Study On Optimization Of Water Environment Monitoring Section Based On Feiyun River Basin

With the rapid economic development,the water environment of my country has experienced a stage of poor water quality.After effective treatment,the current water environment has been improved to some extent,but further treatment is still needed.Surface water environment monitoring is the basis and premise in the process of water environment treatment.has an important position.Aiming at the problems of long-term arrangement of monitoring sections and repeated functions of monitoring sections,this study takes the water environment monitoring sections in Feiyun River Basin as the research object,and uses cluster analysis and improved matter-element analysis to optimize and analyze the monitoring sections.By collecting the basic data of the Feiyun River Basin in Ruian City,including the natural environment,economy and society,and the distribution of river systems,etc.,master the basic theory,basic methods,and future development trends of water environment monitoring section optimization.The Merrow pollution index method was used to evaluate the environmental quality of surface water in the Feiyun River Basin;based on the water quality monitoring data of each section of the Feiyun River Basin during the five-year period from 2016 to 2020,the principle of representativeness and the principle of field conditions was used to evaluate the environmental quality of surface water.p H,DO（dissolved oxygen）,COD_Mn（permanganate index）,BOD₅（biochemical oxygen demand five days）,NH₃-N（ammonia nitrogen）,As（arsenic）,petroleum,EC（conductivity）,Cu（Copper）,Zn（zinc）,TP（total phosphorus）,COD（chemical oxygen demand）,FL（fluoride）,TN（total nitrogen）and FCB（fecal coliform bacteria）,a total of 15 monitoring indicators were optimized and analyzed;Based on the optimization results of section monitoring indicators,the AHP is used to analyze various monitoring section optimization methods,and finally the cluster analysis method and the improved matter-element analysis method are selected for section optimization analysis of the Feiyun River Basin.The research results are as follows:（1）Analysis of Water quality of Feiyun RiverThrough the analysis of the water quality in the Feiyun River basin,the results show that the number of sections that meet the Class III water quality standard of the Surface Water Environmental quality Standard（GB3838-2002）in the Feiyun River basin is basically stable.There are 17 water quality monitoring sections in the Feiyun River basin,of which 71%of the sections can’t reach GB3838-2002 class III water.On the whole,the water quality of the section in the Feiyun River basin is gradually getting better.There is uneven distribution of water quality in the cross-section of the basin,and there is a great difference in water quality between different sections,in which TN is the main pollution index affecting the water quality of the basin.（2）Optimization analysis of monitoring indexBased on the analysis results of water quality monitoring data of Feiyun River Basin in 2020,the conventional water quality monitoring indexes were optimized and the main monitoring indexes were screened.15 conventional physical and chemical indexes including p H,DO,COD_Mn,BOD₅,NH₃-N,As,petroleum,EC,Cu,Zn,TP,COD,FL,TN and FCB were selected,and 15 indexes were optimized and screened by principal component analysis.Through the analysis of nine water quality monitoring indexes,including COD_Mn,BOD₅,NH₃-N,TP,COD,TN,DO,Cu and FL,the current situation of water quality in the study area can be accurately reflected（the total variance explained is 73.78%）.Therefore,the general situation of water quality in Feiyun River basin can be reflected by monitoring the above nine monitoring indicators.（3）Optimization analysis of monitoring sectionThe results of the two cross-section optimization methods show that the sections of Jiulihui,Luofeng,Qitan and Ximen need to be reduced.The results are tested by mean test（T test）and variance test（F test）.The results show that the optimization results are representative.Therefore,the comprehensive analysis suggests that the sections of Jiulihui,Luofeng,Qitan and Ximen should be cut,and the original 17 sections should be reduced to 13 sections.including:Baiyanqiao,Tangxia,Baowu,Nanfan,Panshan,Feiyun Ferry,the third Agricultural Station,Nankou,Ma Road,Caiqiao,Beimen,Fenghu Street and Dushantou.（4）Establishing a research system for cross-section optimizationThe study uses a variety of analysis methods and reasonably combines them to form a complete set of cross-section optimization analysis theory.firstly,Nemero pollution index method is used to evaluate water quality and the necessity of cross-section optimization.secondly,the principal component analysis method is used to optimize the monitoring index to improve the efficiency of subsequent cross-section optimization analysis.Finally,the monitoring indexes selected based on the optimization results of monitoring indicators are optimized by cluster analysis and improved matter element analysis.Using it for cross-section optimization can solve the problems existing in many river basins,such as repeated cross-section layout,low monitoring efficiency,unreasonable monitoring index and so on,and provide theoretical reference for cross-section optimization research.