Lake Turkana is now threatened by the construction of theGilgel Gibe III Dam in Ethiopia due to the damming of theOmo river which supplies most of the lake's water.[4]
Although the lake commonly has been—and to some degree still is—used for drinking water, its salinity (slightlybrackish) and very high levels offluoride (much higher than influoridated water) generally make it unsuitable for drinking directly, 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.[5] The same characteristics that make it unsuitable for drinking, limit its use inirrigation.[6] The climate is hot and very dry.
Therocks of the surrounding area are predominantlyvolcanic.Central Island is an active volcano, emitting vapour. Outcrops and rocky shores are found on the east and south shores of the lake, while dunes, spits and flats are on the west and north, at a lower elevation.
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 (theOmo,Turkwel andKerio) flow into the lake, butlacking outflow, its only water loss is by evaporation. Lake volume and dimensions vary. For example, its level fell by 10 m (33 ft) between 1975 and 1993.[7] Despite the lack of outflow, inecology it is often regarded as a part of—or at least associated with—theNile basin because of its prehistoric connection to this system and the similarities in their aquaticfaunas.[6]
Due to local temperatures (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.[6]Nile crocodiles are found in great abundance on the shore flats. The rocky shores are home toscorpions andcarpet vipers. The lake is rich in fish and fishing is very important to the local economy, but this is threatened by falling water levels andoverfishing.[4]
An abundance ofhominid fossils have been discovered in the area surrounding Lake Turkana.[4]
The area still sees few visitors, being two days' drive fromNairobi. The lake is also an imaginary boundary of the Rendille and Borana and Oromo to the Turkana land. The area is primarily clay-based and is more alkaline than seawater.
After the independence ofKenya, the president, MzeeJomo Kenyatta, renamed it in 1975 after theTurkana, the predominant tribe there. The Turkana refer to the lake asAnam Ka'alakol, meaning "the sea of many fish". It is from the name Ka'alakol thatKalokol, a town on the western shore of Lake Turkana, east ofLodwar, derives its name. The previous indigenous Turkana name for Lake Turkana wasAnam a Cheper. Natives who live around Lake Turkana include theTurkana,Rendille,Gabbra,Daasanach, Hamar Koke, Karo, Nyagatom,Mursi,Surma, andMolo peoples. For the location of many of these peoples, refer to the dialect map in the article.
At some unknown time, the lake acquired an alternative name as theJade Sea from its turquoise colour seen approaching from a distance. The colour comes from algae that rise to the surface in calm weather. This is likely also a European name.
J. W. Gregory reported inThe Geographical Journal of 1894 that it was called "Basso Narok", meaning "Black Lake" in theSamburu language. Likewise, the nearby EthiopianLake Chew Bahir is called "Basso Naibor" in Samburu, meaning "White Lake". The Samburu are among the dominant tribes in the lake Turkana region when the explorers came."[10] What the native form of this phrase was, what it might mean, and in which language is not clear.
Satellite image of Lake Turkana, distinguishable from its jade color. The Omo River enters at the top. The river visible on the lower left is the Turkwel, which has been dammed for hydroelectric power.
The majorbiomes are the lake itself, which is an aquatic biome, and the surrounding region, which is classified asdesert and xeric shrubland. TheChalbi Desert is east of the lake. During moister times, a dry grassland appears, featuringAristida adcensionis andA. mutabilis. During drier times, the grass disappears. The shrublands contain dwarf shrubs, such asDuosperma eremophilum andIndigofera spinosa. Near the lake aredoum palms.
The Lake Turkana region is home to hundreds of species of birds native toKenya.[14] The East African Rift System also serves as a flyway for migrating birds, bringing in hundreds more. The birds are essentially supported by plankton masses in the lake, which also feed the fish.
The lake formerly contained Africa's largest population ofNile crocodiles: 14,000, as estimated in a 1968 study by Alistair Graham.[15]
The lake also has a large population of large water turtles, particularly in the area of Central Island. TheTurkana mud turtle isendemic to the lake.[16]
View of Lake Turkana with theKoobi Fora formations in the background.
