Africa > DR Congo / Rwanda

Lake Kivu in Rwanda and DR Congo

lakeLake Kivu
countryRwanda, DR Congo
surface area2,401 km2
maximum depth480 m
average depth237 m
lake typeRift lake
length89 km
width48 km
catchment area7,422 km2
altitude1,461 m
volume569 km3
outflowsRuzizi River
islandsIdjwi
shore length1,191 km
mixing typeMeromictic
settlementsGoma, Congo, Bukavu, Congo, Kibuye, Rwanda, Cyangugu, Rwanda
residence time102,202 days
trophic stateOligotrophic
originTectonic
average discharge65 m3 / sec.

Lake Kivu Information and Facts

Lake Kivu is one of the African Great Lakes, situated on the border between Rwanda and the Democratic Republic of Congo. Its name originates from a Bantu language and means “lake”.

Geography and Hydrology

The lake is located in the Albertine Rift, on the Western part of the East African Rift. 58% of its waters are lying in the Democratic Republic of Congo, the rest are situated in Rwanda. Its irregular shores form a number of inlets and peninsulas, and plenty of waterfalls. It’s mainly surrounded by mountains, mainly on the Northern and Western parts, with several peaks of 2800 meters or even higher. The Western shore of the lake is home to the Kahuzi Biega National Park.

The lake bed is set on a rift valley that is slowly being pulled apart. This activity has caused significant volcanism in the area, making the valley the 18th deepest in the World, with 480 meters. Lake Kivu is fed by underground springs with high concentrations of carbon-dioxide.

The tenth largest inland island on the planet, Idjwi Island, is located on Kivu Lake. The lake’s main outflow is Ruzizi River, which makes its way and flows into Lake Tanganyika, the second largest freshwater lake in the World.

The lake’s shores are densely populated. Among the main settlements around the lake we can enumerate Kabare, Goma, Bukavu and Sake in DRC, and Gisenyi, Kibuye and Cyanguru in Rwanda.

Geology and Chemistry

In 12 000 BP a big lava flow coming from the Vilunga volcano blocked the lake’s former outlet. In 9000 BP the water was much deeper and had an overflow through Ruzizi River. At about 5000 BP the lake became ruggedly stratified which led to the beginning of volcanism and hydrothermal activities.

Lake Kivu is one of three lakes in the area which experience limnic eruptions, along with Nyos and Monoun lakes. Scientists have found evidence of massive biological extinctions caused by the outgassing events. The gases found in the lake are mostly methane (an estimated 63 km3) and carbon-dioxide (256 km3). Because of its gassy composition the lake temperature is usually between 24OC and 27OC, its pH level is 8.6.

Since the water has such a high concentration of methane, scientists argued the possibility of the formation of methane explosions which could have devastating consequences to the inhabitants of the valley. If the lake’s bottom water would interact with the volcanic activity, the high gas concentration would heat the water, which would push methane out of the water, leading to a drastic explosion, releasing carbon-dioxide and suffocating locals.

An experiment was led at Lake Nyos in 2001, testing a pipe installed in the lake to help remove the gas from the water. This could serve as a solution for the situation of Lake Kivu.

Until 2004, extraction of these gases was done on a smaller scale, using it to run boilers at a local brewery. But the 55 billion m3 of dissolved biogas located 300 meters deep in the lake cannot be ignored.

In 2011 an energy company from the United States launched a methane extraction project on a larger scale, using a barge platform with which they can extract, separate and clean the obtained gases properly. This project is set on increasing Rwanda’s power generation by 20 times, making it possible for the country to sell its electricity to its neighbors.  

Biology in and Around the Lake

The oligotrophic lake is dominated by diatoms. Since it has more methane than any other lake, there are only 28 species of fish living in its waters. Some fish are native (Lake Rukwa minnow, Amphilius catfish, Nile tilapia, Clarias catfish), whilst a few were introduced, such as the Lake Tanganyika sardine and the longfin tilapia. Lake Kivu is the only natural lake to have the Lake Miodon sardine living in its waters. It was introduced to the lake in the 20th century and has adapted to its strange conditions perfectly.

The lake is home to four species of freshwater crab. The lake is poor in fauna, but rich in volcanic substances. Because of its unusually high level of volcanic activity and high methane concentration, crocodiles and hippopotamuses cannot be seen. There are, however, many birds living around its shores, such as pelicans, crowned cranes, malachite and kingfishes.

History

The first European who arrived to Lake Kivu in 1894 was Adolf von Götzen, a German count.

The precinct is known as being one of the centers of the conflict between the Hutu and Tutsi people of Rwanda, which later led to the Rwandan genocide and the First and Second Congo wars. Lake Kivu is also known as the place where the bodies of the victims of the genocide were unloaded.

Tourism and Leisure Activities

The lake is the perfect place for swimming, because of its warm temperature and since it doesn’t have any crocodiles in its waters. People also practice a number of water sports such as waterskiing, kayaking, and windsurfing.

There are organized boat tours on which tourists can learn the techniques of traditional fishermen. Because of the proximity of the Congo-Nile Trail, hiking and cycling are also preferred. Volcanoes National Park is one of the best places for gorilla tracking, since more than half of the World’s last mountain gorillas live on the precinct. Nyungve Forest National Park is a popular spot for chimpanzee tracking.

There are three main cities on the lakeshores. Gisenyi is known for its good quality hotels and active nightlife. Kibuye is the prettiest of the three, a real tropical area, whilst Changugu is an old border town. The three are connected by charter boats and a wide scenic road offering a stunning view over the surroundings.

Lake Kivu Fish Species

Tilapia