The Use of Modified Drastic Method (DRASTIC-LU) for Assessment of Groundwater Vulnerability to Pollution at the Palas Basin/Turkey

Groundwater is one of our major water resources, which is affected by hydrological, climatic, and anthropogenic factors. DRASTIC model is a widely-used index-based method that can be used to evaluate the vulnerability of the groundwater systems to pollution. DRASTIC uses depth to water (D), net recharge (R), aquifer media (A), soil media (S), topography (T), impact of vadose zone (I), and hydraulic conductivity (C) information to create a GIS-based vulnerability map. In this study, we used a modified version of DRASTIC model (DRASTIC-LU) for vulnerability assessment at the Palas Basin/Turkey. DRASTIC-LU uses land use (LU) information in addition to the hydrogeological parameters. The measured nitrate concentrations in the Palas Basin were used to test the original and modified DRASTIC models. The results of the study revealed that the DRASTIC-LU improved predictions of nitrate concentrations. The results of the vulnerability assessment in this study can be used for groundwater management and planning at the Palas Basin.