Lake Turkana is anEast African Rift feature.[18] Arift is a weak place in the Earth's crust due to the separation of twotectonic plates, often accompanied by agraben, or trough, in which lake water can collect. The rift began when East Africa, impelled by currents in themantle,[19] began separating from the rest of Africa, moving to the northeast. Currently, the graben is 320 km wide in the north of the lake, 170 km in the south. This rift is one of two, and is called the Great or Eastern Rift. There is another to the west, the Western Rift.
Lake Turkana is a unique feature of the East African landscape. Besides being a permanent desert lake, it is the only lake that retains the waters originating from two separate catchment areas of theNile. The Lake Turkana drainage basin draws its waters mainly fromKenya Highlands andEthiopian Highlands.
A map of lake turkana
The basement rocks of the region have been dated by two analytical determinations to 522 and 510 million years ago (mya). No rift was in the offing at that time. A rift is signalled by volcanic activity through the weakened crust. The oldest volcanic activity of the region occurred in the Nabwal Hills northeast of Turkana and is dated to 34.8 mya in the lateEocene.[20]
The visible tectonic features of the region result from extensive extrusions ofbasalt over the Turkana-Omo basin in the window 4.18–3.99 mya.[21] These are called the Gombe Group Basalts. They are subdivided into the Mursi Basalts and the Gombi Basalts.
The two latter basalts are identified as the outcrops forming the rocky mountains and badlands around the lake. In the Omo portion of the basin, of the Mursi Basalts, the Mursi Formation is on the west side of the Omo, the Nkalabong on the Omo, and the Usno and Shungura east of the Omo. Probably the best known of the formations are theKoobi Fora on the east side of Turkana and the Nachukui on the west.
Short-term fluctuations in lake level combined with periodic volcanic ash spewings over the region have resulted in a fortuitous layering of the ground cover over the basal rocks. These horizons can be dated more precisely by chemical analysis of thetuff.[22] As this region is believed to have been an evolutionary nest ofhominins, the dates are important for generating a diachronic array of fossils, bothhominoid and nonhominoid—that is, bothape (includes hominins) andnon-ape. Many thousands have been excavated.
Terraces representing ancient shores are visible in theTurkana Basin. The highest is 100 m above the surface of the lake (only approximate, as the lake level fluctuates), which occurred about 9500 years ago, at the end of thePleistocene as part of theAfrican humid period.[23] It is generally theorised that Turkana was part of the upper Nile system at that time, connecting toLake Baringo at the southern end and theWhite Nile in the north, and that volcanic land adjustments severed the connection. Such a hypothesis explains the Nile species in the lake, such as the crocodiles and the Nile perch. High water levels also occurred approximately 9000, 6000 and 5000 years ago, each of which were followed by drops in lake level of more than 40m in less than 200 years.[23] It is thought that changes in the position of the Congo Air Boundary affected the ability of moisture from the Atlantic Ocean to reach eastern Africa,[24][25] which had a profound influence on the level of Lake Turkana and adjacent water bodies.[23][26]
Hominin fossils of some of the earliest human ancestors have been found in the Turkana Basin. Lake Turkana is considered the cradle of human life because of the diverse hominid species found living millions of years apart in this desert landscape. These fossils have facilitated human understanding of the dynamic human evolution process and imply that they descended from more than one common ancestor, diverging into multiple lineages.[27]
The changing forest environment forced the early humans to adapt to a more open grassland that increased their exposure to threatening predators. Volcanic ash and drier climates were ideal for preserving these human fossils but it also caused the lake to shrink or disappear at times.
