Numerical Simulation Of Baiyangdian Hydrodynamics And Water Quality Based On MIKE 21

Baiyangdian Lake is located in the central hinterland of Xiongan New Area,Hebei Province,with a water area of about 300km².As the largest ecological wetland in the North China Plain,Baiyangdian Lake plays an important role in maintaining the balance of regional ecosystem,regulating the climate in the Hebei Plain and even the Beijing-Tianjin-Hebei region,and replenishing groundwater.In view of the complexity of the hydrodynamic regulation scheme and water quality change law of Baiyangdian Lake,the qualitative and quantitative analysis of the water exchange capacity and the spatial and temporal distribution characteristics of pollutant concentration can be carried out by means of mathematical simulation,thus providing scientific data support for the ecological water replenishment scheme and ecological restoration project of Baiyangdian Lake.In this paper,the whole Baiyangdian Lake was taken as the research scope,and the water replenishing period from September 2019 to June 2020 was taken as the research time.Based on the coupling of Mike 21 software,the Hydrodynamic Model and ECO Lab were established,and the conservative substance A was introduced to identify the trend of Baiyangdian Lake hydrodynamic changes.By observing the concentration fields of COD_Cr,NH₃-N,TP and TN to distinguish the trend of Baiyangdian Lake water quality,the main conclusions are as follows:(1)Compared with the current situation,the water exchange capacity of the planned water replenish scheme is significantly improved,which can improve the hydrodynamic situation of Baiyangdian Lake.However,the concentrations of COD_Crand TN are decreased,while the concentrations of NH₃-N and TP are increased,so there are uncertain factors affecting the water quality.pectively.(2)Compared with the current situation,the hydrodynamic situation of Baiyangdian Lake in the planned water quality scheme is exactly the same,and the concentration of COD_Cr,NH₃-N,TP and TN are all reduced,and the water quality is improved.(3)Compared with the present situation,the hydrodynamics and water quality of Baiyangdian Lake are basically the same on the macro level,the surface area of the upper lake area is increased on the micro level,the waterless area and the dead water area are reduced,and the local water exchange is more sufficient.(4)Compared with the current situation,the water exchange capacity of the planned water replenishment quantity,water replenishment quality and silt removal scheme in the district is significantly improved,while the concentration of COD_Cr,NH₃-N,TP and TN are significantly reduced,which can improve the hydrodynamic power and water quality of Baiyangdian Lake at the same time.