Abstract:

Based on the EFDC model,a two dimensional model for hydrojunction projects and main basin of Poyang Lake is established.Study area is divided with Delft3D method,TIN and TP data in 2010 are the  initial condition,and the change characteristics of nitrogen and phosphorus nutrients before and after operating the hydrojunction are imitated.The verification result shows that the calculated values of  TIN and TP are coincide with the measured values,which also prove that the calculated values of model are efficient and reliable.The concentration of TIN and TP have a growth of 2042% and 2055% in dry season after operating the hydrojunction,and the value are 286 mg/L and 044 mg/L,respectively.Raohe River is the main source of regional pollutants.The increasing rate of  TIN and TP are 1339% and 1290% in flat water season,and the concentration are 208 mg/L and 018 mg/L,respectively.Pollutants in lake region mainly come from the confluence of Gan River main branch and Xiuhe River,and the impacts of hydrojunction on nitrogen and phosphorus is mainly reflected in the control of phosphorus.In southern and northern lake regions,the values of TIN in northern lake regions are higher than that in southern lake regions,while the value of TP in southern lake regions is higher than that in northern lake regions.Ratio of N/P in Poyang Lake district is 927, 291% lower  than the measured value,indicating that the pollution degree of phosphorus is heavy