In a dry riverbed, the Lomekwi 3 site recovered primitivehammers,anvils, and cutting tools. However, the emergence of Acheulean technology no longer assumes that tool use was a distinguishing factor amongHomo species asAustralopithecus afarensis were also using simple tools prior to the appearance of the genusHomo, over 3.3 million years ago.[28]
Australopithecus anamensis fossils discovered byMeave Leakey in 1994 date to around 4 million years ago, setting the beginning date of bipedalism back half a million years.Richard Leakey has led numerousanthropological expeditions in the area which have led to many important discoveries of hominin remains.
The two-million-year-oldskull 1470 was found in 1972. It was originally thought to beHomo habilis, but the scientific nameHomo rudolfensis, derived from the old name of this lake (Rudolf) was proposed in 1986 by V. P. Alexeev. In 1984, theTurkana Boy, a nearly complete skeleton of aHomo ergaster juvenile, was discovered byKamoya Kimeu. More recently, Meave Leakey discovered a 3.5 million-year-old skull there, designatedKenyanthropus platyops ("the flat-faced man of Kenya").
Marta Mirazón Lahr discovered early evidence of human warfare at the site ofNataruk, located near the shore of an ancient and larger Lake Turkana, and where numerous human skeletons showing major traumatic injuries to the head, neck, ribs, knees and hands are argued to be evidence of inter-group conflict between nomadic hunter-gatherers 10,000 years ago.[29] With over 230 individuals found at the Koobi Fora site along the western shore, and scatteredHomo sapiens skeletons with bone marks along the eastern shore at the Nataruk Site, this region provides considerable insight to the way these early humans thrived and survived the inconsistent climate along the lake shore and beyond.[30]
Homo erectus is the closest ofHomo sapiens' ancestors and contended to be the first hominin to cross the Levantine corridor out of Africa into Europe and Asia 1.8 million years ago.[31]
Many language groups are represented in the area around Lake Turkana,[32] which is evidence for numerous migrations of diverse people over thousands of years. The current language groups include at least three separate subgroups of theNilotic (Nilo-Saharan) andCushitic (Afro-Asiatic) language families, which have further subdivided into more than 12 languages surrounding the lake today.[33] In the earlyHolocene (during theHolocene Climatic Optimum), lake levels were high and fishing and foraging were the primary subsistence economies. This was mostly supplanted by animal-based agriculture by 5000 years ago, when the lake level was in a period of rapid fluctuation.[34] During the laterHolocene, human responses to climatic changes included intensive fishing when lake level was high and a shift to cattle herding when the level dropped.[34] Megalithic graves are found widely distributed on the lake shores and appear to correspond to the period when domesticated animals were first introduced to the region about 5000 years ago,[35] while later, the dead were buried in small grave cairns.[36] People who live in the region today commonly practice mixed subsistence, switching between hunting, fishing and animal herding based on what is feasible in a given year.[34] However, the construction of infrastructure like Christian missionary stations, energy extraction (wind, oil) andNGO aid distribution points have made the region more connected to and dependent on outside resources for subsistence.[37][38] Traditional modes of subsistence like pastoralism and fishing are now supplemented by the cash-based economy.
The Lake Turkana Wind Power consortium (LTWP) plans to provide 310 MW of power to Kenya's national electricity grid by tapping the unique wind conditions around the lake.[39] The plan calls for 365wind turbines, each with anameplate capacity of 850 kilowatts. As of October 2016 155 turbines had been installed with completion expected in 2017. It will be the largest wind power project in Africa.[40]
Full commercial operation achieved in March 2019. 100% Capacity Factor (meaning full 310 MW generated) achieved in March 2021.[41]
The Gibe III dam is already under construction by Ethiopia along its Omo River, with general recognition that it will cause a major decrease in river flow downstream and a serious reduction of inflow to Kenya's Lake Turkana, which receives 90 per cent of its waters from the river. According to the ARWG[citation needed] report, these changes will destroy the survival means of at least 200,000 pastoralists, flood-dependent agriculturalists and fishers along the Omo River and 300,000 pastoralists and fishers around the shores of Lake Turkana – plunging the region's ethnic groups into cross-border violent conflict reaching well into South Sudan, as starvation confronts all of them.[citation needed]
The report offers a devastating look at a deeply flawed development process fueled by the special interests of global finance and African governments. In the process, it identifies major overlooked or otherwise minimised risks, not the least of which is a U.S. Geological Survey estimation of a high risk for a magnitude 7 or 8 earthquake in the Gibe III dam region.
