Integrated GIS Technique and Electrical Resistivity Sounding (ERS) for Groundwater Prospecting in Yola Catchment Area, Northern Upper Benue Trough, Nigeria

Abstract

Groundwater has become an increasingly vital resource in Nigeria, especially in the semi-arid and rapidly growing regions such as the Yola Catchment Area, located in the Northern Upper Benue Trough. The area faces challenges related to water scarcity, population pressure, climate variability, and complex subsurface geologic conditions which necessitate more effective and sustainable groundwater exploration and management strategies. This study, integrated GIS technique and electrical resistivity sounding (ERS) for groundwater prospecting in the Yola catchment area was carried out to identify zones with good potential for groundwater Using the GIS weighted sum and ERS approach. Seven thematic layers; Precipitation, lithology, lineament density, land use/land cover, Drainage network density, soil type, slope, and distance from rivers-were analyzed and weighted by their contribution to groundwater occurrence. Five zones, each representing a different level of groundwater potential, were identified in the area, these are; very poor, poor, low, moderate, and good. Results showed that approximately 21.88% of the area (110.5 km²) has moderate groundwater potential, while the majority (56.56%, or 285.6 km²) falls into the poor category. Areas with very poor and low potential covered 1.19% (6.0 km²) and 18.36% (92.8 km²) respectively, and only 1.99% (10.1 km²) was found to have good potential. Electrical resistivity sounding at five vertical electrical sounding (VES) locations revealed subsurface layers with resistivity values ranging from 10 Ωm to 57 Ωm. Areas with low resistivity (≤ 20 Ωm) likely indicate clay or water-saturated sediments that restrict water movement, while moderate resistivity values (20–55 Ωm) suggest the presence of silty sands or weathered rock, which may serve as moderate-yield aquifers if porous and saturated.