Investigation of Electrical Resistivity of Soils in Akwa Ibom State Using the Wenner Array Method for Groundwater Exploration

Background: Groundwater is the primary water source for rural communities in Akwa Ibom State, South South Nigeria. Electrical resistivity surveys using the Wenner array method are an effective and non-invasive tool for identifying aquifer zones. Aim: This study investigated the electrical resistivity of soils in selected communities of Akwa Ibom State to identify potential groundwater zones. Methods: Vertical electrical sounding measurements were conducted at 12 stations using the ABEM Terrameter SAS 1000 with a Wenner electrode configuration. Electrode spacings ranged from 1 to 50 metres. Resistivity data were inverted using RES2DINV software to produce 2D subsurface models. Results: Three distinct geoelectric layers were identified across all stations: a topsoil layer (2 to 80 ohm-m), a weathered zone (80 to 250 ohm-m), and a fresh basement layer (above 1000 ohm-m). Aquifer zones were identified at depths between 15 and 32 metres at eight of the 12 stations. Conclusion: Electrical resistivity surveys successfully delineated productive aquifer zones in Akwa Ibom State. The identified locations are recommended for borehole siting, and the study demonstrates the value of geophysical methods in reducing groundwater exploration failure rates in South South Nigeria. Keywords: electrical resistivity, Wenner array, groundwater, Akwa Ibom, geophysics.