Lake Bogoria
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| Lake Bogoria | |
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| Coordinates | |
| Lake type | saline, alkaline, meromictic |
| Primary inflows | Sandai and Emsos rivers, springs |
| Catchment area | 700 km² |
| Basin countries | Kenya |
| Max. length | 34 km |
| Max. width | 3.5 km |
| Surface elevation | 990 m |
Lake 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 times to one of the world's largest populations of lesser flamingoes. The lake is a Ramsar site and has been a protected National Reserve since November 29, 1973. Lake Bogoria is shallow (about 10 m depth), and is about 34 km long by 3.5 km wide, with a drainage basin of 700 km².
Local features include the Kesubo Swamp to the north and the Siracho Escarpment to the east, both within the National Reserve. The reserve is also famous for its geysers and hot springs.
The lake waters are of Na-HCO3-CO3 composition. They originate from inflow from the Sandai and Emsos rivers, and from about 200 alkaline hot springs that are present at three onshore sites: Loburu, Chemurkeu, and a southern group (Ng'wasis, Koibobei, Losaramat). Other springs discharge directly from the lake floor. Lake Bogoria also contains the highest concentration of true geysers in Africa (at least 18 are known). The lake waters are alkaline (pH:10.5) and saline (up to 100 g/L Total Dissolved Salts). The lake has no surface outlet so the water becomes saline mainly through evaporation, which is high in this semi-arid region. The lake itself is meromictic (stratified) with less dense surface waters lying on a denser more saline bottom waters. Although hypersaline, the lake is highly productive with abundant cyanobacteria (Arthrospira fusiformis) that feed the flamingoes, but few other organisms inhabit the lake.
The lake has not always been saline. Sediment cores from the lake floor have shown that freshwater conditions existed for several periods during the past 10,000 years, and that lake level was up to about 9 m higher than its present level of about 990 m above sea-level. At times it might have overflowed northward towards Lake Baringo. At times, during the late Pleistocene it might have been united with a larger precursor of modern Lake Baringo, but this is still uncertain.
The lake area was the traditional home of the Endorois people, who were forced to leave the area in the 1970s and are now challenging their removal at the African Commission on Human and Peoples' Rights.
Hotel accommodation at available near Loboi village at the north end of the lake. Camping is permitted at the southern end of the lake (see North Lewis, 1998, for details).
[edit] References
Tiercelin, J.J. and Vincens, A. (Eds) 1987. Le demi–graben de Baringo–Bogoria, Rift Gregory, Kenya: 30,000 ans d’histoire hydrologique et sédimentaire. Bulletin des Centres de Recherches Exploration-Production Elf-Aquitaine, v. 11, p. 249–540.
Renaut, R.W. and Tiercelin, J.-J. 1993. Lake Bogoria, Kenya: soda, hot springs and about a million flamingoes. Geology Today, v. 9, p. 56-61.
Renaut, R.W. and Tiercelin, J.-J. 1994. Lake Bogoria, Kenya Rift Valley: a sedimentological overview. In: Sedimentology and Geochemistry of Modern and Ancient Saline Lakes. (Eds R.W. Renaut and W.M. Last), SEPM Special Publication, v. 50, p. 101–123.
North Lewis, M. 1998. A Guide to Lake Baringo and Lake Bogoria. Horizon Books. (ISBN 9966-868-17-8)
Harper, D.M., Childress, R.B.. Harper, M.M., Boar, R.R., Hickley, P., Mills, S.C., Otieno, N., Drane, T., Vareschi, E., Nasirwa, O.1, Mwatha, W.E., Darlington, J.P.E.C., and Escuté-Gasulla, X. 2003. Aquatic biodiversity and saline lakes: Lake Bogoria National Reserve, Kenya. Hydrobiologia, v. 500, p. 259-276.
Renaut, R.W. and Owen, R.B. 2005. The geysers of Lake Bogoria, Kenya Rift Valley, Africa. GOSA Transactions, v. 9, 4–18.
