Mitigating climate change in South Africa with managed aquifer recharge: five case studies

Abstract Over the past decade, Southern Africa has experienced periods of extreme drought. This was especially the case in the western Karoo in South Africa. Continuous drought and limited rainfall led to declining groundwater levels that curtailed sustainable water supply for towns and livestock. The western Karoo depends almost entirely on groundwater. Managed aquifer recharge (MAR) is being used to reduce the effects of droughts and mitigate climate change impacts. A good understanding of the geology and the response of aquifers is needed for implementing various MAR designs, including nature-based solutions, which are used to recharge aquifers with limited rainfall. This study discusses five active MAR case studies in the western Karoo. Here, site-specific MAR methods utilising small rainfall events deliver acceptable results, whereas the implemented MAR options keep most aquifers functional. The water quality in terms of salinity and iron at the MAR sites improved during the rainy season, and less bacterial clogging was observed as compared to the dry season. In some cases, the MAR sites improved the environment around the managed aquifer recharge sites, with vegetation helping to stabilise the soil and allow greater groundwater recharge. The MAR methods and designs discussed in this paper can be used both on a larger scale for a town or on a smaller scale for a farm. Maintenance costs are low, which makes these options cost-effective for less affluent areas.