Africa's renewable water resources average 4 050 km3/year,
providing in the year 2000 an average of about 5 000 m3 per
capita/year - significantly less than the world average of 7 000 m3
per capita/year and less than one-quarter of the South American average
of 23 000 m3 per capita/year (Shiklomanov 1999 and United Nations
Population Division 2001).
Rainfall variability in the Lake Chad basin
Over the past 30 years, the surface area of Lake Chad has varied
considerably - from 25 000 to 2 000 km2 - due to rainfall variability
over the past 30 years. The lake supports globally important wildlife,
particularly migratory birds. The economic activities of about 20
million people are based on the lake's resources. A new GEFfunded
project in the Lake Chad Basin aims to decrease environmental degradation
by improving cooperation between interested and affected parties,
with the benefits from projectrelated activities accruing to the
Source: Coe and Foley 2001
Lake Chad in 1973 and 1997; red colour
denotes vegetation on the lake bed
Source: NASA 2001
However, the distribution of both surface water and groundwater is uneven.
For example, the Democratic Republic of Congo is the wettest country,
with average annual internal renewable water resources of 935 km3
compared to the region's driest country Mauritania, where the annual average
is 0.4 km3 (UNDP, UNEP, World Bank and WRI 2000). The spatial
distribution of water resources in the region does not coincide with the
highest population densities, resulting in many areas (particularly urban
centres) being water stressed or dependent on external sources of water.
At least 13 countries suffered water stress or scarcity (less than 1
700 m3 per capita/year and less than 1 000 m3 per
capita/year respectively) in 1990 and the number is projected to double
by 2025 (PAI 1995). This presents a major challenge to water planners
in terms of supply and distribution.
Groundwater is a major source of water in the region, contributing 15
per cent of Africa's resources (Lake and Souré 1997). The major aquifers
are found in the northern Sahara, Nubia, Sahel and Chad basins as well
as the Kgalagadi (Kalahari). Groundwater is used for domestic and agricultural
consumption in many areas, particularly the more arid sub-regions where
surface water resources are limited. However, areas heavily dependent
on groundwater reserves are also at risk of water shortages, as water
is extracted far more rapidly than it is recharged.