Modeling the Process of Hillslope Soil Erosion in the Loess Plateau

Abstract

High-peak short-duration surface runoff is the primary cause of severe soil erosion and hyper-concentrated sediment-laden flow in the Loess Plateau of China. This paper proposed a model to simulate the process of hillslope soil erosion in the Loess Plateau, which is essential to support environmental friendly land use and conservation policies. Infiltration excess runoff in this region is simulated by calculating the infiltration rate of land surface in each hillslope unit. The time series of surface runoff are used as the input to simulate soil erosion process with the same time step of several minutes. A dimensionless equation with obvious physical basis is proposed to quantify the amount of erosion according to the runoff. Two parameters denoting soil erodibility and microtopography are raised in the equation and are proved reasonable by experimental data. The parameters are further calibrated and validated using data from field plots. At last, satisfiable results are achieved when used the model with continuous rainfall data from a watershed in the Loess Plateau, by which the proposed hillslope soil erosion model is approved playing a crucial part in building up a comprehensive watershed model.

Keywords: erodibility, infiltration, Loess Plateau, microtopography, soil erosion modeling, the Yellow River