Geospatial Assessment of Groundwater Availability in Asa and Oyun River Catchments, Northcentral Nigeria
1,2,Mustapha Adedamola Habib, 1,Isiaq Rofiat Ronke, 3Kolawole Lateef Lanre, 1,*Afolabi Adegoke Olukayode, 1,Amos Daphne Deighaladoo and 4Jimoh Razak Onawola
1Department of Earth Sciences, Ladoke Akintola University of Technology, Ogbomoso, P.M.B. 4000 Ogbomoso, Nigeria
2 Ministry of Commerce and Mines, Oyo State Civil Service, Ibadan, Nigeria
3 Independent researcher, Ilorin, Nigeria
4 Department of Chemical and Geological Sciences, Al-Hikmah University, P. M. B. 1601, Ilorin, Nigeria
DOI: 10.36108/laujoces/6202.61.0140
Abstract
Subsurfacewater development in localised crystalline aquifers poses significant challenges to the sustainable supply of potable water in developing countries. This study delineated groundwater potential zones in a basement area with two major rivers, Asa and Oyun, draining it using integrated geospatial techniques and Analytical Hierarchical Process (AHP) model. The processed images from landsat 8 OLI using the Maximum Likelihood Classifier infered 5 classes: Settlement, Bare land, Vegetation, Riparian areas, and Water bodies. Lineaments serving as structural control for the drainage system underlying the area were extracted from Landsat 8 OLI (2015), Digital Elevation Model (DEM), and aeromagnetic data using inverse distance weighted interpolation. A GIS-based AHP model combined six thematic layers (lineament density, lithology, drainage density, rainfall, land use/land cover, and slope) to produce a groundwater potential map, which was validated against twenty two (22) borehole yield data through Receiver Operating Characteristic ROC analysis. The AHP model achieved a consistency ratio (0.077) indicating reliability. Five groundwater potential zones, ranging from very low to very high, were identified. Asa river catchment was dominated by low-potential zones, while Oyun catchment exhibited moderate to high groundwater potential. Borehole yields corresponded with the classified zones, varying from 0.3–1.5 l/s in low-potential areas to above 3.60 l/s in very high-potential areas. ROC validation produced an AUC of 0.777 (77.7%), confirming the robustness of the method.
Keywords: Crystalline-aquifer; Geospatial; Groundwater-potential-zones; Landsat 8 OLI; Rivercatchment.
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