Quantitative effects of hydrodynamic parameters on soil detachment capacity of overland flow

Experiments were performed in a hydraulic flume with varying slope in a larger scale of flow discharge (0.5～2.0 L/s) and slope gradient(5°～25°) to investigate the relationships between soil detachment capacity(Dc) and flow depth, mean flow velocity, flow regime, and friction factor. The objective of this study is to find out the simplest method to predict Dc of overland flow. The results indicated that power function can be used for simulating the relationship between soil detachment capacity and flow depth, and mean flow velocity. There was a close relationship between Dc and flow regime. Dc was more sensitive to Reynolds number than to Flode number. Soil detachment capacity was closely related to friction factor of overland flow. The results of this study suggest that mean flow velocity is the best parameter for predicting the soil detachment capacity. The results are significant to understand the mechanism of soil erosion and to develop process-based erosion model.