Where rivers jump course
Abstract
Rivers can abruptly shift pathways in rare events called avulsions, which cause devastating floods. The controls on avulsion locations are poorly understood as a result of sparse data on such features. We analyzed nearly 50 years of satellite imagery and documented 113 avulsions across the globe that indicate three distinct controls on avulsion location. Avulsions on fans coincide with valley-confinement change, whereas avulsions on deltas are primarily clustered within the backwater zone, indicating a control by spatial flow deceleration or acceleration during floods. However, 38% of avulsions on deltas occurred upstream of backwater effects. These events occurred in steep, sediment-rich rivers in tropical and desert environments. Our results indicate that avulsion location on deltas is set by the upstream extent of flood-driven erosion, which is typically limited to the backwater zone but can extend far upstream in steep, sediment-laden rivers. Our findings elucidate how avulsion hazards might respond to land use and climate change.
Additional Information
© 2022 the authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original US government works. https://www.sciencemag.org/about/science-licenses-journal-article-reuse. Submitted 26 August 2021; accepted 1 April 2022. We thank S. Cohen for sharing the water and sediment data and P. Passalacqua and two anonymous reviewers for constructive comments on a previous version of the manuscript. This work was supported by the National Science Foundation EAR 1935669 (to V.G.) and EAR 1427262 (to M.P.L.). A.J.C. was supported by the Caltech Resnick Sustainability Institute. Author contributions: Conceptualization: V.G., S.B., M.P.L., and A.J.C. Methodology: S.B., V.G., J.S., A.J.C., and D.E. Investigation: S.B., V.G., J.S., A.J.C., and M.P.L. Visualization: S.B. and V.G. Funding acquisition: V.G. and M.P.L. Project administration: V.G. Supervision: V.G. and M.P.L. Writing – original draft: V.G., S.B., and M.P.L. Writing – review and editing: V.G., S.B., M.P.L., A.J.C., J.S., and D.E. The authors declare that they have no competing interests. Data and materials availability: The data analyzed in this study are tabulated in the supplementary materials. The satellite imagery analyzed here is publicly available, with USGS/NASA Landsat satellite imagery and SRTM 1 arcsec elevation data downloaded from the USGS Earth Explorer.Attached Files
Supplemental Material - science.abm1215_movies_s1_and_s2.zip
Supplemental Material - science.abm1215_sm.pdf
Supplemental Material - science.abm1215_table_s1.zip
Files
Additional details
- Eprint ID
- 114959
- DOI
- 10.1126/science.abm1215
- Resolver ID
- CaltechAUTHORS:20220531-912112300
- EAR-1935669
- NSF
- EAR-1427262
- NSF
- Resnick Sustainability Institute
- Created
-
2022-05-31Created from EPrint's datestamp field
- Updated
-
2022-05-31Created from EPrint's last_modified field
- Caltech groups
- Resnick Sustainability Institute, Division of Geological and Planetary Sciences