Studies on the Quality and Vulnerability of Groundwater to Contamination

Abstract

To effectively and properly protect groundwater, it is crucial being able to identify areas where groundwater may be most vulnerable to contamination and translate this information into vulnerability maps that can be used by potential end-users, such as land and water-resources managers to prevent or minimize harmful impacts on groundwater quality. The focus of the study is to evaluate the quality of groundwater around the Niger Delta Basin Development Authority in Nigeria and assess the aquifer characteristics and its vulnerability to contamination  About hundred (100) boreholes spread to cover the study area were sampled. The water samples were analyzed using standard procedures for assessing drinking water qualities in order to understand the existing condition of groundwater quality within the study area. In addition, existing borehole logs were acquired and lithological mapping of the study area was done to acquire relevant data that was needed to generate thematic maps such as; depth to groundwater map, aquifer recharge map, aquifer media map, soil media map, hydraulic conductivity map and the vadose zone map. The topographic map of the study area was generated from the digital elevation model (DEM). To generate the groundwater contamination map, pairwise overlay analysis using geographic information systems (GIS) was employed.Based on the final DRASTIC map, it was observed that most of the locations from where water samples were collected fell within the light brown colouration with computed DRASTIC index of between (140-160) indicating high rate of vulnerability of the aquifer to contamination.

Keywords: DRASTIC, Groundwater quality, Lithological mapping, Overlay analysis, Aquifer media.

DOI: 10.7176/IKM/9-11-05

Publication date: December 31^st 2019