Assessment of the Vulnerability of Water Supply Aquifers in Parts of Imo River Basin, South-eastern Nigeria: The Case of Imo Shale and Ameki Formations

Abstract

Twenty three locations in the study area were investigated to obtain data on the depth to water table, net recharge, aquifer media, soil media, topography, impact of the vadose zone and hydraulic conductivity. These parameters are denoted by the acronym, DRASTIC, an empirical groundwater model that estimates groundwater contamination vulnerability of aquifer systems based on the hydro-geological settings of the area. This was used to develop a groundwater vulnerability map for the study area. The vulnerability map shows that areas within Imo shale and Ameki Formations have generally moderate vulnerability to pollution while locations such as Okwelle, Umuna and Okwe have low vulnerability.

Keywords: Water table, vulnerability, net recharge, aquifer media, soil media, topography. DRASTIC model.