Kenya - Geography
Kenya rises from a low coastal plain on the Indian Ocean in a series of mountain ridges and plateaus which stand above 3,000 meters (9,000 ft.) in the center of the country. The Rift Valley bisects the country above Nairobi, opening up to a broad arid plain in the north. Highlands cover the south before descending to the shores of Lake Victoria in the west. Climate is tropical in south, west, and central regions; arid and semi-arid in the north and the northeast.
Kenya, the heartland of East Africa, encompasses some 580,000 square kilometers, an area slightly smaller than the state of Texas. Bisected by the equator, its southeastern frontier is washed by the Indian Ocean and its southwestern reaches by vast Lake Victoria. Towering mountains, forests, lakes, mangrove swamps, arid plains that include a desert, and many national parks and game preserves teeming with majestic wildlife mark the country as a show case of scenic wonders.
The most striking physiographic distinction in Kenya is between the area of higher land, encompassing roughly the southwestern one-third of the country, and the remaining two-thirds, consisting of low plateaus and plains. The highlands include the only large area - other than the coastal belt — that can count on generally reliable rainfall; they also contain most of the good soils, and the great majority of the settled population lives there. In contrast, the outer arc of lower land is peopled almost entirely by nomadic pastoralists living in a terrain covered mostly by semiarid vegetation and receives highly variable rainfall that in many places rarely exceeds 250 millimeters a year.
The country's number and variety of large animals are an important tourist attraction. Efforts (of varying degrees of success) to conserve and protect this significant natural resource have led to the establishment of parks and game reserves in different parts of the country. For over a century these attributes attracted a growing influx of foreign visitors eager to experience the thrill of safari, a term that has virtually become synonymous with the country's name. In the early years adventurers armed with rifles came to bag impressive animal specimens for their trophy rooms. The quest continued, but the guns were replaced by cameras. Kenyans have capitalized on the striking variety of their topography, climate, and bountiful wildlife, making tourism an important earner of foreign capital.
Kenya is characterized by highly varied terrain and climatic conditions that range from moist to arid. The three principal climatic subdivisions include a narrow coastal belt along the Indian Ocean, which has rainfall adequate for agriculture; a central highlands region and the adjacent lower plateaus to the west that border Lake Victoria, which also have adequate precipitation for crops; and the rest of the country, which usually receives less than 500 millimeters of rain annually and is usable chiefly as rangeland.
The country may be divided into seven major geographic regions that intersect the principal climatic subdivisions. Topography, rainfall, and soil conditions combine to produce substantial differences in natural vegetation.
The Coastal Region exhibits different features in its southern and northern parts. The shoreline, south of the Tana River delta, formed largely of coral rock and sand, is broken by bays, inlets, and branched creeks. Mangrove swamps line these indentations, but along the ocean are stretches of coral sand that form attractive beaches. A rise in the ocean level relative to the land in this area led to the formation of islands in certain places. The most notable of these is Mombasa. The sheltered configuration and deep water of the creeks around Mombasa led centuries ago to its use as a harbor and to its later development as East Africa's most important port.
Not far off the shoreline a barrier reef, broken only at a few points, parallels the coast. Immediately inland from the coast a narrow plain is succeeded by a low plateau area that reaches an elevation of about 150 meters and after a few kilometers terminates in a line of discontinuous ridges. Rainfall in the subregion is adequate for agriculture which, in addition to fertile soils of dried-up lagoons in certain parts of the low plateau, has fostered a rather dense farming population.
The principal physiographic feature of the smaller northern section of the region is the Lamu Archipelago, also formed by the inundation of the coastline as a result of a rise in the ocean level. This area was historically a major center of Arab trade. The northern part is less heavily populated than the south, in part because of the smaller amount of rainfall.
Coastal Hinterland and Tana Plains Region
The coastal hinterland forming the southern part of this region is a relatively featureless plain broken only in a few places by small hills. The plain rises very gradually westward from an elevation of about 150 meters to about 300 meters, where it meets the Eastern Plateau Region. Rainfall is low, and the area is sparsely populated, mostly by nomadic pastoralists. Part of this hinterland falls within the nyika (wilderness), an area of bushland and thicket inhabited largely by wild animals.
The Tana Plains section of the region—equally featureless and deficient in rainfall—extends northward from the upper part of the Coastal Region to the Northern Plainlands Region. The Tana Plains' eastern edge and their western limits are marked by the higher elevation of the Eastern Plateau Region. The vegetation is mainly bush and scattered trees. The population consists of nomadic pastoralists. Considerable sections of the area along the perennial Tana River have been irrigated. A major feature of the Tana Plains is the great Lorian Swamp.
Eastern Plateau Region
The Eastern Plateau Region consists of a belt of plains extending north and south to the east of the Kenya Highlands. Elevations are mainly between 300 and 900 meters (notable exceptions are the Chyulu Range and the Taita Hills, which rise to over 2,100 meters). The monotony of the region is broken by numerous scattered hills and pinnacles, some craggy, others domed and smooth. The southern part of the region includes the Amboseli and Serengeti plains and is the site of the Amboseli and Tsavo national parks.
