The Great Rift Valley is part of an intra-continental ridge system that runs through Kenya from north to south. It is part of the Gregory Rift , the eastern branch of the East African Rift , which starts in Tanzania to the south and continues northward into Ethiopia . It was formed on the "Kenyan Dome", a geographical upwelling created by the interactions of three major tectonics: the Arabian, Nubian, and Somalian plates. In the past, it was seen as part of a " Great Rift Valley " that runs from Madagascar to Syria . Most of the valley falls within the former Rift Valley Province .
60-573: The valley contains the Cherangani Hills and a chain of volcanoes, some of which are still active. The climate is mild, with temperatures usually below 28 °C (82 °F). Most rain falls during the March–June and October–November periods. The Tugen Hills to the west of Lake Baringo contain fossils preserved in lava flows from the period 14 to 4 million years ago. The relics of many hominids, ancestors of humans, have been found here. In March 2018,
120-450: A consequence of faulting. In 1969, it spread over 6 km in length; but water was diverted from the Waseges river and by 2001 it was only 3.5 km long and about 0.5 km wide. At least three warm springs, and groundwater inputs, feed it. The Loboi river also contributes to it but that river periodically shifts its bed ( avulsions ) and that modifies its relative role regarding the swamp. This river
180-450: A denser more saline bottom waters. 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. Of the ca. 60 hot springs that discharge on Loburu delta plain on the western margin of the lake, travertine appears at 20% of them. Carbonate is actively precipitating at several of these, as shown by calcite-encrusted artefacts. This
240-465: A drainage divide that separates lake Bogoria and lake Baringo. The faults control over 200 hot and cold springs and seeps, which bring a significant water input. Core analysis of the lake floor has revealed two types of sedimentation: a shallow fan–deltaic clastic zone; and a deeper zone where Organic matters alternate with evaporites . The organic muds were formed during periods of relatively high lake level and high microbial productivity; whereas
300-511: A giant crack in the Earth, measuring 50 feet deep and 65 feet across, opened in the ground just west of Nairobi . However, it is believed to be due to rain and erosion, and not of tectonic origin. The valley is bordered by escarpments to the east and west. The floor is broken by volcanoes, some still active, and contains a series of lakes. Some of the soils are Andisols , fertile soils from relatively recent volcanic activity. Lake Turkana occupies
360-507: A half- graben basin south of Lake Baringo , Kenya , a little north of the equator . Lake Bogoria, like Lake Nakuru , Lake Elementeita , and Lake Magadi further south in the Rift Valley , and Lake Logipi to the north, is periodically home to one of the world's largest populations of lesser flamingos . The lake is a Ramsar site and Lake Bogoria National Reserve has been a protected National Reserve since November 29, 1973. The lake
420-570: A landmark ruling, ordering the Kenyan government to restore the Endorois to their historic land, compensate them from losses and sharing with them the profits from the Lake Bogoria game reserve. But in 2022, Minority Rights Group reported that that decision had not yet been implemented and has many Endorois were still consigned to 'severe poverty, illiteracy, poor health and a life of destitution.' In 2024
480-417: A large center one and two smaller ones at the north and south extremities. The two narrower areas separating these lobes are shallow, tectonically controlled sills at Nyalibuch and Mwanassis. There are contradictions regarding its altitude. Unesco's Ramsar gives 963 m (3,159 ft). More precise — and more prudent —, Renaut & Owen 1991 give c. 990 m as of August 1977, but also indicate that
540-520: A major fault, with steep slopes that prevent wetland development (the Siracho Escarpment, to the east ). To the west, trachy phonolites (uncommon extrusive igneous rock) are cut through by numerous gently sloping tilt-blocks; rivers oriented north-south feed delta lobes, where spring-fed wetlands have developed. The north opens on a basin with Quaternary silts , sands and gravels; there, the gently sloping Sandai and Loboi plains gradually rise to
600-805: A marginalized hunter-gatherer community called the Sengwer . The Cherang'any Hills were formed due to Faulting. They form the western flank of the Gregory Rift Valley (East African Rift Valley) that stretches from Djibouti in the North to Mozambique in the South. They are located on a forested escarpment with sheer cliff walls surrounding them on three sides. Rocks found in Cherangani Hills are majorly Gneisses rich in Biotite and Muscovite. A Gneiss sample from Chepsiro, one of
660-459: A pH range of 9.3–10.6. Some shallow marginal lagoons have salinities exceeding 100 g l−1. Temperature at the time of sampling ranged between 28 and 33 ◦C, but exceed 60 ◦C at sublacustrine hot spring vents. However, cyanobacteria — mainly Spirulina platensis — are abundant and support up to 2 million flamingoes. Lake Bogoria is in a geothermally active part of the Kenya Rift Valley, and
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#1732848284905720-562: A variety of fluvial, deltaic, and beach settings. It has active hot springs that feed a series of marshes dominated by Cyperus laevigatus . The springs are alkaline, of the Na-HCO 3 type, contain a lot of silica and nitrate, and the temperature near the vents is extremely hot (more than 96◦C). The areas immediately adjacent to the vents and in nearby streamlets commonly include microbial mats of Phormidium, Pseudanabaena , Spirulina , Synechococcus and Calothrix , but are devoid of macrophytes.
