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

This report identifies and delineates Strategic Water Source Areas (SWSAs) for surface water and groundwater across South Africa, Lesotho, and Swaziland. It defines SWSAs as areas providing disproportionate runoff or high groundwater recharge that are nationally important for water security. The study identifies 22 national surface water SWSAs (SWSA-sw) and 37 national groundwater SWSAs (SWSA-gw), analyzing their contribution to urban centers, agriculture, and industry, while assessing threats from land-cover change, mining, and invasive alien plants.

• Strategic Water Source Areas (SWSAs) are defined as land areas that supply a disproportionate quantity of mean annual surface water runoff relative to their size, have high groundwater recharge forming a nationally important resource, or meet both criteria.
• The updated national and transboundary surface water SWSAs (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.
• The study identified 22 national SWSA-sw and 37 national SWSA-gw. The SWSA-gw cover approximately 9% of South Africa's land surface (around 104,000 km²), with 24% of this area overlapping with the updated SWSA-sw.
• Transboundary SWSA-sw in Lesotho and Swaziland contribute significantly to the region's water; Lesotho's portions cover 18,570 km² and generate 3,522 million m³ MAR, while Swaziland's portions cover 9,376 km² and produce 2,053 million m³ MAR. Together, they produce about 11% of the total MAR.
• Major urban centers in South Africa are heavily dependent on SWSA-sw, generally sourcing over 90% of their water from these areas. For example, the City of Cape Town receives 98% of its water from SWSA-sw, and eThekwini and Pietermaritzburg receive 98% from the Southern Drakensberg SWSA-sw.
• Groundwater SWSAs (SWSA-gw) are critical for agriculture and industry in South Africa, supplying approximately 46% of the groundwater used for agriculture and 47% for industrial purposes.
• Protection of SWSAs is insufficient, with only 11% of all SWSAs under Protected Areas (PAs). Some critical areas, such as the Northern Drakensberg SWSA, have only 10% formal protection.
• Invasive alien plants (specifically wattles, pines, and eucalypts) reduce the MAR of SWSA-sw by 485.8 million m³/a, representing 2.6% of the pre-development MAR. This reduction is greater than the 2015 water requirement for the eThekwini metropolis.
• Mining poses significant risks to water quality and quantity. The Upper Vaal and Kroonstad SWSAs completely overlap with coalfields, and the Enkangala Grasslands overlap by 42.13%.
• Groundwater vulnerability is highest in Cenozoic Sand and dolomite aquifers. The Cape Peninsula and Cape Flats SWSA-gw is particularly at risk, with 49% of its area rated as 'very high' vulnerability and 60% covered by urban areas.

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} }