Assessment of Groundwater Vulnerability Using GIS-Based Modified DRASTIC Models, Case Study: Fasarood Plain, South Iran

Abstract

Severe droughts and vast anthropogenic activities have propelled groundwater resource contamination in Iran. An accurate investigation of groundwater vulnerability objectively reflects an area’s potential for groundwater contamination and supplies a reference for contamination control and prevention. Therefore, the groundwater vulnerability of the Fasarood plain, south of Iran, was evaluated using the DRASTIC index (DI), Fuzzy-based DRASTIC index (FDI), Composite DRASTIC index (CDI), and Nitrate Vulnerability Index (NVI) methods. The input hydrogeological parameters were rated, weighted, and integrated via a geographical information system (GIS). The results of all models showed very low to moderate intrinsic and anthropogenic vulnerabilities to groundwater pollution. The zones with the most significant exposure may refer to geological formations and improper agriculture activity. The conclusions recommend that the area which was identified as having a higher groundwater pollution risk needs scientific land-use practise along with appropriate watershed management. The agriculturalists working in more vulnerable areas with high nitrate concentrations must begin practising an organic farming system and should replace chemical fertilisers with biofertilisers to reduce the groundwater contamination rate. Also, government departments should encourage reasonable control of groundwater pollution prohibition and withdraw based on changes in groundwater vulnerability in the area.