CAN THERE BE SOLITARY STEPS MIGRATING UPSTREAM WITH PERMANENT FORMS IN MILD-SLOPE BEDROCK RIVERS?

Abstract

 Solitary steps (isolated waterfalls) caused by tectonic movements such as faulting on exposed bedrock, are said to migrate upstream over time due to increased flow velocities and concentrated erosion of the bedrock at the steps. In the case of bedrock, erosion is caused by sediment transported by flowing water rather than by flowing water, and the erosion process due to sediment transport has recently been formulated¹⁾. However, numerical calculations using that equation have shown that the steps disappear over time. This study theoretically clarified whether solitary steps (isolated waterfalls) can form upstream on mild-slope riverbeds while maintaining their shape.