ABSTRACT:

The model presented here explores one-dimensional river profile evolution in a lithologically heterogeneous setting, where bedrock erosion is modulated by a variably thick layer of gravel-size alluvium. The model combines theory for bedload transport in equilibrium gravel-bed channels with bedrock incision by plucking and abrasion. We explore a scenario in which gravel-sized sediment derives exclusively from a “hard” geologic unit in the upstream part of the fluvial system, which is transported downstream to create an alluvial blanket across a “soft,” fine-grained geologic unit.