Poyang Lake Water Environment Model And Its Uncertainty Research Based On EFDC

First, based on water balance and water quality assessment, Poyang Lake water environment model for total phosphorus(TP) and potassium permanganate index (CODMn) was established by the Environmental Fluid Dynamics Code model package (EFDC), and model data during 2008 was collected from the lake hydrological stations. Then, uncertainty analysis was undertaken using a Generalized Likelihood Uncertainty Estimation method (GLUE) when taking into account the input data and model parameters. On this basis, taking TP as the object, which is the main limiting factor for lake eutrophication, the effect on leading nutrient reduction of the inflow was evaluated to meet the requirements of Poyang Lake water environment functional area.The main research results focus on the following aspects: (1) runoff inflow from the five major rivers accounts for 91% of total inflow into Poyang Lake, while interval runoff, groundwater and lake precipitation the amount of less 4%, respectively; the total load into the lake of TP and CODMn is 7758t and 437215t, respectively, and that from the major rivers is 87% and 72%; the main exceeding standard factor are TP, volatile phenol and ammonia nitrogen, and TP is the most serious;(2)Poyang Lake water environment model was established by EFDC. The results show that the average relative error of water lever elevation between the simulated and measured data, is less than 10%; monthly mean relative error of CODMn is less than 15% , and that of TP is less than 30%;(3)Parameter uncertainty was the main sources of uncertainty of Poyang Lake water quality model; parameters WS_COD, Khcod, Kcd and Krcod had remarkable influence on uncertainty of CODmn and parameter WS_TP had remarkable influence on TP uncertainty;(4)The results of the river pollution control program is that TP load control coefficients of Gangjiangnanzhi, Fuhe and Xinjiangdongzhi are 50%, and that of Xinjiangxizhi , Gangjiangzhongzhi,and Raohe is 65%,70% and 90%.Main innovative points of this paper focus on the following aspects: (1) water environment model on the whole Poyang Lake was established;(2)taking into account the input data and model parameters,uncertainty analysis was undertaken for Poyang Lake water environment model. And the coefficient of variation is adopted in GlUE to quantitate each variable contribution to uncertainty.This theoretical study on the water environment model uncertainty analysis has great significance in Poyang Lake water resources utilization, water pollution control and pollution control practice.