Assessment And Verification Of Groundwater Vulnerability In Villages And Towns

According to the 2014 China Environmental Bulletin, 45.4% monitoring points are poor and 16.1% monitoring points are extremely poor in 4896 groundwater quality monitoring points in China. Groundwater is spreading from point to surface and the contaminant is to penetrate from shallow to deep. The pollution degree of groundwater is increasing continuously. China’s vast rural areas take shallow groundwater as drinking, living water through diging well. Because groundwater flow is slow and it’s alternately is weak. Once the groundwater is contaminated, it is difficult to control and it will bring great risks for rural drinking water safety.Therefore, it is urgent to strengthen the assessment of groundwater vulnerability and the protection of groundwater.The Qiaokou Town, Wangcheng County, Changsha City is selected as objects of groundwater vulnerability assessment. Based on DRASTIC model, According to the investigation of hydrogeology and agricultural production activites in Qiaokou Town,the paper increased land use type, surface water quality, the amount of pesticides, the amount of fertilizer as rural groundwater special vulnerability assessment index.Fuzzy Analytic Hierarchy process is used to get the weight of each vulnerability assessment index. Through the Arc GIS spatial tools, the paper get shallow groundwater vulnerability assessment map of Qiaokou town.Based on the survey data of groundwater sensory traits and quality indicators in the dry reason and wet period, Based on the superposition index method, the vulnerability assessment model of groundwater vulnerability in villages and towns is established and the groundwater vulnerability assessment model is verified. the gorundwater vulnerability evaluation index and validation index has a good correlation by coupling them. This implies that the groundwater vulnerability assessment model can reflect the degree of contamination of groundwater vulnerability and consistent with groundwater quality and it is consistent with actual situation groundwater quality in the study area.Improved DRASTIC Model used to the groundwater vulnerability assessment in Qiaokou Town. Groundwater Vulnerability Validation Figures of dry reason and wet period reflect groundwater quality and its changes. The verification result shows thatgroundwater vulnerability distribution is consistent with its groundwater quality situation.