Experimental study on hydro-dynamic mechanism of sheet erosion processes on loess hillslope

Sheet erosion is the initial form of soil erosion evolution on a hillslope. Revealing the hydrodynamic mechanisms of sheet erosion and determining the hydrodynamic parameters closely related to sheet erosion are of importance to control sheet erosion effectively. The hydrodynamic mechanisms of sheet erosion processes on a loess hillslope were studied by a simulated rainfall experiment. Results showed that: 1) In terms of the correlation coefficients for the responsive relationships of sheet erosion modulus to mean hydrodynamic parameters in a single rainfall on the loess hillslope, the mean parameters examined could be ranged in the order of mean cross-section specific energy > mean stream power > mean unit stream power > mean stream shear stress. 2)In terms of the correlation coefficients for the responsive relationships of sheet erosion rates to instantaneous hydrodynamic parameters in a rainfall process on the loess hillslope, the instantaneous hydrodynamic parameters could be ranged in the order of cross-section specific energy > stream power> unit stream power > stream shear stress. 3) Cross-section specific energy was the hydrodynamic index closely related to hydrodynamic processes of sheet erosion on loess hillslope under the experimental conditions and the best hydrodynamic parameter describing hydrodynamic processes of sheet erosion. Under the experimental conditions, the occurrence and development of hydrodynamic processes of sheet erosion on the loess hillslope were basically driven by the hydrodynamic functions characterized by cross-section specific energy.