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

Map of South Africa (For more information on the datasets used in the map see the geography resources section)

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.

Surface water

Surface Water Map of South Africa (For more information on the datasets used in the map see the surface water resources section)

Soil

Soil Map of South Africa (For map key and more information on the datasets used in the map see the soil resources section)

Land cover

File:South Africa LandCover.png Land Cover Map of South Africa (For map key and more information on the datasets used in the map see the land cover resources section)

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).

Geological Environments

Key Formations	Period	Lithology	Structure
Geological Environment 1
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.

Many hydrogeological and groundwater resource maps are available for South Africa. In particular, these include 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.

A SADC mapping programme produced a Regional Hydrogeological Map for the SADC region ( SADC HGM 1 2010).

The DWAF produces a set of national groundwater maps including an aquifer classification map, groundwater quality map, and aquifer vulnerability map.

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).

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 use and management

Groundwater management

Groundwater resources in South Africa were originally studied by the hydrogeologists of the Geological Survey, now the Council for Geosciences. The Department of Water Affairs and Forestry (DWAF), the Water Resources Commission (WRC), and to a lesser extent the Council for Scientific and Industrial Research (CSIR) have produced major studies of groundwater conditions in South Africa.

DWAF is the main implementer of the National Water Act, and through the Directorate of Surface and Groundwater Information, is responsible for, among other things, groundwater data acquisition and management and the development and maintenance of the main groundwater information systems for South Africa; carrying out regional monitoring; directing and carrying out groundwater resource assessments and exploration, including drilling; and evaluation and recommendations for water licensing.

Legislation

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

Transboundary aquifers===

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.

They, and others, can be accessed through the Africa Groundwater Literature Archive.

Useful web resources

Department for Water Affairs and Forestry - Groundwater. https://www.dwaf.gov.za/groundwater/

Water Research Commission. https://www.wrc.org.za/

Council for Scientific and Industrial Research. https://www.csir.co.za/

Published literature

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.

SADC HGM 1. 2010. Technical Assistance to the SADC - 'SADC Hydrogeological Mapping Project' (9 ACP RPR 39-89); Final Report. Southern African Development Community European Development Fund, March 2010; a technical report to the Southern African Development Community (SADC) and Cooperating Partners: European Union and GTZ.

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