EFFECT OF THE AMOUNT OF SEDIMENT SUPPLY ON THE UPSTREAM PROGRESS OF WATERFALLS

Abstract

 We performed flume experiments to study the effect of the amount of sediment supply on the migration process of a knickpoint formed on bedrock. We supplied sediment in a flume with a modeled bedrock with an initial drop, and observed the migration process of the drop. We find that, if the initial drop is sufficiently large, the migration process of a waterfall is of an overhanging type when the sand supply is large, but of a vertical erosion-dominated type when the sand supply is small. Under the experimental conditions of this study, there is a threshold that separates the migration process at a sediment supply rate between 25-35 g/min.