The Great Rift Valley is an approximately 6,000 km continuous geographic trench on the earth’s crust which stretches from Lebanon’s Beqaa Valley in Asia through Kenya to Mozambique in South-Eastern Africa. The vast valley holds some of the planets greatest lakes, plains and mountains. The Great Rift Valley literally cuts Kenya into two. This section of the rift is referred to as the Kenyan Rift Valley and runs from north to south.
About the Kenyan Great Rift Valley
The Kenyan Rift Valley is part of the East African Rift (Gregory Rift- eastern branch) which stretches from Northern Ethiopia to Southern Tanzania. The intra-continental ridge system was formed on the upwelling created by the interactions of the Nubian, Somalian and Arabian plates. The former Rift Valley Province covered most of the Kenyan Rift Valley.
The Kenyan Rift system comprises a number of hills including the Cherangani Hills, Tugen Hills and a chain of volcanoes, some of which are still active. The rift features a mild climate with temperatures frequently below 28° C. It experiences rainfall during the October to November and March to June periods.
Features of the Kenyan Great Rift Valley
Escarpments enclose the valley to the east and west. A series of lakes and volcanoes lie on the rift floor. Lake Turkana occupies the northern end of the Kenyan Great Rift Valley. Lake Baringo and Bogoria lie further south of Lake Turkana and Mount Paka.
Volcanoes spread through the region in Lake Turkana and in the Suguta mudflats, or Suguta Valley south of Lake Turkana. Emuruangogolak, a shield volcano, straddles the valley to the south of Suguta and further south, Mount Paka and Silali tower from the valley floor. Paka, a shield volcano, has an extensive geothermal activity. Mount Korosi rise to the south of Paka. Menengai, a vast shield volcano, contains a caldera that was formed approximately 8,000 years ago. The crater is a major tourist attraction in the rift and overlooks Lake Nakuru to the South. This region also includes Lake Elmenteita, Mount Kipipiri, and Lake Naivasha.
On the South of Lake Naivasha lies the Hell’s Gate National Park and Mount Longonot, a dormant stratovolcano that erupted in the early 1900s. Suswa, a shield volcano, is located between Nairobi and Narok. In this region, lava flows from recent eruptions (less than 100 years old) are still uncovered by vegetation. Lake Magadi is the most southern rift valley lake in Kenya, although the northern end of Lake Natron in Tanzania reaches into Kenya.
Escarpments form the walls of the rift valley. The Elgeyo Escarpment forms a section of the western wall. Between the escarpment and the Tugen Hills lies the Kerio Valley at an elevation of 1,000 meters (3,300 ft.). The Kerio Valley area contains large deposits Fluorite. A steep, natural cliff, Mau Escarpment, runs along the western edge of the Rift Valley near Lake Naivasha. It is approximately 3,000 meters (10,000 ft.) high. Further south, the Nguruman Escarpment stretches 50 km long and elongates in a northwest direction. Its northern edge is approximately 120 km southwest of Nairobi, while the southern edge is close to the Tanzanian border, at the north-western limit of Lake Natron.
The Aberdare Range forms a section of the eastern rim of the Kenyan Great Rift Valley to the north of Nairobi. Mount Satima, the highest point of the Aberdares, lies at the northern edge, and Mount Kinangop, the second-highest point, at the southern end. The mountains peaks form a ridge between the two peaks. Ngong Hills are peaked in a ridge along the east of the Great Rift Valley, located southwest near Nairobi.
The Great Rift Valley contains fertile soils such as Andisols as a result of moderately recent volcanic activities.
The Kenyan Rift Valley Lakes
The Kenyan Rift Valley is home to eight of the total lakes in Kenya. From south to north, the lakes include Lake Magadi, Lake Naivasha, Lake Elmenteita, Lake Nakuru, Lake Bogoria, Lake Baringo, Lake Logipi and Lake Turkana. Only Lake Naivasha and Lake Baringo are freshwater, the rest alkaline. The lakes are all unique and support a staggeringly large proportion of wildlife and famous for large flocks of flamingo that feed on crustaceans.
- Lake Magadi is a shallow soda lake that lies in the borderlands of the Rift Valley near the southern border with Tanzania. Trona, an evaporative mineral, used for sodium carbonate production, has been mined at the lake for nearly 100 years. The produces about 250,000 metric tonnes per year.
- Lake Naivasha is a freshwater lake that draws a healthy population of hippos. It covers approximately 160 sq. km although it varies somewhat with rainfall.
- Lake Elmenteita is a shallow soda lake that attracts large numbers of flamingo. The lake appears pink from an aerial view due to the opulence of flamingos.
- Lake Nakuru is a shallow soda lake that has been a national park since 1968. The astonishing lake and its immense numbers of flamingos are the main reasons why Lake Nakuru National Park is one of the most popular national parks in Kenya.
- Lake Bogoria is a shallow soda lake and a national reserve. The caustic cauldron is frequently inhabited by huge flocks of the lesser flamingo and contains more true geysers than any other area of equal size in the world.
- Lake Baringo is the second largest of the Kenyan Rift Valley lakes with a surface area of 210 sq. km. It homes about 500 species of bird and is a crucial stop off for migrant bird populations. Precious minerals such as pink sapphires and rubies and pink sapphires have been found and mined from areas around this lake.
- Lake Logipi is a shallow hot-spring fed soda lake in the Suguta Valley just south of Lake Turkana.
- Lake Turkana is the largest of the Kenyan lakes, on the border of Kenya and Ethiopia. It lies at the end of the rift, covers a surface area of 6,405 sq. km stretches 250 km long and varies 15 km to 30 km in width. Its greatest depth is 125 m. Lake Turkana is home to a range of incredibly resilient life-forms. It is the largest desert lake in the world and supports Africa’s biggest population of Nile Crocodiles.
- Other lakes are Lake Chew Bahir, in the northeast extension. This lake lies mainly in Ethiopia but extends into Kenya in the rainy season. Lake Kamnarok is another small ox-bow lake.
These lakes 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.
The Kenya Lake system
The three shallow alkaline lakes (Lake Bogoria, Lake Nakuru and Lake Elmenteita) and their surrounding lands make up the Kenya Lake system. This system has one of the most diverse populations of birds in the world and is the home of thirteen globally threatened species of birds. It is an important nesting and breeding site for great white pelicans and is the most important feeding area for lesser flamingos in the world. The system is home to globally important populations of African spoonbill, little grebe, black-necked grebe, little grebe, pied avocet, black-winged stilt, yellow-billed stork, gull-billed tern, and grey-headed gull.
The Kenya Lake system is a significant location on the West Asian-East African Flyway, a route followed by huge numbers of birds in their annual migration from breeding grounds in the north to wintering places in Africa. The lands around the lakes include large populations of Rothschild’s giraffe, black rhino, greater kudu, lion, cheetah and wild dogs. The system is surrounded by the steep escarpment of the Rift Valley, which provides a spectacular backdrop and vista.
The lakes, their feeder and outlet rivers, as well as the rich volcanic soil, are the key to life in the Great Rift Valley. Despite a decline in the total wildlife numbers due to human activities, the rift valley plains are still lush with game.