The changing pattern of rainfall erosivity and its impact on sediment load in the Loess Plateau, China: A case study of a typical watershed

The widespread occurrence of soil erosion reflects the accelerated deterioration of the surface ecological environment. The spatiotemporal variation of rainfall erosivity is the key driving factor for soil erosion by water, especially in the Loess Plateau in China. The Fenhe River basin in the Loess Plateau was selected as a case study based on the daily rainfall data from 1962 to 2019. Using a rainfall erosivity model based the daily rainfall, we studied the changing pattern. Furthermore, the impact of rainfall erosivity on sediment load was evaluated, and the possible causes for changes in sediment load were discussed. The results showed that the annual rainfall erosivity of the 12 weather stations experienced an insignificant change (p > 0.05). Moreover, before the 1980s, the decrease in annual watershed average rainfall erosivity may be the main reason for the decrease in annual sediment load, while after the 1980s, the construction of check dams may be the main factor leading to annual sediment load reduction, especially around 1993. However, the increase of vegetation was a main reason for the reduction of annual sediment load after 1999. Given Fenhe River basin as a typical watershed of the Loess Plateau, the study of rainfall erosivity and its impacts on the sediment in this area can provide a useful reference for further ecological construction and soil erosion control in the Loess Plateau.