QUANTIFYING INFILTRATION POTENTIAL: A DUAL-METHOD INVESTIGATION USING GEOPHYSICS AND INFILTRATION TESTING FOR MANAGED AQUIFER RECHARGE

Managed aquifer recharge (MAR) is crucial in addressing water resource challenges in coastal regions, where over-extraction and saltwater intrusion often threaten freshwater availability. This study specifically focuses on utilizing geophysics datasets, particularly the airborne electromagnetic (AEM), electrical resistivity tomography (ERT), and field infiltration testing, to identify and characterize suitable areas for MAR in the West Coast Aquifer System of South Africa. These techniques were used to determine subsurface properties and hydrogeological conditions within a wellfield. The ERT investigation was conducted along defined areas within the wellfield, and infiltration tests were conducted in five strategic areas within the same wellfield. Findings were validated against the AEM data. By geophysically mapping variations within the subsurface and interpreting results from field infiltration tests, areas with enhanced potential for recharge were effectively pinpointed. The study's findings underscore the critical role of integrating geophysical datasets and soil hydraulic conductivity data in identifying optimal locations for MAR facilities. This research emphasizes the importance of employing geophysical methods to make informed decisions in MAR site selection and overall groundwater resource management. Through these techniques, we can contribute to the sustainable utilization of coastal aquifers, ensuring a reliable source of fresh water for future generations amidst the challenges of increasing water scarcity and climate change.