Study And Application On Donghu Lake Hydro-Ecology Network Engineering Dispatching Model

Currently,China is promoting fundamental shifts in the mode of economic growth and is stepping forward into a new development stage of resource-conserving and environmentally friendly society.In this new stage,the needs of water environmental restoration are changing greatly.The restoration practice in Taihu,Chaohu and Dianchi, proves that it should abandon the water restoration road of "Firstly polluted then restored and polluting as abating".Now,a restoration project of Donghu Lake is carrying forward to reestablish its hydraulic relations with the adjacent Yangtze River and to restore its water environment,and its aim is to explore a new lake restoration road that can promote shifts in the mode of economic growth.The water currents regime is the research basis of lake water environment and its influence comes from the meteorology,hydrology and many other aspects.The water quality,suspend transport and other process are determined or at least influenced by the lake currents,especially in the flat and shallow lakes.The project of Donghu hydro-ecology network will reestablish Donghu hydraulic relations with the adjacent Yangtze River.After the completion of project,Donghu hydrodynamic regime will change completely.How these changes influence the water environment of Lake Donghu? Is the inflow operation plan effective? To answer these questions,it needs to research and evaluate thoroughly in theory and technique.To study the inflow/outflow plan,a hydraulic operation model of Donghu hydro-ecology network is established.The model is running under the weather scenario of July and August 1978.For the evaluation of hydraulic reconnection with the Yangtze River,the model simulates different inflow/outflow plan of present status,reconnected status and dike-breaked status.Based on the simulation result,the current patterns,water renewability and water quality are evaluated.The dissertation includes two main parts.The first part is the establishment of hydraulic operation model of Donghu hydro-ecology network,which is based on the theory of lake hydrodynamic and using the concept of Donghu virtual boundary.The second part is the modal application under different inflow/outflow plan.The main innovations are summarized below.(1) The dike in the lake is generalized with the concept of thin plates to solve the problem of lake part.The inflow/outflow of Donghu hydro-ecology network is generalized with the concept of source/sink for the model simulation.(2) The hydraulic operation model of Donghu hydro-ecology network is established based on lake hydrodynamic theory and by using the concept of Donghu virtual boundary.(3) The tentative inflow/outflow is proposed for the project of Donghu dydro-ecology network.In the initial operation stage,only the outflow in Shaojihu and Shuiguohu are used.After 40 days,the outflow in Houhu is lead into the lake.After the water quality of all parts of the lake is improved,the dike should be altered with the bridge or culvert for the full function of Donghu hydro-ecology network.The research object is Donghu Lake,which is located in the humid area,and is very interesting in its distinctive regional feartures.The research can support the implementation and operation of Donghu hydro-ecology network in the theories and techniques,and it is very meaningful to the water environment restoration of the lake in Wuhan.