780-619: A wetter area populated by near pure stands of Cyperus papyrus that are rooted or floating in water up to 1.5 m deep. Acacia scrub occurs on an adjacent horst block to the west, with grasses such as Sporobolus spicata on adjacent plains. These are also to the north of the lake, east of the Loboi swamp. They rest at the southern end of an extensive alluvial fan formed by the Sandai river. The Kesubo Floodplain Marshes are seasonally flooded and lie between
840-539: Is a dormant stratovolcano located southeast of Lake Naivasha . Mount Suswa is a shield volcano located between Narok and Nairobi . Lava flows from the most recent eruptions are still not covered by vegetation, and may be no more than one hundred years old. Lake Magadi is the most southern rift valley lake in Kenya, although the northern end of Lake Natron in Tanzania reaches into Kenya. The Elgeyo escarpment forms part of
900-399: Is a massive shield volcano in the floor of the rift with a caldera that formed about 8,000 years ago. It overlooks Lake Nakuru to the south. This region also includes Lake Elementaita , Mount Kipipiri and Lake Naivasha . The Hell's Gate National Park lies south of Lake Naivasha . In the early 1900s, Mount Longonot erupted, and ash can still be felt around Hell's Gate. Mount Longonot
960-504: Is above 2500 mm, thus inducing a water deficit and creating semi-arid conditions over most of the lower parts of the Bogoria basin. Although the lake is in a semi-arid part of Kenya Rift Valley , it is surrounded by numerous and varied wetlands along its shorelines, along faults where hot, warm and cold springs have developed, and along rivers that run across the rift floor. Six major types of wetland have been defined around lake Bogoria:
1020-549: Is cool and only slightly alkaline. The springs have a similar chemistry but they are warmer, have a higher nitrate content, and are slightly acidic. The resulting waters of the Loboi Swamp are also slightly alkaline, and generally reflect the mixing of fluvial, spring and groundwater inflows. Its areas of semi-permanent or seasonal standing water are dominated by Typha domingensis and also have some Leersia hexandra , Ipomoea aquatica , and other taxa . These areas surround
1080-531: Is famous for geysers and hot springs along the bank of the lake and in the lake. There are about 200 hot springs, most of which are distributed along the shoreline. In four locations around the lake can be observed at least 10 geysers, which erupt up to 5 m high. Geyser activity is affected by the fluctuations of lake level, which may inundate or expose some geysers. Lake Bogoria occupies an asymmetric basin approximately 20 km long and 10 km wide, bordered by faults . The east and south borders are marked by
1140-430: Is generally 3,300 ha (8,200 acres) but this fluctuates, essentially according to the amount of rainfall. Most of the rain falls between April and November, and precipitation ranges average about 700 mm on the Loboi plain and 1200 mm on the adjacent highlands. But El Nino years bring increased rainfall and flooding of the lake shores. For example, in 2020 its area increased to about 4,690 ha (11,600 acres): 2020
1200-535: Is the most important feeding area for lesser flamingos in the world. The system is home to globally important populations of black-necked grebe , African spoonbill , pied avocet , little grebe , yellow-billed stork , black-winged stilt , grey-headed gull and gull-billed tern . The Kenya lake system is a key location on the West Asian-East African Flyway , a route followed by huge numbers of birds in their annual migration from breeding grounds in
1260-472: Is unusual, in that this precipitation most probably occurs at temperatures over 80 °C. The geysers are believed by some to have medicinal value. The terrestrial vegetation that immediately surrounds the lake is mainly a thorny bushland dominated by Acacia , Salvadora , Balanites and Commiphora species. There are also patches of riverine woodland with Ficus capensis , Acacia xanthophloea and Acacia tortilis . One species dominates
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#17328482849051320-463: The Brachionus plicatilis cryptic species complex) is found in high densities. A new alkaliphilic purple nonsulfur bacterium was discovered in lake Bogoria; it has been named Rhodobaca bogoriensis . The lake supports more than 300 waterbird species. It is an important stopover site for a population of up to 1.5 million migratory birds, notably for the lesser flamingo ( Phoeniconaias minor ). In
