The Study Of Two-dimensional Flow-pollutant Mathematic Model Of Lake Jinshan

The quick development of economy and urbanization brings more and more industry and living waste water, which has polluted a majority of the lakes in our country. Now, protecting lake aquatic environment has no time to delay. The mathematic model of the lake aquatic environment is an important technique to protect lake aquatic environment for its ability to simulate the hydrodynamic characteristic of the lakes and the change rules of the water quality, and thus providing scientific reference for lake aquatic environment protecting work. "Lake Jinshan" construction project is a part of the significant special technological project of our country's tenth five-year plan—"ZhenJiang aquatic environment quality improving and ecology restoring technology study and synthetic demonstration". The construction of Lake Jinshan will improve the aquatic environment quality of ZhenJiang City and gradually ameliorate the ecologic system, which can provide model for the aquatic environment management for other cities near rivers. Basing on the status quo and the outlook of the lake flow-pollutant mathematic model development inside and outside of our country, associating with the "Lake JinShan" construction project, a two-dimensional flow-pollutant mathematic model is established which is disseminated by finite element method. To the conflict between long term property of the water quality changing between long time needed for corresponding mathematic simulation, the uniformity of the flow-velocity, area of the backwater section and the rate of the water replacement are used as the criteria to distinguish which water circulation mode is best, those criteria can reflect the changing trend of the water quality. By simulating the two-dimensional hydrodynamic characteristics and the change rules of the water quality of Lake Jinshan under different situation, the import water location and the quantity of the import water are optimized, the influence of the water level and landforms on the flow field of Lake Jinshan is analyzed. Basing on the simulation results of the impact of point pollutant, non-point pollutant and import water on Lake Jinshan's water quality, and the one year's change of the lake water quality during design hydrologic year, aquatic environment protection measures, the aquatic ecologic system construction and the best times and the quantity of the import water of one year are brought forward, thus provide scientific reference for the construction of Lake Jinshan.