Background This work aims to analyze the spatial distribution differences of topographic factors in the hinterland of the Three Gorges Reservoir area, and to provide scientific basis for further strengthening the accuracy and rationality of the application of soil erosion models in the Three Gorges region.

Methods Based on the DEM data of 30, 12.5 and 5 m resolution, the multi-flow direction method, catchment area method and segmented slope length method were used to analyze the terrain factors in combination with the GIS platform, and the CSLE model was used to explore the difference of soil erosion information.

Results 1) Under the three resolutions, the terrain factors of the three methods are higher in maximum value and lower in average value. The higher the resolution, the higher the average value. The terrain factors extracted and calculated based on the DEM with the resolution of 30.0 and 12.5 m have a large number of zero-value grids, which are not enough to represent the specific terrain factors. It is recommended to use the terrain factors with the resolution of > 5 m when evaluating the spatial distribution of regional soil erosion. 2) The terrain factors calculated by three algorithms based on DEM are generally higher than those obtained by the measured slope length on each slope section, and the relative error of terrain factors with slope > 25° is relatively large. 3) There is no significant difference in the regional average soil erosion modulus evaluated by CSLE model based on three terrain factor algorithms, but there are differences in the specific analysis of erosion intensity, erosion modulus or erosion amount of each slope section.

Conclusions The segmented slope length method is relatively reasonable for the terrain factors in the Three Gorges Reservoir area, but it is still necessary to consider the impact of the rill and gully erosion ratio on the model to evaluate the soil erosion in the area. This study can provide reference for the application of empirical model to accurately evaluate soil erosion in the Three Gorges Reservoir area.