九江市地下水易污性评价——基于DPASTIC指标的模糊综合评价模型

从污染物入渗土壤-包气带-含水层的过程出发，以地质、地貌、水文地质条件为主控因素，选取地下水埋深〖WTBX〗(D)、降雨入渗补给量(P)、含水层岩性(A)、土壤类型(S)、地形坡度(T)、非饱和带介质(I)及含水层渗透系数(C)〖WTBZ〗7个指标，建立了九江市地下水易污性评价DPASTIC指标体系。结合模糊数学理论和方法，建立了基于DPASTIC指标的模糊综合评价模型。该模型克服了指标参数级别划分定额差异和指标值不连续性变化的缺陷，寻求出最优的级别定额划分状态和指标值的连续性变化情况；在指标级别定额划分上，引用了指标标准特征值的概念，根据实测参数数据资料，建立了10个级别的指标标准特征值矩阵，确定指标参数的最优相对隶属度。结合MAPGIS软件得出最后的地下水易污性分区，评价结果与规划区的实测及预测的水环境质量相吻合。

ASSESSMENT OF UNDERWATER VULNERABILITY IN JIUJIANG CITY〖WT4”BZ〗——FUZZY SYNTHESIS APPROACH BASED ON DPASTIC INDEXES

Based on the process of contamination filtering into soil adose zone aquifer，geology，physiognomy and hydrogeology have been considered and indexes including depth to water，precipitation recharge，aquifer media，soil media，topography，impact of vadose zone and penetrability coefficients have been selected to establish DPASTIC index system of groundwater vulnerability assessment in Jiujiang City. The approach of fuzzy synthesis using DPASTIC indexes has been established according to fuzzy theory and method. It overcomes difference of rating and discontinuousness on index value and tries to seek optimization of rating and continuous change on parameters. The concept of index standard eigenvalue has been cited in order to determine index rating. Considering the data and information obtained in the study area，index standard eigenvalue matrix which sets corresponding to 10 linguistic classes used for determining the groundwater contamination degree of every parameter has been founded and relative optimization value been established. The map of groundwater vulnerability subarea has been drawn by MAPGIS soft. The distribution pattern of contamination is well consistent with groundwater environment quality forecasted and measured in this area，which has practical meaning for government agencies to set up prevention projects and management steps of groundwater contamination. It is considered that the method used in the present study has reference value to groundwater vulnerability assessment in similar areas.