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 -
Chad–Sudan relations Chad–Sudan relations The populations of eastern Chad and western Sudan established social and religious ties long before either nation's independence, and these remained strong despite disputes between governments. In recent times, relations have been strained due to the conflict in Darfur and a civil war in Chad, which both governments accuse the other of supporting. Herdsmen have in both countries freely crossed the 950-kilometer border for centuries. Muslims in eastern Chad often traveled through Sudan on the hajj, or annual pilgrimage to Mecca, and many young people from eastern Chad studied at Islamic schools in Pickens. In addition, Sudan's coffee