|
|
7: Geography |
Notes and Comments
Provisional version by Neil Parsons April 1999
The Republic of Botswana is a landlocked country in the centre of southern Africa with an area of about (581,700 sq km (224,000 sq miles). The capital is Gaborone (until 1969 spelt Gaberones, i.e. "Gaborone's" named after Chief Gaborone), the modern city having been founded in 1964.
The territory is approximately 1000 kilometres from north to south and 1000 kilometres from east to west. Eastern and southern borders are river-courses and an old wagon-road; the western border consisits of lines of longitude and latitude, and the northern border combines straight line projections between distant beacons with a river course.
Botswana is bounded by Namibia to the west and north (the Caprivi Strip), Zambia to the northeast, Zimbabwe to the north-east, and South Africa to the southeast and south. The actual border with Zambia along the Zambezi River, at the east end of the thin finger of Namibian territory known as the Caprivi Strip, is only a few hundred metres long. The precise demarcation of this unique four-way border junction in the Zambezi river between Botswana, Namibia, Zambia, and Zimbabwe has never been satisfactorily determined in international law. It was disputed by South Africa in the early 1970s when Botswana up-graded the 100-year old ferry service to the Zambian bank.
Namibia has challenged Botswana's ownsership of Sedudu or Kachikili island in the Chobe river. The matter is now (APRIL 1999) before the International Court of Justice at the Hague. For the latest news, see the newspaper etc. links on Page 15.
For government surveys and mapping see Ministry of Local Government, Lands & Housing.
The annual climate ranges from months of dry temperate weather during winter to days or weeks of sub-tropical humidity interspersed with drier hot weather during summer. In summer (which lasts from October to March) temperatures rise to above 34 C (93 F) in the extreme north and south-west. In winter (which lasts from April to September), there is frequent frost at night and temperatures may fall below 2 C (37 F) during the day, but skies are usually cloudless and sunny. Summer is heralded by a windy season, carrying dust from the Kalahari, from about late August to early October.
Annual rainfall, brought by winds from the Indian Ocean, averages 460 mm (18 in), including a range from 640 mm (25 in) in the extreme north-east to less than 130 mm (5 in) in the extreme south-west. The rains are almost entirely limited to summer downpours between December and April, which also mark the season for plowing and planting. Cyclical droughts, lasting up to five or six years in every two decades, can limit or eliminate harvests and reduce livestock to starvation.
The country has a mean altitude of about 1000 metres (3300 ft) above sea level, and largely consists of a sand-filled basin, with gently undulating plains -- rising to the highlands of Zimbabwe in the northeast and the Transvaal in the southeast, and to the highlands of Namibia in the west. The highest point is 1400 metres (4600 ft) on the Male Hill in the Tsodilo Hills in the northwestern corner of the country; the lowest point is 660 metres (2170 ft) at the country's most easterly extreme in the Limpopo valley between the Zimbabwe and Transvaal plateaux.
The country is divided into three main environmental regions. The HARDVELD region, where most population and economic activity of concentrated, consists of rocky hill ranges and areas of shallow sand cover in south-eastern and east-central Botswana. (There is also a small area of hardveld in the extreme west, the Ghanzi ridge extending from the Namibia highlands.) The SANDVELD region is the area of deep Kalahari sand covering the rest of the country. A small number of out-cropping rocky hills extrude from the sandveld in the north and west. The third region of the country, consisting of ANCIENT LAKE BEDS in the base of the Kalahari basin, is superimposed on the sandveld in north-western Botswana.
The ancient lake beds of Botswana date from wet climatic periods when the Makgadikgadi Pans and Okavango Delta were lakes covering up to three times their present areas. Lake levels are known to have been high 40,000-35,000 years ago, and as recently as 15,000-10,000 years ago. Even 2,000 years ago there were considerable areas of wetlands around Lake Makgadikgadi.
The ancient lakes of Okavango and Makgadikgadi are evidence of ancient tectonic movements in northern Botswana. Geologists believe that at an earlier date the Okavango and Chobe-Zambezi rivers flowed through the area of the Makgadikgadi to the middle Limpopo valley and thence to the sea. (See Page 12: Science (Geology)). But warping of the earth's crust, associated with the extension of the Great African Rift south-westwards to beneath the sandveld of the Okavango Delta area, opened up a new passage for the Zambezi to the sea over the Victoria Falls. It also blocked off the old Zambezi-Limpopo course by a new ridge south-east of the Makgadikgadi. The water which was backed up behind this ridge formed Lakes Makgadikgadi and Okavango.
Support for this theory was given in 1967 by discovery that diamonds washed down the Motloutse valley, the present tributary of the Limpopo thought to have been the course of the old Zambezi-Limpopo, had come from diamond pipes now on the other side of the Motloutse- Makgadikgadi ridge.
Present day drainage through the marshes of the Okavango Delta is complex and imperfectly understood. (See Page 14: Tourism). The perennial Okavango river runs southwards into its delta across the Caprivi Strip from the highlands of Angola. Most of its water evaporates from the 1400 sq km (4000 sq miles) of the delta wetlands. Flood water reaches down through the eastern side of the marshes to the Boteti River, which flowed sporadically to Lakes Xau (Dow) and Mopipi and the Makgadikgadi Pans (also roughly 4000 sq km in area) till the 1980s - since when it has stopped.
Less and less water has been flowing through the western side of the Okavango marshes during the 20th century, so that 180 sq km (70 sq mile) Lake Ngami - famous a century ago - is today dry and almost unrecognizable as a lake. Meanwhile the eastern Makgadikgadi Pans are annually flooded by the otherwise ephemeral Nata River from the Zimbabwe highlands, while the southern tributaries of the pans are now dry fossil valleys.
