A modified DRASTIC model for assessing contamination risk of groundwater in the northern suburb of Yinchuan, China

Groundwater vulnerability assessment is a common method to describe groundwater contamination. However, intensive human activities have a marked impact on subsurface environment. Therefore, in this paper, the DRTILSQ model which is based on DRASTIC and considers human influences was proposed. The contamination risk of groundwater underlying the northern suburb of Yinchuan city was assessed. According to local hydrogeological settings, seven factors were singled out for representing intrinsic vulnerability, pollution loading and groundwater value, respectively. Analytical hierarchy process was adopted to determine weights, which makes the model harmonize with the study area and easy to transplant. The results show that high contamination risk area is in the central zone with shallow buried depth of groundwater, highly permeable vadose zone, high recharge and agricultural pollution. Except that, extremely high contamination risk is associated with high groundwater value and industrial threats. Compared to the vulnerability map, the contamination risk map presents a more reasonable classification. The maps are valuable tools for environmental management. The DRTILSQ can be transplanted to Yinchuan Plain or northwest China, and provides experience for developing models of groundwater contamination risk assessment for individual regions.