Rift Valley lakes
Encyclopedia
Great Rift Valley
The Great Rift Valley is a name given in the late 19th century by British explorer John Walter Gregory to the continuous geographic trench, approximately in length, that runs from northern Syria in Southwest Asia to central Mozambique in South East Africa...
formed by the East African Rift
East African Rift
The East African Rift is an active continental rift zone in eastern Africa that appears to be a developing divergent tectonic plate boundary. It is part of the larger Great Rift Valley. The rift is a narrow zone in which the African Plate is in the process of splitting into two new tectonic plates...
which runs through the whole eastern side of the Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
n continent from north to south. These lakes include some of the oldest, largest and deepest lakes in the world, and many are freshwater ecoregion
Ecoregion
An ecoregion , sometimes called a bioregion, is an ecologically and geographically defined area that is smaller than an ecozone and larger than an ecosystem. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural...
s of great biodiversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
, while others are alkaline or soda lakes supporting highly specialised organisms.
The Rift Valley Lakes are well known for the evolution of at least 800 cichlid
Cichlid
Cichlids are fishes from the family Cichlidae in the order Perciformes. Cichlids are members of a group known as the Labroidei along with the wrasses , damselfish , and surfperches . This family is both large and diverse. At least 1,300 species have been scientifically described, making it one of...
fish species that live in their waters. More species will be discovered.
The World Wildlife Fund has designated the African Rift Valley lakes one of its Global 200
Global 200
The Global 200 is the list of ecoregions identified by the World Wildlife Fund as priorities for conservation. According to the WWF, an ecoregion is defined as a "relatively large unit of land or water containing a characteristic set of natural communities that share a large majority of their...
priority ecoregions for conservation.
In this article, the major lakes are listed, generally in order from north to south, and more detailed articles on each lake can be accessed through the linked names.
Geology
The East African RiftEast African Rift
The East African Rift is an active continental rift zone in eastern Africa that appears to be a developing divergent tectonic plate boundary. It is part of the larger Great Rift Valley. The rift is a narrow zone in which the African Plate is in the process of splitting into two new tectonic plates...
came into being approximately 40 million years ago as the African tectonic plate
African Plate
The African Plate is a tectonic plate which includes the continent of Africa, as well as oceanic crust which lies between the continent and various surrounding ocean ridges.-Boundaries:...
began to split. Lakes such as Lake Malawi
Lake Malawi
Lake Malawi , is an African Great Lake and the southernmost lake in the Great Rift Valley system of East Africa. This lake, the third largest in Africa and the eighth largest lake in the world, is located between Malawi, Mozambique, and Tanzania...
and Lake Tanganyika
Lake Tanganyika
Lake Tanganyika is an African Great Lake. It is estimated to be the second largest freshwater lake in the world by volume, and the second deepest, after Lake Baikal in Siberia; it is also the world's longest freshwater lake...
have formed in the various valleys of the rift zone, including the huge Lake Victoria
Lake Victoria
Lake Victoria is one of the African Great Lakes. The lake was named for Queen Victoria of the United Kingdom, by John Hanning Speke, the first European to discover this lake....
.
Ecology
Although the East African Rift lakes contribute comparatively little greenhouse gasGreenhouse gas
A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone...
emission, nonetheless there is a need to reduce the deforestation
Deforestation
Deforestation is the removal of a forest or stand of trees where the land is thereafter converted to a nonforest use. Examples of deforestation include conversion of forestland to farms, ranches, or urban use....
rate of surrounding areas and restore cleared areas. These forests provide carbon sinks for greenhouse gases and therefore mitigate climatic changes.
Ethiopian Rift Valley lakes
Ethiopia
Ethiopia , officially known as the Federal Democratic Republic of Ethiopia, is a country located in the Horn of Africa. It is the second-most populous nation in Africa, with over 82 million inhabitants, and the tenth-largest by area, occupying 1,100,000 km2...
the Great Rift Valley
Great Rift Valley
The Great Rift Valley is a name given in the late 19th century by British explorer John Walter Gregory to the continuous geographic trench, approximately in length, that runs from northern Syria in Southwest Asia to central Mozambique in South East Africa...
splits the Ethiopian highlands
Ethiopian Highlands
The Ethiopian Highlands are a rugged mass of mountains in Ethiopia, Eritrea , and northern Somalia in the Horn of Africa...
into northern and southern halves, and the Ethiopian Rift Valley lakes occupy the floor of the rift valley between the two highlands. Most of the Ethiopian Rift Valley lakes do not have an outlet, and most are alkaline
Alkalinity
Alkalinity or AT measures the ability of a solution to neutralize acids to the equivalence point of carbonate or bicarbonate. The alkalinity is equal to the stoichiometric sum of the bases in solution...
