In order to improve water quality

it is essential to identify non-point source risk areas for pollution control when the point sources have been controlled.Modified USLE model was used to identify the risk areas of the Hangbu-Fengle watershed with the help of the spatial analysis tool of GIS.The risk maps were classified.Results show that the high risk areas are mainly distributed around the upper area of Longhekou reservoir.The upper and middle areas of Fengle watershed and the lower area of Hangbu watershed near Longhekou reservoir are critical for eutrophication of Chao Lake.The regions with the risk bigger than average cover less than 5.62% of the total watershed area

in which the agricultural landuse accounts for 86.47%.This indicates that agricultural landuse has higher risk.