Abstract
Several rivers in Hokkaido are facing riverbed degradation by countermeasures such as Sabo dams. The riverbed widely exposed can be eroded by collision of gravel particles. Previous studies have discussed sandbar formation on the fixed-bed and mechanisms of bedrock erosion. However, bedrock erosional morphology by sandbar formation had not been carried out. The experiments are conducted in the flume into which mortar is placed to imitate bedrock. Alternate sandbars are observed during the experiments. The results suggest that both sides of the channel are eroded with sediment transportation by sandbar formation. Moreover, it is confirmed that sediment supply rate and initial alluvial thickness have a large impact on bedrock erosional morphology.
