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Precipitation and topography are the most important influence factors of non-point source pollution, especially for soil
erosion. Based on the SWAT model and ArcGIS, the Fuhe watershed was divided into 50 sub-basins. Combined with the
standard deviation gradational method, statistical analyses on characteristics of the spatial and temporal variation of
rainfall in Fuhe watershed were carried out1 based on the rainfall observation data from January 1st, 1986 to December
31st, 2005 from 25 stations within the watershed. The results showed that the spatial-temporal distribution of
precipitation was uneven. Spatially, the average annual rainfall was divided into five grades. Temporally, there was great
variation in inter-year precipitation. The inter-year rainfall distribution was extremely uneven, focused on March to June,
which accounted for 56 % of the total. The analysis of topography in Fuhe watershed was carried out by using the
standard deviation gradational method. The slope of the basin was divided into five grades. The basin was divided into
four grades of the NPS risk by using pollution average slope and rainfall to calculate a weighted value of the risk of NPS
pollution. The first and second level district were mainly distributed in the western, the eastern area, and sporadically
distributed in certain areas of the southern in the watershed, which accounted for 55.6% of the basin area; the risk values
were very large in these districts.
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