Africa’s climate and inland waters

Africa’s inland waters belong to the Atlantic and Indian Ocean basins and to a closed basin. The Nile is one of the longest rivers in the world (about 6 650 km): the White Nile starts from Lake Victoria and the Blue Nile from the Ethiopian Highlands; they join at Khartoum, and where the river meets the Mediterranean it forms a large delta. Our compatriot Ahmad al-Farghani (9th century) built a “nilometer” to measure the Nile’s water level. The Congo is second in length in Africa (about 4 700 km) but first in water volume and basin area; in the world it is second to the Amazon in volume, it crosses the equator twice, is full of water all year and forms no delta. The Niger and Orange belong to the Atlantic basin; the Zambezi and Limpopo to the Indian Ocean basin. Victoria Falls on the Zambezi (about 1 700 m wide and about 108 m high) is one of the biggest waterfalls in the world. The big lakes: Victoria (the largest in Africa, in a tectonic depression), Tanganyika and Nyasa (in the rift, deep); Chad and Rudolf (Turkana) are closed lakes. Lake Chad has shrunk considerably in recent decades. In dry regions groundwater may be the only source of water.