Many attempts have been made at local, national and international scales in Africa to estimate how much groundwater is being used, how many people depend on groundwater, and the kinds of activities which groundwater is used for - domestic water supply, small scale irrigation, industry, etc. Because groundwater use is so varied and dispersed, and because of problems collecting, recording, managing and accessing relevant information on groundwater use, these estimates are done in different ways, based on different information, and give different results. However, they are all useful towards increasing understanding of the role of groundwater in Africa and how it could be better developed and used in future. This page describes some ways of addressing the issue of groundwater use. It is not a comprehensive assessment; more information can be obtained by following the links to other organisations below.
Using population data to estimate groundwater use
An indication of groundwater use across Africa has been developed using rural and urban population data. Gridded datasets of population and urban extent across Africa were processed to provide an estimate of the number of people living on each main aquifer type, and what proportion of this population lives in rural and urban areas.
The gridded population data are derived from the United Nations Environment Programme/Global Resource Information Database (UNEP/GRID) Africa Population Distribution Database (4th edition). This dataset uses population data from 109,000 administrative units across Africa, the most recent of which were compiled for the year 2000. The regional data are gridded using an interpolation method based on settlement locations and transport infrastructure, which helps to distribute the population across an administrative area. The gridding approach and the key sources of uncertainty in the dataset are discussed in detail in the data documentation (Nelson 2004).
The gridded rural-urban data (Balk et al. 2006) are derived from the Global Rural-Urban Mapping Project (GRUMP) Urban Extents Grid (v1). This dataset is produced by the Centre for International Earth Science Information Network (CIESIN) at Columbia University, the International Food Policy Research Institute (IFPRI), The World Bank, and the Centro Internacional de Agricultura Tropical (CIAT). The dataset is based on a combination of population counts, settlement points, and the presence of nighttime lights as observed by a series of US Department of Defence meteorological satellites over several decades.
Nelson A. 2004. African Population Database, UNEP GRID Sioux Falls. Retrieved 29th October 2014. (see Links to Other Data, below)
Nelson A. 2004. African Population Database Documentation, UNEP GRID Sioux Falls. Retrieved 29th October 2014. (see external links below)
CIESEN, IFPRI, The World Bank and CIAT. 2011. Global Rural-Urban Mapping Projectm Version 1 (GRUMPv1): Urban Extents Grid. Palisades, NY: NASA Socioeconomic Data and Applications Centre. Accessed 30th October 2014.
Balk DL, Deichmann U, Yetman G, Pozzi F, Hay SI and Nelson A. 2006. Determining Global Population Distribution: Methods, Applications and Data. Advances in Parasitology 62, 119-156. (http://dx.doi.org/10.1016/S0065-308X(05)62004-0)
WHO/UNICEF Joint Monitoring Programme for Water Supply and Sanitation
Update with Kerstin's data on changes in number of people using specific drinking water supply types (groundwater, surface water etc) from 2000 to 2010
Links to Other Data
The UNEP/GRID Africa Population Distribution Database can be accessed via the UNEP website
The GRUMP Urban Extents Grid can be accessed via NASA’s Socioeconomic Data and Applications Centre (SEDAC)
Further Sources of Information
AQUASTAT is the FAO’s global water information system, providing data for countries in Africa, Asia, Latin America, and the Caribbean.
Each country profile contains general information on the geographical and economic situation of the country, and more detailed information on water resources (major sources of surface water and groundwater), water use (with a particular focus on irrigation), and water management.
AQUASTAT country profiles and other useful information can be accessed via the AQUASTAT website