Assessment of groundwater quality and groundwater vulnerability in the northern Ordos Cretaceous Basin, China

As a result of serious groundwater pollution in the northern Ordos Cretaceous Basin, China, it is necessary to carry out groundwater quality and groundwater vulnerability assessment. In this study, groundwater quality was assessed by principal component analysis (PCA) and groundwater vulnerability was assessed by a modified DRASTIC model. Then, the assessment results of groundwater vulnerability were verified by comparing the corresponding relation between groundwater vulnerability and groundwater quality. Finally, the map removal method was utilized to analyze the parameter sensitivity of groundwater vulnerability. The research results show that more than half of the study area has moderate degree of groundwater pollution. Groundwater is polluted serious in the south of study area. The groundwater vulnerability assessment results based on modified DRASTIC model are more consistent with actual conditions of study area. The high groundwater vulnerability is mainly distributed in middle east of study area. The sensitivity of the groundwater vulnerability from largest to smallest are impact of the vadose zone, depth to water, net recharge, type of soil media, type of aquifer media, and topography. Above researches provide a good approach for assessing groundwater vulnerability accurately and a strong scientific basis for protecting the groundwater environment across the study area.