Lake Turkana, formerly known as Lake Rudolf, is a lake in the Kenyan Rift Valley, in northern Kenya, with its far northern end crossing into Ethiopia.. By volume it is the world's fourth-largest salt lake after the Caspian Sea, Issyk-Kul, and Lake Van (passing the shrinking South Aral Sea), and among all lakes it ranks 24th.
Lake Turkana has an area of 6.405 km², reaching the length of 290 km and the depth of 109 m. It is the world's largest permanent desert lake and the world's largest alkaline lake.
Although the lake commonly has been —and to some degree still is— used for drinking water, its salinity (slightly brackish) and very high levels of fluoride (much higher than in fluoridated water) generally make it unsuitable, and it has also been a source of diseases spread by contaminated water.
Increasingly, communities on the lake's shores rely on underground springs for drinking water. The same characteristics that make it unsuitable for drinking limits its use in irrigation. The climate is hot and very dry.
On-shore and off-shore winds can be extremely strong, as the lake warms and cools more slowly than the land. Sudden, violent storms are frequent.
Three rivers (the Omo, Turkwel and Kerio) flow into the lake, but lacking outflow, its only water loss is by evaporation. Lake volume and dimensions are variable. For example, its level fell by 10 m (33 ft) between 1975 and 1993.
Despite the lack of outflow, in ecology it is often regarded as a part of —or at least associated with— the Nile basin because of its prehistoric connection to this system and the similarities in their aquatic faunas.
Due to temperature (its surface water typically is 27–31 °C [81–88 °F] and the mean air temperature of the region generally is similar or slightly higher), aridity and geographic inaccessibility, the lake retains its wild character.
According to en.wikipedia