Lukuga River - Location

Location

The Lukuga runs along the northern edge of the Katanga Plateau. The river leaves lake Tanganyika at Kalemie and flows through a gap in the highlands westward through the Tanganyika District to join the Lualaba between Kabalo and Kongolo. Typically the river accounts for 18% of water loss from the lake, with the rest being due to evaporation. The Lukuga is heavily mineralized. The proportions of ionic contents where the Lukuga River leaves the lake, with magnesium and potassium more prevalent than calcium and sodium, are caused by the Albertine Rift's hydrothermal inputs seen also at the outlets of Lake Kivu and Lake Edward.

It seems likely that the present hydrological system was extablished quite recently when the still-active Virunga volcanoes erupted and blocked the northward flow of water from Lake Kivu into Lake Edward, causing it instead to discharge southward into Lake Tanganyika through the Ruzizi River. Before that Lake Tanganyika, or separate sub-basins in what is now the lake, may have had no outlet other than evaporation.

The Lukuga is of considerable interest to hydrologists, since the volume of water it carries from the lake varies considerably from time to time. The river flow is greatest in May and least in November, corresponding to seasonal fluctuations in the lake level. The river is highly sensitive to longer-term climate variations such as the Neolithic Subpluvial around 4000 BCE. Since 1965 the outflow has tended to increase, although the total outflow of the Congo has been declining.

The Lukuga has formed relatively recently, providing a route through which aquatic species of the Congo Basin could colonize Lake Tanganyika, which formerly had distinct fauna. The river is home to hippopotamus and crocodiles. There are low-grade coal deposits along the river's tributaries north of Kalemie and Moluba.