Non-point Source Pollution Simulation Research On Fen He Reservoir Basin

With the rapid development of economy, the water environment issue such as shortage of water resources and deterioration of water quality have become increasingly significant. Due to the positive control and governance around the world, point source pollution has been effectively controlled in recent years. However, non-point source pollution has become increasingly serious, because it did not attract enough attention.Fenhe reservoir is located upstream of Fen River, which is the largest reservoir in Shanxi Province. This paper proposed a method for topographic analysis based on DEM. Using this method, this paper analyzed the topography of Fenhe reservoir basin. Using GIS, RS and other technology, it achieved the basic information digitized and gridded through extracting and processing the basic information of Fenhe reservoir basin. By studying the mechanism of non-point source pollution, it constructed non-point source pollution model and analyzed the situation of non-point source pollution. This study has theoretical guidance and reference for non-point source pollution control planning and water management. Its main results list as follows:(1) Basic information processing. Using GIS, RS and other technology, this paper achieved the basic information digitized and gridded through extracting and processing the spatial data and attribute data of Fenhe reservoir basin, including remote sensing image pretreatment, interpretation, the extraction of land-use, vegetation cover, soil types and soil parameters and so on. Rainfall and temperature data of Fenhe reservoir basin were interpolated by spatial interpolation technology.(2) Topographic analysis. A method for topographic analysis was proposed based on DEM. Using this method, this paper analyzed the topography of Fenhe reservoir basin. The purpose of topographic analysis is to obtain topographic information of the valley, including boundary and river network, to divide sub-watershed and define hydrologic response units, and then to extract a series of hydrological parameters information, such as slope, slope length, sub-watershed area, river length and so on.(3) Non-point source pollution model. Through studying the mechanism of non-point source pollution, non-point source pollution model was constructed, which include three modules, namely hydrologic model, sediment model and pollutant loss model.(4) Model calibration and uncertainty analysis. Model uncertainty analysis, calibration and validation were performed by SUFI-2optimization algorithm based on monitoring data of Jingle station, Shangjingyou station, and Fenhe reservoir station from1980to1989. The validity and applicability of model was verified due to the consistency of analog data with monitoring data.(5) Non-point source pollution analysis. Optimal parameters were set to simulate non-point source pollution of Fenhe reservoir basin from2006to2010. Then load of non-point source pollution was analyzed from three angles, including time, space and land use. From the time view, this paper used time step of year or month to analyze the distribution of sediment, organic Nitrogen, nitrate Nitrogen, organic Phosphorus and dissolved Phosphorus pollution load. Furthermore, it studied on the correlation between non-point source pollution load and rainfall, water yield or other factors. From the angle of space, through the analysis of non-point source pollution load of each sub-watershed, this paper researched the spatial distribution of non-point source pollution load, which can be visualized by GIS technology. Non-point source pollution loads of different land use were compared, and the status of non-point source pollution load in woodland, grassland, arable land, mining and unused land was found out.(6) Non-point source pollution control measures. This paper presented three different measures to control non-point source pollution, namely chemical fertilizer management, buffer strip, returning cultivated land to forest. In addition, it analyzed the reduction rate of non-point source pollution load when control measures were taken.