2008
Sklar, L. S.; Dietrich, W. E.
Implications of the saltation-abrasion bedrock incision model for steady-state river longitudinal profile relief and concavity Journal Article
In: Earth Surface Processes and Landforms, vol. 33, no. 7, pp. 1129-1151, 2008.
Abstract | Links | BibTeX | Tags: bedrock channels, bedrock channels;erosion, erosion, geomorphology, laser altimetry
@article{DOI:10.1002/esp.1689,
title = {Implications of the saltation-abrasion bedrock incision model for steady-state river longitudinal profile relief and concavity},
author = {L. S. Sklar and W. E. Dietrich},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Sklar_2008_EarthSurProc.pdf},
doi = {DOI:10.1002/esp.1689},
year = {2008},
date = {2008-05-22},
journal = {Earth Surface Processes and Landforms},
volume = {33},
number = {7},
pages = {1129-1151},
abstract = {The saltation–abrasion model predicts rates of river incision into bedrock as an explicit
function of sediment supply, grain size, boundary shear stress and rock strength. Here we
use this experimentally calibrated model to explore the controls on river longitudinal profile
concavity and relief for the simple but illustrative case of steady-state topography. Over a
wide range of rock uplift rates we find a characteristic downstream trend, in which upstream
reaches are close to the threshold of sediment motion with large extents of bedrock exposure
in the channel bed, while downstream reaches have higher excess shear stresses and lesser
extents of bedrock exposure. Profile concavity is most sensitive to spatial gradients in runoff
and the rate of downstream sediment fining. Concavity is also sensitive to the supply rate
of coarse sediment, which varies with rock uplift rate and with the fraction of the total
sediment load in the bedload size class. Variations in rock strength have little influence on
profile concavity. Profile relief is most sensitive to grain size and amount of runoff. Rock
uplift rate and rock strength influence relief most strongly for high rates of rock uplift.
Analysis of potential covariation of grain size with rock uplift rate and rock strength suggests
that the influence of these variables on profile form could occur in large part through
their influence on grain size. Similarly, covariation between grain size and the fraction of
sediment load in the bedload size class provides another indirect avenue for rock uplift and
strength to influence profile form.},
keywords = {bedrock channels, bedrock channels;erosion, erosion, geomorphology, laser altimetry},
pubstate = {published},
tppubtype = {article}
}
The saltation–abrasion model predicts rates of river incision into bedrock as an explicit
function of sediment supply, grain size, boundary shear stress and rock strength. Here we
use this experimentally calibrated model to explore the controls on river longitudinal profile
concavity and relief for the simple but illustrative case of steady-state topography. Over a
wide range of rock uplift rates we find a characteristic downstream trend, in which upstream
reaches are close to the threshold of sediment motion with large extents of bedrock exposure
in the channel bed, while downstream reaches have higher excess shear stresses and lesser
extents of bedrock exposure. Profile concavity is most sensitive to spatial gradients in runoff
and the rate of downstream sediment fining. Concavity is also sensitive to the supply rate
of coarse sediment, which varies with rock uplift rate and with the fraction of the total
sediment load in the bedload size class. Variations in rock strength have little influence on
profile concavity. Profile relief is most sensitive to grain size and amount of runoff. Rock
uplift rate and rock strength influence relief most strongly for high rates of rock uplift.
Analysis of potential covariation of grain size with rock uplift rate and rock strength suggests
that the influence of these variables on profile form could occur in large part through
their influence on grain size. Similarly, covariation between grain size and the fraction of
sediment load in the bedload size class provides another indirect avenue for rock uplift and
strength to influence profile form.
function of sediment supply, grain size, boundary shear stress and rock strength. Here we
use this experimentally calibrated model to explore the controls on river longitudinal profile
concavity and relief for the simple but illustrative case of steady-state topography. Over a
wide range of rock uplift rates we find a characteristic downstream trend, in which upstream
reaches are close to the threshold of sediment motion with large extents of bedrock exposure
in the channel bed, while downstream reaches have higher excess shear stresses and lesser
extents of bedrock exposure. Profile concavity is most sensitive to spatial gradients in runoff
and the rate of downstream sediment fining. Concavity is also sensitive to the supply rate
of coarse sediment, which varies with rock uplift rate and with the fraction of the total
sediment load in the bedload size class. Variations in rock strength have little influence on
profile concavity. Profile relief is most sensitive to grain size and amount of runoff. Rock
uplift rate and rock strength influence relief most strongly for high rates of rock uplift.
Analysis of potential covariation of grain size with rock uplift rate and rock strength suggests
that the influence of these variables on profile form could occur in large part through
their influence on grain size. Similarly, covariation between grain size and the fraction of
sediment load in the bedload size class provides another indirect avenue for rock uplift and
strength to influence profile form.