ABSTRACT
The indoor fine simulated rainfall experiment was conducted to reveal the variation regularity of the rill boundary and the response of the erosion and sediment yield under the fixed slope gradient (20°) and three rainfall intensities (66, 94, 127 mm/h). Results showed that the response of the slope sedimentation process to the rill boundary changes is obvious. Rill traceability is the most active way of determining sediment yield during rill formation and development; it is the main source of sediment in the early stages of rill development. Rill wall collapse and bed cut are the more active ways of sediment yield during rill network development and formation; they directly lead to increase in soil erosion rate in the middle stages of rill development. Rill bed cut is the more active way of sediment yield during rill network adjustment. The change in the relationship between runoff shear and sediment concentration directly leads to the continuous fluctuation of soil erosion rate in the later stage of erosion. The sand production is affected by the development of the rill. There is a correspondence between the rill network at different developmental stages and the sediment yield. The sediment concentration of runoff is relatively low before the formation of the rill, and then fluctuates continuously in the rill development stage and tends to be relatively stable in the stable development stage; while the sediment concentration of runoff is proportional to the rain intensity. This study can provide basic data for the establishment of rill erosion dynamic model.
