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Scale-dependent influence of permafrost on riverbank erosion rates
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  • Joel Carey Rowland,
  • Jon Schwenk,
  • Eitan Shelef,
  • Jordan Muss,
  • Daniel Ahrens,
  • Sophie Stauffer,
  • Anastasia Piliouras,
  • Benjamin Thomas Crosby,
  • Austin J Chadwick,
  • Madison M Douglas,
  • Preston Cosslett Kemeny,
  • Michael P Lamb,
  • Gen Li,
  • Lawrence Vulis
Joel Carey Rowland
Los Alamos National Laboratory (DOE)

Corresponding Author:[email protected]

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Jon Schwenk
Los Alamos National Laboratory
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Eitan Shelef
University of Pittsburgh
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Jordan Muss
Los Alamos National Lab
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Daniel Ahrens
Stanford Law School
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Sophie Stauffer
Sealaska
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Anastasia Piliouras
Pennsylvania State University
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Benjamin Thomas Crosby
Idaho State University
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Austin J Chadwick
Department of Earth and Environmental Sciences, St. Anthony Falls Laboratory, University of Minnesota
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Madison M Douglas
California Institute of Technology
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Preston Cosslett Kemeny
University of Chicago
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Michael P Lamb
California Institute of Technology
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Gen Li
University of California Los Angeles
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Lawrence Vulis
University of California, Irvine
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Abstract

Whether the presence of permafrost systematically alters the rate of riverbank erosion is a fundamental geomorphic question with significant importance to infrastructure, water quality, and biogeochemistry of high latitude watersheds. For over four decades this question has remained unanswered due to a lack of data. Using remotely sensed imagery, we addressed this knowledge gap by quantifying riverbank erosion rates across the Arctic and subarctic. To compare these rates to non-permafrost rivers we assembled a global dataset of published riverbank erosion rates. We found that erosion rates in rivers influenced by permafrost are on average six times lower than non-permafrost systems; erosion rate differences increase up to 40 times for the largest rivers. To test alternative hypotheses for the observed erosion rate difference, we examined differences in total water yield and erosional efficiency between these rivers and non-permafrost rivers. Neither of these factors nor differences in river sediment loads provided compelling alternative explanations, leading us to conclude that permafrost limits riverbank erosion rates. This conclusion was supported by field investigations of rates and patterns of erosion along three rivers flowing through discontinuous permafrost in Alaska. Our results show that permafrost limits maximum bank erosion rates on rivers with stream powers greater than 900 W/m-1. On smaller rivers, however, hydrology rather thaw rate may be dominant control on bank erosion. Our findings suggest that Arctic warming and hydrological changes should increase bank erosion rates on large rivers but may reduce rates on rivers with drainage areas less than a few thousand km2.
04 Feb 2023Submitted to ESS Open Archive
09 Feb 2023Published in ESS Open Archive