Can Barrier Islands Survive Sea‐Level Rise? Quantifying the Relative Role of Tidal Inlets and Overwash Deposition

Barrier island response to sea‐level rise depends on their ability to transgress and move sediment onto and behind the barrier, either through flood‐tidal delta deposition or via overwash. Our understanding of these processes over decadal or longer timescales, however, is limited. Here we use a rece...

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Bibliographic Details
Published in:Geophysical research letters 2019-12, Vol.46 (24), p.14613-14621
Main Authors: Nienhuis, Jaap H., Lorenzo‐Trueba, Jorge
Format: Article
Language:English
Subjects:
Barrier Island
Barrier islands
Beach
Bottom trawling
Deltas
Deposition
Dredging
Floods
Fluxes
Inlets
Inlets (topography)
Islands
Morphodynamics
Overwash
Sea level
Sea level rise
Sediment
Sediment transport
Sediments
Stratigraphy
Survival
Tidal dynamics
Tidal floods
Tidal Inlet
Tidal inlets
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Summary:Barrier island response to sea‐level rise depends on their ability to transgress and move sediment onto and behind the barrier, either through flood‐tidal delta deposition or via overwash. Our understanding of these processes over decadal or longer timescales, however, is limited. Here we use a recently developed barrier island model (BRIE) to better understand the interplay between tidal dynamics, overwash fluxes, and sea‐level rise on barrier coasts and barrier island stratigraphy. Model results suggest that in microtidal environments with large alongshore sediment transport fluxes, tidal inlets are ephemeral and migrate rapidly. These conditions lead to effective deposition of flood‐tidal deltas and allow inlets to constitute most of the landward sediment flux. Whether barrier islands can survive sea‐level rise depends on the combined landward sediment flux from overwash and flood‐tidal delta deposition, likely making barrier islands with artificially stabilized inlets (via jetty construction or maintenance dredging) more vulnerable to sea‐level rise. Key Points Flood‐tidal deltas built by ephemeral and rapidly migrating tidal inlets contribute significantly to barrier landward movement in response to sea‐level rise Additional landward sediment flux from tidal inlets can help barrier islands keep pace with sea‐level rise Barrier stratigraphy is not always a good indicator of formative landward sediment fluxes
ISSN:0094-8276
1944-8007
DOI:10.1029/2019GL085524