Autocyclic secondary channels stabilize deltaic islands undergoing relative sea level rise
- Creators
- Salter, Gerard
- Lamb, Michael P.
Abstract
Understanding what sets the size and stability of deltaic islands is critical for predicting how deltas will respond to sea level rise. Models of overbank sedimentation produce an exponentially decaying sedimentation profile, seemingly incompatible with island stability, which requires uniform sedimentation balancing sea level rise. However, secondary channels provide a mechanism for delivering sediment deeper into island interiors, potentially stabilizing islands. Using a 1D morphodynamic model, we found that autogenic secondary channels allow islands or parts of islands to maintain a stable profile dynamically through cycles of channel incision and aggradation. However, when islands are too large, secondary channels grow to become stable, primary channels, thereby bisecting the island, resulting in smaller, stable islands with more connectivity to the channel network. Rather than passively drowning, our results indicate that deltaic islands can respond to sea level rise through morphodynamic feedbacks that act to enhance island accretion.
Additional Information
© 2022 American Geophysical Union. Accepted manuscript online: 09 August 2022. Manuscript accepted: 14 July 2022. Manuscript revised: 05 July 2022. Manuscript received: 26 March 2022. The NASA Delta-X project is funded by the Science Mission Directorate's Earth Science Division through the Earth Venture Suborbital-3 Program NNH17ZDA001N-EVS3. We thank Marc Simard, Paola Passalacqua, Sergio Fagherazzi, and Justin Nghiem for insightful discussions. Model code and results can be downloaded from https://doi.org/34310.3334/ORNLDAAC/2106.Attached Files
Accepted Version - Geophysical_Research_Letters_-_2022_-_Salter_-_Autocyclic_secondary_channels_stabilize_deltaic_islands_undergoing_relative.pdf
Supplemental Material - 2022gl098885-sup-0001-supporting_information_si-s01.pdf
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Supplemental Material - 2022gl098885-sup-0003-movie_si-s02.gif
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Supplemental Material - 2022gl098885-sup-0005-movie_si-s04.gif
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Additional details
- Eprint ID
- 116229
- Resolver ID
- CaltechAUTHORS:20220810-402978000
- NNH17ZDA001N-EVS3
- NASA
- Created
-
2022-08-12Created from EPrint's datestamp field
- Updated
-
2022-09-02Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences