The Research Of Temporal And Spatial Variation Of Water Quality And Affecting Factors In Hanfeng Lake

With the rapid development of society and urbanization in China,rich in nutrient substances,industrial and agricultural production generated wastewater and domestic sewage discharged into the lake.At the same time,hydraulic erosion formed by rainwater eroded soil surface pollutants into the lake water.In addition,the lake water flows slowly,pollutant capacity limited,self depurative capacity is relatively low and the enrichment of all kinds of impurities so that it will cause the water deterioration,threatening the safe operation of the lakes and the whole ecosystem function.In recent years,the Three Gorges reservoir water quality and health and water eutrophication has long become the focus of social attention.However,Xiaojiang River is a tributary of the Yangtze River Basin,which as a result of human activities,the development of industry and agriculture,such as soil and water loss brings nutrients discharged into the river,brought greater load to Xiaojiang River Basin water quality.Multiple River are in mesotrophic and eutrophic state in Xiaojiang river.The water eutrophication of second stage river constant threat to the ecological environment of the Three Gorges Reservoir area.And Hanfeng Lake as began trial operation in 2013,which is an important water source of Xiaojiang River.But the Hanfeng lake appear duckweed floating phenomenon in may,so that the lake water quality deterioration degree aggravate.Therefore,research and management of this lake has appeared to crunch time.To study the Han Feng Lake Pollution of riparian zone of water quality has an important significance.So that it could maintain ecological safety and balance of the Han Feng lake and establish water quality change mechanism for maintaining long observation of the three gorges.Combining the method and quality evaluation of multi sequence statistical methods,this paper continuous observation of water quality and Soil erosionin storage period of 2013 April to 2014 March.And determine the concentrationof nutrient,water physical parameters and chlorophyll.In addition to analysis date of water quality monitoring and through the search water pollution data and field investigation,between water pollution and characteristics of soil and water loss in this basin,the following results are obtained:(1)Attentions should be paid to the concentrationof TN,TP is over algae growth limit value,it is easy to cause water eutrophication in Hanfeng lake.The single factor evaluation of Chl-a reflects Han Feng Lake water quality in most time of a year in nutrition and poor nutritional status,in the winter for the development of water eutrophication.The results of N/P showed that TN in Han Feng Lake as a factor to limit the growth of alga in different period,in April to December,2013 and February,2014,TN limited the growth of alga.In January and March,2014,TP limited the growth of alga.(2)The sampling can be divided into corresponding storage period and flood season,at temporal scale.water quality in water storage period by the water storage of the Three Gorges region,and the water quality performs variation heavily when it rains heavily in flood season;At spatial scale,the water quality of sampling could be grouped into two groups,reflecting the state of water quality and water quality are disturbed degree of change in different geographical position,the degree of disturbance,hydrological characteristics,and water of tributaries,consistent with the spatial distribution of Han Feng Lake water quality.(3)Correlation analysis of the water quality in Hanfeng lake showed that Chl-a had a significant positive correlation to pH,DO,N03--N,TP,TN,NH4+-N and permanganate indexand.With permanganate indexand,TN and TP are significant positive correlation,which show that the water quality influenced by the same source of pollution.SD had a significant negative correlation to TSS,which show that SD is mainly influenced by TSS.By stepwise regression analysis,established the leading equation Chl-a and the related factors.(4)The result of factor analysis showed that the water quality of Hanfeng lake is mainly affected byChl-a,TP,TN,N03--N,DO,pH.however,TSS and Aerobic organics pollution can not be ignored.According to the results of the nutritional status of the time factor analysis show that Hanfeng Lake,in winter and spring,are suitable for the growth of algae,easily caused eutrophication.Summer and autumn the eutrophication degree is relatively weak.But winter and spring by human interference is more serious.The clustering results to illustrate the impoundment of the Three Gorges Project nutrient degree caused by eutrophication based on higher degree,so that we must to strengthen the impoundment of the Three Gorges Project during eutrophication prevention and control work and should not be underestimated the influence of soil and water loss.According to the results of factor analysis of nutritional state space show that the most serious pollution is Zhen Dong Da Qiu,and the water quality in self purification in the flow to Tiaojieba of the way.From Lake space polluted degree of performance show that Southriver>the center of the lake>Eastriver,the Eastriver water quality is good,but the South River should be used as the main control object.(5)To evaluate water quality of Han Feng Lake show that the lake water quality in a year to the national surface water standard time accounted for about 42%,Hanfeng lake water body by TN,TP pollution is more serious.Hanfeng Lake of water quality,in a year,changes between in nutrition to moderate eutrophication,especially in the winter and Spring Festival eutrophication is serious.Affected by the impoundment of the Three Gorges Project of Hanfeng Lake,the water quality is in mild to moderate eutrophication.(6)Correlation analysis by changes in rainfall and water quality,the results showed that the half of the total rainfall,the half erodibility rainfall and rainfall of half erosion force had a significant positive correlation to the mass concentration variation of TN and TP.The result Show that there is a significant relationship to increase the concentration of nitrogen and phosphorus nutrient quality through soil and water loss and surface resulting in the basin under the action of rainfall in flood season.TN and TP are significant positive correlation,which show that the water quality influenced by the same source of pollution.Water quality of Hanfeng lake disturbed by both soil erosion and human activities in the flood season.During the impoundment of the Three Gorges Project,the water quality was affected by soil erosion is weak.(7)Put forward the comprehensive measures,through the investigation analysis on the natural situation,Hanfeng Lake Basin industrial pollution,agricultural pollution,life pollution,endogenous pollution,to control water pollution in Hanfeng lake.The measure conclude the control of pollutant emissions,strengthen urban production and living sewage emissions,strengthen administrative supervision and management,improve the residents environmental awareness and promote the work of the construction of soil and water conservation.