Modeling fluvial erosion on regional to continental scales

TLDR

Fluvial systems are central to landform evolution under tectonic deformation, with bedrock, coarse‑bed alluvial, and fine‑bed alluvial channels differing in controlling factors, transitions driven by sediment characteristics and tectonic changes, bedrock erosion governed by detachment capacity linked to drainage area and gradient, and alluvial sediment routing requiring consideration of slope erosion, transport, abrasion, and sorting. The study aims to develop implicit rate laws for sediment production from erosion of sub‑grid‑scale slopes and small channels in regional landform modeling. The authors implement implicit rate laws that quantify sediment production from erosion of sub‑grid‑scale slopes and small channels.

Abstract

The fluvial system is a major concern in modeling landform evolution in response to tectonic deformation. Three stream bed types (bedrock, coarse‐bed alluvial, and fine‐bed alluvial) differ in factors controlling their occurrence and evolution and in appropriate modeling approaches. Spatial and temporal transitions among bed types occur in response to changes in sediment characteristics and tectonic deformation. Erosion in bedrock channels depends upon the ability to scour or pluck bed material; this detachment capacity is often a power function of drainage area and gradient. Exposure of bedrock in channel beds, due to rapid downcutting or resistant rock, slows the response of headwater catchments to downstream baselevel changes. Sediment routing through alluvial channels must account for supply from slope erosion, transport rates, abrasion, and sorting. In regional landform modeling, implicit rate laws must be developed for sediment production from erosion of sub‐grid‐scale slopes and small channels.