Study On The Assessment Of Water Environmental Quality In Mianyang Section Of Fujiang River

Based on the systematic study and analysis of the assessment methods of river water equality and the water quality monitoring results of Mianyang section of Fujiang river in the last 3 years, the gray decision making-comprehensive index assessment method was developed after the deep analysis on the gray decision-making assessment method and comprehensive index assessment method. This developed assessment model has been used in the water environmental quality assessment in Mianyang section of Fujiang river. Further more, the water environmental capacity of Mianyang section of Fujiang river was primarily calculated, according to this, the basic ideas to treat the water environmental of Mianyang section of Fujiang river was put forward.Through comparison between the gray decision-making assessment method and the gray decision making-comprehensive index assessment method, it was found that the latter has more advantages such as its higher sensitiveness and accuracy, the assessment results reflect the dynamic change trend of water environmental quality more objectively, and the gray making-comprehensive index assessment model is more scientific and reasonable.Through assessment, it can be concluded that the water quality in Mianyang section of Fujiang river was better; the water quality improves gradually in the last 3 years but this trend was not stable either in space or in time; the water quality was best in low water period but it's worse in flush water period and slack water periodjln space the water quality in Pingwu section was best, it's the second place in Fujiangqiao section and Baiqing section while it's worst in Fengu section.After calculating the water environmental capacity, it was shown that Mianyang section of Fujiang rive has some capacity in incepting CODMn, BODs, volatile hydroxybenzene, CN", As, THg, TPb, TCd, petroleum and F", but the fecal coliform concentration has exceed the national standard.At last, the primary measures on the water environmental treatment in Mianyang section of Fujiang river were put forward. These measures include increasing thetreatment proportion of sewage, controlling and preventing the area-pollution, planning the industry category and layout with reason.