The magnitude of the impact that the dam and possible irrigation projects induced by the dam will have on the water level of Lake Turkana is controversial. A hydrological study conducted for the African Development Bank in November 2010 concluded that the filling of the dam will reduce the lake's water level by two metres, if no irrigation will be undertaken. Irrigation would cause a further drop in the lake level.[29]
Friends of Lake Turkana, a Kenyan organisation representing indigenous groups in northwestern Kenya whose livelihoods are linked to Lake Turkana, had previously estimated that the dam could reduce the level of Lake Turkana by up to 10 meter affecting up to 300,000 people.[30] This could cause the brackish water to increase in salinity to where it may no longer be drinkable by the indigenous groups around the lake. Currently, the salinity of the water is about 2332 mg/L, and it is estimated that a 10-meter decrease in the water level of Lake Turkana could cause the salinity to rise to 3397 mg/L.[20] Raising salinity could also drastically reduce the number of fish in the lake, which the people around Lake Turkana depend on for sustenance and their livelihoods. According to critics, this "will condemn the lake to a not-so-slow death."[9]
According to dam proponents, the impact on Lake Turkana will be limited to the temporary reduction in flows during the filling of the reservoir. Various sources state that the filling could take between one and three wet seasons.[9][26] The total storage volume of the reservoir of Gibe III dam will be between 11.75 and 14 billion cubic meter, depending on sources. According to the firm that builds the dam this would reduce the water level in the lake by "less than 50 cm per year for three years" and that salinity "will not change in any way".[26]
According to the International Lake Environment Committee, 90% of Lake Turkana's water is delivered by the Omo River on which the Dam would be built.[31] With no outlet, Lake Turkana loses 2.3 meters of water every year to evaporation, and its level is sensitive to climatic and seasonal fluctuations. For purposes of comparison, the historic level of Lake Turkana declined from a high of 20m above today's level in the 1890s to the same level as today in the 1940s and 1950s. Then it increased again gradually by 7 metres to reach a peak around 1980, and subsequently decreased again.[31]
The Environmental and Social Impact Assessment (ESIA) summary of the project did not assess the impact of the dam on the water level and water quality of Lake Turkana.[32] The director of Kenya's Water Services Regulatory Board, John Nyaoro, argued that the dam would have no negative impact on Lake Turkana.[33]
A Kenya Government report in 2021 estimated that the surface area of Lake Turkana had increased by 10% between 2010 and 2020.[42][43]
Lake Turkana is featured in the 2002 video gameXenosaga Episode I: Der Wille zur Macht. In the game’s prologue, set in 20XX AD, an archaeological expedition at Lake Turkana uncovers the Zohar, a mysterious monolith that serves as a central element in the game's story.[44]
Part of the events in the novel“Невозвращенец” (“The Non-Returnee”) byAndrei Gusev takes place on the shores of Lake Turkana in Loiyangalani (in the second part of this novel).[45][46]
^The boundary between Ethiopia and Kenya has been a contentious matter. A brief consideration of the topic can be found in the State Department document,Ethiopia – Kenya BoundaryArchived 18 March 2009 at theWayback Machine
^abcJohnson, T.C.; J.O. Malala (2009). "Lake Turkana and its connection to the Nile". In H.J. Dumont (ed.).The Nile. Monographiae Biologicae. Vol. 89. Springer Science + Business Media B.V. pp. 287–306.ISBN978-1-4020-9725-6.
^A summary of the European discovery as well as Teleki's map and some Turkana tribe legends are stated in aUniversity of TriesteArchived 6 December 2007 at theWayback Machine document online.
