Shallow Groundwater Vulnerability Assessment in the Upper and Middle Reaches of the Huai River

Groundwater vulnerability is basement of evaluating risk of groundwater contamination and groundwater vulnerability assessment is one of management methods for preserving the quality of groundwater. Based on DRASTIC model and GIS techniques, shallow groundwater vulnerability assessment was carried out in Xiangcheng City, China. The results indicate that the studied area can be divided into three zone: middle groundwater vulnerability zone (vulnerability index <;140) which locates in the south; higher vulnerability zone (vulnerability indexes 140-160) which locates in the middle-east and south; highest groundwater vulnerability zone (vulnerability index >160) which locates in the middle-west and north. The highest groundwater vulnerability zone mainly locates in the groundwater recharge areas and the urban areas. The middle, higher and highest groundwater vulnerability zones cover around 2.2%, 78.2% and 19.6% of the area studied, respectively. Nitrate concentration distribution in shallow groundwater is mainly consistent with vulnerability zone.