Assessment of Aquifer Indices in Kano State, Nigeria Using Aeromagnetic and Digital Elevation Model Data

Aeromagnetic and Digital Elevation Model (DEM) data were analyzed to identify subsurface water-bearing zones and examine the topographical trends of surface and basement complex rocks in a portion of Kano State, Nigeria, bounded by latitudes 800'00"N to 900'00"N and longitudes 1130'00"E to 1230'00"E.The aeromagnetic data, sourced from the Nigerian Geological Survey Agency (NGSA), were subjected to filters, including Residual Magnetic Intensity (RMI) and Source Parameter Imaging (SPI), to estimate residual magnetic fields and depths to the basement complex rocks.The SPI results revealed two distinct depth classes: deeper and shallow regions.Deeper zones, characterized by depths ranging from 123.1 m to 414.4 m, were identified in the following areas: between 800'00"N and 838'24"N, 1212'00"E to 1230'00"E; 849'48"N to 900'00"N, 1212'00"E to 1230'00"E; 800'00"N to 807'12"N, 1140'48"E to 1200'00"E; 821'36"N to 837'48"N, 1140'48"E to 1200'00"E; 851'03"N to 900'00"N, 1140'48"E to 1200'00"E; and 814'24"N to 822'12"N, 1133'36"E to 1138'24"E.These regions, characterized by depression-like features, were suggested as optimal zones for groundwater exploration.The topographical analysis of the surface indicates that rainwater and leachates were transported toward the northern region of the study area, which exhibits relatively low elevations (448 m to 468 m above mean sea level).This region was identified as a likely accumulation area for surface water.The fresh basement complex rocks were observed to gently slope from south to north, with depth values ranging from 112.6 m to 117.7 m in deeper areas and 91.6 m to 109.8 m in shallower zones.The flow direction of surface water aligns with the underlying basement rock structure, suggesting that surface water runoff is likely influencing aquifer recharge processes.A cross-correlation coefficient of -0.99981 was observed between the surface and basement complex rock trends, indicating a strong inverse relationship between the two topographies.Consequently, the surface water accumulation zone was inferred to be a critical aquifer recharge area, though it may also facilitate the leaching of contaminants into the groundwater system, raising potential concerns for aquifer quality.