Rainfall is relatively low, particularly in the more northerly sections. The Chyulu Range and the Taita Hills have greater precipitation, but rainfall in the former is highly unreliable. At times the seasonal Namanga River pours a large amount of water onto the flat Amboseli Plain to form Lake Amboseli, which at its fullest has an area of about 114 square kilometers. During the dry season the lake disappears, and the area becomes a dusty plain. Much of the vegetation in the region is bushed grassland and thicket that gradates in the north into semidesert bush and grass. The higher elevations of the Taita Hills, however, have woodland growth.
Northern Plainlands Region
The vast Northern Plainlands Region consists of a series of arid plains and includes within its limits Lake Rudolf and the Chalbi Desert. Rainfall in the area west of the lake is under 250 millimeters; in some years it is almost negligible. Streams flowing through the area in the rainy season to empty into Lake Rudolf dry up at certain times of the year. Water holes remain, however, and at other points water lies only a short distance below riverbeds. The area is inhabited by the nomadic Turkana, who graze their camels, goats, and sheep on scattered bush and grass. Lake Rudolf is the site of fishing activity.
Significant features east of Lake Rudolf include the Chalbi Desert, Kenya's only true desert. The plains around Mount Marsabit consist of a vast lava plateau. Erosion on those plains farther east has dotted the landscape with hills of varying shapes and sizes.
The area east of the Chalbi Desert is generally arid and ordinarily supports vegetation only of the semidesert kind. Certain spots are more favored, including Mount Marsabit, which at higher elevations may receive up to 760 millimeters of rain annually and has an upper forest cover. Foothills of the southern Ethiopian highlands extending into Kenya also have more rainfall, and several perennial rivers flow south- southeastward from these hills onto the plains. The area supports a sparse nomadic population except for a few cultivators in the Marsabit area and the Ethiopian foothills.
Kenya Highlands Region
The Kenya Highlands Region comprises the complex of high land in west-central Kenya. It consists of two major divisions lying east and west of the great north-south Rift Valley. Each major section has a number of subdivisions, but the whole area is tied together by the common denominators of markedly higher altitude, cooler temperatures, and generally greater precipitation than found in other regions.
A striking feature on the eastern edge of the highlands is Mount Kenya, the country's highest point, which rises to 5,200 meters. Among the more important subdivisions of the eastern highlands is the area east of the Aberdare Range, which is populated by the Kikuyu, the country's largest ethnic group. Much of the original forest in this area has been cut down, and the land is cropped intensively.
To the west of the Rift Valley many upper elevations in the southern part of the highlands remain covered by forest. Small farms dot the area at somewhat lower levels. Forest also still covers large areas of the northern part of the western highlands. The local population grows wheat and maize, and cattle are grazed on the area's rich grassland. On the northwestern edge of the highlands lies Mount Elgon, an extinct volcano rising to over 4,320 meters above sea level.
Rift Valley Region
The great Rift Valley of eastern Africa, formed by a long series offaulting and differential rock movements, extends in Kenya from the Lake Rudolf area in the north generally southward through the Kenya Highlands and into Tanzania. In the vicinity of Lake Rudolf the valley floor is about 455 meters above sea level, but southward it rises steadily until in its central section in the area of Lake Naivasha the elevation is close to 1,890 meters. From that point southward it drops off to about 610 meters at the Kenya-Tanzania border.
The central section of the valley, about 65 kilometers in width, is rimmed by high escarpments. To the east is the Ilkinopop Plateau, some 610 meters above the valley floor, and east of that plateau lies the Aberdare Range, which has elevations above 3,960 meters. On the valley's western side are the Mau Escarpment, rising to nearly 3,050 meters, and farther north the Elgeyo Escarpment and the Cherangany Hills, the latter having elevations of over 3,350 meters. The valley floor has been subjected to extensive volcanic activity, and several cones rise high above it; the area remains one of latent volcanism, hot springs and steam emerging at numerous spots. Volcanoes and lava heaps divide the central section into compartments in which lie a series of lakes that have no outlets. Their content ranges from the alkaline but relatively fresh water of lakes Baringo and Naivasha, both of which support fish populations, to the higher soda content of lakes Elmenteita, Bogoria, and Nakuru and the almost solid and commercially exploited soda ash of Lake Magadi.
The northern and southern parts of the valley receive a yearly rainfall averaging between 250 and 560 millimeters. They have semidesert vegetation consisting of grass, bush, and scattered trees and are inhabited by nomadic pastoralists. The more elevated central section around Nakuru has higher precipitation, and the vegetation includes wooded grassland. The heavier rainfall in this part, especially close to the escarpments, allows the cultivation of grain crops.
Western Plateaus Region
The Western Plateaus Region forms part of the extensive basin in which Lake Victoria lies. It consists mainly of faulted plateaus marked by escarpments that descend in a gentle slope from the Kenya Highlands Region to the shore of the lake. The region is divided by the secondary Kano Rift Valley into northern and southern components having somewhat different features. This faulted valley lies at a right angle to the main rift running through the highlands and is separated from that valley by a great lava mass. The lake intrudes into the Kano rift for about 80 kilometers to form Winam Bay, at the eastern end of which is Kisumu, the country's fourth largest town and a major lake port. East of this arm of the lake is the low-lying Kano Plain, which suffers periodically from drought and floods. Good soils and generally adequate rainfall for crops led to a very high concentration of rural population in this region.
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