Simulation and analysis of soil erosion in small watershed in the upstream of Yangtze River

This paper presented a model to simulate and forecast soil erosion changes with geographic cellular automata. Shanggou watershed,sub-watershed of Jialingjiang river watershed,was chosen as the typical study area. GIS software and remote sensing images were used to establish the spatial database. Based on the GIS’s function of raster spatial analysis,the watershed was divided into uniform grids,and USLE was integrated with GIS software to predicted soil erosion in the Shanggou sub-watershed after selecting reasonable USLE factor values. Then,the soil erosion was estimated and the relationshi Pamong soil erosion and its background was revealed. Finally,the geographic cellular automata model was constructed to simulate spatial evolution process during 2004~2020. Results show that the amount of soil erosion in 2004 decreased remarkably than in 1998 and the erosion area,according to the soil erosion classification,also changed apparently. Soil erosion was serious respectively from 25 to 35 of slope degree,south aspect,elevation area from 1300 to 1400 meters,where was the particular area of soil and water loss prevention. As far as land use was concerned,soil losses were highest in dry cultivated land,and those in grass land were second. It was estimated that the total eroded area and loss of study area will be reduced to 93.49km2 and 73.15×104t respectively in 2010.