综合考虑区域浅层地下水脆弱性的影响因素,初步认为地下水脆弱性的影响因子包括:固有脆弱性评价因子和特殊脆弱性评价因子.固有脆弱性评价因子主要包含5个评价单元:土壤性质、包气带特征、含水层特征、补给量、地形.特殊脆弱性评价因子为区域特性评价单元.根据政府政策研究评价部门专家、科研单位环境评价研究专家意见,确定各个评价单元的指标,采用模糊综合判断法,分层进行地下水脆弱性评价,在此基础上,基于GIS技术进行脆弱性评价结果可视化表征,形成了一套通用性好、操作简便、信息清晰的区域浅层地下水脆弱性评价方法.以常州市为例,利用该方法对其浅层地下水进行脆弱性评价,研究表明常州市地下水脆弱性由北向南逐渐增大,脆弱性相对最高区域分布在常州市最南部,相对最低区域分布在常州市北部大部分地区及东北部小部分地区.常州市浅层地下水脆弱性评价模型局部灵敏度与全局灵敏度分析结果显示除土壤评价单元中的土壤成分指标灵敏度较低外,其余评价单元的评价指标均具有较高的灵敏度,充分体现了该评价方法的可靠性,准确性.
A preliminary view was raised that the influence factors of groundwater vulnerability was determined by the inherent vulnerability assessment factors and the specific vulnerability assessment factors. The inherent vulnerability assessment factors included 5 assessment units: soil properties, characteristics of the vadose zone, aquifer characteristics, recharge amount and terrain. The specific vulnerability assessment factor was the assessment unit of the regional characteristics. Each assessment unit was confirmed by the experts, who are from the government and scientific research units. The fuzzy comprehensive evaluation method was applied to evaluate the groundwater vulnerability. Based on the results, the vulnerability evaluation results were visually presented on GIS. A good commonality, easy operation, clear information of the regional groundwater vulnerability assessment methods was formed. Changzhou taken as an example to assess its shallow groundwater vulnerability with this method. The results show that the groundwater vulnerability of Changzhou gradually increased from north to south, and the area of highest vulnerability was the southernmost of Changzhou. The areas of lowest valnerability was located in most parts of north and a few parts of northeast of Changzhou. The local sensitivity and global sensitivity analysis results showed high sensitivity of the indicators of most of the assessment units except the soil composition, which indicated that the assessment method was reliable and accurate.