Determination of potential recharge zones and its validation against groundwater quality parameters through the application of GIS and remote sensing techniques in uMhlathuze catchment, KwaZulu-Natal, South Africa

Urbanization has accelerated changes in the quantity and stability of the water resources in the uMhlathuze watershed of KwaZulu-Natal. This study applied the use of GIS and remote sensing to demarcate groundwater potential recharge zones in the uMhlathuze catchment using AHP approach and Catastrophe theory by assigning weights to 10 parameters with their sub-criteria and the results were validated against groundwater quality data. It was discovered that 22.92% and 26.38% of the catchment is encompassed by ‘Low’ groundwater potential recharge zones, 0.37% and 0.08% by ‘Very low’ groundwater potential recharge zones, 9.42% and 10.26% by ‘Good’ groundwater potential recharge zones, 66.87% and 63.19% by ‘Moderate’, and 0.42% and 0.09% by ‘Very good’ for AHP and Catastrophe theory respectively. The resultant map demonstrated that recharge potential of groundwater is lowest in mountainous regions coupled with hard rock geology of low transmissivity, whereas the highest potential prevails in lower slopes and plains with more permeable soil. The findings of the validation revealed that the lowest and highest total dissolved solid, nitrate and groundwater level overlaps with the ‘Good and Very good’ and ‘Low and Very low’ groundwater potential recharge zones respectively. From the collective findings of this study, it is inferred that the convergence and use of GIS and remote sensing for delineating the groundwater potential recharge zones are effective. The study further recommends that this method can be applied in research/projects involving the implementation of artificial groundwater recharge structures for better groundwater planning and governance. [Display omitted] •Application of GIS and multi-criteria decision-making techniques in predicting the potential recharge occurrence.•Values of 9.84 % (AHP) and 10.35 % (Catastrophe theory) indicates good groundwater recharge potential.•Validation of the above results against TDS, nitrate and groundwater level exhibits close to accurate positive results.•Construction of artificial recharge structures in the low recharge zone is recommended to improve and manage aquifers.