Consequences of Abrading Bed Load on Vertical and Lateral Bedrock Erosion in a Curved Experimental Channel

Abstract

In this study, we conducted multiple physical experiments to estimate the efficacy and spatial pattern of erosion by abrading sediment moving through a simple U-shaped channel bend with erodible bed and banks. The experiments showed that in the bend, lateral abrasion followed a monotonically increasing linear relationship with sediment feed rate. However, vertical incision had a more complex relation with the sediment feed rate, with an initial increase in abrasion as the feed rate increased followed by a decrease in abrasion of the bed as cover effects became dominant at higher feed rates. Bank erosion was large in places where the width and the lateral slope of the point bar were relatively large. On the other hand, in places where the width of the point bar was smaller, the bedrock bed was eroded primarily along the boundary of the point bar, resulting in a bedrock bench near the outer bank.