Research On Water Quality And Quantity Response And Multi-drive Factor Evaluation Of Nansi Lake Basin In Shandong Province

The world is facing a profound water crisis;water pollution has become an important cause of water crisis.The sources of water pollution are divided into point sources and non-point sources.With the effective control of point source pollution,the non-point source pollution is becoming increasingly prominent.As the North China's largest shallow lake,Nansi Lake is the most important storage places of South to North Water Diversion Project,the water quality directly affects the operation of the east line project,with the development and utilization of rain flood resources in Shandong Province the recent and future period of time,Nansi Lake will also become the backbone project in the use of Shandong province rain flood resources and flood control,irrigation,a set of aquatic products,shipping and other functions as one of the reservoir lakes.Therefore,water quality has attracted much attention in Nansi Lake.Until 2010,the water quality monitoring data show that the lake non-point source TN,TP proportion has more than 60%,for the non-point source of Nansi Lake Basin management and control effectively,it is necessary to do research on study the loss of migration about non-point source pollution.Based on the analysis and summary of the previous research of Nansi Lake and non-point source pollution,this paper takes use of the statistical data and the export coefficient model,analysis of the 2008?2010 year in Nansi Lake Basin non-point source nitrogen and phosphorus into the river,the lake.The simulation combines many methods together,such as theory with practice,typical and generalization methods.The watershed model selected with emphasis on hydrological and physical process simulation and continuous spatial distribution,which is called SWAT model to analysis non-point source pollution in Nansi Lake basin.A typical non-point source SWAT model of coupled ARCGIS has been established by simulating the temporal and spatial variation of non-point source pollution output load in a multi-scenario,and the key area of non-point source output has been identified in the typical study area(Sihe River Basin and Zhuzhaoxin River Basin).Based on the output of HRUs,the response relationship between the main factors affecting the non-point source pollution and the output load has been studied,and a non-point source multivariate factor evaluation model for watershed non-point source identification and evaluation has been established.This paper is divided into seven chapters.The main research results are as follows.(1)Established the SWAT model of Si River Basin and Zhuzhaoxin River Basin,and simulated the non-point source pollution under current condition.The model was calibrated and verified with the data series of measured runoff,TN,TP and NH3-N of Liangshan station and Shuyuan station.The coefficient R2 and the coefficient of NS were all above 0.6 in the calibration and validation period,to meet the requirements of simulation precision.(2)Using established the SWAT model of Si River Basin and Zhuzhaoxin River Basin to Simulate the total output load of non-point source nitrogen and phosphorus of the year 2008?2014 under current situation of precipitation and fertilization.Concluding the total average annual output load of entering lake TN,TP and NH3-N in Zhuzhaoxin River Basin and Si River Basin is 3213.85t/a,57.54 t/a,4.32 t/a,4698.55 t/a,42.71 t/a,7.11 t/a.(3)The paper selected output load of TN,TP,NH3-N and sediment load as the index and took the precipitation and chemical fertilizer application as variables(precipitation frequency:P1,P2,P5,P10,P25,P50,P75,P95;nine fertilization scenes:A-I)to study the spatial and temporal distribution characteristics and the response relationship between water quality and water quality under the scenes of non-point source pollution in Nansi Lake Basin.(4)Based on the main effect factors of non-point source pollution(precipitation,land use types,slope of basin)to analyze the response relationship of output load of pollutants under the change of various effect factors on the level of hydrological response units(HRUs).(5)In this paper,the results of the above studies and related scholars are summarized,based on the Watershed topographic factor(L),climate factor(Q),human activity factor(R)and introduced multi criteria analysis(MCA)method to establish the multi-driving factor evaluation model of the non-point source pollution in Nansi Lake Basin.The evaluation model can be applied to the qualitative and quantitative evaluation of non-point source pollution.This method can provide reference for the calculation of non-point source pollution in other similar basins.