| Based on the combined evaluation factor weights of entropy weight method and relative standard deviation method, an improved fuzzy comprehensive evaluation method was established by integrating the principles of maximum membership and weighted average. This method was applied to evaluate the quality of shallow groundwater in a coal mine area, and compared with other evaluation methods. The results showed that among 33 shallow groundwater monitoring sites in the study area, there were 4, 16 and 13 sites belonging to ClassⅠ, Class Ⅱ and Class Ⅲ water respectively. The most belonged to Class Ⅱ water, accounting for 48.5%. There was no Class Ⅳ or Ⅴ water. The water quality was generally good. Through comparison, the water quality was relatively poor in industrial parks, followed by coal mine areas and industrial squares, and was relatively good in farmland and residential area. The improved fuzzy comprehensive evaluation method comprehensively considered the internal relationship between evaluation factors, which not only reduced the influence of subjective factors on the evaluation process, but also avoided the limitations of single evaluation principle on the determination of water quality grade, and the evaluation results were more in line with the actual situation. |
