An assessment of groundwater resource vulnerability to pollution in the Jiangjia spring basin, China

Assessment of the vulnerability of karst groundwater to pollution can help in managing and protecting groundwater resources. Most karst areas with important groundwater reservoirs in southwest China are not protected by regulations governing environmental pollution, so the groundwater is easily polluted. In this paper, a case study of the vulnerability of groundwater to pollution is presented from the karstic, subtropical Jiangjia spring area (Chongqing, China). The methodology in this paper is based on the pan-European approach to assessing the vulnerability of groundwater to pollution, and is complemented by newly acquired fieldwork data. Two earlier approaches developed for case studies in Slovenia and Vietnam are tested in the present study area, and improvements to the approached are proposed. Both approaches yield reasonable results, with some notable differences. A degree of extreme vulnerability is assigned by both methods to an area with a sinking river, and also to local depressions where an estavelle is present. The main difference in the results of the two methods is the vulnerability of most karst areas. The Slovenian approach classified most of the karst areas as highly vulnerable, whereas the Vietnamese approach assigned a medium degree of vulnerability. The Slovenian approach requires more information and data, when compared with the Vietnamese approach. The results of vulnerability assessment were independently verified by spatial variation diagrams for nitrate.