. Although the Ethiopian Rift Valley Lakes are of great importance to Ethiopia's economy, as well as being essential to the survival of the local people, there were no intensive and extensive limnological studies undertaken of these lakes until recently.
The major ones are
- Lake AbayaLake AbayaLake Abaya is a lake in the Southern Nations, Nationalities, and Peoples Region of Ethiopia. It was named Lake Margherita by the Italian explorer Vittorio Bottego, the first European commonly thought to visit the lake, to honor the wife of king Umberto I of Italy, Queen Margherita...
(1162 km2, elevation 1285 m), the largest Ethiopian Rift Valley lake - Lake ChamoLake ChamoLake Chamo is a lake in the Southern Nations, Nationalities, and Peoples Region of southern Ethiopia. It is located in the Great Rift Valley at an elevation of 1,110 meters. It is just to the south of Lake Abaya and the city of Arba Minch, and east of the Guge Mountains.The lake's northern end...
(551 km2, elevation 1235 m) - Lake ZwayLake ZwayLake Zway or Lake Ziway is one of the freshwater Rift Valley lakes of Ethiopia. It is located about 60 miles south of Addis Ababa, on the border between the Regions of Oromia and of the Southern Nations, Nationalities, and Peoples; the woredas holding the lake's shoreline are Adami Tullu and Jido...
(485 km2, elevation 1636 m) - Lake ShalaLake ShalaLake Shala lies in Ethiopia south of Addis Ababa, in the Abijatta-Shalla National Park. The lake is 28 kilometers long and 12 wide, with a surface area of 329 square kilometers. It has a maximum depth of 266 meters and is at an elevation of 1,558 meters...
(329 km2, elevation 1558 m), the deepest Ethiopian Rift Valley lake - Lake Koka (250 km2, elevation 1590 m)
- Lake LanganoLake LanganoLangano is a lake in the Oromia Region of Ethiopia, exactly 200 kilometers by road south of the capital, Addis Ababa, on the border between the Misraq Shewa and Arsi Zones. The first European to record its existence, Oscar Neumann, records that it was also known as "Lake Kore"...
(230 km2, elevation 1585 m) - Lake AbijattaLake AbijattaLake Abijata lies in Ethiopia south of Addis Ababa, in the Abijatta-Shalla National Park. According to the Statistical Abstract of Ethiopia for 1967/68, the lake is 17 kilometers long and 15 km wide, with a surface area of 205 square kilometers...
(205 km2, elevation 1573 m) - Lake AwasaLake AwasaLake Awasa is an endorheic basin in Ethiopia, located in the Rift Valley south of Addis Ababa. According to the Statistical Abstract of Ethiopia for 1967/68, the lake is 16 km long and 9 km wide, with a surface area of 129 square kilometers...
(129 km2, elevation 1708 m)
Lake Tana
Lake Tana
Lake Tana is the source of the Blue Nile and is the largest lake in Ethiopia...
, the source of the Blue Nile
Blue Nile
The Blue Nile is a river originating at Lake Tana in Ethiopia. With the White Nile, the river is one of the two major tributaries of the Nile...
, lies in the Ethiopian highlands north of the Rift Valley; it is not a Rift Valley lake.
Eastern Rift Valley lakes (Kenya and Tanzania)
South of the Ethiopian highlands, the rift valley splits into two major troughs. The Eastern Rift is home to the KenyaKenya
Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...
n Rift Valley lakes, while most of the Central African Rift Valley lakes lie in the Western Rift. The Kenyan section of the Rift Valley is home to eight lakes, of which 3 are freshwater and the rest alkaline. Of the latter, the shallow soda lakes of the Eastern Rift Valley have crystallised salt turning the shores white, and are famous for the large flocks of flamingo
Flamingo
Flamingos or flamingoes are gregarious wading birds in the genus Phoenicopterus , the only genus in the family Phoenicopteridae...
that feed on crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s.
- Lake TurkanaLake TurkanaLake Turkana , formerly known as Lake Rudolf, is a lake in the Great Rift Valley in Kenya, with its far northern end crossing into Ethiopia. It is the world's largest permanent desert lake and the world's largest alkaline lake...
