Application of fuzzy comprehensive evaluation method using entropy weight in groundwater quality evaluation: A case study on Xianyang, China

Abstract

Groundwater, especially unconfined water, is easy to be polluted in Xianyang of Guanzhong Basin. Therefore, the evaluation of groundwater quality is of great significance for the safety of drinking and control of pollution. In order to find out the water quality, 14 water quality assessment indicators were selected for 16 points. And the fuzzy comprehensive evaluation method based on entropy weight is used to evaluate the groundwater quality. The results show that the water quality level determined by the weighted average principle is better than that by the maximum membership principle. Nearly 75% of the water quality ranks are Class IV and Class V, and evaluation of water not exceed groundwater Class III water standard is solely approximately 25%. Moreover, the water quality in upstream of groundwater flow field is better than that in downstream. The main indicators of groundwater pollution are fluoride from the impact of geological environment and human activities and hexavalent chromium contained in wastewater discharged from industrial development in Xianyang city.