The Molopo River (with its Ramatlhabama tributary) on the southern border of Botswana, with a course flowing into the Orange River, today rarely floods more than 80 km from their source. Most Botswana rivers are ephemeral channels rarely flowing above ground except in the summer rainy season. The two great exceptions to this rule are vigorous channels fed by the rains of central Africa - the Okavango River above its delta, and the Chobe (Kwando, Mashi or Linyanti) River flowing through its marshes along the northern border to join the Zambezi above the Victoria Falls.
For Geology see under Page 12: Science.
The soils of the eastern hardveld consist of moderately dry red loamy mokata soils on the plains, or mixed chalky and sandy chawana soils, with brownish rocky seloko soils on and around hills. Seloko soils are considered best for grain crops. The fertility of all soils being limited by rainfall, which is sometimes inadequate on the hardveld and regularly unable to support any cultivation on the sandveld.
The Kalahari sandveld shows evidence of having been a barren sand desert in periods of the geological past. Dune patterns are still visible from the air, but not from the ground as the dunes have been covered by grass and tree or bush vegetation. The sandveld consists of very dry light red to yellowish sands. The sands are redder in the south- western corner of the country - where some dunes have been exposed by erosion. Other patches of "desertification" are evident from satellite imagery: notably the area around Hukuntsi where yellowish sands have been stripped bare by over-grazing.
The alluvial soils of the ancient lake beds range from grey loamy soils in the wetlands, and gray-green saline soils on the pans, to gray clayish soils to yellowish sandy soils around the wetlands and very chalky light gray soils round the pans. There are also areas of gray to black cracking clay in former wet areas, such as those around Pandamatanga where 'virgin land' maize farming is now being attempted on a commercial scale.
For Agriculture see Page 5: Economics
The human and livestock population of Botswana is concentrated around the hill ranges of the eastern hardveld and along the perennial rivers of the north. Approximately one third of the population lives in scattered rural settlements, usually based around livestock pens. More than half the population lives in rural village settlements of over a thousand people, including traditional towns with up to 40,000 people. A growing proportion of the population, now exceeding one fifth, live in the seven modern towns and cities classified as urban areas.
The typical rural settlement and land use pattern of the eastern highveld in the past may be characterized as having been concentric circles around a concentrated village nucleus. The family had a home base in the village, where most of its members spent most of the year. In the appropriate season it cultivated 'lands' (fields) within a day or two's walk from the village. The family cattle, on the other hand, were pastured for most of the year at 'cattle-posts' a number of days walk from the village. Finally, beyond the cattle-posts, there were hunting lands.
This "traditional" pattern, inherited from the late 19th century, has however fragmented in the 20th century with the decline of traditional political controls, the break-up of the family through long-distance labour migration, and the increased mobility offered by motor transport and options for new settlement offered by drilling of bore-holes (artesian wells) for water. Private and public capital investment in village centres has also precluded communities from moving their whole village, as in a bygone age, when nearby cultivable land and pastures become depleted.
See also "Village Life" on Page 13: Society.
The villages and traditional towns of Botswana are still basically laid out around the kgotla (courtyard) and cattle kraal (corral) of a traditional ruler, and are sub-divided into wards each of which mimics the village or town plan with its own central kgotla and kraal. But, since the 1970s, traditional settlements have been sliced through by modern roads and facilities such as schools and offices, as well as by shopping malls and bars.
Traditional architecture of thatch roofing and clay walling has given way to corrugated metal roofing and brick walls. The new middle class is expressing its independence from traditional contraint, while retaining locational identity with traditional village roots, by building large modern suburban houses outside the old wards - especially on the paved approach roads to the traditional state capitals of Serowe, Kanye, Mochudi, Molepolole, Maun, Tlokweng and Ramotswa. Other villages have similarly burgeoned with new construction, particularly along the line of rail.
Two of the seven "modern" towns of Botswana date from origins as small urban centres on the railway for white settler farming communities in the colonial period - Francistown (1897) and Lobatse (1900). Both began to develop in size and function in the 1950s as employment in non-agricultural services expanded.
Gaborone, the capital city, was founded in 1964, since when it has grown to over 185,000. Selebi-Phikwe (1971) and Jwaneng (1979) are the only substantial mining towns; Orapa (1971) being a small company town in the sandveld, closed off from spontaneous accretion by security fences. The newest mining township, really a village, is Sua (1991), which is based on the soda ash deposits of the eastern Makgadikgadi Pans.
For government town and regional planning see Ministry of Local Government, Lands & Housing
For climatology in colonial Africa including Bechuanaland (Botswana) see Surface Climate Data by John F. Griffiths and Thomas C. Peterson.
See Page 2 for other comments and general Links. For details of the numerous geographical publications of the Botswana Society see the Botswana Society's page on publications.
(7a) David S.G. Thomas & Paul A. Shaw, The Kalahari Environment (Cambridge; Cambridge University Press, 1991) ISBN 0 521 37080 9
(7b) The Botswana Society Social Studies Atlas (Gaborone: Botswana Society & Stockholm: Esselte, 1987) ISBN 99912-60-03-X
(7c) Robson M.K.Silitshena & G. McLeod, Botswana: a Physical, Social and Economic Geography (Gaborone: Longman Botswana, 1989) ISBN 0 582 98302 9
Copyright © 1999 Neil Parsons
The Botswana History Pages by Neil Parsons may be
freely reproduced, in print or electronically, on condition
(i) that full acknowledgement of the source is made.
Last updated 19 August 1999