RUNOFF AND SEDIMENT YIELD VARIATIONS UNDER DIFFERENT PRECIPITATION CONDITION AND LAND-USE TYPE: A CASE STUDY OF FANGXI WATERSHED IN THE POYANG LAKE BASIN, CHINA

A research was conducted on runoff and sediment yield variations under different precipitation and land-use conditions was performed based on the Soil and Water Assessment Tool (SWAT) model using China Meteorological Assimilation Driving Datasets (CMADS). The observation data was collected in the Fangxi Lake Watershed, a typical irrigation district in the Poyang Lake basin of China The results indicated a positive correlation between annual runoff and precipitation, as well as between annual sediment yield and precipitation. The correlation coefficient of annual runoff yield and precipitation was 0.94, whereas that of annual sediment yield and precipitation was 0.85. The monthly yield of runoff and sediment of a typical year (2004) was simulated. The runoff and sediment yields had the same tendency of changes with precipitation variations. Differences were found among the per unit area yield of total runoff from different land-use types in 2004. The order from highest to lowest was paddy land > rural residential land > dry land > water area. For the per unit area yield of total sediment from different land-use types, the order from highest to lowest was rural residential land > dry land > water area > paddy land. The results of this study might provide guidance for soil erosion control in irrigation districts.