Major Environmental Concerns  

[ Land | Forest | Biodiversity | Water | Marine & Coastal Environments | Urban & Industrial Environments ]

Underlying Causes

[ Social | Economic | Institutional | Environmental ]

The availability of water in Africa is highly variable both in space and in time. Precipitation over the continent varies from practically zero over the Horn of Africa and the Namibian Desert to more than 4,000 millimetres a year in the western equatorial region. A large proportion of the continent is semi-arid, receiving between 200 and 800 millimetres a year of variable rainfall. Droughts that last between one and five years occur frequently.

The rainfall records from the early 1900s to mid-1980s show that the continent's average annual rainfall has decreased since 1968, and has been fluctuating around a notably lower mean level (UNEP, 1985). (See Figure 2.3.) The impact of variable rainfall and drought has been accentuated by land degradation and deforestation, which have led to more soil erosion and hence increased sediment transport-which adversely affects water quality, aquatic ecology, reservoir volumes, estuaries, ports, and hydroelectric dams (World Bank, 1996).

In Africa some 4 trillion (4,000 billion) cubic metres of renewable water is available annually, but only about 4 per cent is used (WRI/UNEP/UNDP/WB, 1996). (See Table 2.1.) The infrastructure and technical and financial means do not exist to use effectively the water available (UNEP, 1996b). Runoff is concentrated in limited upland areas (such as Fouta Djallon in Guinea, the Jos Plateau in Nigeria, the Cameroon Mountains, the Ethiopian Highlands, the Aberdares and the slopes of Mount Kenya, and Mount Kilimanjaro and Lesotho and Swaziland Highlands), and relatively few lengthy rivers run through downstream dry terrain (for example, into Sudan and Egypt for the Nile River). The fresh water available to downstream countries, often with a dry climate, depends on actions taken by upstream countries to develop their own water resources (World Bank, 1996).

The continent's ground-water resources, although widespread, are limited. In sub-Saharan Africa , about 15 per cent of the renewable water resources is ground water and more than three quarters of the population uses this as their main source of supply (World Bank, 1996). There are a few large sedimentary basins in the region with substantial renewable ground-water reserves and numerous smaller sedimentary aquifers along the major rivers, coastal deltas, and plains.

Ground-water quality is deteriorating in some areas due to lack of proper assessment and management, which leads, for example, to overexploitation (World Bank, 1996). This is particularly true in northern Africa .

The proportion of people without access to adequate water is greater here than anywhere else: Africa has 19 of the 25 countries in the world with the highest percentage of populations without access to safe drinking water (WRI/UNEP/UNDP/WB, 1996). West and central Africa have more than enough water on a per capita basis, but in most other areas, population growth and economic development create excess demand over supply.

For example, Algeria , Egypt , Morocco , and Tunisia suffer water scarcity and stress (Population Action International, 1994). In Libya , more than 100 per cent of the renewable water supply is already being consumed, and fossil water is also being tapped. The freshwater supply is particularly limited in the Sudano-Sahelian belt and parts of southern Africa . (See also Figure 2.4.)

All the countries in continental sub-Saharan Africa share one or more river basins. There are at least 54 rivers or water bodies cross or form international boundaries in the region. However, few are effectively managed jointly. The Nile , Zambezi , Volta , and Niger rivers and Lake Victoria all have the potential to create serious conflicts as well as cooperation and economic integration.

The various activities competing to use fresh water include individual consumption, agriculture, fisheries, industry, power supply, livestock, wildlife resources and recreation, and watershed protection. The competition is becoming more intense, increasing the potential for conflicts at local, national, and regional levels (World Bank, 1996). The most important issue for Africa is to increase investment and cooperation among riparian States to manage the freshwater resources in an efficient and sustainable manner (UNEP, 1996b).

United Nations Environment Programme