Soil Erosion, Deposition and Transport Processes at Hillslopes of the Loess Plateau

摘要

Soil detachment, deposition and transport processes occur simultaneously during erosive rainfall events. Up to date, numerous studies have been conducted on soil detachment, deposition and transport processes. However, how to quantitatively depict detachment, deposition and transport is a still unsolved problem. Studies on detachment, deposition and transport processes are important for establishing a process-based erosion model. A dual-box system (one is a feeder box located at up-slope, and the other is a test box located at down-slope) was used to quantify hillslope detachment-deposition-transport processes and run-on water and sediment effects on down-slope erosion process. The results showed that sediment regime was detachment-transport dominant when rill erosion or shallow gully erosion was dominated at steep hillslopes. Up-slope runoff discharging into down-slope caused the additional sediment delivery (net detachment) at down-slope section. The net detachment caused by up-slope runoff increased either a decrease of sediment concentration in up-slope runoff and an increase of rainfall intensity, or change of surface conditions from dry to wet. Rill erosion, ephemeral gully erosion played important roles in hillslope erosion process. Sediment delivery at steep hillslope was associated with rill head-cuts advance or ephemeral gully head-cuts advance. These findings will help to improve the understanding of run-on water and sediment effects on down-slope erosion process and control strategies to minimize the run-on water impacts.