1380-524: The Cherangani Hills Forest . The De Brazza's monkey has been sighted here. The monkeys are confined to small areas in the Cherang'any Hills that offer them little protection. This Kenya location article is a stub . You can help Misplaced Pages by expanding it . Lake Bogoria Lake Bogoria (formerly Lake Hannington) is a saline , alkaline lake that lies in a volcanic region in
1440-630: The Nguruman Escarpment is around 50 kilometers long and elongated in N-W direction. Its northern edge is about 120 kilometres (75 mi) southwest of Nairobi, while the southern edge is near the Tanzanian border, at the northwestern corner of Lake Natron . The Aberdare Range forms a section of the eastern rim of the Great Rift Valley to the north of Nairobi. Mount Satima lies at the northern end of
1500-560: 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 have been active in the 35 years before 2008). The lake is meromictic (stratified) with less dense surface waters lying on
1560-541: The Waseges river (or Sandai river), the latter bringing a small permanent flow of the diverted Loboi river. These wetlands are fed by ephemeral or perennial streams, and by springs. In the south, two freshwater springs supply permanent streams. All three (the Wasenge river and the two streams) are used extrensively for drinking, as well as the water from some hot springs streams — some of these being substantially less salty than
1620-966: The phytoplankton : Arthrospira fusiformis , a cyanobacterium spirulina . But all these wetlands see the occurrence of diatoms in at least parts of them; these diatoms vary in diversity, abundance and species composition. The main factors directing these variables are pH, temperature, and specific conductivity; secondary factors are Si and nitrate . Hot springs generally have a low diversity of diatoms, with variable abundance; they commonly include Anomoeoneis sphaerophora var. guntheri , Navicula tenella , Navicula cuspidata , and Nitzschia invisitata . In other wetland types, distinctive diatom floras variously include Fragilaria brevistriata , Gomphonema parvulum , Navicula tenelloides , Nitzschia communis , N. latens , N. sigma , Rhopalodia gibberula , and Stauroneis anceps . The flamingoes feed on Arthrospira fusiformis . The monogonont rotifer species Brachionus sp. Austria (belonging to
1680-645: The plateau that rises to the slopes of Mount Elgon . The Cherangany Hills span three counties namely Trans Nzoia , Elgeyo Marakwet and West Pokot . The highest point of the range is the summit of Nakugen at 3530 m, which can be ascended from the south from a parking space at a Kenyan Wildlife Service station, located at 1°09′46″N 35°29′36″E / 1.16284°N 35.49325°E / 1.16284; 35.49325 . Other notable peaks include; Chemnirot (3520 m), Kameleogon (3500 m), Chebon (3375 m), Chepkotet (3370 m), Karelachgelat (3350 m) and Sodang (3211 m). They are home to
1740-543: The 1990s, two episodes of mass deaths occurred among flamingos, all starting from Lake Bogoria. The first episode, in 1993-1995, saw about 35,000 flamingos dying between August and November 1993 and about 15,000 dying in August 1995. The second episode occurred in 1999-2000; the number of deaths for 2000 was estimated at around 100,000. In both cases, flamingos were the only water bird species falling victim to this unknown phenomenon. The studies on these events were not conclusive as to
1800-551: The Aberdares and is their highest point, and Mount Kinangop at the southern end is the second highest. The mountains form a ridge between these two peaks. Ngong Hills are peaks in a ridge along the east of the Great Rift Valley, located southwest near Nairobi. Kenya is home to 64 (9.50%) of the total lakes found within the continent of Africa. Eight of these make up the main lakes in the Kenyan Rift Valley. From north to south,
1860-458: The Cyperus marshes, which have similar water chemistries, are dominated by short reeds less than 20 cm high. Temperatures range from about 32◦C to about 60◦C near the hot spring streamlets that cross the marshes. There are also algal and cyanobacterial mats. The lake shoreline at Loburu (and other shorelines) does not present many aquatic macrophytes. The lake brine is of Na-CO3-HCO3-Cl composition, with
