Overview of Groundwater in Africa

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Africa Groundwater Atlas >> Overview of Groundwater in Africa


Groundwater is an invaluable resource in Africa. Groundwater provides safe and reliable source drinking water for hundreds of millions of people across the continent; and supports food production and economic development through irrigation and livestock watering.

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Groundwater has excellent natural microbiological quality, and generally has adequate chemical quality for most uses. However problems can arise from the chemistry of groundwater in some circumstances: for example, high sulphate from some types of weathered basement and mudstones; or excessive hardness in limestone aquifers or sandstones cemented with carbonate material. Minor and trace constituents, which make up about 1% of the solute content of natural groundwaters, can also sometimes lead to health problems or make the water unacceptable for human and animal consumption. For example, high fluoride in some volcanic aquifers; elevated iron and manganese where groundwaters are anoxic; high arsenic in some unconsolidated sediments; and a lack of iodine in aquifers far from the sea (MacDonald and Davies 2001).

Groundwater is generally more resilient to short-term climate variability and less vulnerable to pollution than surface water sources. However, sustainable groundwater development requires a good understanding of the groundwater resource, in order to avoid over-abstraction and environmental degradation. This will become more and more important in future, as pressure increases on Africa's groundwater resources because of growing population and increasing demands on water supplies - for domestic, agricultural (especially growing demand for irrigation) and industrial use.

How and where groundwater occurs depends on many interacting factors. The most important of these are geology; geomorphology (including weathering; and climate - rainfall and evapotranspiration. Spatial and temporal variations in these factors across Africa mean that hydrogeological environments are complex and variable, with very different aquifer properties and recharge. Understanding these factors, and how they interact, is necessary in order to properly characterise the groundwater resources in any one area.

For many parts of Africa, there is a lack of information on groundwater. This may be because data aren't being collected - or haven't been in the past; or because data aren't easily avaialble or accessible. This makes it very difficult to assess the groundwater resources. It can lead to inappropriate groundwater development - such as over-abstraction, or groundwater contamination - which can have long term implications for groundwater availability and quality.

However, there is also much work that has been done to address some of the key issues relating to groundwater resources in Africa. This section of the Atlas brings together available information to provide a continental-scale overview of the main aquifer groups (or hydrogeological environments) of Africa, as well as recharge and groundwater quality in Africa, among other issues. These pages provide general background and context for the more detailed information available in each country profile.

There is more information on specific groundwater issues in these Resource Pages:

Supporting information

- Topography
- Geology
- Climate
- Land cover
- Soil
- Surface water

Hydrogeology

- Hydrogeology map
- Aquifer properties
- Recharge
- Groundwater quality
- Long term groundwater datasets

Groundwater development

- Groundwater development techniques
- Groundwater development best practices

Groundwater use and management

- Groundwater use
- Groundwater management
- Transboundary aquifers.


References

MacDonald AM and Davies J. 2000. A brief review of groundwater for rural water supply in sub-Saharan Africa. British Geological Survey Report WC/00/033, 30pp.


Africa Groundwater Atlas >> Overview of Groundwater in Africa