The Effects Of Different Precipitation Levels And Land Use Change On Non-point Pollution Load In Junshan Lake Basin

With the rapid development of social economy, urbanization is speeding up, the city scale unceasingly expands, the human activities cause the increase in the greenhouse effect to make the great change on characteristics of surface water, thus increase runoff, reduce the water containing water, cause the water supply problem.Therefore, the study of effects on land use change and different precipitati on years in Junshan lake basin is of great significance. This article selects the south poyang lake of Junshan lake basin as the research object, using the study area’s many years of rainfall and soil and land use materials, basing on the SCS model simulation research area of runoff,analysis the relationship between rainfall and runoff. With ArcGIS for technical tool,by reference poyang lake surface runoff pollutants output concentration,it is quantitative simulation to the research area of non-point source pollution,and discusses the effects of different rainfall years and land use changes on Junshan lake basin of non-point source pollution load, and puts forward the land use management strategy which is suitable for Junshan lake basin.According to the regional21years of annual rainfall datas, through deriving the area annual rainfal under different frequencies, we select three typical years,2000as median water year,2005as low flow year and2010as high flow year. In combination with regional soil, land use materials, using SCS model, calculate from the three stages of annual runoff which were823.95mm and706.82mm and1242.06mm.By the use of improved dissolved nitrogen and phosphorus load model for2000to2010, the total amount of TN and TP from1649.42t,147.59t increase to2555.53t and258.55t, which was increased by54.9%and75.1%respectively. Based on the GIS,during ten years area of cultivated land continuously changed to forestland and residents land and traffic land, the urban area was in the expansion, sensitive area ofTN, TP load constantly increased. Meanwhile the research shows that the greater the rainfall of the year, the output of nonpoint source pollution load amount is bigger also, sort by output size is high flow year> median water year> low flow year.