agricultural practices. Cultivated by the Kanembu and Yedina, the polders are devoted chiefly to wheat. The exploitation of such forest products as gum arabic, honey, beeswax, and firewood is of considerable importance in the region. Production of these, however, has been adversely affected by the decline of the forested areas, aggravated by the explosive growth of cattle populations.