EVALUATION OF WATER QUALITY IMPROVEMENT EFFECT IN HAIHE RIVER BASIN IN HENAN PROVINCE FROM 2015 TO 2018

This paper evaluated and analyzed the water quality improvement effect in Haihe River Basin in Henan province during 2015—2018 using single factor evaluation method, comprehensive pollution index evaluation method, and fuzzy comprehensive evaluation method. The results showed that the three evaluation methods were basically consistent, and the overall water quality in Haihe River Basin in Henan province showed a trend of improvement in 2015—2018. But the emphasis of each method was different. The results of single factor evaluation showed that the number of category Ⅰ—Ⅲ pollution factors of 21 pollution factors in Haihe River Basin increased from 69.63% in 2015 to 89.52% in 2018, and the number of category inferior Ⅴ pollution factors decreased from 15.13% in 2015 to 0.85% in 2018. The comprehensive pollution index of Haihe Basin in Henan province decreased from 0.89 in 2015 to 0.56 in 2018, and water quality grades were improved from moderate pollution to light pollution. The water quality grades of the eight rivers in 2015 were lower than moderate pollution, including Wei River, Communist Canal, Dasha River, Anyang River, Tang River, Majia River. The results of fuzzy comprehensive evaluation showed that the weights of ammonia nitrogen and total phosphorus were the largest among the nine evaluation factors, the main pollution factors in Haihe River Basin in Henan province. And the water quality of eight rivers was improved to category Ⅰ—Ⅲ by 2018. Single factor evaluation method, comprehensive pollution index evaluation method were more suitable for management analysis, while fuzzy comprehensive evaluation was prefered in research work.