Mapping Groundwater Potential Zones in Ebonyi State Using Remote Sensing and GIS

Identification of groundwater potential zones through remote sensing and geographic information systems offers a cost-effective approach to guiding borehole siting in basement complex terrain, particularly in states like Ebonyi where rural water supply depends heavily on groundwater development. This study maps groundwater potential zones in Ebonyi State using multi-criteria integration of remotely sensed and geographic data. Thematic layers including geology, lineament density, slope, drainage density, land use and land cover, and soil type were derived from Landsat imagery, digital elevation models, and existing geological maps. Each thematic layer was reclassified and assigned standardised weights through the Analytical Hierarchy Process based on expert judgement. Weighted overlay analysis was conducted in ArcGIS to produce a composite groundwater potential zone map classified into very high, high, moderate, low, and very low categories. Field validation at 22 existing boreholes tested the accuracy of the model output against documented yield data. Results indicate that approximately 29 percent of Ebonyi State's land area falls within high to very high groundwater potential zones, concentrated along river valleys, weathered basement zones, and structural lineament intersections. Model validation achieves 78 percent accuracy in correctly classifying borehole yield categories. Low potential zones are concentrated in undissected plateaux in the central part of the state. The study provides a spatial decision support tool for the Ebonyi State Rural Water Supply and Sanitation Agency to prioritise future borehole drilling locations. Keywords: groundwater potential zones, remote sensing, GIS, Ebonyi State, borehole siting.