Soil erosion processes and sediment sorting associated with transport mechanisms on steep slopes

Summary Sediment size distribution greatly affects sediment transport and deposition. A better understanding of sediment sorting will improve understanding of erosion and sedimentation processes, which in turn will improve erosion modeling. To address this issue, a total of 12 rainfall simulation experiments were conducted in a 1 m by 5 m box with varying steep slopes (10°, 15°, 20° and 25°), and the simulated rainfall lasted for 1 h at a rate of 90 mm h−1. For each simulated event, runoff and sediment were sampled at 3-min intervals, which were performed to study in detail the temporal change in size distribution of the eroded materials. These data were used to interpret the real-time sequence of transport mechanisms acting in response to the simulated rainfall. Total soil loss is the sum of suspended, saltating and contact loads. The proportion of sediment