Study On Improving Characters Of Flow And Water Quality In Nansihu Lake After South-to-North Water Diversion And Pollution Control Technology In Lakeside Zone

Based on the analyzing and summarizing the achievements of the previous studies, this thesis continued a deeper study than before focused on the Nansihu lake that would be an important impound lake in Shandong Province. The study was suitable for the Eastern Route Project (ERP) in Shandong Province.The thesis combined the South-to-North Water Diversion Project with the ecosystem character of Nansihu Lake closely. Started with the research on ecological effect mechanism, the thesis studied and analyzed the change of the flow and water quality characters in Nansihu Lake before and after water diversion, the regular effect and optimum distribution of the constructed wetland, the technologies of the water quality protection in lakeside zone. The study also based on water diversion theory, hydrology and water resources theory, hydrodynamic theory and ecology theory.In the paper, water quality protection system was provided pointed to the pollution character of ERP in Shandong Province. The system would be systemic, effective, dependable and economical, also would be very significant for pollution treatment of ERP.The drag term about the effects of aquatic vegetation on flow was introduced into the depth averaged 2-D hydrodynamic model. The thesis simulated the fluid field distribution of every working condition when the flow direction reversed in the lake .The results solved a series of problems that need prompt solution of the water diverting project design. The achievements were applied directly to the design decision of the water diverting project, directed the layout and design of subsidiary projects. In a word, the results would be good references to the Running and Management of water transfer through the lake.In this paper, the distribution of pollutants concentration field before and after water transfer in the Nansihu Lake was analyzed and studied. Moreover, it was predicted that the pollutants reduction throughout the lake, strengthened the pollution treatment. The water quality flowed out of the lake was simulated and the functional districts of water environment were partitioned. All these results would provide the scientific basis for working out reasonable implementary scheme of pollution treatment of Nansihu Lake Basin, the artificial wetland constructing at the entrances of the rivers into the lake and the constructing of the riparian ecosystem rehabilitation engineering. Furthermore, anecological model of fuzzy synthetical judgment was provided. The vibrations of the model included factor set(U),evaluation set(V) and fuzzy relation(R) relating to the ecological factors such as lights, temperature, soil, water and human disturbance based on the fuzzy mathematics theories.In order to study the self-purification principles of pollutants entered the lake, the experimental research on the constructed wetland at the entrances of the rivers into the lake based on the pollution control planning of EPR was implemented. The biodegradation capability of the wetland to remove the pollutants such as COD, BOD5, TN, TP in the waste water which meet the National Wastewater Integrated Discharge standard was discussed, hi addition, the experiment results taken as parameters, further study was done on the place that the wetland was constructed, the width and the ability of the wetland to remove the pollutants. It was also analyzed the main design parameters of the wetland ecosystem and the biodegradation principles of pollutants in the diverted water. Accordingly, the achievements mentioned above would provide the theoretical and practical basis for the Water Pollution Control Planning putting into effect of ERP.