Geophysical insights into groundwater aquifer characterization in a geologically complex region: a case study from the Meki–Alemtena area, central Ethiopia

Abstract

This study aimed to map geological structures and characterize groundwater aquifers in the Meki–Alemtena area of the East Shewa Zone, Ethiopia. Sixteen Vertical Electrical sounding data were collected to reveal five to seven subsurface layers across the profiles, with resistivity values indicating lithologic units such as alluvial deposits, fractured ignimbrite, and rhyolite, forming aquifers with thicknesses of 9 to 76 m. Areas with low resistivity are found to correspond with groundwater-saturated zones, particularly in the northwestern part of the study area. Aquifer characterization using Dar Zarrouk Parameters identifies three primary water-bearing zones: freshwater, brackish, and saline aquifers. High longitudinal conductance (≥ 6 Ω−1) and transmissivity values in the northwestern section indicate the highest groundwater potential, while hydraulic conductivity analysis suggests efficient water flow through this zone. Magnetic data further highlight structural influences on groundwater flow, with high magnetic anomalies in the south-central and northwestern areas associated with faulted and fractured zones that act as conduits for groundwater. The integration of these methods offers a comprehensive assessment of groundwater resources, establishing a framework for targeted extraction and sustainable management in the Rift Valley’s water-scarce regions.