KIVU, a large lake of central Africa, lying in the western rift valley and mid-way between Lakes Edward and Tanganyika; it discharges into the latter by the river Russisi. It is 55 m. long and 3o m. wide at its widest point. It is about 4,83o ft. above sea-level and is roughly triangular in outline, the longest side lying to the west. The coast-line is much broken, especially on the south-east, where the indentations have a fjord-like character. The rift valley has dropped down Archaean gneisses and schists but both north and south of the lake are volcanic centres (the lavas are phonolites, etc.) some of which are still active. The lake, is deep, and the shores are everywhere high, rising in places in bold precipitous cliffs of volcanic rock. A large island, Kwijwi runs in the direction of the major axis of the lake, south-west of the centre, and there are many smaller islands. The lake has
many fish, but no crocodiles or hippopotami. South of Kivu the rift valley is blocked by huge ridges, through which the Russisi now breaks its way to descend 2,000 ft. to the lacustrine plain at the head of Tanganyika. The lake fauna is fresh-water, presenting no affinities with the so-called marine fauna of Tanganyika, but is similar to that shown to have existed in the more northern parts of the rift valley. The former outlet or extension in this direction seems to have been blocked in recent geological times by the elevation of the volcanic peaks. This volcanic region is of great interest and has various names, that most used being Mfumbiro (q.v.). Kivu and Mfumbiro were first heard of by J. H. Speke in 1861, and first visited by a European, Count von Gotzen, in 1894. The lake now lies entirely in the Belgian Congo.