Groundwater Vulnerability Mapping Using DRASTIC Model: A Case Study at the Palas Basin in Turkey

The study aims to estimate groundwater vulnerability against pollution at the Palas Basin (Turkey) by using geographical information system based DRASTIC model. A DRASTIC model integrates information for seven hydrogeological parameters: depth to water (D), net recharge (R), aquifer media (A), soil media (S), topography (T), impact of vadose zone (I), and hydraulic conductivity (C), and identifies spatial vulnerability. The study area, Palas Basin, is a hydrologically closed, agricultural basin, where groundwater is used for meeting irrigation and municipal water requirements. Seven hydrogeological parameters were combined to classify the basin into three vulnerable zones (as low, moderate, and high). The central part of the basin was identified to be highly vulnerable, while the eastern and southern parts were characterized by moderate to low vulnerable areas. Intensive agricultural activities, widespread in the central basin, create high pollution potential. This study showed that the DRASTIC approach provided a simple and efficient tool for evaluating groundwater vulnerability. The results can be used by water managers in groundwater management in the Palas Basin