Hydrogeophysical appraisal of groundwater potential in the fractured basement aquifer of the federal capital territory, Abuja, Nigeria

Abstract

In this study, eighteen (18) vertical electrical sounding (VES) data points were located in the Federal Capital Territory (FCT), Abuja, Nigeria with ABEM Terrameter using Schlumberger array to delineate potential groundwater development areas. Groundwater flow direction map was produced using the elevation of the water level from sea level with GIS Arc/Info Point coverage. The investigated areas have four geoelectric sections, categorized as topsoil, clay, fractured/weathered basement, and fresh basement. The groundwater is mainly confined in the fractured/weathered basement. It generally flows from NW to SE, but this flow is not steady. It has been obstructed and reoriented towards the south, whereas some portion flows towards the northern parts of the aquifer system peradventure due to the variation in aquifer depth from place to place. Out of the 18 VES points, 9 points located around the NE and SE peripherals of the study area have groundwater development potentials at depths ranging from 40 - 80 m and aquifer thickness of 25 – 65 m, characterized by resistivity values that varied from 80 – 680 Ωm, whilst the other nine in the SW and central parts do not show promising groundwater development potentials because they lack fractured/weathered zones. The northern and SE zones, which comprise areas such as Bwari, Kuje, Idu CITEC, Sherete, and GTSSC are the preferred targets for water well drilling than the southern zone. However, other communities including Gwagwalada and Gugugu in the southern zone also offer promising groundwater potentials.