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1920-680: The Endorois allied with the Ogiek people — who have themselves been initially evicted in 1920 from their ancestral grounds in the Mau Forest (south-west Kenya) by the British colonial government. In 2017 the Ogiek also won a court case against the Kenian government, whereby the latter was supposed to restitute the Ogiek ancestral land and pay a compensation of 157,000 Kenyan shillings ($ 1,026) per person. As of 2024, not only
1980-598: The Major Tributaries of River Nzoia. Visible are forested ridges and stark, rocky gorges. The hills form the source of Moiben River, one of the two tributaries of the Nzoia River , the other being Mount Elgon . The Cherang'any Hills are monitored by the United Nations Environmental Programme as one of the five most important water catchment areas in Kenya. As of the last report, monitoring
2040-484: The change in forestation between 2000 and 2003, the Cherang'any Hills were the least affected of the forests monitored, with 174.3 hectares deforested, this loss is occurring within Marakwet District and West Pokot District . Since this forest cover is indigenous , the report recommends that the area be closely watched to prevent further destruction. The thirteen forest reserves there are collectively known as
2100-470: The common hippopotamus ( Hippopotamus amphibius ) and African lion ( Panthera leo ); another important species is the greater kudu ( Tragelaphus strepsiceros ). The lake's stable water level makes it doubly important during periods of drought, when water levels in other East African lakes drop. The Site is a UNESCO World Heritage Site since 2011 and an Important Bird and Biodiversity Area (IBA). The Ramsar site, designated on August 27, 2001, covers
2160-555: The entire National Reserve, with an area of 10,700 ha (26,000 acres), shared between the 3,300 ha lake and 7,400 ha of riparian and terrestrial habitats. 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 . In 2009 the African Commission on Human and Peoples' Rights (ACHPR) made
2220-706: The evaporites were formed during drier periods. The cores attest of many environmental fluctuations during the past 30 000 years, linked to regional climatic changes and to local tectonic and hydrological conditions. Lake Bogoria is a soda lake : it has no surface outlet, its waters are strongly alkaline ( pH :10.5). High salt concentrations are also given (40‰) and this increases when the total amount of water decreases (evapoconcentration). Thus, following an extreme draught from March to October 2009, salt saturation reached 48‰. Soda lakes are highly productive ecosystems. Its waters contain large concentrations of Na , HCO 3 , CO 3 et Cl ions. They originate from inflow from
2280-569: The government has so far failed to implement the court's orders as in the case of the Endorois, but has persisted in further evictions imposed in November 2023 by the Kenyan authorities during the visit of Britain's King Charles III . On 6 February 2024, both ethnies demonstrated together in Nairobi with the support of the International Network for Economic, social and cultural rights to demand
2340-404: The government implement the rulings. The area is inhabited by Tugen and Jemps pastoralists, and livestock grazing is the main land use in the area. The lake and its surroundings attract 200,000 tourists per year, due to the wildlife, the hot springs, the spectacular cliffs and escarpments and the rich indigenous culture. Hotel accommodation is available near Loboi village at the north end of
2400-443: The graminoid vegetation is interspersed with cyanobacterial and algal mats. Water from the blister mounds, and other seeps and springs, support wet meadows and Typha swamps. The blister mounds and Typha swamps have a more or less neutral pH, low conductivities and total alkalinity. The marshes to the north of the lake do not feed any river outlet. They are linked to both Lake Bogoria and adjacent Lake Baringo ; both lakes are fed by
