Hysteresis Effects in Splash Sediment Transport

Temporally variable rainfall was applied on an initially dry, ploughed and smoothed agricultural soil to investigate the hysteresis pattern in the sediment concentration- discharge relation using laboratory flume experiments. The erosion flume had dimensions of 5-m × 2-m and consisted of two collectors at either side of the outlet. The slope was fixed at 2% and seven sequential events involved 20-min precipitation rates of 15, 30, 45, 60, 45, 30 and 15 mm h -1, were performed. Due to the cohesive agricultural soil, and low discharge and slope, rainfall detachment was the only erosion mechanism operating. The data collected at the two flume exits were analyzed by measuring the discharge and total sediment concentration. A clockwise hysteresis loop was found for total sediment concentration because of the easily erodible soil condition at the beginning of the experiment. It was also found that the Hairsine-Rose model was in agreement with the experimental data, which showed its capability to predict the characteristics of hysteretic sediment transport arising in time varying rainfall events.