Lake Kivu
Lake Kivu lies on the border between the Democratic Republic of the Congo and Rwanda. It is one of Great Lakes in the Albertine Rift, the western branch of the East African Rift. There are about 200 small rivers that flow into it from a relatively small catchment whilst the outflow is to the Ruzizi River, which flows southwards into Lake Tanganyika and ultimately into the mighty Congo.
Lying at 1463 m above sea level, it's surface area is 2,370 km2, the average depth is 240m, the maximum depth is 485m and its total volume is an impressive 560 km3. Lake Kivu has a very irregular shape with a large island, Île Idjwi, the tenth largest inland lake in the world, in the southern DRC part of the lake. The maximum distance from one end of the lake to the other is 103km whilst it's about 48km across. The kayaking distance from Cyangugu in the south to Gisenyi in the north is about 120km.
Lake Kivu is unique with many features setting it apart from all others in the world.
Lying at 1463 m above sea level, it's surface area is 2,370 km2, the average depth is 240m, the maximum depth is 485m and its total volume is an impressive 560 km3. Lake Kivu has a very irregular shape with a large island, Île Idjwi, the tenth largest inland lake in the world, in the southern DRC part of the lake. The maximum distance from one end of the lake to the other is 103km whilst it's about 48km across. The kayaking distance from Cyangugu in the south to Gisenyi in the north is about 120km.
Lake Kivu is unique with many features setting it apart from all others in the world.
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It used to flow to the north and drain into the Nile until around 12,000 years ago, lavas flows from the Virunga volcanoes dammed this outflow, reversing the direction of its waters and also causing the depth to increase. Around 5,000 years ago when local volcanism and hydrothermal activities began to affect the lake, it became very stratified with different layers that hardly interact with each other.
This stable stratification is the secret to it's huge resource, more than any other lake in the world, it has vast quantities of trapped methane at depths of over 200m so there are projects near to Gisenyi and Kibuye that are beginning to extract this reserve. The surface water temperature is 24 °C, and the pH is about 8.6. At depth, almost every other |
(non-frozen) lake in the world is cooler than at the surface with the usual bottom temperature being about 4 °C. However, in Lake Kivu, geothermal activity keeps the temperature in the lower layers at 26 °C - higher than at the surface.
With very steep sides river run offs and most pollutants from the towns around the lake descend quickly to the depths. The surface layer therefore comprises very clean, fresh water, in which some 31 species of fish live, many of which are caught by local fishing cooperatives using their unique fishing boats. However, there are no large animals such as hippopotamus or crocodiles. Furthermore, with few habitats for the host snails to live in and almost no human habitation close to the water (due to a law banning all dwellings within 50m of the shore), Lake Kivu has one of the lowest instances of Schistosomiasis (bilharzia) in any African body of water.
If it is not removed by - for example the current methane extraction process - the dissolved methane and carbon dioxide in the deep layers, will (when the partial pressures of these gasses become more than the pressure of water from above), eventually cause a limnic eruption. However, the scientific analysis indicates that this is many decades away, so for now we are free to enjoy the beauty and tranquillity of Lake Kivu.
You can learn much more information from the Lake Kivu Monitoring Programme.
With very steep sides river run offs and most pollutants from the towns around the lake descend quickly to the depths. The surface layer therefore comprises very clean, fresh water, in which some 31 species of fish live, many of which are caught by local fishing cooperatives using their unique fishing boats. However, there are no large animals such as hippopotamus or crocodiles. Furthermore, with few habitats for the host snails to live in and almost no human habitation close to the water (due to a law banning all dwellings within 50m of the shore), Lake Kivu has one of the lowest instances of Schistosomiasis (bilharzia) in any African body of water.
If it is not removed by - for example the current methane extraction process - the dissolved methane and carbon dioxide in the deep layers, will (when the partial pressures of these gasses become more than the pressure of water from above), eventually cause a limnic eruption. However, the scientific analysis indicates that this is many decades away, so for now we are free to enjoy the beauty and tranquillity of Lake Kivu.
You can learn much more information from the Lake Kivu Monitoring Programme.
