A reduced-complexity model for sediment transport and step-pool morphology
A new particle-based reduced-complexity model to simulate sediment transport and channel morphology in steep streams in presented. The model CAST (Cellular Automaton Sediment Transport) contains phenomenological parameterizations, deterministic or stochastic, of sediment supply, bed load transport,...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2016-07-01
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| Series: | Earth Surface Dynamics |
| Online Access: | http://www.earth-surf-dynam.net/4/549/2016/esurf-4-549-2016.pdf |
| _version_ | 1819032706678259712 |
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| author | M. Saletti P. Molnar M. A. Hassan P. Burlando |
| author_facet | M. Saletti P. Molnar M. A. Hassan P. Burlando |
| author_sort | M. Saletti |
| collection | DOAJ |
| description | A new particle-based reduced-complexity model to simulate sediment transport and channel morphology in steep streams in presented. The model CAST (Cellular Automaton Sediment Transport) contains phenomenological
parameterizations, deterministic or stochastic, of sediment
supply, bed load transport, and particle entrainment and deposition in a
cellular-automaton space with uniform grain size. The model reproduces a
realistic bed morphology and typical fluctuations in transport rates observed
in steep channels. Particle hop distances, from entrainment to deposition,
are well fitted by exponential distributions, in agreement with field data.
The effect of stochasticity in both the entrainment and the input rate is
shown. A stochastic parameterization of the entrainment is essential to
create and maintain a realistic channel morphology, while the intermittent
transport of grains in CAST shreds the input signal and its stochastic
variability. A jamming routine has been added to CAST to simulate the
grain–grain and grain–bed interactions that lead to particle jamming and step
formation in a step-pool stream. The results show that jamming is effective
in generating steps in unsteady conditions. Steps are created during
high-flow periods and they survive during low flows only in sediment-starved
conditions, in agreement with the jammed-state hypothesis of Church and
Zimmermann (2007). Reduced-complexity models like CAST give new insights
into the dynamics of complex phenomena such as sediment transport and bedform
stability and are a useful complement to fully physically based models to
test research hypotheses. |
| first_indexed | 2024-12-21T07:06:13Z |
| format | Article |
| id | doaj.art-0222a6aebaea44bfb2770b74d3a13853 |
| institution | Directory Open Access Journal |
| issn | 2196-6311 2196-632X |
| language | English |
| last_indexed | 2024-12-21T07:06:13Z |
| publishDate | 2016-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Earth Surface Dynamics |
| spelling | doaj.art-0222a6aebaea44bfb2770b74d3a138532022-12-21T19:12:06ZengCopernicus PublicationsEarth Surface Dynamics2196-63112196-632X2016-07-014354956610.5194/esurf-4-549-2016A reduced-complexity model for sediment transport and step-pool morphologyM. Saletti0P. Molnar1M. A. Hassan2P. Burlando3Institute of Environmental Engineering, ETH Zurich, Zurich, SwitzerlandInstitute of Environmental Engineering, ETH Zurich, Zurich, SwitzerlandDepartment of Geography, The University of British Columbia, Vancouver, BC, CanadaInstitute of Environmental Engineering, ETH Zurich, Zurich, SwitzerlandA new particle-based reduced-complexity model to simulate sediment transport and channel morphology in steep streams in presented. The model CAST (Cellular Automaton Sediment Transport) contains phenomenological parameterizations, deterministic or stochastic, of sediment supply, bed load transport, and particle entrainment and deposition in a cellular-automaton space with uniform grain size. The model reproduces a realistic bed morphology and typical fluctuations in transport rates observed in steep channels. Particle hop distances, from entrainment to deposition, are well fitted by exponential distributions, in agreement with field data. The effect of stochasticity in both the entrainment and the input rate is shown. A stochastic parameterization of the entrainment is essential to create and maintain a realistic channel morphology, while the intermittent transport of grains in CAST shreds the input signal and its stochastic variability. A jamming routine has been added to CAST to simulate the grain–grain and grain–bed interactions that lead to particle jamming and step formation in a step-pool stream. The results show that jamming is effective in generating steps in unsteady conditions. Steps are created during high-flow periods and they survive during low flows only in sediment-starved conditions, in agreement with the jammed-state hypothesis of Church and Zimmermann (2007). Reduced-complexity models like CAST give new insights into the dynamics of complex phenomena such as sediment transport and bedform stability and are a useful complement to fully physically based models to test research hypotheses.http://www.earth-surf-dynam.net/4/549/2016/esurf-4-549-2016.pdf |
| spellingShingle | M. Saletti P. Molnar M. A. Hassan P. Burlando A reduced-complexity model for sediment transport and step-pool morphology Earth Surface Dynamics |
| title | A reduced-complexity model for sediment transport and step-pool morphology |
| title_full | A reduced-complexity model for sediment transport and step-pool morphology |
| title_fullStr | A reduced-complexity model for sediment transport and step-pool morphology |
| title_full_unstemmed | A reduced-complexity model for sediment transport and step-pool morphology |
| title_short | A reduced-complexity model for sediment transport and step-pool morphology |
| title_sort | reduced complexity model for sediment transport and step pool morphology |
| url | http://www.earth-surf-dynam.net/4/549/2016/esurf-4-549-2016.pdf |
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