Author(s): Jingya Cai, Zuhao Zhou
Keywords: Gullied rolling loess region; Physically-based; Slope-gully-river; Gully erosion; WEP-SED;
Abstract: In the gullied rolling loess region on the Loess Plateau of China, most of the sediment comes from gully areas. Lots of soil erosion models has been applied to the Loess Plateau for the severe erosion problems. However, nearly all these models only consider slope and river erosion processes. The absence of gully erosion process significantly limits their application to the Loess Plateau. Therefore, this paper proposes a three-process-based distributed soil erosion model (WEP-SED) to investigate soil erosion on the Loess Plateau based on the Water and Energy Transfer Processes in Large River Basins (WEP-L). In the WEP-SED, a sequential “slope-gully-river” structure is built for the physically-based simulation of soil erosion and sediment yield. The proposed model is applied to the Baijiachuan hydrological station in the Wuding River basin. The simulated monthly average sediment transport rate is pretty good with a correlation coefficient (R) of 0.77 and Nash-Sutcliffe Efficiency (NSE) of 0.58. The average annual sediment yield is calculated with a relative error of -1.07%. The simulation results demonstrate the applicability and efficiency of WEP-SED. Furthermore, the simulated average annual amount of gully erosion attains a ratio of 54.3% to the total soil erosion and more than 95.0% gully erosion occurs in several months from June to October, which justifies that the gully erosion process must be considered separately in the gully areas.