(6405 km², elevation 360 m, freshwater) is the largest of the Kenyan lakes, on the border of Kenya and Ethiopia. - Lake LogipiLake LogipiLake Logipi is a saline, alkaline lake that lies at the northern end of the arid Suguta Valley in the northern Kenya Rift. It is separated from Lake Turkana by the Barrier volcanic complex, a group of young volcanoes that last erupted during the late 19th Century or early 20th Century...
is a shallow hot-spring fed soda lake in the Suguta Valley just south of Lake Turkana. - Lake BaringoLake BaringoLake Baringo is, after Lake Turkana, the most northern of the Great Rift Valley lakes of Kenya, with a surface area of about and an elevation of about . The lake is fed by several rivers, El Molo, Perkerra and Ol Arabel, and has no obvious outlet; the waters are assumed to seep through lake...
(80 sq miles, elevation 1000 m) freshwater, second largest of the Kenyan Rift Valley lakes, - Lake BogoriaLake BogoriaLake Bogoria is a saline, alkaline lake that lies in a volcanic region in a half-graben basin south of Lake Baringo, Kenya, a little north of the equator. Lake Bogoria, like Lake Nakuru, Lake Elmenteita, and Lake Magadi further south in the Rift Valley, and Lake Logipi to the north, is home at...
(34 km², elevation 990 m) shallow soda lake, a national preserve - Lake NakuruLake NakuruLake Nakuru is one of the Rift Valley soda lakes at an elevation of 1754 m above sea level. It lies to the south of Nakuru, in the rift valley of Kenya and is protected by Lake Nakuru National Park....
(40 km², elevation 1759 m) shallow soda lake, has been a national park since 1968 - Lake ElmenteitaLake ElmenteitaLake Elmenteita, also spelled Elementaita, is a soda lake, in the eastern limb of East Africa's Great Rift Valley, about 120 km northwest of Nairobi, Kenya.- Geography :...
, shallow soda lake - Lake NaivashaLake NaivashaLake Naivasha is a freshwater lake in Kenya, lying north west of Nairobi, outside the town of Naivasha. It is part of the Great Rift Valley. The name derives from the local Maasai name Nai'posha, meaning "rough water" because of the sudden storms which can arise...
(160 km² — varies somewhat with rainfall, elevation 1,890 m), freshwater lake, is the highest in this group. - Lake MagadiLake MagadiLake Magadi is the southernmost lake in the Kenya Rift Valley, lying in a catchment of faulted volcanic rocks, north of Tanzania's Lake Natron. During the dry season, it is 80% covered by soda and is well known for its wading birds, including flamingos....
, shallow soda lake near the southern border with Tanzania.
The Tanzanian section of this group has alkaline lakes:
- Lake NatronLake NatronLake Natron is a salt lake located in northern Tanzania, close to the Kenyan border, in the eastern branch of Africa's Great Rift Valley. The lake is fed by the Ewaso Ng'iro River but also by mineral-rich hot springs and is quite shallow, less than three meters deep, and varies in width depending...
, shallow soda lake which has categorised by the World Wildlife Fund as the East African halophytics ecoregionEcoregionAn ecoregion , sometimes called a bioregion, is an ecologically and geographically defined area that is smaller than an ecozone and larger than an ecosystem. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural...
. - Lake ManyaraLake ManyaraLake Manyara is a shallow lake in the Natron-Manyara-Balangida branch of the Great Rift Valley in Tanzania. Said by Ernest Hemingway to be the "loveliest [lake] .....
, - Lake EyasiLake EyasiLake Eyasi is a seasonal shallow endorheic salt lake on the floor of the Great Rift Valley at the base of the Serengeti Plateau, just south of the Serengeti National Park and immediately southwest of the Ngorongoro Crater in the Crater Highlands of Tanzania...
, shallow soda lake - Lake Makati, shallow soda lake
Western or Albertine Rift Valley Lakes
The lakes of the Western or Albertine Rift, together with Lake VictoriaLake Victoria
Lake Victoria is one of the African Great Lakes. The lake was named for Queen Victoria of the United Kingdom, by John Hanning Speke, the first European to discover this lake....
, include the largest, deepest and oldest of the Rift Valley lakes. They are also referred to as the Central African lakes. Lakes Albert, Victoria, and Edward are part of the Nile River basin.
Lake Victoria
Lake Victoria
Lake Victoria is one of the African Great Lakes. The lake was named for Queen Victoria of the United Kingdom, by John Hanning Speke, the first European to discover this lake....
(elevation 1134 m), with an area of 68,800 km², is the largest lake in Africa, but is not actually within the rift valley; it occupies a depression between the eastern and western rifts, formed by the uplift of the rifts to either side. Lakes Victoria, Tanganyika, and Malawi are sometimes collectively known as the African Great Lakes
African Great Lakes
The African Great Lakes are a series of lakes and the Rift Valley lakes in and around the geographic Great Rift Valley formed by the action of the tectonic East African Rift on the continent of Africa...
