Sediment Entrainment and Slump Blocks Limit Permafrost Riverbank Erosion
Abstract Climatic warming and permafrost thaw are predicted to increase Arctic riverbank erosion, threatening communities and accelerating sediment, carbon and nutrient cycling between rivers and floodplains. Existing theory assumes that pore‐ice thaw sets riverbank erosion rates, but overpredicts o...
Published in: | Geophysical Research Letters |
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Online Access: | https://doi.org/10.1029/2023GL102974 https://doaj.org/article/caa460778776492ea3ee5402c34afc04 |
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ftdoajarticles:oai:doaj.org/article:caa460778776492ea3ee5402c34afc04 2024-09-15T18:11:30+00:00 Sediment Entrainment and Slump Blocks Limit Permafrost Riverbank Erosion Madison M. Douglas Kieran B. J. Dunne Michael P. Lamb 2023-06-01T00:00:00Z https://doi.org/10.1029/2023GL102974 https://doaj.org/article/caa460778776492ea3ee5402c34afc04 EN eng Wiley https://doi.org/10.1029/2023GL102974 https://doaj.org/toc/0094-8276 https://doaj.org/toc/1944-8007 1944-8007 0094-8276 doi:10.1029/2023GL102974 https://doaj.org/article/caa460778776492ea3ee5402c34afc04 Geophysical Research Letters, Vol 50, Iss 11, Pp n/a-n/a (2023) permafrost Arctic river erosion slump blocks Geophysics. Cosmic physics QC801-809 article 2023 ftdoajarticles https://doi.org/10.1029/2023GL102974 2024-08-05T17:49:23Z Abstract Climatic warming and permafrost thaw are predicted to increase Arctic riverbank erosion, threatening communities and accelerating sediment, carbon and nutrient cycling between rivers and floodplains. Existing theory assumes that pore‐ice thaw sets riverbank erosion rates, but overpredicts observed erosion rates by orders of magnitude. Here, we developed a simple model that predicts more modest rates due to a sediment‐entrainment limitation and riverbank armoring by slump blocks. Results show that during times of thaw‐limited erosion, the river rapidly erodes permafrost and undercuts its banks, consistent with previous work. However, overhanging banks generate slump blocks that must thaw and erode by sediment entrainment. Sediment entrainment can limit bank and slump block erosion rates, producing seasonally averaged rates more consistent with observations. Importantly, entrainment‐limited riverbank erosion does not depend on water temperature, indicating that decadal erosion rates may be less sensitive to warming than predicted previously. Article in Journal/Newspaper Ice permafrost Directory of Open Access Journals: DOAJ Articles Geophysical Research Letters 50 11 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
permafrost Arctic river erosion slump blocks Geophysics. Cosmic physics QC801-809 |
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permafrost Arctic river erosion slump blocks Geophysics. Cosmic physics QC801-809 Madison M. Douglas Kieran B. J. Dunne Michael P. Lamb Sediment Entrainment and Slump Blocks Limit Permafrost Riverbank Erosion |
topic_facet |
permafrost Arctic river erosion slump blocks Geophysics. Cosmic physics QC801-809 |
description |
Abstract Climatic warming and permafrost thaw are predicted to increase Arctic riverbank erosion, threatening communities and accelerating sediment, carbon and nutrient cycling between rivers and floodplains. Existing theory assumes that pore‐ice thaw sets riverbank erosion rates, but overpredicts observed erosion rates by orders of magnitude. Here, we developed a simple model that predicts more modest rates due to a sediment‐entrainment limitation and riverbank armoring by slump blocks. Results show that during times of thaw‐limited erosion, the river rapidly erodes permafrost and undercuts its banks, consistent with previous work. However, overhanging banks generate slump blocks that must thaw and erode by sediment entrainment. Sediment entrainment can limit bank and slump block erosion rates, producing seasonally averaged rates more consistent with observations. Importantly, entrainment‐limited riverbank erosion does not depend on water temperature, indicating that decadal erosion rates may be less sensitive to warming than predicted previously. |
format |
Article in Journal/Newspaper |
author |
Madison M. Douglas Kieran B. J. Dunne Michael P. Lamb |
author_facet |
Madison M. Douglas Kieran B. J. Dunne Michael P. Lamb |
author_sort |
Madison M. Douglas |
title |
Sediment Entrainment and Slump Blocks Limit Permafrost Riverbank Erosion |
title_short |
Sediment Entrainment and Slump Blocks Limit Permafrost Riverbank Erosion |
title_full |
Sediment Entrainment and Slump Blocks Limit Permafrost Riverbank Erosion |
title_fullStr |
Sediment Entrainment and Slump Blocks Limit Permafrost Riverbank Erosion |
title_full_unstemmed |
Sediment Entrainment and Slump Blocks Limit Permafrost Riverbank Erosion |
title_sort |
sediment entrainment and slump blocks limit permafrost riverbank erosion |
publisher |
Wiley |
publishDate |
2023 |
url |
https://doi.org/10.1029/2023GL102974 https://doaj.org/article/caa460778776492ea3ee5402c34afc04 |
genre |
Ice permafrost |
genre_facet |
Ice permafrost |
op_source |
Geophysical Research Letters, Vol 50, Iss 11, Pp n/a-n/a (2023) |
op_relation |
https://doi.org/10.1029/2023GL102974 https://doaj.org/toc/0094-8276 https://doaj.org/toc/1944-8007 1944-8007 0094-8276 doi:10.1029/2023GL102974 https://doaj.org/article/caa460778776492ea3ee5402c34afc04 |
op_doi |
https://doi.org/10.1029/2023GL102974 |
container_title |
Geophysical Research Letters |
container_volume |
50 |
container_issue |
11 |
_version_ |
1810449088234127360 |