Evaluation Of Water Pollution Control Measures In Yanghe Basin Based On MIKE SHE Model

Water shortage and water pollution have become the main water environment problems in the Yangtze River Basin,which not only restricts the local economic development,but also becomes a major obstacle to the construction of a water source ecological conservation area in the northwest of Beijing,Tianjin and Hebei.In order to match the water resources demand for the coordinated development of Beijing,Tianjin and Hebei,the 2022 Winter Olympics will be held smoothly to ensure the safety of water supply to the Beijing-Tianjin region and solve the water environment problems in the Yangtze River Basin.In this paper,the MIKE SHE water environment model is used to simulate the hydrological process and water quality of the Yanghe River Basin.The basic scenario construction of the Yanghe River Basin under the three inflow conditions of rich,flat and dry water is completed,and the three inflow conditions are simulated separately.The pollution control effect of the four water pollution prevention and control measures,and evaluation of the following conclusions:(1)Analyzed the pollution load and water environment status of Yanghe River Basin.In 2014,the largest contribution rate of pollution load was urban domestic pollution,with COD entering the river 5363.13 tons,NH3-N entering the river 536.05 tons,and TP entering the river 66.94 tons;the largest contribution rate of non-point source pollution was rural domestic pollution.The amount of COD entering the river was 2673.35 tons,NH3-N was 366.63 tons,and TP was 27.13 tons.The water quality of the Sanggan River in the upper section of Bridge No.8 is better than that of the Yanghe River.The main pollution factors are COD and TP.(2)Based on the meteorological and hydrological data,digital elevation model(DEM),soil type map,land use map,hydrogeological data,and water quality of the Yanghe River Basin from 2013 to 2014,the Yanghe River Basin was successfully constructed Hydrological and water quality model,and the Manning coefficient of slope flow,the saturated water content and saturated hydraulic conductivity of the main soil in the unsaturated zone,the horizontal and vertical hydraulic conductivity of the saturated zone,unit water production,unit water storage,river flow The roughnessof the riverbed,the leakage coefficient of the channel and the reduction coefficients of the three pollutants were determined.(3)This paper divides the hydrological years of abundant,flat and dry water into the water inflow conditions in Yanghe River basin,and simulates three basic situations of water inflow conditions.Based on this,the effects of four kinds of water pollution control measures demonstration projects are simulated and evaluated.The results show that the low-temperature river wetland project is more effective in four demonstration projects.The COD and TP compliance rates in normal water years were raised to 66.7% and 66.7%,the COD and TP compliance rates in high water years were raised to 50% and 50% respectively,and the COD and TP concentrations in low water years were significantly reduced but still not up to the standard.After the integration of the four demonstration projects,the water quality of no.8 bridge is still not up to the standard.(4)for simulating the water pollution prevention and control measures applied,and comparison,cold river wetland effect best,four types of water pollution prevention and control measures in different extent of yanghe no.8 bridge section water quality promotion effect,including low temperature river wetland technical effect is most obvious,and farmland water pollution control technology is the worst.The four kinds of water pollution prevention and control technologies could not reach the standard of COD and TP in the dry year,and could not achieve good effect in the control of TP concentration.(5)Four combined application schemes of water pollution prevention and control measures were designed and simulated.Finally,among the four schemes,scheme 4had the best effect,while scheme 1,2 and 3 could not reach 100%.The effect of plan 2and 3 is close to that of Plan 4.Considering the stability of water pollution prevention and control measures,plan 4 is a better choice.