Author(s): Nosizwe Haru Kunene; Ching-Nuo Chen; Samkele Tfwala

Linked Author(s): Nosizwe Haru Kunene

Keywords: Rainfall pattern; Soil erosion; Sediment yield; Physiographic Soil Erosion–Deposition (PSED) model

Abstract: Large amounts of soil erosion are often generated from rainfall of high intensity in a watershed. In turn, this influences the characteristics of sediment transport and riverbed evolution, leading to enormous sediment related disasters and shortens the lifespan of reservoirs. In addition, sediments deposited in river channels increases the probability of floods and is likely to cause significant changes in the natural environment of the watershed. Therefore, to identify proper soil management approaches for the watershed, a soil erosion model is applied to estimate the soil loss and sediment yield during rainfall events. Laonung River watershed is used as an illustrative example, and the physiographic soil erosion–deposition (PSED) model is applied to simulate runoff, soil erosion, and sediment yield, caused by various rainfall events. Three groups of rainfall pattern (falling, middle and splitting pattern) were used and a total of six real rainfall events were used for simulation. The simulation results shows that the falling rainfall pattern produced the highest total soil erosion, and the splitting rainfall pattern had the least soil erosion and sediment yield even though both patterns had similar amount of rainfall and duration. The findings from this study shows that slight changes in rainfall can produce significant changes in channel behavior as shown from the results difference in rainfall intensity caused varying results. This study will help expand the database of soil erosion, and sediment disaster records and provides a lab reference for details on sediment disaster prevention and control and overall watershed management.

DOI: https://doi.org/10.3850/IAHR-39WC252171192022894

Year: 2022