Groundwater potential assessment in the Eastern Cape, South Africa, using analytical hierarchical process (AHP) technique

Abstract

Abstract Groundwater is crucial for the growth of any country. It is a vital resource for drinking water, agriculture, industry, and economic development. However, delineating the groundwater potential zones requires a systematic approach. This study assessed the groundwater potential zones (GWPZ) in the Ntabankulu municipality using remote sensing, geographic information systems, and analytical hierarchical process (AHP) techniques. Six groundwater controlling parameters were integrated to assess groundwater potential zones, including lithology, slope, lineaments density, land use/land cover, drainage density, and rainfall. The AHP pairwise comparison matrix was utilized to determine the normalized weight of the parameters. The parameters and their classes were assigned ranks, taking into account their influence on groundwater accumulation. The resultant GWPZ map was generated by integrating the parameters and their assigned weights in ArcGIS 10.8 software. The final map from the AHP technique showed five GWPZ, including very poor (13.06%), poor (25.36%), moderate (26.93%), good (22.72%), and very good (11.93%). Validation was done by using the existing 242 boreholes in the study area. Furthermore, the receiver operating characteristics (ROC) curve was plotted, and the area under the curve (AUC) analysis indicated a satisfactory accuracy prediction (AUC = 61%). The results of this study will assist in developing a proper plan for sustainable utilization of groundwater resources within the Ntabankulu municipality.