The SPACE 1.0 model: a Landlab component for 2-D calculation of sediment transport, bedrock erosion, and landscape evolution
Models of landscape evolution by river erosion are often either transport-limited (sediment is always available but may or may not be transportable) or detachment-limited (sediment must be detached from the bed but is then always transportable). While several models incorporate elements of, or t...
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doaj-fd284aec24904852ac8863175b8328ad2020-11-24T22:28:52ZengCopernicus PublicationsGeoscientific Model Development1991-959X1991-96032017-12-01104577460410.5194/gmd-10-4577-2017The SPACE 1.0 model: a Landlab component for 2-D calculation of sediment transport, bedrock erosion, and landscape evolutionC. M. Shobe0G. E. Tucker1K. R. Barnhart2CIRES and Department of Geological Sciences, University of Colorado, Boulder, Colorado, USACIRES and Department of Geological Sciences, University of Colorado, Boulder, Colorado, USACIRES and Department of Geological Sciences, University of Colorado, Boulder, Colorado, USAModels of landscape evolution by river erosion are often either transport-limited (sediment is always available but may or may not be transportable) or detachment-limited (sediment must be detached from the bed but is then always transportable). While several models incorporate elements of, or transition between, transport-limited and detachment-limited behavior, most require that either sediment or bedrock, but not both, are eroded at any given time. Modeling landscape evolution over large spatial and temporal scales requires a model that can (1) transition freely between transport-limited and detachment-limited behavior, (2) simultaneously treat sediment transport and bedrock erosion, and (3) run in 2-D over large grids and be coupled with other surface process models. We present SPACE (stream power with alluvium conservation and entrainment) 1.0, a new model for simultaneous evolution of an alluvium layer and a bedrock bed based on conservation of sediment mass both on the bed and in the water column. The model treats sediment transport and bedrock erosion simultaneously, embracing the reality that many rivers (even those commonly defined as <q>bedrock</q> rivers) flow over a partially alluviated bed. SPACE improves on previous models of bedrock–alluvial rivers by explicitly calculating sediment erosion and deposition rather than relying on a flux-divergence (Exner) approach. The SPACE model is a component of the Landlab modeling toolkit, a Python-language library used to create models of Earth surface processes. Landlab allows efficient coupling between the SPACE model and components simulating basin hydrology, hillslope evolution, weathering, lithospheric flexure, and other surface processes. Here, we first derive the governing equations of the SPACE model from existing sediment transport and bedrock erosion formulations and explore the behavior of local analytical solutions for sediment flux and alluvium thickness. We derive steady-state analytical solutions for channel slope, alluvium thickness, and sediment flux, and show that SPACE matches predicted behavior in detachment-limited, transport-limited, and mixed conditions. We provide an example of landscape evolution modeling in which SPACE is coupled with hillslope diffusion, and demonstrate that SPACE provides an effective framework for simultaneously modeling 2-D sediment transport and bedrock erosion.https://www.geosci-model-dev.net/10/4577/2017/gmd-10-4577-2017.pdf |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
C. M. Shobe G. E. Tucker K. R. Barnhart |
spellingShingle |
C. M. Shobe G. E. Tucker K. R. Barnhart The SPACE 1.0 model: a Landlab component for 2-D calculation of sediment transport, bedrock erosion, and landscape evolution Geoscientific Model Development |
author_facet |
C. M. Shobe G. E. Tucker K. R. Barnhart |
author_sort |
C. M. Shobe |
title |
The SPACE 1.0 model: a Landlab component for 2-D calculation of sediment transport, bedrock erosion, and landscape evolution |
title_short |
The SPACE 1.0 model: a Landlab component for 2-D calculation of sediment transport, bedrock erosion, and landscape evolution |
title_full |
The SPACE 1.0 model: a Landlab component for 2-D calculation of sediment transport, bedrock erosion, and landscape evolution |
title_fullStr |
The SPACE 1.0 model: a Landlab component for 2-D calculation of sediment transport, bedrock erosion, and landscape evolution |
title_full_unstemmed |
The SPACE 1.0 model: a Landlab component for 2-D calculation of sediment transport, bedrock erosion, and landscape evolution |
title_sort |
space 1.0 model: a landlab component for 2-d calculation of sediment transport, bedrock erosion, and landscape evolution |
publisher |
Copernicus Publications |
series |
Geoscientific Model Development |
issn |
1991-959X 1991-9603 |
publishDate |
2017-12-01 |
description |
Models of landscape evolution by river erosion are often either
transport-limited (sediment is always available but may or may not
be transportable) or detachment-limited (sediment must be detached
from the bed but is then always transportable). While several
models incorporate elements of, or transition between,
transport-limited and detachment-limited behavior, most require that
either sediment or bedrock, but not both, are eroded at any given
time. Modeling landscape evolution over large spatial and temporal
scales requires a model that can (1) transition freely between
transport-limited and detachment-limited behavior,
(2) simultaneously treat sediment transport and bedrock erosion, and
(3) run in 2-D over large grids and be coupled with other surface
process models. We present SPACE (stream power with alluvium
conservation and entrainment) 1.0, a new model for simultaneous
evolution of an alluvium layer and a bedrock bed based on
conservation of sediment mass both on the bed and in the water
column. The model treats sediment transport and bedrock erosion
simultaneously, embracing the reality that many rivers (even those
commonly defined as <q>bedrock</q> rivers) flow over a partially
alluviated bed. SPACE improves on previous models of
bedrock–alluvial rivers by explicitly calculating sediment erosion
and deposition rather than relying on a flux-divergence (Exner)
approach. The SPACE model is a component of the Landlab modeling
toolkit, a Python-language library used to create models of Earth
surface processes. Landlab allows efficient coupling between the
SPACE model and components simulating basin hydrology, hillslope
evolution, weathering, lithospheric flexure, and other surface
processes. Here, we first derive the governing equations of the
SPACE model from existing sediment transport and bedrock erosion
formulations and explore the behavior of local analytical solutions
for sediment flux and alluvium thickness. We derive steady-state
analytical solutions for channel slope, alluvium thickness, and
sediment flux, and show that SPACE matches predicted behavior in
detachment-limited, transport-limited, and mixed conditions. We
provide an example of landscape evolution modeling in which SPACE is
coupled with hillslope diffusion, and demonstrate that SPACE
provides an effective framework for simultaneously modeling 2-D
sediment transport and bedrock erosion. |
url |
https://www.geosci-model-dev.net/10/4577/2017/gmd-10-4577-2017.pdf |
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