Chad Basin demand for ivory, but stocks have since recovered. The seasonal Korama River in the south of Niger does not reach Lake Chad. Nigeria includes two sub-basins that drain into Lake Chad. The Hadejia - Jama'are - Yobe sub-basin in the north contains the Hadejia and Jama'are rivers, which supply the Hadejia-Nguru wetlands. They converge to form the Yobe, which defines the border between Niger and Nigeria for , flowing into Lake Chad. About of water reaches Lake Chad annually. Construction of upstream dams and growth in irrigation have reduced water flow, and the floodplains are drying up. The Yedseram -
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