Origin of a preferential avulsion node on lowland river deltas
Abstract
River deltas are built by cycles of lobe growth and abrupt channel shifts, or avulsions, that occur within the backwater zone of coastal rivers. Previous numerical models differ on the origin of backwater‐scaled avulsion nodes and their consistency with experimental data. To unify previous work, we developed a numerical model of delta growth that includes backwater hydrodynamics, river mouth progradation, relative sea level rise, variable flow regimes, and cycles of lobe growth, abandonment, and reoccupation. For parameter space applicable to lowland deltas, we found that flow variability is the primary mechanism to cause persistent avulsion nodes by focusing aggradation within the backwater zone. Backwater‐scaled avulsion nodes also occur under less likely scenarios of initially uniform bed slopes or during rapid relative sea level rise and marine transgression. Our findings suggest that flow variability is a fundamental control on long‐term delta morphodynamics.
Additional Information
© 2019 American Geophysical Union. Received 17 FEB 2019; Accepted 31 MAR 2019; Accepted article online 4 APR 2019; Published online 25 APR 2019. We acknowledge National Science Foundation grant EAR 1427262 and the Resnick Sustainability Institute at Caltech for support. We thank Vamsi Ganti, Gail Kineke, Ben Hobbs, Hongbo Ma, Brandee Carlson, Kensuke Naito, and Lisa Kumpf for insightful discussions, and Elizabeth Hajek and Wonsuck Kim for constructive reviews. Data are available at: http://sead-published.ncsa.illinois.edu/seadrepository/api/researchobjects/urn:uuid:5c37c889e4b0a8e144f6565f Code is available at: https://github.com/achadwick2323/Origin-of-a-preferential-avulsion-node-on-lowland-river-deltasAttached Files
Published - Chadwick_et_al-2019-Geophysical_Research_Letters.pdf
Supplemental Material - grl58837-sup-0001-2019gl082491-si.pdf
Files
Name | Size | Download all |
---|---|---|
md5:de2db0095edaa28e82ee61e03517d83b
|
1.5 MB | Preview Download |
md5:38bdc733476c5ae76215177a373d0097
|
931.4 kB | Preview Download |
Additional details
- Eprint ID
- 94588
- Resolver ID
- CaltechAUTHORS:20190409-112905807
- NSF
- EAR-1427262
- Resnick Sustainability Institute
- Created
-
2019-04-09Created from EPrint's datestamp field
- Updated
-
2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Resnick Sustainability Institute, Division of Geological and Planetary Sciences