Effects of Runoff and Sediment from Upslope on Downslope Erosion Process

A dualbox system (one is test box and the other is feeder box) and clay loess were used to quantify effects of runoff and sediment from upslope on downslope erosion process under different sediment concentrations in upslope runoff, rainfall intensities and soil surface conditions. The experiment results showed the sediment delivery S caused by upslope runoff accounted for the total sediment delivery Sft at downslope 72.4% to 92.7% and 45.5% to 83.7% for the loose and compact surface treatments separately. After runoff and sediment from upslope discharging into downslope, sediment concentrations in runoff increased 2.4~6.1 and 1.4~3.6 times for the loose and compact surface treatments separately.Effects of runoff and sediment from upslope on slope velocity and rill development is closely related with increase of rainfall intensity or soil bulk density. Meanwhile, slope erosion process is corresponded with rill erosion development.