Modelling gully erosion for a small catchment on the Chinese Loess Plateau

摘要: The rolling hills region of the Chinese Loess Plateau is one areas with highest erosion rates on earth. A striking feature this area occurrence many large, permanent gullies. 3.5-km2 catchment was selected to study processes and adapt storm-based Limburg Soil Erosion Model (LISEM) conditions prevailing Plateau. Part work consisted mapping measuring largest gully headcuts. amount loose soil material beneath headcuts also estimated. Observations suggest that are relatively stable (i.e., do not migrate rapidly), but gullies can nevertheless produce significant amounts sediment during overland flow events. occurs mainly by falls in between storms. produced these accumulates bottom. As LISEM simulates storm erosion, development over time be ignored, only them runoff events needs studied. digital elevation model (DEM) used estimate position existing heads applying an adapted form Montgomery Dietrich [Science 255 (1992) 826] index. Using assumption vertical, it possible calculate headcut height from slope angle map. simple stability model, which assumes a function moisture content height, applied. This daily-based then simulate accumulation below headcut. results show while DEM accurate enough allow detection individual headcuts, method reasonable available. map showing accumulated serve as input for such LISEM.