Identification, Delineation and Importance of the Strategic Water Source Areas of South Africa, Lesotho and Swaziland for Surface Water and Groundwater

The report defines and maps 22 national Strategic Water Source Areas for surface water (SWSA-sw) and 37 for groundwater (SWSA-gw) in South Africa, including transboundary areas in Lesotho and Swaziland. It links these areas to major urban centres and agricultural sectors, highlighting that a small percentage of land provides a disproportionate amount of the region's water. The study identifies significant threats from invasive alien plants, mining, and land degradation, and recommends integrating SWSAs into national policy, legislation, and spatial planning to ensure long-term water security.

• The updated national and transboundary Strategic Water Source Areas for surface water (SWSA-sw) cover approximately 124,075 km² (10% of the region) and provide a mean annual runoff (MAR) of 24,954 million m³, which is 50% of the total.
• Strategic Water Source Areas for groundwater (SWSA-gw) in South Africa cover around 9% of the land surface (approximately 104,000 km²) and account for up to 42% of the baseflow in those areas, playing a critical role in sustaining surface water during dry seasons.
• Transboundary SWSA-sw in Lesotho and Swaziland are critical for South African water security; Lesotho's portions generate about 3,522 million m³ (79% of Lesotho's MAR), and Swaziland's portions produce about 2,053 million m³ (83% of Swaziland's MAR).
• Major urban centres in South Africa are heavily dependent on SWSA-sw, with many sourcing over 90% of their water from these areas. For example, the City of Cape Town receives 98% of its water from SWSA-sw.
• Groundwater from SWSA-gw is vital for agriculture and industry, supplying approximately 46% of the groundwater used by agriculture and 47% of that used for industrial purposes in South Africa.
• Protection of SWSAs is insufficient, with only 11% of all SWSAs falling under Protected Areas (PAs). Specifically, only 10% of the Northern Drakensberg SWSA is under formal protection.
• Invasive alien plants (specifically wattles, pines, and eucalypts) reduce the MAR of SWSA-sw by 485.8 million m³/a, which is 2.6% of the pre-development MAR.
• Mining poses a significant risk to SWSAs, particularly coal mining in the Highveld, Witbank, and Ermelo fields. The Upper Vaal and Kroonstad SWSAs completely overlap with coalfields.
• Certain groundwater aquifers are highly vulnerable to contamination; the Cenozoic Sand aquifers and dolomite aquifers are the most susceptible, with some areas like the Cape Peninsula and Cape Flats having 49% 'very high' vulnerability.
• Groundwater drought risk is most pronounced in the northwest of South Africa, while coastal areas in the south and east, such as the Zululand Coastal Plain, have very low drought risk.

APA

Le Maitre, D., Seyler, H., Holland, M., Smith-Adao, L., Nel, J., Maherry, A., & Witthüser, K. (2018). Identification, Delineation and Importance of the Strategic Water Source Areas of South Africa, Lesotho and Swaziland for Surface Water and Groundwater. Centre for Environmental Rights. https://cer.org.za/wp-content/uploads/2019/03/WRC-SWSAs-of-SA-Lesotho-and-Swaziland.pdf?x21779

Chicago

Le Maitre, David, Helen Seyler, Martin Holland, Lindie Smith-Adao, Jeanne Nel, Ashton Maherry, and Kai Witthüser. Identification, Delineation and Importance of the Strategic Water Source Areas of South Africa, Lesotho and Swaziland for Surface Water and Groundwater. Centre for Environmental Rights, 2018. https://cer.org.za/wp-content/uploads/2019/03/WRC-SWSAs-of-SA-Lesotho-and-Swaziland.pdf?x21779.

Wikipedia

{{cite report |last1=Le Maitre |first1=David |last2=Seyler |first2=Helen |last3=Holland |first3=Martin |last4=Smith-Adao |first4=Lindie |last5=Nel |first5=Jeanne |last6=Maherry |first6=Ashton |last7=Witthüser |first7=Kai |title=Identification, Delineation and Importance of the Strategic Water Source Areas of South Africa, Lesotho and Swaziland for Surface Water and Groundwater |publisher=Centre for Environmental Rights |date=July 2018 |url=https://cer.org.za/wp-content/uploads/2019/03/WRC-SWSAs-of-SA-Lesotho-and-Swaziland.pdf?x21779 |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{lemaitre2018identification, author = {Le Maitre, David and Seyler, Helen and Holland, Martin and Smith-Adao, Lindie and Nel, Jeanne and Maherry, Ashton and Witthüser, Kai}, title = {{Identification, Delineation and Importance of the Strategic Water Source Areas of South Africa, Lesotho and Swaziland for Surface Water and Groundwater}}, institution = {Centre for Environmental Rights}, year = {2018}, month = jul, url = {https://cer.org.za/wp-content/uploads/2019/03/WRC-SWSAs-of-SA-Lesotho-and-Swaziland.pdf?x21779}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }