Improvement and Application of Fuzzy Synthetic Evaluation of Groundwater Quality

Based on the traditional fuzzy synthetic evaluation theory,a new model was developed to overcome the limitations of traditional model in practice.In the procedures of selecting assessment indices,calculating weighted values,choosing fuzzy synthetic operator and analyzing object vectors of fuzzy synthetic evaluation,the methods of cumulative frequency,modified clustering weight,weighting average operator and level eigenvalue were proposed,respectively.Finally,a case study of groundwater quality assessment using the improved model on a well field in Dagu River watershed was presented.The results show that only 30.43% of the water samples in the well field fit the quality standard of potable water,with levels ranging from 2.50 to 3.00.Nearly 70% of the groundwater samples are of bad quality,with level of 3.50-4.50.Compared with the scoring method recommended by the current groundwater quality criteria(GB/T 14848-93) in China,the improved model is proved to be reliable and superior.