The introduction of rainwater catchment tanks and micro-irrigation to Botswana

ITDG, . (1969) The introduction of rainwater catchment tanks and micro-irrigation to Botswana. Technical Report. Intermediate Technology Development Group Ltd, London.

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Abstract

Botswana is a vast country of 225,000 square miles with a low rainfall and a long dry season. Much of the country is a relatively featureless, gently undulating, sand-covered plain with low scrub vegetation. Nearly 75% of the total population of 540,000 (in 1964)* live in the east of the country, that is to the east of the sandy plain, in the more developed region which is traversed by the railway from South Africa to Rhodesia. (See Figs I to 3) Botswana is not economically self sufficient: its economy is centred on livestock and arable agriculture, but the export of meat is insufficient to provide the foreign exchange necessary to pay for essential imports, and the country relies heavily on development grants from other countries. Recently, exploratory work has been started to evaluate the mineral potential of Botswana, but as yet this does not contribute noticeably to the economy. It is hoped that within the next ten years the production of minerals will make a sizeable contribution to the economy. 2. Physiography The land surface of Botswana is a slightly basin-shaped plain, lying mainly between 3,000 and 4,000 feet above sea level. About 85% of the country is covered by geologically recent wind-blown or fluviate sands of the Kalahari system.? (See Fig 2) 3. Vegetation Reference to Fig 3 shows that the vegetation over most of the country is very sparse, being desert grasses and shrubs. However, in a few areas the desert grasses give way to more dense forms of vegetation. This sparseness is due both to the type of soil (predominantly sandy) and the low rainfall (see Fig 4). 4. Rainfall From Fig 4 it can be seen that at Mahalapye the rainy season is short, and this is typical of the whole country. Emphasis is placed by the people on ploughing and planting sorghum during and immediately after the rains, and on the tending of cattle during the long dry season. However, the total amount of rainfall from one year to the next is very variable,and this can create large problems of food shortage. Also the rainfall may be of considerable quantity but also torrential and is therefore quickly lost in flash floods, thus benefiting the people very little. Futher, evaporation is great (see Fig 4) and therefore a considerable part of the total rainfall is lost in this way. All of these put a premium on water storage and control for existing crops and livestock, for drinking water and for supplementary cropping (including horticulture). 5. Temperatures As may well be expected of a country partly situated within the tropics, the air temperatures in Botswana are high, as the diagram of mean temperatures at Mahalapye shows. (See Fig 5).-The temperatures indicated in that diagram are fairly typical of the country as a whole, although local variations will always occur

Item Type: Monograph (Technical Report)
Uncontrolled Keywords: Micro-irrigation, Radisele climate, Rainwater, River beds, Wells, Boreholes, Dams, P2751
Subjects: Social Sciences
Divisions: General
Depositing User: Ms Ishrath Durafsha
Date Deposited: 21 May 2014 10:00
Last Modified: 21 May 2014 10:00
URI: http://eprints.icrisat.ac.in/id/eprint/13036

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