Study On Water Quality Monitoring And Water Quality Evaluation Of Rivers And Lakes Based On The Time Dimension

Recently,many rivers and lakes are facing with serious of water pollution and eutrophication.Water quality monitoring and water quality assessment as an important measure to protect the water environment,has been paid more and more attention.This paper is mainly focus on the water quality monitoring and water quality evaluation of the two aspects of the research.In the aspects of water quality monitoring and design,this paper studied from three aspects: automatic monitoring,routine monitoring and emergency monitoring,including the basic thought,principles and methods on the establishment of water quality monitoring indicators,monitoring frequency,monitoring instruments and monitoring points of the layout.The research found there are exsiting problems in the optimal method of layout of water quality monitoring points: first,just to consider the importance of temporal factor,while ignoring the changes about the importance of monitoring region because of the time factor;second,the result of clustering is poor while using the average monitoring data of every monitoring index;third,ignoring the influence of the weight of index to optimization of monitoring points.In this paper,the method has been improved by the combination of analytic hierarchy process and similarity to solve such problem.By the new methods,the monitoring data has been grouped according to the seasons,at last,we can get an optimization by dealing with every group of the monitoring data.Using this method to optimize the manual monitoring points,we can not only make full use of the flexibility of manual monitoring,but also reflect the importance changes of monitoring region.The result of the application to optimize monitoring point in a diversion channel turns out to be more practical.In the aspect of water quality assessment,the problem of the method of fuzzy comprehensive evaluation is studied,that is ignoring the influence of the seasons.This paper on water quality index weight vectors were improved and put forward the concept of weight matrix of temporal distribution.Using the analytic hierarchy process(AHP)to process the measured data of water quality for many years,calculating the weight matrix which can effectively reflect the changes of the importance of water quality index during years.Taking the newly-built Dragon Lake as an example,a water quality monitoring system is designed according to the methods proposed in the paper.Using new method to optimize the layout of the channel of Dragon Lake,and to assess water quality of every monitoring point,the results turn out to be more in line.These researches provide a more systematic direction for the management of water quality while playing a guiding role in the protection ? monitoring and management of water quality.