Miyun Reservoir Upstream Land Use On Non-point Source Pollution Of Surface Water

As an important water source, Miyun reservoir plays a crucial role in the people's daily life in Beijing. The water quality of Miyun reservoir is at medium-eutrophication situation, which is mainly caused by the non-point source pollution (NPS) in the watershed. NPS is mostly affected by the land use Activities.Compared with traditional method, GIS technology is able to produce, organize and manage this data well. This thesis constructs a basic spatial database using GIS which includes landuse, type of soil, DEM and sub-watershed, The distribution of fluvial contamination and influence of land use on surface water are analyzed by combining the monitoring data of surface water.Firstly, the research area is divided into three districts according to the physiognomy and the terrain: the northwest low mountainous area, north hilly area and northeast low mountainous area. TP concentrations of surface water in northern and northeastern part of reservoir are higher, and that of northwestern part of reservoir is low .N exists mainly in the form of NO3-N, no matter in rainy reason or after rainy season. So the distribution of NO3-N is similar with TN, the concentration of TN and NO3-N is high in all three research sites when it is raining, after rain the concentration of TN and NO3-N in northern and northeastern part of reservoir is higher than that of northwestern part of reservoir; the concentration of NH4-N is similar among the three research sites in the rainy season ,however, it is sharply low in northwestern part of reservoir , compared with the northern and northeastern part after rain.The concentration of other contaminant during the rainy season is higher than that of after rainy season, except that the concentration of TP in northern area during rain is less than that of after rainy season, it proves that non-point pollution is exactly corresponding with rainfall. Rain season has dense rainfall, human activity is morefrequent, and all of these will have an obvious effect on non-point pollution. By analyzing the relationship between land use and index of non-point pollution, we draw the conclusion that in the structure of land which is dominated by single land use, forest land and grass land can constrain the non-point pollution, and forest land has an obvious constraint effect on non point pollution than that of grass land; in the land mixed with both forest and grassplot, the concentration of all contaminant is relatively low. The effect of land use on surface water non point pollution is not only manifested by the proportion of each kind of land, but the spatial distribution of land use ,especially when the difference between each land structure is small ,the effect of spatial distribution of land on non point pollution is much more obvious...