Traceable Model Of Water Quality And The Control Countermeasures Of Eutrophication In Shihou Lake

Shihou Lake is one of the most typical lakes in the Baiyang Lake. It is difficult.to protect its aqueous environment because the lacustrine and swampy environment is interdependent in the area. The environmental protection draws much attention of the national and local governments owing to its pivotal location. Recently, some measures were carried out to protect and recover environment of Baiyang and Shihou Lake, such as upstream sewage control, industrial pollution treatment, wetland protection and ecological restoration. However, these measures did not change the negative effect of eutrophication on environment. Therefore, it is urgent and important to research cycles of nutrient pollution sources and the traceability and response model of water quality in Shihou lake. Countermeasures about controlling eutrophication would also be got from these findings.Based on monitoring and evaluation of aqueous environmental quality and pollution sources, this paper investigated migration and diffusion of contaminants in Shihou Lake and built a response model of water quality by using linear regression methods. Countermeasures were also proposed to control eutrophication according to surrounded natural environment and socio-economic conditions. The conclusions were listed as follows:(1) Systematical monitoring on aqueous environment and quantitative evaluation on eutrophication in Baiyang and Shihou Lake showed these two lakes had severe eutrophication. Total nitrogen and total phosphorus were the dominant factors of eutrophication. They mainly came from surrounding residents, aquaculture and sediment in the lakes.(2) Characteristics on pollution sources of Shihou Lake were researched by survey, monitoring and analysis of domestic pollution source, aquaculture source and sediment. The type, load, production and polluting process of major contaminants were quantitatively determined.(3) Migration and diffusion of these contaminants in Shihou Lake was revealed. Domestic pollution source and aquaculture source were analyzed according to hydrodynamics and input characteristics of pollution sources. Two-dimensional diffusion model of pollutants were built to simulate and calculate contribution rate of two types of pollution sources to water quality in the lake. Nitrogen and phosphorus exchange characteristics within sediment-water interface with the influence of concentration gradient were also studied. Thereafter, migration and transformation of nitrogen and phosphorus in the overlying water-interstitial water-sediment systems were revealed.(4) Water quality response model based on source control was built. It was proved that the model has good practicability by carrying out regression analysis on different flow field when combined this model with velocity field, as well as verifying using measured data on aqeuous quality of Shihou Lake.(5) The measures of preventing and controlling eutrophication in Shihou Lake were studied. According to pollution source characteristics and natural and socio-economic conditions of Shihou Lake, methods of domestic and international lake eutrophication control were adopted. Meanwhile, the effective treatment countermeasures were put forward to guard against pollution from domestic and aquaculture sources, sediment respectively, with the application of economic and technical and system analysis method. The results provide a theoretical foundation for comprehensive improvementof Shihou Lake.