Study On Water Environment Quality Evaluation Of Minjiang River Based On Spatial And Temporal Data Analysis

The surface water environment of the river basin is in the changing time and space.Therefore,it is necessary to study the temporal and spatial integration of the water environment dynamics by considering the temporal and spatial dimensions of the surface water environment.Based on the temporal and spatial data analysis meth-od,the water quality of the surface water is analyzed from the water quality and pol-lution sources,which provides a reliable decision basis for effective understanding,control of surface water pollution in the watershed,scientific evaluation and devel-opment of regional implementation measures.Based on the data of 19 water quality monitoring sections of Minjiang River Basin from 2014 to 2015 and the social,eco-nomic and pollutant discharge of 36 administrative units within the Minjiang River Basin,this study is based on the time,space and pollution The temporal and spatial characteristics of the surface water environment and the various factors influencing the water quality were analyzed.Take Minjiang river basin as the study object and the main study contents:(1)The self-organizing map(SOM)and Principal Co-mponent Analysis(PCA)are used to make a comprehensive assessment on watershed surface water quality:The spatial and temporal characteristics of watershed water quality are exp-lained by using the self-organizing map neural network and principal compone-nt analysis.The water quality samples are divided into three space groups,and the water quality change period is divided into two Stage:April to November and December to March of the following year.PCA analysis showed that the tributaries of Shaxi and Futunxi tributaries in the spring and winter,and the lower reach of the Minjiang river,Fu-zhou urban areas have a higher nutrient stratifucation,while the organic pollution is higher in the part of the river in the upper reaches of the spring and summer and the lower reaches of Minjia-ng river.Based on SOM clustering,single factor evalua-tion and comprehensive identification index,the water quality monitoring data set of the basin is evaluated synthetically.The results show that the surface water quality of the Min-jiang river basin is good,but the TP index has the pollution risk.The order of the water quality of the three basins as well as the Minjiang river is as fo-llows:Jianxi river basin>Fu Tun river basin>Shaxi river basin>Minjiang riv-er basin.(2)Quantitative analysis of non-point source pollut-ion load are made based on inventory analysis and GIS technology:The emission load of the chemi-cal oxygen demand(COD),total nitrogen(TN),t-otal phosphorus generated from 4 source of pollution(urban and rural life,livest-ock breeding,farmland runoff,aqua-culture of 36 country(city,district)-level u-nit in Minjiang river basin)are analyzed by inventory analysis and equal sta-ndard pollution load method.The paper uses SPSS and GIS software to cluster and analyze the pollutant emission intensity,the sensitivity,the classificat-ion control of each unit in the basin.The results show that TP is the main po-Ilutant in the watershed,and the contribution rate of pollution is more than 46%.It is concluded that the lower reaches of the Fu Tunxi,downstream of the Shaxi river basin and the lower reaches of the Minjiang river is a high se-nsitive area.Furthermore,It is recognized that the urban and rural living pollu-tion is the priority control type of non-point source in the region.Aquatic po-llution and comprehensive pollution have the highest contribution rate of pollu-tion in the basin and are the most difficult type to control and handle.Meanw-hile,and the comparison result given by the spatial resolution of pollution sen-sitivity is consistent with the comprehensive evaluation of water quality.