Hydrogeology of South Africa
Africa Groundwater Atlas >> Hydrogeology by country >> Hydrogeology of South Africa
Authors
Brighid Ó Dochartaigh, Kirsty Upton, British Geological Survey, UK
Geographical Setting
General
Estimated Population in 2013* | 52,980,000 |
Rural Population (% of total) (2013)* | 36% |
Total Surface Area* | 1,213,090 sq km |
Agricultural Land (% of total area) (2012)* | 79% |
Capital City | Pretoria (executive); Bloemfontein (judicial); Cape Town (legislative) |
Region | Southern Africa |
Border Countries | Namibia, Botswana,Zimbabwe, Mozambique, Swaziland, Lesotho. |
Annual Freshwater Withdrawal (2013)* | 12.500 Million cubic metres |
Annual Freshwater Withdrawal for Agriculture (2013)* | 63% |
Annual Freshwater Withdrawal for Domestic Use (2013)* | 31% |
Annual Freshwater Withdrawal for Industry (2013)* | 6% |
Rural Population with Access to Improved Water Source (2012)* | 88% |
Urban Population with Access to Improved Water Source (2012)* | 99% |
* Source: World Bank
Climate
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Koppen Geiger Climate Zones
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Average Annual Precipitation
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Average Temperature
Temporal variations in temperature and rainfall. Rainfall time-series and graphs of monthly average rainfall and temperature for each individual climate zone can be found on the South Africa Climate Page.
For further detail on the climate datasets used see the climate resources section.
Climate zones
Surface water
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Soil
Land cover
Geology
This section provides a summary of the geology of South Africa. More detail can be found in the references listed at the bottom of this page. Many of these references can be accessed through the Africa Groundwater Literature Archive.
The geology map on this page shows a simplified version of the geology at a national scale (see the Geology resources page for more details). The map is available to download as a shapefile (.shp) for use in GIS packages.
Key Formations | Period | Lithology | Structure |
Geological Environment 1 | |||
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Name of formation1 | Time period | Description | Structure |
Geological Environment 2 | |||
Geological Environment 3 | |||
Hydrogeology
This section provides a summary of the hydrogeology of the main aquifers in South Africa. More information is available in the references listed at the bottom of this page. Many of these references can be accessed through the Africa Groundwater Literature Archive.
The hydrogeology map on this page shows a simplified version of the type and productivity of the main aquifers at a national scale (see the Aquifer properties resource page for more details). The map is available to download as a shapefile (.shp) for use in GIS packages.
Many other hydrogeological and groundwater resource maps are available, including the Hydrogeological Map Series of 21 hydrogeological maps at 1:500,000 scale produced by the Department of Water Affairs, which covers the whole country. These show aquifer type (e.g. intergranular or fractured) and median borehole yield, with geology, rainfall and other information (Cobbing 2011). These are available to purchase as hard copies from the Department of Water Affairs.
Dominantly Unconsolidated
Named Aquifers | General Description | Water quantity issues | Water quality issues | Recharge |
Coastal sand, gravel and other unconsolidated sediments; alluvial sand and gravel in river valleys | Typically shallow and unconfined. Usually less than 30 m thick. Relatively homogenous over short distances. Typical yields in alluvial deposits are 3 to 8 l/s; typical yields in coastal sands are 3 to 16 l/s (Pavelic et al. 2012). | Highly vulnerable because of high permeability. However, significant attenuation is expected where there is clay in the aquifer sequence (Pavelic et al. 2012) | Recharge rate is generally high. Some 15 to 30 percent of rainfall infiltrates to aquifers (Pavelic et al. 2012).
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Sedimentary - Intergranular Flow
Named Aquifers | General Description | Water quantity issues | Water quality issues | Recharge |
Sedimentary - Intergranular & Fracture Flow
Named Aquifers | General Description | Water quantity issues | Water quality issues | Recharge |
Sedimentary - Fracture Flow
Named Aquifers | General Description | Water quantity issues | Water quality issues | Recharge |
Dolomite | Found predominantly in northwest South Africa. The dolomite ranges from 200 to 1900 m thick. Karstic features are developed in the dolomite and they can form high yielding aquifers. Typical borehole yields are 20 to 50 l/s (Pavelic et al. 2012). Dissolution channels developed along fractures can extend to the ground surface, allowing direct recharge and groundwater flow (Pavelic et al. 2012). | Vulnerable to pollution, because of thin soil cover and high permeability with rapid fracture flow | Direct rainfall recharge through fractures. | |
Karoo sedimentary | Low yielding aquifers, with typical borehole yields 1 to 3 l/s (Pavelic et al. 2012). |
Basement
Named Aquifers | General Description | Water quantity issues | Water quality issues | Recharge |
Groundwater Status
Groundwater use and management
Groundwater use
Groundwater management
The National Water Act (Act 36 of 1998) recognised groundwater as a common asset (DWA 2010).
The National Environmental Management Act of 1998 and the Minerals and Petroleum Resources Development Act of 2002 make new legal obligations for the mining and other industries in terms of the monitoring and remediation of pollution of water resources, including groundwater (DWA 2010). Further protocols, strategies and standards are listed in DWA 2010
The South Africa Department of Water Affairs stores groundwater data in a database called the National Groundwater Archive (NGA), which in 2010 contained about 250,000 groundwater source records (DWA 2010). Another database, the Water Authorisation and Use database, stores information on volumes of groundwater used, based mainly on licensed volumes (DWA 2010).
Groundwater monitoring
For further information about transboundary aquifers, please see the Transboundary aquifers resources page
References
The following references provide more information on the geology and hydrogeology of South Africa.
These, and others, can be accessed through the Africa Groundwater Literature Archive
Geology: key references
Hydrogeology: key references
DWA (Department of Water Affairs). 2010. Groundwater Strategy 2010.
Pavelic P, Giordano M, Keraita B, Ramesh V and Rao T (eds.). 2012. Groundwater availability and use in Sub-Saharan Africa: a review of 15 countries. IWMI, Sri Lanka, 2012.
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