A study of gully erosion process in rolling hill region of Northeast China based on GIS

Gully erosion of tillage land in northeast China cause mass land degradation and threaten the safety of grain production of China. The relationship between the spatial distribution of gullies and topographic factors, such as slope angle, aspect, slope form, SPI and TWI, as well as land use and lithology are discussed in the Keshan County of Heilongjiang province. The topographic factors are derived from Digital Elevation Model, and landuse as well as gully distribution data were interpreted from satellite images and field survey. Basis on mapped controlling factors, single factor analysis was taken to recognize high risk region of gully erosion. The result of overlay analysis showed that nearly 80% of gullies occurred in farmland and concave slope elements; high slope angle and SPI value are identified as the high gully initiation regions due to the enhancement of runoff convergence. The two patterns of gully erosion were identified via the overlay analysis of different substratum. Based on the analysis, two processes of gully erosion were identified.