WATER QUALITY EVALUATION OF YANHE RIVER BASED ON THE IMPROVED WATER POLLUTION INDEX

Considering the problems that exist in water quality assessment by using Water Pollution Index (WPI), an improved WPI method is proposed, in which entropy method is used to get each indictor's weight and then the improved WPI is calculated. The improved WPI method was tested and validated using the data from 5 monitoring sections of Yan'an environmental monitoring station, and the results were compared with the evaluation results by traditional WPI method, fuzzy comprehensive evaluation method, set pair analysis method based on entropy weight, combination model evaluation method and comprehensive pollution index method. Results show that the improved WPI method is more accurate and objective. What's more, it retains low computational complexity. That demonstrates that the improved WPI method is reasonable and suitable in application of water quality evaluation.