[Classification and pollution characteristic analysis for inflow rivers of Chaohu Lake]

Based on main pollution sources and characteristics of inflow rivers of Chaohu Lake, the inflow rivers are clustered and the pollution levels are classified by statistical methods. In addition, the correlation between algal biomass and the river nutrients input loads is derived according to the inflow river water quality monitoring parameters and the Chl-a concentrations in lake areas. Results show that the inflow rivers are classified into three groups. Urban pollution, soil and water conservation, and non-point source pollution are the major factors which influence water quality respectively. The input loads of permanganate index, NH4(+) -N, TN, TP from urban pollution rivers to the whole lake are 41.29%, 89.49%, 72.27% and 60.14% to all inflow rivers respectively. Organic pollution is the main pollution source of inflow rivers by factor analysis. The pollution rank of nine inflow rivers are as follows: Nanfei River > Shiwuli River > Paihe River > Shuangqiao River > Zhegao River> Yuxi River> Baishishan River > Zhaohe River> Hangbu River. The algal biomass and the NH4(+) -N, TN, TP inputs of inflow rivers are positively correlated.