2460-511: The lake water. Other streams, such as the Emsos to the south and the Parkirichai to the west, are ephemeral: they flow only after heavy rains. This swamp is to the north of the lake. It hugs the base of a horst block (raised fault block bounded by normal faults) oriented north-south. According to radiocarbon datation, it was created only 700 years ago in a former floodplain environment — possibly as
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2520-478: The lake's level fluctuates seasonally by 50 to 100 cm; and that it can vary by several meters for short periods, having fluctuated between c. 988 and c. 996 m during the 20th century. Lake-shore terraces around the shoreline, made of coarse angular gravel and angular orthoconglomerates, mark higher lake levels from the Pleistocene and Holocene. They are visible on 45% of the present level, and some are about 9 m above
2580-445: The main cause of death. Heavy metal poisoning was suggested but such poisoning does not have a periodic effect: its effect are continuous, and in these cases not compatible with the periodic dying; nor was it coherent with that birds of all ages were concerned, whereas such poisoning affects older individuals more than younger ones (ther older ones have had more time to accumulate poison in their bodies). Food poisoning has also been cited.
2640-445: The main food for lesser flamingo is Spirulina platensis , which is abundantly produced in the lakes of that region; but around the years that saw this heavy mortality toll, there had been an important increase of toxic cyanobacteria , especially during periods of algal blooms ; and the symptoms of dying flamingos were similar to those of algal toxicity. Its immediate surroundings are a critical habitat for vulnerable species such as
2700-448: The names of these lakes are Lake Turkana , Lake Logipi , Lake Baringo , Lake Bogoria , Lake Nakuru , Lake Elmenteita , Lake Naivasha , and Lake Magadi . Of those eight, only Lakes Baringo and Naivasha are fresh water. Lake Turkana, at the northern end of the rift, is 250 kilometres (160 mi) long, between 15 kilometres (9.3 mi) and 30 kilometres (19 mi) wide and is 125 metres (410 ft) at its greatest depth. Most of
2760-523: The north to wintering places in Africa. The lands around the lakes include large populations of black rhino, Rothschild's giraffe, greater kudu, lion, cheetah and wild dogs. The Kenya lake system is surrounded by the steep escarpment of the Rift Valley, which provides a spectacular backdrop. Other lakes are Lake Chew Bahir , in the northeast extension. This lake lies mainly in Ethiopia but extends into Kenya in
2820-562: The northern end of the Great Rift Valley in Kenya. There are also volcanoes in Lake Turkana. The Suguta Valley , or Suguta Mud Flats, is an arid part of the Great Rift Valley directly south of Lake Turkana . The shield volcano Emuruangogolak straddles the valley to the south of Suguta, and further south Mount Silali and Paka rise from the valley floor. Paka is a shield volcano, with widespread geothermal activity. South of Paka are Mount Korosi , Lake Baringo and Lake Bogoria . Menengai
2880-402: The other endorheic lakes in Kenya. The Rift Valley lakes undergo regular (and cyclic) changes in water levels mostly in response to precipitation, which is unreliable and unpredictable. In this region, lake Bogoria is the only alkaline lake that has minimal lake water fluctuations, and is used as a refuge for flamigos and other animals when other relatively shallow lakes dry out. Its surface
2940-402: The other lakes are shallow and poorly drained, and therefore have become alkaline. They have waters that are rich in blue-green algae, which feed insect larvae, small crustaceans and lesser flamingos . The larvae and crustaceans are food for fish and greater flamingos . Massive flocks of these birds have been found to have an effect on the lakeside sediments also. Their numbers cause trampling of
3000-446: The present shoreline. In 1991 the maximum length is 17.6 km (10.9 mi) and its width ranges from 0.5 km (0.31 mi) to 3.6 km (2.2 mi). The drainage basin is 700 km (270 sq mi) . The lowest point of the drainage divide is at 999 m near Loboi village; when the level of the lake reaches that altitude, its waters flow northward in lake Baringo drainage basin . In 1978 its maximum depth
