不确定性条件下的下辽河平原地下水脆弱性评价及空间分布软区划

建立地下水脆弱性评价的DRASTICH模型,辨析各个参数的不确定性特征,采用随机模拟方法同时对随机性参数和模糊性参数模拟赋值。分别对模糊性参数和脆弱性指数统计值设立具有概率分布意义的置信水平和百分位,得到多重地下水脆弱性的指数区间,在此基础上,分别绘制地下水脆弱性的保守分布图和冒险分布图,并对研究区地下水脆弱性分布状况进行分析。结果表明：① 以模糊区间形式表示的地下水脆弱性评价结果,能反映多种不确定因素综合影响下的地下水脆弱性客观实际情况,可提供更多可靠性方面的信息;② 以软区划方式制作地下水脆弱性分布图,保留了不确定性客观存在的事实,可给予决策者更多参考信息和调整余地;③ 地下水脆弱性软区划分布图显示：保守分布的脆弱性程度总体要高于冒险分布,置信水平选择越高,冒险分布与保守分布的空间分布差异越接近,且与最大可能性分布情况越接近;④ 研究区地下水脆弱性分布具有明显的空间集聚现象,地下水高脆弱性区域主要集聚在下辽河平原中部和南部地区,低脆弱性区域一般分布在下辽河平原东、西两侧地区。

Assessment and Soft Zoning of Groundwater Vulnerability in the Lower Reach of the Liaohe River Plain Under Uncertainty Condition

Based on the DRASTICH model of groundwater vulnerability assessment, the uncertainty characteristics of each parameter were analyzed, and the stochastic simulation method was used to simulate both random parameters and fuzzy parameters. By setting the confidence level of the fuzzy parameters and the percentile of the vulnerability index, we obtain the confidence interval of the multiple groundwater vulnerability. On this basis, the soft zoning distribution of the groundwater vulnerability was plotted according to the expectation vulnerability index of upper limit fuzzy interval and the lower limit fuzzy interval. The results showed that: 1) The evaluation results of groundwater vulnerability in the form of the confidence interval can reflect the objective reality of the groundwater vulnerability under the influence of various uncertain factors, and provide more reliability than the conventional method; 2) The soft zoning distribution of groundwater vulnerability map, which preserves the fact that uncertainty is objective, can give decision maker more reference information; 3) The soft zoning distribution of groundwater vulnerability showed: the degree of vulnerability of the conservative distribution of the overall higher than the risk distribution, the higher the confidence level selection, adventure distribution and conservative distribution of the spatial distribution of the difference, and with the maximum possible; 4) The distribution of groundwater vulnerability in the study area was spatial agglomeration, high groundwater vulnerability areas were generally concentrated in the middle and the southern region of the lower Liaohe River Plain, low groundwater vulnerability areas were generally distributed in both east and west sides of the lower Liaohe River Plain.