Study On Dynamic Water Environment Capacity Based Onmike11 At Shapotou District,Zhongwei City(South Of Yellow River)

The water environment capacity is the basis and basis for rational planning of water resources.With the development of industry and urbanization,the problem of water pollution is becoming more and more serious.In order to use water resources for social and economic construction reasonably and effectively,it is neeessary to calculate the water environment capacity in order to provide a basis for environmental management.Based on the investigation and analysis of the current water quality of the drainage ditch in the south of the Yellow River in Shapotou District of Zhongwei City and the economic and ecological factors of Shapotou District,the chemical oxygen demand(COD)and amnonia nitrogen(NH3-N)are determined.The daily biochemical oxygen demand(BOD5),total phosphorus(TP),permanganate index(CODMn),fluoride and volatile phenol were the main pollutant indicators in the study area,and the characteristics of different water quality models and water environment capacity calculation methods were analyzed.Based on the coupling of rainfall runoff modiile,hydrodynamic module and water quality module in Mikell,the riverbed roughness and pollutant degradation coefficient of the drainage ditch in the study area were determined.The drainage of the area south of the Yellow River in Shapotou District based on Mike simulation results was studied.The main results of the research on the dynamic water environment capacity of the ditch are as follows:(1)According to the analysis and comparison of the characteristics of QUAL,Mike,WASP and other water quality models,aceording to the research area is the plain irrigation area,the Mike 11 model is used for water quality simulation,and the flow section standard calculation method in the one-dimensional water environment capacity model is used to calculate the water environment,capacity.(2)According to the Ningxia Water Resources Bulletin,the main pollutants in the drainage ditch in the last ten years are selected from seven pollutants such as COD,NHa-N,BOD5,TP,COOMn,fluoride and volatile phenol to evaluate the pollution of the water body.The measured data analyzed and evaluated the water quality of the drainage ditch,and the overall pollution was serious.The distribution of pollutant concentration in the whole basin was produced and analyzed by ArcGis.(3)According to the analysis and evaluation results and the data collation,the COD and NH3-N pollutant indicators were selected to construct the water quality model.The combination of Mike 11 and water environment capacity was used to integrate the data into the Mike 11 rainfall based on the basic information collected.The flow-coupled hydrodynamic model and the simulation of runoff have achieved good results.Based on this,the AD parameter file and the water quality boundary file are set up to construct the rainfall-flow-hydrodynamic-water quality coupling model to obtain pollutants in the water body.Time and space distribution.(4)Using the flow,flow rate,and pollutant concentration data in the calculation results of Mikell,a water environment capacity model based on Mikell was established Calculated by model and algorithm:a,the hydrodynamic roughness value is 0.03,the COD degradation coeflBcient in the water quality model is 1.68×10-6s-1,and the NH3-N degradation coefficient is 1.31×10-6s-1;b.The average water environment capacity of the drainage ditch NH3-N calculated from the water environment capacity is 10991.29 g/d on March 16,-18601.98 g/d on May 9,15732.44g/d on June 24,and November 26th.240.10 g/d;COD average water environment capacity is March-15849.46 g/d,May 9 158062.89 g/d,June 24 45177.89 g/d,November 26 556450.17 g/d,different locations The water environment capacity varies from period to period,and the dynamic changes of different space-time water environment capacity are obtained through the model.Based on the study of hydrological conditions and water quality conditions in the river section,this study studies the dynamic model of water environment capacity to provide technical support for regional water quality safety and comprehensive water environment management.In line with the current research of the smart watershed,it can provide some reference for the development of the smart watershed.