Dynamic Changes of Water Quality in Hongze Lake Using Fuzzy Comprehensive Assessment

In this paper, We used fuzzy comprehensive assessment method to evaluate the changing of water quality of six national water quality monitoring points in Hongze Lake basin (Jangba Township, Center of Chenghe Township, Linhuai Township, Laoshang Township, Gao Liangjian Township, North Longji Township) from October 2006 to October 2008, in order to assess the water quality of the whole Hongze Lake. The results showed that water quality was the worst in wet season (August 2007 and August 2008), while the best was in dry season (December 2006 and February 2008) from October 2006 to October 2008. The changing trend of water quality in 2007 decreased from February 2007 to August 2007 and then increased from August 2007 to February 2008. Water quality of the estuary (Laoshang Township) was the worst in six national water quality monitoring points. Water qualities of other points were better than estuary (Laoshang Township). Regardless of judging from the time or the space, nitrogen and phosphorous are the major pollutants of Hongze Lake.