Lake Chad the Yobe River in Nigeria/Niger. Despite high levels of evaporation, the lake is fresh water. Over half of the lake's area is taken up by its many small islands (including the Bogomerom archipelago), reedbeds and mud banks, and a belt of swampland across the middle divides the northern and southern halves. The shorelines are largely composed of marshes. Because Lake Chad is very shallow—only at its deepest—its area is particularly sensitive to small changes in average depth, and consequently it also shows seasonal fluctuations in size. Lake Chad has no apparent outlet, but its waters percolate into the Soro and
Colony of Niger Tibesti Cercle ceded to Chad Colony in French Equatorial Africa, and in 1932, the colony of French Upper Volta was divided amongst its neighbors, with the Cercles of Dori and Fada N'gourma ceded to Niger Colony. Niger Colony officials, unlike neighboring Chad, remained loyal to the French Vichy government after 1940, and thus closed its southern border (to Nigeria) and eastern border until 1944. On 31 December 1946 the Military Territories of N'Guigmi and Agadez were ceded to Niger Colony, leaving only Bilma Cercle as the last military-run section of modern Niger. This area in the far north east only