Application Of 1D And 2D Coupled Hydrodynamics And Water Quality Model In The Controlled River Of Sluice

Human activities have caused a certain impact on the ecological environment.The deterioration of water quality in rivers,lakes and oceans has become a prominent environmental problem in China.In predicting and treating water pollution,it is necessary to master the change rule of pollutant with water flow.Fen river is the largest river in Shanxi Province,along which there are many cities,factories and irrigation areas,which are of great significance to the social and economic development of Shanxi Province.At the same time,there are rubber DAMS,slugs and many other buildings to prevent water in the urban river section,forming a natural landscape.In order to deal with the adverse effects caused by water pollution events,it is necessary to conduct an in-depth study on the hydrodynamic characteristics of fenhe sluice-controlled reach and the rule of pollutant migration and diffusion.This article USES the MIKE software,in order to control the premise of fen river Er Ba storage level maintain normal storage level,for the distribution of the upstream fenhe Er Ba two abnormal discharge sewage plant,considering the river to flow,sewage,entrance location and emission concentration three influence factors,set up six computing,simulate the hydrodynamic characteristic of the brake control section and the migration of chemical oxygen demand(COD)concentration change law,the paper research mainly include:1.A two-dimensional coupling hydrodynamic water quality mathematical model was es Tab.lished in the research area,and the simulation process of flood evolution and the calculation effect of constant flow were verified and analyzed by using the measured hydrological data and theoretical analysis methods respectively.The relative deviation of the model was within a reasonable range,and the simulation results of the coupling model were believed to be reliable.2.Collected and sorted out the hydrology data of the research area and the sewage discharge data of A and B sewage plants,and the ecological base flow,the flow volume of fen river and xiaohe river was 3.75 m3 / s and 0.22 m3 / s respectively;Under typical flood conditions,the peak discharge of fenhe river and xiaohe river is 97m3 / s and 10m3 / s respectively.The discharge rates of sewage treatment plants A and B were 5.56m3/s and 6.62m3/s,respectively.The normal discharge concentration was 30mg/L,while the abnormal discharge concentration was 100mg/L and 200mg/L.Scenario 1 and 2 correspond to the ecological base flow,and the pollutant discharge concentration of plants A and B is 200 mg/L.Scenario 3 and 4 correspond to the typical flood,and the pollutant discharge concentration of plants A and B is 200 mg/L.Scenario 5 and 6 correspond to the ecological base flow,and the pollutant discharge concentration of plants A and B is 100 mg/L.3.The following conclusions can be drawn from the analysis of flow characteristics of river reach in the study area:(1)Ecological base flow.Under the condition that the gate is opened with two holes,the average gate discharge and gate opening of the second dam sluice are 16.05m3/s and 0.15 m respectively;The overall flow velocity in the backwater area of the second dam sluice is small,the flow velocity in the main flow area is 0.019m/s,and the flow velocity in the exit position is the largest,which is 0.21m/s.Plant A drainage has A great influence on the river flow field,forming A clockwise circulation with an influence range of 270-300 m.(2)For typical flood,under the condition that the gate is opened with six holes,the gate discharge rate of the second dam sluice is basically matched with the gate regulation process,and the maximum gate discharge rate and gate opening rate are 139.89m3/s and 0.4m respectively.The upstream flow velocity of the backwater area of the second dam sluice is larger,while the central flow velocity is smaller.The maximum flow velocity at the exit position of the sluice is 0.59m/s.Plant A's drainage has little influence on the flow field of the river,and only has A certain influence on the flow field within A range of about 40 m near the sewage outlet.4.The following conclusions can be drawn from the analysis of pollutant transport rules in river reach:(1)In the case of scenario 1,2,5 and 6 ecological base flows,the pollutants diffuse in a radial manner around the high concentration pollution point,and move down slowly in a mass,with diffusion playing a leading role;In the case of typical flood,the high concentration of pollutants is mainly distributed close to the riverbank,and the concentration gradually decreases to the middle part of the river,and the pollutants move down rapidly in a band,which is because the convection plays a leading role.(2)Large river flow is conducive to the rapid discharge of pollutants from the second dam backwater area,reducing the concentration of pollutants.Compared with the inflow and outflow of ecological base flow in scenario 1 and 2,under the typical flood conditions in scenario 3 and 4,the discharge time of pollutants from sluicing holes in plants A and B was 19.83 h and 35.16 h ahead of schedule,respectively,and the peak concentration decreased by 14.19 mg/L and 3.32mg/L,respectively.(3)When the water flow conditions and abnormal discharge concentration are the same,the pollutants of plant B far away from the second dam stay in the backwater area of the second dam for A long time,and the area of the polluted water area of the second dam backwater area and the water area of the five types of inferior water quality caused by its discharge are both increased compared with the corresponding area of plant A.(4)Under the condition of the ecological base flow to flow,reduce the abnormal emission concentration of pollutant discharge time is affected,but makes the concentration of pollutants out of the gate and Er Ba backwater reach high levels of pollution area reduced obviously compared with the scenario one,two,five and six from the peak concentration of COD were decreased by 15.57 mg/L and 9.53 mg/L,Er Ba streamwise worse five water quality water area has fallen by 57.48% and 61.69%.(5)Computing scene Er Ba downstream of sluices in the cross section of the typical concentration caused by abnormal discharge wave gradually temple,size and high concentration of pollutants from the pollutants concentration effect point of view such as time,scene of A pair of Er Ba downstream of the river water environment caused by the bad influence,the largest Er Ba Yi Tang whole river all have more than 5 kinds of water quality period,qing xu cross section and section qixian period of more than 5 kinds of water quality of inferior quality,were 5.50 and 4.50 h h,time needed for A factory to Yi Tang pollutant migration section 116.00 h.