Water Quality Analysis And Prediction Research Of South-to-North Water Diversion Project In Beijing Section

South-to-North water transfer has become a main water source of Beijing as the coordinated development of Beijing-Tianjin-Hebei’s strong support.Study the change of water quality of the South-to-North water diversion, accurate evaluation of the influence of different water conveyance method for water quality, has important scientific value and practical significance.Based on the middle route of South-to-North water transfer project of Daning reservoir, Qi Lizhuang, Hui Nanzhuang and TuanCheng lake views as the research object, such as selection of Ammonia Nitrogen and Chemical Oxygen Demand (COD), Biochemical Oxygen Demand, Potassium Permanganate index (CODMn) Dissolved Oxygen (DO), Total Nitrogen, Total Phosphorus, Chlorine and other routine water quality parameters, using the observed data from 2008 to 2014, analyzes the different modes of water conveyance to the space-time change law of each index in water, the establishment of the Beijing section of South-to-North water transfer project water quality change model, and puts forward protection countermeasures of water quality, working for the South-to-North water transfer project water quality protection to provide comprehensive technical support, advanced and feasible.Main conclusions are as follows:(1) From the point of view of interannual variability, Qi Lizhuang, Hui Nanzhuang, Daning adjustable pressure pool and Tuancheng lake water quality in the selected period of time more obvious changes, from 2008 to 2010 the water quality index is relatively stable, from 2011 to 2013, the frequent changes, the 2014 appear relatively stable trend. That there is a direct relationship and each year the different water sources, from 2008 to 2013, respectively from the Huangbizhuang, Gangnan, Wangkuai, Engelhard Zhuang four reservoir water diversion,2014 began from the Danjiangkou reservoir water diversion. It should be noted that, in 2008-2010, water quality indicators showed an increasing trend, in 2011, the reduction of organic matter, and then in 2012, organic matter and showed an increasing trend.(2) From the point of changing seasons, Qi lizhuang, TuanCheng lake, Daning and Hui Nanzhuang observation point water quality parameters of seasonal change is obvious.Qi lizhuang observation point water quality index of the gradually decreasing trend with the seasons, especially in the 7-8 months, index decrease obviously, shows that the water quality can be attained with the seasons change gradually get better;TuanCheng lake water quality observation point in the trend of water quality index in spring and summer.Daning and Hui Nanzhuang during the observation period are of a similar change trend after two observation points in the early stage of the conventional organic pollutants increase, taking corresponding measures.(3) From the point of view of different water, dark culvert of pH value and the water temperature below the reservoir water and dark culvert space difference less than reservoir water, less susceptible to external environmental impact; dark culvert water Dissolved Oxygen,Chemical Oxygen Demand and Potassium Permanganate index below the reservoir water; water oxygen index system in Biochemical Oxygen Demand (BOD5) dark culvert pipe and reservoir water with little difference. Ammonia nitrogen element nutrition index of water quality, dark culvert and reservoir water difference is small, and dark culvert space difference less than reservoir water, reservoir water diversion way than the dark culvert way stronger nitrification; water nutrient elements in the total nitrogen content, dark way of the culvert is higher than that of reservoir water, dark culvert space consistency is higher; water nutrient elements in the Total Nitrogen content, dark way of the culvert is slightly higher than that of the reservoir water. But the dark culvert delivery process eased, and way of reservoir water conveyance is the opposite.(4)Using routine Daning reservoir water quality monitoring data in 2012 and 2010-2014 South-to-North water transfer project of Beijing section of the pipe culvert water quality monitoring data, the water quality security model of water transfer project, Daning reservoir tail first, in the library, library and validate Beijing section of the pipe culvert water quality model, the model calculated values and measured values are in good agreement, water quality simulation error within 30% accuracy, to achieve a better level.(5) Application of South to North Water Diversion Middle Route Project of the Beijing section of the water quality security model, the Daning reservoir and along the pipe culvert for water quality and safety analysis, establish the concept of comprehensive pollution index, the number of pollution indicators were analyzed, to conduct a comprehensive assessment of water quality. The year 2012, Daning reservoir comprehensive pollution index change interval is 0.43-1.38, library head and tail of the reservoir comprehensive pollution index are less than 0.8, the change trend is stable on the whole, to meet the requirements of surface water quality; along the pipe culvert, comprehensive pollution index is relatively high, in the future managers need to take targeted measures.(6) According to the present situation of water quality in Beijing, analyses the main risk of water quality of South-to-North water diversion project, and puts forward the relevant guarantee measures, method of risk prevention and emergency plan, to ensure the security of the south-north water diversion project of water diversion.