Evaluation of AVI and DRASTIC Methods for Groundwater Vulnerability Mapping

Abstract

The Densu River Basin is one of the important basins in Ghana. A large number of residents in this basin are dependent on groundwater for their livelihood. However, with the growing population, urbanization and impact of climate change, it is imperative to develop ways to protect and manage the limited groundwater resource that is supporting the communities. As a result, this paper assessed the groundwater vulnerability by comparing two methods – the Depth to water, net Recharge, Aquifer media, Soil media, Topography, Impact of the vadose zone, and hydraulic Conductivity DRASTIC an the Aquifer Vulnerability Index (AVI). The results show that DRASTIC is more precise and representative of the groundwater vulnerability in the basin. The AVI statistically show a relatively lower risks compared to DRASTIC. It is recommended, AVI which is oversimplified may be useful for larger basins.