.
The Western Rift Valley Lakes are fresh water and home to an extraordinary number of species. Approximately 1,500 cichlid
Cichlid
Cichlids are fishes from the family Cichlidae in the order Perciformes. Cichlids are members of a group known as the Labroidei along with the wrasses , damselfish , and surfperches . This family is both large and diverse. At least 1,300 species have been scientifically described, making it one of...
fish (Cichlidae) species live in the lakes (See Hubert Sauper's Darwin's Nightmare
Darwin's Nightmare
Darwin's Nightmare is a 2004 French-Belgian-Austrian documentary film written and directed by Hubert Sauper, dealing with the environmental and social effects of the fishing industry around Lake Victoria in Tanzania. It premiered at the 2004 Venice Film Festival, and was nominated for the 2006...
concerning a reduction in biodiversity). In addition to the cichlids, populations of Clariidae, Claroteidae
Claroteidae
The Claroteidae are a family of catfish found in Africa. This family was separated from Bagridae. However, the monophyly of the family is sometimes contested....
, Mochokidae
Mochokidae
The Mochokidae are a family of catfishes that are known as the squeakers and upside-down catfish. There are 10 genera and about 188 species of mochokids. All the mochokids are freshwater species originating from Africa....
, Poeciliidae
Poeciliidae
Poeciliidae is a family of fresh-water fish which are live-bearing aquarium fish . They belong to the order Cyprinodontiformes, tooth-carps, and include well-known aquarium fish such as the guppy, molly, platy, and swordtail...
, Mastacembelidae
Mastacembelidae
The Mastacembelidae are a family of fishes, known as the spiny eels. The Mastacembelids are part of the Order Synbranchiformes, the swamp eels, which are part of the Actinopterygii ....
, Centropomidae
Centropomidae
The Centropomidae are a single genus family of freshwater and marine fishes in Order Perciformes, including the common snook or róbalo, Centropomus undecimalis...
, Cyprinidae, Clupeidae
Clupeidae
Clupeidae is the family of the herrings, shads, sardines, hilsa and menhadens. It includes many of the most important food fishes in the world.-Description and biology:...
and other fish families are also found in these lakes. The lakes are also important habitats for a number of amphibian species, including Amietophrynus kisoloensis
Amietophrynus kisoloensis
Amietophrynus kisoloensis is a species of toad in the Bufonidae family.It is found in Democratic Republic of the Congo, Kenya, Malawi, Rwanda, Tanzania, Uganda, Zambia, and possibly Burundi....
, Bufo keringyagae, Cardioglossa cyaneospila
Cardioglossa cyaneospila
Cardioglossa cyaneospila is a species of frog in the Arthroleptidae family.It is found in Burundi, Democratic Republic of the Congo, and Rwanda.Its natural habitats are subtropical or tropical moist montanes and rivers.-Source:...
, and Nectophryne batesii.
- Lake Albert (5300 km², elevation 615 m) is the northernmost lake in the western rift.
- Lake EdwardLake EdwardLake Edward or Edward Nyanza is the smallest of the African Great Lakes. It is located in the western Great Rift Valley, on the border between the Democratic Republic of the Congo and Uganda, with its northern shore a few kilometres south of the Equator...
(2325 km², elevation 912 m) drains north into Lake Albert - Lake KivuLake KivuLake Kivu is one of the African Great Lakes. It lies on the border between the Democratic Republic of the Congo and Rwanda, and is in the Albertine Rift, a part of the Great Rift Valley. Lake Kivu empties into the Ruzizi River, which flows southwards into Lake Tanganyika...
(2220 km², elevation 1460 m) empties into Lake Tanganyika via the Ruzizi RiverRuzizi RiverThe Ruzizi , is a river which flows from Lake Kivu to Lake Tanganyika in Central Africa, descending rapidly from about 1,500 metres above sea level to about 770 metres above sea level over its length...
. - Lake TanganyikaLake TanganyikaLake Tanganyika is an African Great Lake. It is estimated to be the second largest freshwater lake in the world by volume, and the second deepest, after Lake Baikal in Siberia; it is also the world's longest freshwater lake...
(32,000 km², elevation 773 m) is the largest and deepest of the Rift Valley lakes (more than 1400 meters), and is the second deepest fresh water lake on the planet (after Lake BaikalLake BaikalLake Baikal is the world's oldest at 30 million years old and deepest lake with an average depth of 744.4 metres.Located in the south of the Russian region of Siberia, between Irkutsk Oblast to the northwest and the Buryat Republic to the southeast, it is the most voluminous freshwater lake in the...
