Marsh-induced backwater: the influence of non-fluvial sedimentation on a delta's channel morphology and kinematics
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Published:2023-11-01
Issue:6
Volume:11
Page:1035-1060
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ISSN:2196-632X
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Container-title:Earth Surface Dynamics
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language:en
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Short-container-title:Earth Surf. Dynam.
Author:
Sanks Kelly M.ORCID, Shaw John B., Zapp Samuel M., Silvestre José, Dutt Ripul, Straub Kyle M.
Abstract
Abstract. We investigate the interaction of fluvial and non-fluvial sedimentation on the channel morphology and kinematics of an experimental river delta. We compare two deltas: one that evolved with a proxy for non-fluvial (“marsh”) sedimentation (treatment experiment) and one that evolved without the proxy (control). We show that the addition of the non-fluvial sediment proxy alters the delta's channel morphology and kinematics. Notably, the flow outside the channels is significantly reduced in the treatment experiment, and the channels are deeper (as a function of radial distance from the source) and longer. We also find that both the control and treatment channels narrow as they approach the shoreline, though the narrowing is more pronounced in the control compared to the treatment. Interestingly, the channel beds in the treatment experiment often exist below sea level in the terrestrial portion of the delta top, creating a ∼ 0.7 m reach of steady, non-uniform backwater flow. However, in the control experiment, the channel beds generally exist at or above relative sea level, creating channel movement resembling morphodynamic backwater kinematics and topographic flow expansions. Differences between channel and far-field aggradation produce a longer channel in-filling timescale for the treatment compared to the control, suggesting that the channel avulsions triggered by a peak in channel sedimentation occur less frequently in the treatment experiment. Despite this difference, the basin-wide timescale of lateral channel mobility remains similar. Ultimately, non-fluvial sedimentation on the delta top plays a key role in the channel morphology and kinematics of an experimental river delta, producing channels which are more analogous to channels in global river deltas and which cannot be produced solely by increasing cohesion in an experimental river delta.
Funder
National Science Foundation
Publisher
Copernicus GmbH
Subject
Earth-Surface Processes,Geophysics
Reference86 articles.
1. Aslan, A., Autin, W. J., and Blum, M. D.: Causes of River Avulsion: Insights from the Late Holocene Avulsion History of the Mississippi River, U.S.A., J. Sediment. Res., 75, 650–664, https://doi.org/10.2110/jsr.2005.053, 2005. a 2. Barefoot, E. A., Nittrouer, J. A., and Straub, K. M.: Non-Monotonic Floodplain Responses to Changes in Flooding Intensity, J. Geophys. Res.-Earth, 126, e2021JF006310, https://doi.org/10.1029/2021JF006310, 2021. a 3. Beltrán-Burgos, M., Esposito, C. R., Nepf, H. M., Baustian, M. M., and Di Leonardo, D. R.: Vegetation-Driven Seasonal Sediment Dynamics in a Freshwater Marsh of the Mississippi River Delta, J. Geophys. Res.-Biogeo., 128, e2022JG007143, https://doi.org/10.1029/2022JG007143, 2023. a 4. Bhattacharya, J. P.: Delta: Facies Models Revisited, Soc. Sediment. Geol., 84, 237–292, 2006. a 5. Brooke, S., Chadwick, A. J., Silvestre, J., Lamb, M. P., Edmonds, D. A., and Ganti, V.: Where rivers jump course, Science, 376, 987–990, https://doi.org/10.1126/science.abm1215, 2022. a
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