| Sancha River is the source of the Wujiang River as well as significant drinking water source of Guizhou province, whose upstream is Guizhou water conservancy project, so that it has a great value of ecology and conservation.. This paper not onlyselected 26 sampling points of Sancha River to analyze the water quality of dry season and wet season, and to explore the characteristics of water quality according to the seasonal shifts and the spatial differences, but also assessed the degree of contamination of water bodies by using different water quality assessment and analyze its influencing factors. This paper provided a scientific ground for control, management, and improvement of Sancha River water quality.Firstly, 26 samples covering the whole basin of Sancha River were collected and analyzed during each seasons in this study. We applied the box plot based on STATISTICA 10 to show the temporal distribution of various water quality indicators. The Sancha River Watershed was divided into the upper, middle and downstream, respectively for the analysis of the spatial distribution of main stream and tributaries. The main conclusions were as follows: The results showed that Sancha River water quality had obvious spatial and temporal distribution characteristics. From the perspective of spatial distribution, the upstream water quality was better than that in the midstream and downstream, and the peak arised in the upper and middle reaches of Sancha River. From the point of view of temporal distribution, the fuzzy index of dry season was higher than that in the rain season. The main pollutant was nitrogen, followed by the COD and the total phosphorus. NH3-N, TN, TP and COD were significant positive correlation, which demonstrated that they came from a common point source and nonpoint source water pollution.Then, we analyzed and evaluated the water quality in Sancha River with the methods of single factor water quality identification index, comprehensive water quality identification index and improved fuzzy identification index respectively and made a comparison with other methods. The main conclusions were as follows: The improved fuzzy identification index evaluation, which was based on comprehensive water quality identification index method and fuzzy analytic hierarchy process method showed that, the water quality in dry season mainly in the V class water, and the water quality of the wet season was mainly based on the II and III class water. The whole areas water pollution was serious.Finally this study focused on the precipitation, population, industry layout, land use of Sancha River watershed based on the characteristics of river basin, providing references for the governmental treatment and administration as well as scientific research basis for the later generations. The main conclusions were as follows: Sancha River water quality was affected by Rainfall, population density, industrial structure, land use and other factors. The discharge of industrial waste water was a predominant reason to abate the water quality of Sancha River among all the factors. Land use and the river water quality parameters had significant correlation. Forest land, grassland had positive effect on water quality,but cultivated land, construction land and waters had negative effects on water quality. |
