Water Environment Analysis In Yuqiao Reservoir Influenced By Contamination Accident

The Yuqiao Reservoir, an important adjusting reservoir in the project of diverting water from the Luan River to Tianjin City, functions as the water resource for the water supply of drinking, which bear the burden of supplying water for Tianjin, is the origin of social and economic development in Tianjin provides important material base for the Sustainable Development of Tianjin. The water quality is one of the important factors which affect social stability and economic development of Tianjin.In recent years, The quality of the source water became worse obviously, water pollution problem is more and more prominent, the reservoir eutrophication aggravation with the changing of water environment conditions in the reservoir surrounding area, like the aggravated non-point source pollution and the increased nutrient salt loads of upstream and so on.The paper set the backdrop of the current situation of drinking water source environment in Tianjin, based on the Yuqiao Reservoir area, make full use of existing data, estimate the agricultural non point sources pollution the bridge agricultural non-point source pollution conforms to the Yuqiao Reservoir area; And water supply, water demand structure and the status quo of Tianjin is analyzed, at the same time, in combination with the practical situation of reservoir and improve the security of water supply and do model analysis by using the established coupling model of hydrodynamic model and water quality model analyses of hydrodynamic coupling water quality model, supply the management and operation for the safe operation of the reservoir and the downstream of the urban water safety.The specific research results are as follows:1. Using the method of improved standard farmland and discharge coefficient method of reservoir area to estimate the agricultural non-point source pollution load. Calculation results show that the seven townships in the Yuqiao Reservoir area of non-point source pollution in 2008 total nitrogen(TN) 45.86 t, total phosphorus(TP), 9.28 t respectively. The largest proportion is rural life pollution load, total nitrogen(TN) 53.7%, the total phosphorus(TP) 68.6% respectively; Livestock farming produce second pollution load.2. According to the simulation results of different working conditions of non-point source pollution to input the conclusions:(1) During the flood season, the highest total nitrogen content of the Yuqiao Reservoir is in September, the lowest total nitrogen content of the Yuqiao Reservoir is in August. Subjected to wind current library body surrounding water quality affected by pollution.Liu-Xiang ying, Wu-Bai hu Towns and Huo-Jia dian is the main flow for nitrogen pollutants into the Treasury. The minimum total phosphorus content is in September, the highest for the total phosphorus content is in July. The spatial distribution of the trend shows east high west low. The south of reservoir body is the mainly entrance of the total phosphorus.(2) During the flood season in the years of flooding, under the effects of flood runoff scour, pollution load increased significantly. But keep the reservoir of high water level operation can make the flow velocity reduced, a large number of pollution load under the dilution and sedimentation of a large amount of water, will be reduced at a rapid rate, make the quality of the outbound water improve a lot than input water, which can ensure the safety of the flood season of downstream water supply.(3) In the torrential rain period, because of the scouring and leaching of heavy rain on the surface, makes a lot of non-point source pollutants with rainfall runoff into the treasury; Due to heavy rains concentrated during rainfall, under the huge input water flow action of hydrodynamic, pollution will affect the reservoir internal quickly, pollution area range will enlarge under the action of wind field in the later.