The Risk Assessment of Groundwater Pollution in the Dawu Water Source

The paper takes the typical Karst-Phreatic in the north of China-Dawu Water Source as an example, and the risk assessment of groundwater pollution is conducted by using the Overlay and Index method. Unsaturated zone media, net recharge, rich water property of aquifer and depth to groundwater table are chose as the intrinsic vulnerability indexes, and types of land use, sources of pollutants and extent of groundwater exploitation are chose as the special vulnerability indexes. Indexes weights are determined by using the Analytic Hierarchy Process. The risk assessment map is obtained based on the spatial analysis platform of Geographical Information System. The rationality of the risk assessment model and risk assessment results are validated by using the Single-Parameter Sensitivity Method and groundwater anomalies, respectively. The study area is classified into highest risk, higher risk, middle risk, lower risk and lowest risk sub areas based on the qualitative evaluation results. Results show that highest and higher risk sub areas account for 39.0%, which are located at a certain Petrochemical Company and the Gougao-Xiaowu area, the unsaturated zone media is the most sensitive factor in the risk assessment of groundwater pollution. The risk map obtained from the Overlay and Index Method is a promising tool for the design of groundwater management and protection schemes, which contributes to the development of human survival.