^[Wakefield, Thomas. "Routes of Native Caravans From the Coast to the Interior of Eastern Africa, Chiefly from Information Given by Said Bin Ahedi, a Native of a District Near Gazi, in Udigo, a Little North of Zanzibar." Journal of the Royal Geographical Society of London 40 (1870): 303–39
^Rhodin, A.G.J.; Iverson, J.B.; Bour, R.; Fritz, U.; Georges, A.; Shaffer, H.B.; van Dijk, P.P.; et al. (Turtle Taxonomy Working Group) (2017). Rhodin, A.G.J.; Iverson, J.B.; van Dijk, P.P.; Saumure, R.A.; Buhlmann, K.A.; Pritchard, P.C.H.; Mittermeier, R.A. (eds.).Turtles of the World: Annotated Checklist and Atlas of Taxonomy, Synonymy, Distribution, and Conservation Status. Conservation Biology of Freshwater Turtles and Tortoises: A Compilation Project of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group. Vol. 7 (8 ed.). pp. 1–292.doi:10.3854/crm.7.checklist.atlas.v8.2017.ISBN9781532350269.{{cite book}}:|journal= ignored (help)
^"Lake Turkana".www.kenya-and-beyond.com. 21 September 2016. Archived fromthe original on 7 August 2020. Retrieved27 May 2020.
^abcBloszies, C.; Forman, S. L.; Wright, D. K. (1 September 2015). "Water level history for Lake Turkana, Kenya in the past 15,000 years and a variable transition from the African Humid Period to Holocene aridity".Global and Planetary Change.132:64–76.doi:10.1016/j.gloplacha.2015.06.006.
^Tierney, Jessica E.; Russell, James M.; Sinninghe Damsté, Jaap S.; Huang, Yongsong; Verschuren, Dirk (1 April 2011). "Late Quaternary behavior of the East African monsoon and the importance of the Congo Air Boundary".Quaternary Science Reviews.30 (7–8):798–807.Bibcode:2011QSRv...30..798T.doi:10.1016/j.quascirev.2011.01.017.
^Junginger, Annett; Roller, Sybille; Olaka, Lydia A.; Trauth, Martin H. (15 February 2014). "The effects of solar irradiation changes on the migration of the Congo Air Boundary and water levels of paleo-Lake Suguta, Northern Kenya Rift, during the African Humid Period (15–5 ka BP)".Palaeogeography, Palaeoclimatology, Palaeoecology.396:1–16.Bibcode:2014PPP...396....1J.doi:10.1016/j.palaeo.2013.12.007.
^Grillo, Katherine M.; Hildebrand, Elisabeth A. (1 June 2013). "The context of early megalithic architecture in eastern Africa: the Turkana Basin c. 5000–4000 BP".Azania: Archaeological Research in Africa.48 (2):193–217.doi:10.1080/0067270X.2013.789188.ISSN0067-270X.S2CID162193899.
^MONTCLOS, M.-A. P. D.; KAGWANJA, P. M. (1 June 2000). "Refugee Camps or Cities? The Socio-economic Dynamics of the Dadaab and Kakuma Camps in Northern Kenya".Journal of Refugee Studies.13 (2):205–222.doi:10.1093/jrs/13.2.205.ISSN0951-6328.S2CID145079117.
Chambers World Gazetteer, ed. David Munro, W & R Chambers Ltd. & The Press Syndicate of the University of Cambridge, 5th Edition, 1988,ISBN978-1-85296-200-5 underTurkana, Lake.
Quest for the Jade Sea: Colonial Competition Around an East African Lake, byPascal James Imperato and published by Westview Press, 1998ISBN0813327911.
Where Giants Trod: The Saga of Kenya's Desert Lake, by Monty Brown and published by Quiller Press, 1989ISBN1870948254. Descriptions of the various discovery expeditions to Lake Turkana in the 19th century. The accounts inevitably offer observations about the geology and anthropology of the area.
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