Africa > Tanzania

Lake Rukwa, Tanzania

lakeLake Rukwa
countryTanzania
surface area5,895 km2
maximum depth15 m
average depth4 m
lake typeAlkaline
length180 km
width32 km
catchment area79,611 km2
altitude801 m
volume21 km3
shore length591 km
residence time459 days
originTectonic
average discharge521 m3 / sec.

Lake Rukwa Information and Facts

Lake Rukwa is an endorheic lake, part of the Western Rift Valley of Africa, located in the Southwestern area of Tanzania.

Geography

The lake is of tectonic origin, situated halfway between lakes Tanganyika and Nyasa, at an altitude of approximately 800 meters. It was described as an “impossible swamp” during the XIX-th century, probably because at times the lake is partially dried up, and its shoreline remains wet.

Half of the reservoir is part of the Uwanda Game Reserve, an extension of the Katavi National Park, the third largest National Park of Tanzania and one of the least visited reserves of the country.

The lake is located in a region where earthquakes are quite frequent.

Hydrology

The lake has a large floodplain, and its size varies depending on the amount of rain that falls during rainy season and the inflowing rivers. Rungwa River flows in from the North, while the Momba approaches the lake from the Western area. Three other large inflows come in from the South, the Lupa, Chambua and Songwe rivers. Although there are many incoming rivers, Rukwa Lake doesn’t have any outlets.

The Northern part of the basin is often dry, whilst the Western area is shallow, and presents the ideal place for crocodile habitats. The Southern basin is deeper, with an average depth of 4-6 meters, and the maximum depth is 15 meters.  

Climate

Rukwa Lake is situated in a tropical, wet climate region. There is an annual rainy season between the months of October and April, when the heavy rainfall contributes to the growth of the lake. In the Southern part of the reservoir the annual average rainfall is about 650 millimeters, while in the Northern part there is even more rain, circa 900 millimeters.

The average surface temperature of the lake is between 20 and 35 degrees Celsius.

Animal Life

The Western, shallow part of the lake is home to a lot of crocodiles. Between 1994 and 1996 a lot of hunting permits were issued, which resulted in over 400 crocodiles being killed in less than two years’ time.

The basin is also frequently visited by hippopotamus and otters, and is a preferred place for over 80,000 breeding great white pelicans, which meet here yearly. A large number of non-breeding wetland birds often gather around the lake as well.

Lake Rukwa is home to nearly 60 fish species, of which one-third are considered endemic.

Effects of Population Growth

Although the lake is pretty unstable, considering the fact that its width, depth and length are under continuous change because of the weather and its inflows, it is important to the local population who lives out of commercial fishing. Because of the abundance of this activity, there have been increases in agricultural runoffs, as well as aggravation of erosion, which may lead to the disappearance of this African rift lake.