Optimal Selection For River Restoration Schemes Based On Experimental Design And Water Quality Simulation Model

River system is a kind of important ecosystem.It can provide human with productional water,domestic water and ecological water,and also maintaining material circulation and energy flow.With disturbance of human activities increased,there are some ecological and environmental problems in the river.And water pollution is one of the most serious problem,even affects the other connected rivers and lakes.In order to prevent or alleviate these problems,human began to take various river restoration measures.In order to make scientific judgment on the present situation of water quality,provide the basis for optimizing river restoration measures,and then make better choice of protection and management of rivers,Experimental Design methods and Water Quality Simulating models are integrated to assess those river restorational schemes.In this study,the city river,i.e.Shiwuli river is the research area.Through investigation of watercourse and water quality,the status of the Shiwuli River can be analyzed.By considering the actual characteristics of the Shiwuli River,hydrological and water quality models of Shiwuli River based on MIKE11(a kind of software of one-dimensional model)are build.According to comprehensive renovation program of the Shiwuli River,ecological water supplement,sewage interceptional engineering and wetland restoration are selected as factors.Different river restoration schemes are designed through the orthogonal experimental design method,and the water quality effects after restoration are simulated by using the water quality model then the sustainability index was calculated based on the results of the simulation.The results of orthogonal experimental design were analyzed by minitab software,and the optimal restoration program of Shiwuli River was selected.The main conclusions are as follows:(1)Through investigation of watercourse and water quality,it is found that there are black and odorous water body in some areas of the Shiwuli River and the riparian zone is mainly grown by natural plants.After water quality assessment,Shiwuli River is inferior?class water body.(2)Hydrological and water quality models are build based on MIKE11,and the parameters of models are calibrated and validated.It is found that the errors are reasonable and within rational ranges.It indicates that the model is suitable for application at Shiwuli River.(3)Different river restoration programs are designed by using the orthogonal experimental design.The changes of water quality indicators under different programs are simulated with the model.It is found that the water quality are improved after the restoration schemes at control sections(Xiwang Bridge and Jingtai high-speed road Bridge).(4)The sustainability index was calculated with the goal of?class water quality.The Minitab software was used to make range analysis and variance analysis based on the calculation results.The results showed that the river restoration scheme is the most effective way to improve the water quality of the Shiwuli River,when the total ecological filling water is 25 m~3/d,the percentage of pollutant reduction is 70%,and the wetland area is 260 ha(after constructed the Huizhou Road wetland and the Chaohu Lake wetland).