GROUNDWATER EXPLORATION USING 2D RESISTIVITY IMAGING WITHIN ABUJA MUNICIPAL AREA COUNCIL, NIGERIA

Abstract

The fast-growing population of Abuja, Nigeria has over-stretched the public water supply capacity of the city. Like in many expensive cities, people live mostly in a conurbation of towns within Abuja metropolitan area (like the Kurudu area) where the public water supply is inadequate.  The inhabitants are compelled to explore other sources of water for survival. Groundwater is a readily available source and its exploration becomes a necessity. In this research, a two-dimensional (2D) electrical resistivity imaging survey technique is carried out within the Kurudu area of the Abuja Municipal Area Council in Nigeria. The ABEM terrameter (SAS 1000) with Schlumberger configuration is used to acquire resistivity data from eleven profiles. The RES2DINV is used to interpret the data and to model the subsurface. Three geoelectric layers with varying resistivities are identified beneath the study area. The top layer (top soil) has resistivity range of 5 - 3500 Ohm meters (Ωm) with thickness of 1.5 - 2.55 meters (m). The second layer comprises of the weathered/fractured basement with depths of 1.5 - 15.8 m and ranges in resistivity values between 1 Ωm and 3000 Ωm. The bedrock which makes the third layer at depths of 10 - 15.8 m has resistivity range of 300 Ωm to 3500 Ωm. The result of the inverse resistivity model suggests the presence of an eleven-meter aquifer in the western flank of the study area. The average depth of the subsurface is about 15 meters.