Abstract
Bedrock degradation is a topic of current high interest for river engineering, geomorphology and ecology. Bedrock incision by abrasion may be correlated to the ratio of covered bed because abrasion is active at the portion where bedrock is repeatedly covered with sediment and exposed. In curving bedrock-alluvial channels, the ratio of covered bed gradually increases toward the inner bank due to sediment transport caused by secondary flow. It is expected, therefore, that significant bedrock degradation will take place partially at the portion where the ratio of covered bed is moderate.
In the present work, we performed experiments in an annular flume with mixed bedrock-alluvial bed where bedrock incison was simulated. In the experiment, patterns of sediment deposition and the preferential zones of erosion by abrasion could be observed.
