Study On The Assessment Of Water Quality And Water Environmental Capacity Of Fuxi River In ZiGong City

The water quality status, the character of pollution fountain and contamination and the water environmental capacity of Fuxi river in Zigong were studied in this paper. According to the water quality monitoring results of Fuxi river in the last two years, the assessment of water quality was made by using single-index assessment method. It was shown that the main contaminative indexes of Fuxi river were TN, NH3-N, TP, petroleum and COD_Mn. At Shuanghekou section where its branches incorporated, NH3-N, TN and the fecal coliform concetration all exceeded the national standard at different extent whether in the high, par or low water period. Thereinto, the maximal excess multiple was respectively 13.4, 31.5 and 45. At Tanyansuo section, which was the background control section of Fuxi river, NH3-N, TN and TP all exceeded the national standard at different extent whether in the high, par or low water period. What's more, the maximal excess multiple was respectively 38.7, 41.3 and 4.1 which all appeared in the low water period. The trend analysis of water quality in Fuxi river was made by using average-index assessment method and Spearman coefficient of correlation method. The result indicated that worsening trend of Fuxi river was evident, while trend of water quality of the section where its upriver branches incorporated was not evident, which owed to the control of sewage quantity flowing and the regulation of pollution-lets. Based on comprehensive assessment of water quality and analysis of pollution fountain, according to the principle of maximal contamination tolerance, water environmental capacity of Fuxi river was computed by using one-dimension model to simulate water quality. The result showed that the water environmental capacity for COD was 19739 t/a, and for NH3-N was 845 t/a, then the cut portion for COD was 2692 t/a, and forNH3-N was 3103 t/a. Thus, countermeasures and measures of contamination gross control of this area were put forward.This study can offer important gist for the long programming of the water environment comprehensive recondition of Fuxi river, in the meanwhile, its thought and method can be used in the similar work of other areas for reference.