). Below roughly 200 meters depth, its water is anoxic, and devoid of most larger aquatic life. It is part of the Congo RiverCongo RiverThe Congo River is a river in Africa, and is the deepest river in the world, with measured depths in excess of . It is the second largest river in the world by volume of water discharged, though it has only one-fifth the volume of the world's largest river, the Amazon...
basin, feeding into the River Congo via the Lukuga River.
Southern Rift Valley lakes
The Southern Rift Valley lakes are like the Western Rift Valley lakes in that, with one exception, they are freshwater lakes.- Lake RukwaLake RukwaLake Rukwa is a lake in southwestern Tanzania. The alkaline Lake Rukwa lies midway between Lake Tanganyika and Lake Nyasa at an elevation of about 800 metres, in a parallel branch of the rift system. The lake has seen large fluctuations in its size over the years, due to varying inflow of streams...
(about 5670 km² but quite variable) in Tanzania is the alkaline exception, lying south-east of Tanganyika, and has no outlet. - Lake MalawiLake MalawiLake Malawi , is an African Great Lake and the southernmost lake in the Great Rift Valley system of East Africa. This lake, the third largest in Africa and the eighth largest lake in the world, is located between Malawi, Mozambique, and Tanzania...
(30,000 km², elevation 500 m), the second largest and second deepest of the Rift Valley lakes at over 700 meters, is drained by the Shire RiverShire RiverThe Shire is a river in Malawi and Mozambique. The river has been known as the Shiré or Chire River. It is the outlet of Lake Malawi and flows into the Zambezi. Its length is 402 km; including Lake Malawi and the Ruhuhu, its headstream, it has a length of about 1200 km...
, a tributary of the Zambezi River. Also known as Lake Nyasa. - Lake MalombeLake MalombeLake Malombe is a lake in southern part of Malawi, on the Shire River, in the Southern Region. It is located at around . It has an area of about . In recent years the number of fishermen on the lake rose substantially, this led to local decline in some fish species, such as chambo.- References :*...
(450 km²) is on the Shire RiverShire RiverThe Shire is a river in Malawi and Mozambique. The river has been known as the Shiré or Chire River. It is the outlet of Lake Malawi and flows into the Zambezi. Its length is 402 km; including Lake Malawi and the Ruhuhu, its headstream, it has a length of about 1200 km... - Lake ChilwaLake ChilwaLake Chilwa is the second-largest lake in Malawi after Lake Malawi. It is in eastern Zomba District, near the border with Mozambique. Approximately 60 km long and 40 km wide, the lake is surrounded by extensive wetlands....
(1750 km², elevation 622 m) has no outlet but extensive wetlands. It is the southernmost of the Rift Valley lakes.
Other lakes of the Great Rift Valley
- Lake MweruLake MweruLake Mweru is a freshwater lake on the longest arm of Africa's second-longest river, the Congo. Located on the border between Zambia and Democratic Republic of the Congo, it makes up 110 km of the total length of the Congo, lying between its Luapula River and Luvua River segments.Mweru...
(4350 km², elevation 922 m) lies in the Lake Mweru-Luapula grabenGrabenIn geology, a graben is a depressed block of land bordered by parallel faults. Graben is German for ditch. Graben is used for both the singular and plural....
which is a branch off the Albertine rift. - Lake Mweru WantipaLake Mweru WantipaLake Mweru Wantipa is a lake and swamp system in the Northern Province of Zambia. It has been regarded in the past as something of mystery, displaying fluctuations in water level and salinity which were not entirely explained by variation in rainfall levels; it has been known to dry out almost...
(1500,km², elevation 930 m) is a marshy lake between lakes TanganyikaLake TanganyikaLake Tanganyika is an African Great Lake. It is estimated to be the second largest freshwater lake in the world by volume, and the second deepest, after Lake Baikal in Siberia; it is also the world's longest freshwater lake...
and MweruLake MweruLake Mweru is a freshwater lake on the longest arm of Africa's second-longest river, the Congo. Located on the border between Zambia and Democratic Republic of the Congo, it makes up 110 km of the total length of the Congo, lying between its Luapula River and Luvua River segments.Mweru...
, and is endorheicEndorheicAn endorheic basin is a closed drainage basin that retains water and allows no outflow to other bodies of water such as rivers or oceans...
but may overflow into Lake Mweru at times of very high flood.