Aquifer Vulnerability Assessment in Ekowe, Bayelsa State, Niger Delta Area, Nigeria using GIS-Based on Drastic Method

Abstract

: This study on aquifer vulnerability assessment in Ekowe town of Southern Ijaw Local Government Area of Bayelsa State, Niger Delta Area, Nigeria, adopted the use of DRASTIC method and geographic information system (GIS) model to delineate areas susceptible to contamination depending on the collective nature of the Seven hydro geologic parameters applied for the aquifer vulnerability evaluations which include depth to water table, net recharge, soil media, impact to vadoze zone, aquifer media, topography, and hydraulic conductivity. Data relating to the seven hydro geologic parameters of the model were obtained and transformed systematically by GIS to develop the DRASTIC vulnerability map which shows the three different forms of aquifer vulnerability namely high, moderate, and low zones. High vulnerable Areas is influenced mainly by high net recharge, shallow depth to water table, porosity of the sandstones in the aquifer media and permeability of the surface soil while the low vulnerability zone is domiciled with Straight slope, high depth to water table, presence of clay and silt in the soil and vadoze zone media, and the distinctive characteristics of the high and low vulnerability zones define the moderate vulnerable Areas.