| The surface water samples from 12 monitoring sections in Guishui River and its tributaries were collected during rainy, normal and dry seasons in 2017, the water quality indexes such as COD，NH3 N，TP，DO，pH，etc. were detected and evaluated by single factor evaluation method, water pollution index method, principal component analysis method and fuzzy comprehensive evaluation method, and the applicability of these four methods was discussed according to the evaluation results. It turned out that among the 12 sections, the water quality at S2, S10 and Z2 sections was polluted heavily, which belonged to Ⅴ grade surface water quality, while the rest 9 sections belonged to Ⅳ grade and were moderately polluted. The water quality at International Horticultural Exhibition section was better than that at upstream or downstream. COD was the main pollutant. Agricultural and domestic pollution were the main sources in Guishui river. The water quality in dry season was better than that in normal and rainy seasons. The water pollution index method was more feasible for qualitative and quantitative evaluation of water quality in small watershed, and the calculation was simple. |
