Water Environmental Capacity Analysis Of Shijiazhuang Section Of Hutuo River Based On MIKE 11 Hydrodynamic Water Quality Model

In recent years,the shortage of water resources and the problems of water environment have become increasingly prominent in China,which seriously restrict the rapid development of economy.River water environment capacity reflects the supporting effect of water environment on economic development and the reaction of economic development on water body,which is an important basis for establishing water environment management system in sustainable economic development.In view of this,this thesis takes Hutuo River Shijiazhuang section as the research object,uses comprehensive water quality evaluation method to analyze the water environment quality of the river.According to the basic situation investigation,such as hydrology,pollution source in the study region using MIKE 11 hutuo river hydrodynamic-water quality model was constructed,on the basis of the rate constant of model parameter,using a one-dimensional water environmental capacity model,estimate the Hutuo river target pollutants altogether,level period and the mutagenicity of water environmental capacity,and the comparision of the amount of pollutants into the river in the study area,determine the cutting quantity of pollutants,Some suggestions on"increasing capacity and reducing emission"of effluent environment were put forward to provide theoretical basis for pollution prevention and control research in the study area.The main contents and conclusions are as follows:（1）The water quality of Shijiazhuang Section of Hutuo River is generally poor,and TN in all sections is the main pollutant exceeding the standard,which is in the inferior V standard.The water quality of the study area varies significantly in space.The water quality of the upper reaches of the main stream of Hutuo River is slightly polluted,and TN is the only excessive factor,however,the water quality of the downstream is Moderately polluted state.The water quality of Xizhuang Water Station and Longquan Solid water Station is the worst,which is severely polluted,and COD,NH₃-N and TP are the main pollution factors.The variation of pollutants in huangzhuang water station,Xizhuang water station and Longquan solid water station is obvious in different water periods,while the variation of pollutants in other sections is not obvious in different water periods.The water quality of the tributaries of Hutuo River is generally good,and the variation of COD,NH₃-N,TP and TN in different sections is small.（2）The output coefficient model was used to calculate the inflow amount of main pollutants into the river in 2017 in the study area.The inflow amount of COD was the largest,9327.86t,followed by TN,NH₃-N and TP,which were 5953.85t,403.50t and153.21t,respectively.According to the pollution load of each district and county in the study area,the amount of pollutants into the river in Zhengding County,Gaocheng District and Wuji County is large,accounting for 45.2%of the total amount of pollutants into the river in the study area.From the source of pollutants,the main pollution sources of the upper Hutuo River are livestock and poultry breeding and agricultural cultivation,while the main pollution sources of the lower Hutuo River are urban living and agricultural cultivation.（3）The hydrodynamics-water quality model of the study reach was established,and the measured values of the south and micro-water sections were selected to calibrate the model parameters.Re and Ens of the discharge were 8.46%and 0.891,respectively,and Re and Ens of the water level were 6.62%and 0.923,respectively.The model fitting effect was good,which could provide good hydrodynamic conditions for water quality simulation.The simulation errors of COD,NH₃-N and TP of water quality simulation components are all within the acceptable range and have high accuracy,which can reflect the actual temporal and spatial variation of pollutants（4）The study area was divided into 12 control units.One-dimensional water environmental capacity model was used to calculate the water environmental capacity of different water periods in 2017.The water environmental capacity of COD,NH₃-N and TP in the study area was the largest in wet season,followed by normal season and dry season.Combined with the target amount of pollutants into the river in the study area,the reduction amount of each control unit is determined.The pollutants that need to be eliminated are mainly concentrated in the corresponding control unit of the main stream of Hutuo River from Section 5（Sanshengyuan Bridge-Huangzhuang Water Station）to Section 9（Longquan Gushui Water Station-Mapucun water station）.In view of this,on the basis of determining the main pollution sources,this thesis puts forward specific suggestions on"increasing capacity and reducing emissions"of water environment...