Nonlocal Sediment Transport on Steep Lateral Moraines, Eastern Sierra Nevada, California, USA
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Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Geophysical Research
Abstract
Recent work has highlighted the significance of long-distance particle motions in hillslope
sediment transport. Such motions imply that the flux at a given hillslope position is appropriately
described as a weighted function of surrounding conditions that influence motions
reaching the given position. Although the idea of nonlocal sediment transport is well grounded
in theory, limited field evidence has been provided. We test local and nonlocal formulations
of the flux and compare their ability to reproduce land-surface profiles of steep moraines
in California. We show that nonlocal and nonlinear models better reproduce evolved landsurface
profiles, notably the amount of lowering and concavity near the moraine crest and
the lengthening and straightening of the depositional apron. The analysis provides the first
estimates of key parameters that set sediment entrainment rates and travel distances in nonlocal
formulations, and highlights the importance of correctly specifying the entrainment
rate when modeling land-surface evolution. Moraine evolution associated with nonlocal and
nonlinear transport formulations, when described in terms of the evolution of the Fourier
transform of the moraine surface, displays a distinct behavior involving growth of certain
wavenumbers, in contrast to the decay of all wavenumbers associated with linear transport.
Nonlinear and nonlocal formulations share key mathematical elements yielding a nonlinear
relation between the flux and the land-surface slope.
Description
Available for download is the author's version of the paper. The final, publisher's version is available at https://dx.doi.org/10.1002/2017JF004325
The dataset DOI is https://doi.org/10.15695/vudata.cee.1
Keywords
Numerical Models, Land-Surface Spectra