Evaluation Of Groundwater Vulnerability In Chengdu City

Water resource is a kind of important environment factor, and human life has a inextricably linked. Along with the improvement of economic level, for the construction of the urban expansion and population surge, also increased the demand for groundwater resources. Therefore, to prevent groundwater resources destruction, groundwater resources it becomes very important to achieve sustainable use. Domestic and foreign research more and more about the vulnerable. It represents the groundwater system is subject to damage potential, is the basis for the work of protection of groundwater system.In recent years, the Chengdu Economic obtained fast development, massive expansion of urban area, the number of plants increased exponentially, leading to Chengdu cited that Ho's water resources began to appear in short supply. Due to groundwater exploitation of resources and unreasonable factors of groundwater pollution, so that the traditional advantage of Chengdu "groundwater resources storage quantity, mining area is large, easy mining, the water quality is good" is destroyed. There is an urgent need to carry out of Chengdu area of groundwater vulnerability assessment, for local water resources management departments act in accordance with the condition of Chengdu city groundwater protection measures to provide guidance, better protection of underground water resources.This paper introduced the concept and evaluation method of vulnerability, this paper introduces the general situation of the evaluation area, including the natural and geographical conditions, social economic situation and hydro geological conditions. In the evaluation area collected more than 400 shallow groundwater monitoring wells and water quality data, using the comprehensive index method to evaluate the status of groundwater in Chengdu city. Using the DRASTIC model on the Arcgis platform to evaluate the intrinsic vulnerability of groundwater in Chengdu City, the evaluation result has certain regularity, such as quaternary river terraces in areas of high vulnerability, other areas of vulnerability is relatively low. Net recharge aquifer, groundwater depth, soil type, vadose zone lithology, hydraulic conductivity of the aquifer, the aquifer medium, the status of land use, groundwater quality of 8 indexes, construct the evaluation index system; AHP to determine the evaluation index of the right Weight; established under the influence of human activity evaluation of groundwater vulnerability assessment model. In the ArcGIS platform using human activity based groundwater vulnerability model evaluation of the Chengdu city groundwater special vulnerability, evaluation results and the intrinsic vulnerability with a high degree of consistency, due to the influence of human activity, high vulnerability of the area has increased, increased area mainly in the areas of urban industrial areas and water pollution is serious.The results showed that the District Assessment of groundwater vulnerability and the area with water medium, the vadose zone media such as spatial distribution is similar, can objectively reflect the evaluation of groundwater protection, for the relevant functional departments of reasonable water resources planning provide the basis.