Evaluation of Groundwater Potential Zone in Selected Coastal and Non-Coastal Regions of Nigeria

For socioeconomic development, groundwater is a vital resource, especially in areas with limited water supplies. This study assesses groundwater potential zones (GWPZs) in two distinct Nigerian regions, the inland crystalline basement complex of Ile-Ife and the coastal sedimentary basin of Ilaje using integrated geospatial techniques. The novelty of this research lies in its direct comparative analysis of these two disparate hydrogeological and anthropogenic contexts, which fills a critical gap in the existing literature. The study utilized Remote Sensing, GIS, and the Analytical Hierarchy Process (AHP), including a sensitivity analysis to improve methodological robustness. For GWPZ delineation, nine key thematic layers, including geology, land use/land cover, NDWI, NDVI, drainage density, lineament density, rainfall, DEM, and slope, were processed and weighted using AHP. Significant differences were found in the results. Ilaje had a higher percentage of highly available GWPZs (6.15%) than Ile-Ife (4.00%), which was indicative of fundamental variations in hydrogeological, geomorphological, and hydrological controls. Importantly, the results highlight how these differences call for tailored management approaches; Ile-Ife's resources are being depleted by increasing urbanization, while Ilaje's potential is accompanied by serious risks of pollution and saltwater intrusion. This research demonstrates that a “one-size-fits-all’’ approach to groundwater management is untenable in diverse environments and offers fresh empirical insights for both hydrogeological theory and practical policy formulation. It is important to note that the resulting GWPZ maps, based on secondary data, should be interpreted as preliminary indicators requiring future validation through borehole logs and pump test data.