GIS-Based Groundwater Potential Mapping in Crystalline Basement Terrain of Ekiti State

Reliable groundwater mapping in crystalline basement terrain is particularly challenging due to the discontinuous nature of aquifers controlled by fracturing and weathering. This study develops an integrated GIS and remote sensing approach for groundwater potential mapping in Ekiti State, located in the crystalline basement complex of South West Nigeria. Structural lineaments interpreted from Landsat 8 Band 8 panchromatic imagery are extracted using directional filtering and manually verified. Lineament density, intersection density, and lineament proximity layers are generated as primary hydrogeological indicators. Secondary thematic layers including weathered zone thickness from existing borehole logs, drainage density, slope, and land use are integrated in a weighted overlay analysis calibrated against 120 borehole yield records. Results identify high groundwater potential zones concentrated along NE-SW trending lineament corridors in the Ekiti East, Moba, and Ido-Osi LGAs. Validation using independent borehole data achieves a prediction accuracy of 77 percent. Keywords: groundwater potential, GIS, crystalline basement, lineament, Ekiti State