|  The Rift Valley lakes
are a group of lakes formed by the Great Rift Valley of eastern Africa.
These lakes include some of the oldest, largest and deepest lakes in
the world, and are a freshwater ecoregion of great biodiversity. The
Ethiopian Rift Valley lakes are the northernmost of the African Rift
Valley lakes. In central Ethiopia the Great Rift Valley splits the Ethiopian
highlands 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. The largest of these lakes is Lake Abaya (1160
km², elevation 1285 m); other major lakes include Lake Chamo
(551 km², 1235 m), Lake Awasa (129 km², elevation 1708
m), Lake Zway (485 km², elevation 1636 m), Lake Abijata
(205 km², elevation 1573 m), and Lake Koka (250 km²,
elevation 1590 m). Lake Tana (3600 km², elevation 1788 m),
the source of the Blue Nile, is not a Rift Valley lake, but lies in
the Ethiopian highlands north of the Rift Valley.
South of the Ethiopian highlands, the Rift Valley splits in two. The
Eastern Rift is home to the Kenyan Rift Valley lakes, and 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 two are
freshwater and the rest alkaline. The largest of the Kenyan lakes is
Lake Turkana (elevation 360 m), a large alkaline lake on the border
of Kenya and Ethiopia with an area of 6405 km². Lake Logipi
is a seasonal hot-spring fed lake in the Suguta Valley just south of
Lake Turkana. Further south are lakes Baringo, Bogoria, Nakuru, Elmenteita,
Naivasha and Magadi.
Lake Baringo is the second largest of the Kenyan Rift Valley
lakes at 80 square miles, and is one the two fresh water lakes in Kenya.
Four hundred bird species have been listed in the area, and the Goliath
heronry is located on a rocky islet in the lake known as Gibraltar.
Lake Naivasha is Kenya's other freshwater lake, with an area
of 160 square kilometres, which varies somewhat with rainfall. It is
the highest of the Kenya's Rift Valley lakes at an altitude of 1,890
m (5900 ft). Njorowa gorge used to form the lake's outlet, but it is
now high above the lake and forms the entrance to Hell's Gate National
Park. Over 450 species of birds are found in the immediate area. Kenya's
other rift valley lakes are small shallow soda lakes, with crystallised
salt turning the shores white. The lakes are famous for the large flocks
of flamingo that feed on the crustaceans. Lake Nakuru (40 km²,
elevation 1759 m) is a national park since 1968, and Lake Bogoria (34
km², elevation 990 m) is a national preserve. The eastern rift
continues into Tanzania, where alkaline Lake Natron and Lake Eyasi host
huge flocks of flamingoes.
The lakes of the Western or Albertine Rift, together with Lake Victoria,
include the largest, deepest and oldest of the Rift Valley lakes. The
Central African lakes are freshwater, home to an extraordinary number
of endemic species. Approximately 1,500 cichlid fish (Cichlidae) species
live in the lakes (See Hubert Sauper's Darwin's Nightmare and the resulting
plummet in biodiversity). In addition to the cichlids, endemic species
of Clariidae, Claroteidae, Mochokidae, Poeciliidae, Mastacembelidae,
Centropomidae, Cyprinidae, Clupeidae and other fish families are also
found in these lakes. The lakes are also important habitats for a number
of amphibian species, including Bufo kisoloensis, Bufo keringyagae,
Cardioglossa cyaneospila, and Nectophryne batesii.
The alkaline Lake Rukwa lies in Tanzania to the southeast of Lake Tanganyika
and north of Lake Malawi, in a parallel branch of the rift system. Lake
Malawi (30,000 km², elevation 500 m) lies south of Lake Tanganyika
in the rift valley, and is the second deepest at over 700 meters. It
empties south into smaller Lake Malombe, which is drained by the Shire
River, a tributary of the Zambezi River. Lake Chilwa (1750 km²,
elevation 622 m) lies southeast of Lake Malombe, and is the southernmost
of the Rift Valley lakes.
Lake Victoria, Lake Tanganyika, and Lake Malawi are sometimes
collectively known as the African Great Lakes. these are the best known
since the vast majority of african cichlids in the hobby come from these
lakes. the others are not economically advantageous for the hobby.
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