Water Aualitv Model Of Liangxi River In Wuxi And Its Uncertainty Analysis

The river network,including Liangxi River and the segment of the Beijing-Hangzhou Grand Canal in Wuxi,is considered in this thesis.Based on the regional hydrodynamic paths and controlling conditions of flow,the river network is conceptualized.Then the water quality model is constructed on the basis of MIKE11.The constructed model is elaborated and verified according to the measured hydrologic data and water quality monitoring data in the period of 2013-2014.The Morris method is applied to analyze the sensitivity of the major parameters of the model.Additionally,the GLUE method is used to analyze the uncertainty of the input data and parameters of the model.From the preceding calculation and analysis,the following conclusions can be drawn.Firstly,the MIKE 11 model has good applicability in the study area.Secondly,the riverbed roughness coefficient is the three-level sensitivity coefficient,while the diffusion coefficient is one-level,meaning that it is less sensitive than the former.The bigger the bed roughness values,the higher the simulated water level is.Finally,the uncertainty of COD stems from parameters N and D,and the uncertainty of TP stems from the diffusion coefficient D.Compared with COD,TP is more susceptible to the influence of the uncertainty of the input data.The uncertainty of water quality model of Liangxi River primarily results from the uncertainty of parameters.