Numerical Simulation On Hydrodynamics Of Qilihai Lagoon For Ecology Environment Renovation In Changli

The quality of water environment influences directly the development of thewater landscape. Considering the water environment factors into the process ofplanning, some bad water environment problems, such as poor water exchange andwater quality deterioration, can be avoided by making a hydrodynamic and waterquality analysis on form design and control measures. In order to make a feasibilityanalysis on planning scheme, the3D numerical model simulating hydrodynamics andwater quality of Qilihai lagoon is established.The numerical model is verified by measured data. The calculation value agreeswell with measure data, so the numerical model is practical and effective.We make an analysis on flow field of planning scheme. The results show that theflow flows from inlet to inside of lake and no circulation flow during the flood and itflows from inside to inlet and no circulation flow during the ebb.We make an analysis on water exchange of planning scheme. The results showthat the water exchange volumes vary with the flood and the ebb. The water exchangeis quick near the inlet and slow in the lake center.We make an analysis on sediment deposition of planning scheme. The sedimentdeposition happens at the junction between inlet and inside of lake, the depositionthickness is lower than0.4m. The scour happens at the inside of inlet, the maximumscour thickness is0.5m.We make an analysis on pollutant dispersion of planning scheme. The resultsshow that the pollutants diffuse from point source to two sides (the east and westsides). One side, the pollutants diffuse toward inlet and the diffusion distance varywith the flood and the ebb. The other side, the pollutants diffuse along northwestshores, flow into the main lake and take the semi-ringlike appearance.