Study And Application Of Plane 2D Flow-quality Couple Model In Oujiang Estuary

Oujiang River, which is the second river in Zhejiang Province, is located in south of the Province and converges to the East China Sea through Wenzhou City. In order to develop the Wenzhou city from a riverine city to a coastal city, it was put forwarded that the South branch of Oujiang Estuary should be jamed since the 1970s. The implement of the project will change the water flow movement and the water environment. Therefore, building the plant 2D flow-quality in Oujiang estuary, which can be used to analyse the changes of the water environment, is of great significance for the water environment protection in Oujiang Estuary and sea area near. The main contents and results discussed in this paper are as follows:(1) The basic principles and the calculation methods of the hydrodynamic model and water quality model were studied. The Delft3D hydrodynamic model and the water quality analysis simulation program 5 are selected to simulate the water quantity and water quality in Oujiang estuary respectively.(2) The hydrodynamic model and the quality model were verified which use the data of tidal levels, velocities and water quality concentrations. Results shows that the precision of the hydrodynamic model and the quality model which we have built are well and can be used to simulation the water environment in Oujiang estuary area.(3) The water quality analysis simulation program 5 provide a joint of hydrodynamic data. After we calculate the water level and velocities of grid nodes used the hydrodynamic model, the water level, velocities in segment and the flow between segments can be calculated by interpolation method. Based on the changes, the plant 2D flow-quality in Oujiang estuary would be build.(4) With the implemention of the project, the changes of contamination zone around discharge outlet and the effects on the water environment in water area nearby were studied. Both east jammed and the west jammed would increase the contaminated areas, and the east jammed larger than the west jammed. The results can be used as references for the comparison and selection of the project which include the east jammed and the west jammed.