Research On Water Quality Change Characteristics Of Plain River Cross-section-taking Haniiang River Fork South Cross-section Of Ancient Canal As An Example

The development of Yangzhou is closely related to the development of the Yangzhou Canal.The canal nurtures Yangzhou,which is the "root,of Yangzhou,and water is the "soul" of the canal.Not only must there be water,good water quality is also necessary.The Yangzhou section(urban area)of the ancient canal is 29.3km long from Guazhou to Wantou,and there are many surrounding residential areas,as well as many industrial enterprises and some farmland.The southern section of the Fork of the Oujiang River in the ancient canal is located south of the Sanjing River of the ancient canal.It is 4.5km upstream of the Guazhou Sluice..The section is the main section of the Yangtze River’s main urban water system(Ancient Canal-Yiyang River)into the Yangtze River.The water quality at the southern section of the Minjiang River fork louth directly determines the quality of the water entering the Yangtze River.The water quality status of a river section is usually determined by factors such as the upstream water flow and water quality,and the load of pollutants entering the river.Because river sections usually use their compliance standards to determine their water quality,this article mainly focuses on water quality analysis,pollution cause analysis,Water environmental capacity analysis and calculation,model construction and analysis of water quality standards are considered.The meanings of DO,COD,BODs,TP,and NH3-N are detailed in the symbol description.The main research results of the paper are as follows:(1)Investigate the current status of emissions from different pollution sources,Predict the amount of pollutants entering the river in the future,and find that for different pollutants,the proportion of each pollution source is very different,and the proportion of internal sources in each pollutant is very small,which can be almost ignored For COD and BOD,.point sources account for more than 50%and non-point sources account for about 40%.For TP and NH3-N,non-point sources account for the vast majority of total pollutants.Therefore、for COD and BOD5.point and non-point sources are the main sources.For TP and NH3-N,non-point sources are their main sources.Therefore,to reduce COD and BODS,it is necessary to reduce both point and non-point sources.TP and NH3-N,and mainly reduce non-point sources.Internal sources have little effect.(2)By analyzing the time-varying characteristics of the water quality of the four sections of the ancient canal,the frequency calculation and analysis of the pollutant concentration,the correlation between the water quality indicators between adjacent sections and the correlation between different water quality indicators,and the combination of the upper and lower sections Determine the control indicators for water quality compliance,and analyze the frequency of pollutant concentrations.It is found that for COD,the compliance rate of each section is higher than 90%;for BODS,it is found that the compliance rates of sections 1 and 2 are higher.Above 95%,the compliance rate of sections 3 and 4 is medium,and above 80%,but the difference is not large;for TP,the compliance rate of sections 1 and 2 is extremely high,both above 96%,and sections 3 and 4 The compliance rate is medium,above 70%,but there is not much difference between them.It is found that for NH3-N,the compliance rate of sections 1 and 2 is extremely high,both are above 88%,and the compliance rate of sections 3 and 4 is low.Above 55%,but there is not much difference between the two.The actual compliance rate of each section is in good agreement with the frequency calculation compliance rate.(3)Analyze and calculate the design hydrological conditions.When the frequency is 75%and 95%,the calculated design flow calculated by dividing the measured flow of Siyuangou Sluice and Guazhou Sluice is smaller than the calculated design flow.It is determined that the design flow is much smaller than the design flow derived from the measured flow data,because the measured flow data includes the Shaobo Lake water introduced by the Yangzhou Sluice;the difference between the water environmental capacity calculated by the direct method and the indirect method is relatively large,and the water environmental capacity and flow The assumption that it is the same frequency does not hold true;the water environment capacity calculated directly by the river as a whole is larger than the value of the piecewise solution.This article finally uses the piecewise solution result(4)The established hydrodynamic model simulates the change of discharge of the ancient canal.The measured value and the simulated value of the water level are fitted to the simulated value.It is found that the fit is good and the simulation results meet the requirements.It can be used to simulate the discharge and water level of the ancient canal.Analyze the annual water environmental capacity and the alount of pollutants entering the river at different levels,and obtain the reduction amount of each pollution source.Based on the analysis of the current year,five schemes are proposed fron three aspects:poilit source,non-point source,and water diversion.Finally,plan 5 is feasible.Sex.An analysis of the reduction potential of various pollutants shows that the annual level of pollutants can be reduced at various levels.