Application of DRASTIC and extension theory in the groundwater vulnerability evaluation

Groundwater vulnerability assessment plays a vital role in the utilization and protection of groundwater resources. DRASTIC is one of the most widely used models for groundwater vulnerability assessment. However, the DRASTIC model should be modified based on the local hydrogeological conditions in order to get a relatively accurate result. In this study, Baotou, China was chosen as a case study. The groundwater vulnerability was assessed using DRASTIC at first, but the evaluation results were not consistent with the groundwater quality. So the DRASTIC model was modified based on extension theory and analytic hierarchy process (AHP) method. The extension theory could be used to divide the groundwater vulnerability grades in the DRASTIC model. It is a new attempt to use extension theory and DRASTIC in the assessment of groundwater vulnerability, and the research results show that this method is better for assessing groundwater vulnerability.