Assessment of Groundwater Recharge Potential in the Northern Parts of Auchi and Environs, Edo State, Nigeria, Using Geospatial Techniques

Groundwater accounts for about 30% of earth’s freshwater, the demand for this natural resource is increasing due to rapid industrialization and population growth, leading to its scarcity in some regions, Auchi is an area experiencing groundwater stress, were water table depth decreases rapidly and boreholes have to be drilled to great depths to get this scarce resource. The replenishment of this resource to a groundwater flow system is groundwater recharge. The study aims to delineate groundwater recharge potential zones of the northern part of Edo state comprising of Auchi and sorrounding communities, utilizing remote sensing, geospatial techniques and weighted index overlay analysis model. Six multi-influencing factors of lithology, soil cover, lineament density, drainage density, land use and land cover and slope were all generated from Landsat ETM, topographic map and shuttle radar topographic mission (SRTM) data, producing the various thematic layers. The multi-layers were then reclassed and weighed according to their varying influence to groundwater recharge. The resultant groundwater recharge potential map revealed that majority of the study area, comprised partly of the hilly terrain of the north eastern and north western part and the gentle slope regions had moderate recharge, while parts of the south eastern and south western part of Auchi had low groundwater recharge. This research could serve as a base line study for future groundwater studies in the area.