Abstract:
The characteristics of water and sediment and the response to runoff velocity in rill developmental stage under the different slope conditions were studied by using indoor simulated rainfall test. The results show that as for the soil which collected from Yangling, the rill erosion process is roughly divided into three stages, namely, surface erosion period (stage A), rill network development period (stage B) and rill network stability period (stage C). The effect of erosion stage on runoff rate is not significant, which has significant effect on sediment concentration. In the A and B stages, the sediment yield increased with time, and in the C stage the sediment concentration increased gradually, this manifestation is particularly evident at large slopes. In different stages of erosion, the influence degree of slope is different, and in the C stage, the effect of slope on the rill erosion is the most significant. During the process of rill erosion, the change of runoff velocity is complicated. There are no obvious regularities in different slope and different erosion stages. In general, when the slope is small, the high flow rate and low frequency are relatively scattered in the A stage and the B stage. When the slope is large, it is concentrated in the B stage and the C stage. It explains the B stage is the active period of rill erosion. At this stage, the fluctuation of runoff velocity is large and the probability of large runoff velocity increases obviously.
