Optimisation of groundwater exploration through integrated geospatial and hydro-geophysical approaches in semi-arid basement aquifers of Zimbabwe

ABSTRACT Owing to climate change and variability, optimisation of groundwater exploration remains a key driver in improving water security and achieving Sustainable Development Goal 6, especially in semi-arid regions underlain by basement aquifers. However, in-depth studies that focus on enhancing the process through systematic, time and cost-saving approaches in such regions still remain limited. This study investigated the potential to leverage scientific insights from geospatial and conventional hydro-geophysical groundwater exploration methods to enhance exploration of productive boreholes in semi-arid basement aquifers of Buhera, Nyanga and Mudzi districts of Zimbabwe. Integrated groundwater potential ratings inferred by a two-tier integrated approach exhibited a much stronger Spearman's rho (ρ) of 0.923 ≤ ρ ≤ 0.941 with actual borehole yields (p < 0.05) compared with one-tier approaches, where Spearman's rho (ρ) was found to be 0.654 ≤ ρ ≤ 0.712 for geospatial and 0.812 ≤ ρ ≤ 0.842 for hydro-geophysical methods, respectively. Thus, an integrated two-tier geospatial and hydro-geophysical approach is recommended to improve groundwater exploration of productive boreholes in data-scarce semi-arid regions underlain by basement aquifers. Such an approach reduces the chances of dry or low-yield boreholes, exploration costs and saves exploration time.