At orogen scale, rock uplift rates are strongly influenced by erosional efficiency, which is set by climatic conditions, bedrock quality, and the sediment load carried by rivers. And, river incision rates ultimately control regional denudation rates and patterns because rivers set the boundary condition for hillslope erosion. This project will develop and test process-specific models of river incision into bedrock. In particular, the quantitative relationships among bedrock properties, river sediment load (flux, size, sorting), flow hydrodynamics, and bed morphology remain important unknowns and support the conceptual framework that erosion rates depend on evolving feedbacks among bed topography, fluid flow, and sediment transport. A refined, physically reasonable, quantitative model of bedrock incision into bedrock will be developed to rationally interpret specific erosional morphologies observed in the field in terms of flow and sediment transport conditions. Preliminary experiments have been conducted in (SAFL, UMn) and a new flume to be constructed at MIT.
