Taking Harbin region for an example

the spatiotemporal pattern and dynamic changes of soil erosion in Songhuajiang watershed from 1995 to 2005 are studied by using the ArcGIS and DEM. The topographic characteristics of spatial distribution of soil erosion is analyzed based on the DEM. Results show that water erosion is the main form of soil erosion in the watershed. Weak erosion mainly occurs at the altitude between 0 and 400 m where the transformation of weak slight erosion

slighter osion weaker osion

slight ° moderate erosion

and moderate intensive erosion in the area are intensive. Erosion changes mainly occur in the area less than 25° where erosion changes decrease firstly and then increase with the increase in slope degree. In the 0°~ 6°area

soil erosion mainly occurs on the 0.5°~ 5°cropland. In the 6°~ 15°area

the transformation of weak slight erosion and slight weak erosion is relat ively strong. Slope aspectin erosion change is characterized by a double- peak structure

while strong water erosion change occurs in northeast and southwest aspects. The proportion of weak erosion change in the flat area is greater.