Autocyclic Secondary Channels Stabilize Deltaic Islands Undergoing Relative Sea Level Rise
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 unif...
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| Format: | Article |
| Language: | English |
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Wiley
2022-08-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2022GL098885 |
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| author | Gerard Salter Michael P. Lamb |
| author_facet | Gerard Salter Michael P. Lamb |
| author_sort | Gerard Salter |
| collection | DOAJ |
| description | 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. |
| format | Article |
| id | doaj-art-448d2953301249aaae1aa96c194b0b09 |
| institution | OA Journals |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2022-08-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-448d2953301249aaae1aa96c194b0b092025-08-20T02:12:53ZengWileyGeophysical Research Letters0094-82761944-80072022-08-014915n/an/a10.1029/2022GL098885Autocyclic Secondary Channels Stabilize Deltaic Islands Undergoing Relative Sea Level RiseGerard Salter0Michael P. Lamb1Division of Geological and Planetary Sciences California Institute of Technology Pasadena CA USADivision of Geological and Planetary Sciences California Institute of Technology Pasadena CA USAAbstract 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.https://doi.org/10.1029/2022GL098885deltaislandstabilityresiliencemorphodynamicsdynamics |
| spellingShingle | Gerard Salter Michael P. Lamb Autocyclic Secondary Channels Stabilize Deltaic Islands Undergoing Relative Sea Level Rise Geophysical Research Letters delta island stability resilience morphodynamics dynamics |
| title | Autocyclic Secondary Channels Stabilize Deltaic Islands Undergoing Relative Sea Level Rise |
| title_full | Autocyclic Secondary Channels Stabilize Deltaic Islands Undergoing Relative Sea Level Rise |
| title_fullStr | Autocyclic Secondary Channels Stabilize Deltaic Islands Undergoing Relative Sea Level Rise |
| title_full_unstemmed | Autocyclic Secondary Channels Stabilize Deltaic Islands Undergoing Relative Sea Level Rise |
| title_short | Autocyclic Secondary Channels Stabilize Deltaic Islands Undergoing Relative Sea Level Rise |
| title_sort | autocyclic secondary channels stabilize deltaic islands undergoing relative sea level rise |
| topic | delta island stability resilience morphodynamics dynamics |
| url | https://doi.org/10.1029/2022GL098885 |
| work_keys_str_mv | AT gerardsalter autocyclicsecondarychannelsstabilizedeltaicislandsundergoingrelativesealevelrise AT michaelplamb autocyclicsecondarychannelsstabilizedeltaicislandsundergoingrelativesealevelrise |