3060-464: The rainy season. Lake Kamnarok is another small lake. Cherangani Hills The Cherang'any Hills are a range of hills in the western highlands of Kenya . The hills are one of Kenya's five main forests and catchment areas. The highlands, the large central plateau, is divided by the Mau Escarpment which rises from the border with Tanzania up to the Cherang'any Hills. The escarpment bounds
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#17328482849053120-496: The rift valley boundary faults, to the east, and a small horst block, to the west. The river waters are slightly alkaline, cool, and have a low total alkalinity. The marshes are similar in their general water chemistry, but are slightly acidic and have a distinctly lower NO3 content. Short grasses are the dominant vegetation type and cattle graze the area. These lie near the Lake Bogoria National Reserve entrance, to
3180-626: The silts in certain areas, while the feeding grounds are oxygenated due to probing beaks in the mud. Their nest mounds can also be preserved and cemented as the lake's water levels change. These form irregularities in the lakeside topography. Trona , an evaporative mineral, used for sodium carbonate production, has been mined at Lake Magadi for nearly 100 years. It produces about 250,000 metric tonnes per year. Other precious minerals like rubies and pink sapphires have been found and mined from areas around Lake Baringo. In 2004, over 2 kilograms of Corundum were collected. Three shallow alkaline lakes and
3240-549: The smaller peaks of Cherangani was found to be containing Iron Ore. White Quartzite rocks are found in Lelan in West Pokot. Other minerals that have been recorded before by Geologists in Cherangani Hills include Red Garnets near Talau in West Pokot and Beryl in Sebit. Chromite has also been found by Geologists in the colonial era. The Cheranganyi Hills are a source to River Moiben and Chepkaitit,
3300-432: The south of the Loboi swamp, and at the limit dividing faulted volcanic uplands and colluvial-alluvial sediments. They contain several types of habitats. Ashley et al. 2002 defined them as an 'Artesian Blister Wetland' (see Types of wetlands above), and that wetland also includes slightly acidic, nitrate enriched, warm springs. This is on the western shore of Lake Bogoria. It is composed of silts and gravels, and shows
3360-422: The surrounding lands make up the Kenya lake system: Lake Bogoria at 10,700 hectares (26,000 acres), Lake Nakuru at 18,800 hectares (46,000 acres) and Lake Elmenteita at 2,534 hectares (6,260 acres). This system has one of the most diverse populations of birds in the world, and is the home of thirteen globally threatened species of bird. It is an important nesting and breeding site for great white pelicans , and
3420-570: The western wall. The Kerio Valley lies between the Tugen Hills and the Elgeyo escarpment at an elevation of 1,000 metres (3,300 ft) There are large deposits of Fluorite in the Kerio Valley area. Further south the Mau Escarpment is a steep natural cliff approximately 1,000 m (3,300 ft) high, running along the western edge of the Great Rift Valley about Lake Naivasha . Yet further south
3480-526: Was formerly named after Bishop James Hannington who visited in 1885. Lake Bogoria is located in Baringo County, about 120 km north of Nakuru city and 240 km north of Nairobi . It is in the Gregorian Rift Valley . It was once part of a larger freshwater lake, joined with the current Lake Baringo . As shown on the satellite picture at the top of this page, it is divided in three lobes:
3540-419: Was one of the hottest years on record, but despite depressed rainfall in the short-rains season (October to December, or OND) it also saw a wetter than normal January and February because of the strong positive Indian Ocean Dipole index during that period, and enhanced rainfall during the long-rains season (March to May, or MAM) (that year, Lake Victoria rose to a new record level). However, evaporation rate
3600-475: Was recorded as 12 m (39 ft) or 11.5 m (38 ft), and Renaut & Owen 1991 precise that this was in the largest sub-basin or lobe; and that the two smaller parts at the north and south extremities were 5.5 m (18 ft) deep at that time. In 2003 its maximum depth is just over 10 m (33 ft) in an area of 3,000 ha (7,400 acres). This is relatively shallow, but nevertheless deeper — and therefore hydrologically more stable — than
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