Details:

Journal Title:
Earth Surface Dynamics
Personal Author:
Ciarletta, Daniel J. ; Miselis, Jennifer L. ; Shawler, Justin L. ; Hein, Christopher J.
Ciarletta, Daniel J. ; Miselis, Jennifer L. ; Shawler, Justin L. ; Hein, Christopher J. Less -
NOAA Program & Office:
Sea Grant ; OAR (Oceanic and Atmospheric Research)
Sea Grant ; OAR (Oceanic and Atmospheric Research) Less -
Sea Grant Program:
VSGCP (Virginia Sea Grant)
Description:
Barrier coasts, including barrier islands, beach-ridge plains, and associated landforms, can assume a broad spectrum of morphologies over multi-decadal scales that reflect conditions of sediment availability, accommodation, and relative sea-level rise. However, the quantitative thresholds of these controls on barrier-system behavior remain largely unexplored, even as modern sea-level rise and anthropogenic modification of sediment availability increasingly reshape the world's sandy coastlines. In this study, we conceptualize barrier coasts as sediment-partitioning frameworks, distributing sand delivered from the shoreface to the subaqueous and subaerial components of the coastal system. Using an idealized morphodynamic model, we explore thresholds of behavioral and morphologic change over decadal to centennial timescales, simulating barrier evolution within quasi-stratigraphic morphological cross sections. Our results indicate a wide diversity of barrier behaviors can be explained by the balance of fluxes delivered to the beach vs. the dune or backbarrier, including previously understudied forms of transgression that allow the subaerial system to continue accumulating sediment during landward migration. Most importantly, our results show that barrier state transitions between progradation, cross-shore amalgamation, aggradation, and transgression are controlled largely through balances within a narrow range of relative sea-level rise and sediment flux. This suggests that, in the face of rising sea levels, subtle changes in sediment fluxes could result in significant changes in barrier morphology. We also demonstrate that modeled barriers with reduced vertical sediment accommodation are highly sensitive to the magnitude and direction of shoreface fluxes. Therefore, natural barriers with limited sediment accommodation could allow for exploration of the future effects of sea-level rise and changing flux magnitudes over a period of years as opposed to the decades required for similar responses in sediment-rich barrier systems. Finally, because our model creates stratigraphy generated under different input parameters, we propose that it could be used in combination with stratigraphic data to hindcast the sensitivity of existing barriers and infer changes in prehistoric morphology, which we anticipate will provide a baseline to assess the reliability of forward modeling predictions.
Keywords:
[+]
Coasts Mathematical Models Sediments
Source:
Earth Surf. Dynam., 9, 183–203
DOI:
https://doi.org/10.5194/esurf-9-183-2021
Sea Grant Document Number:
VSGCP-R-21-006
Document Type:
Journal Article
Funding:
Grant no. NA18OAR4170083
Rights Information:
CC BY
Compliance:
Library
Main Document Checksum:
[+]
urn:sha256:ff2c26b8e5a624b52fd49055b49b84c8c300d528b2410e137f2fbfa6110a17b7
Download URL:
https://repository.library.noaa.gov/view/noaa/37498/noaa_37498_DS1.pdf
File Type:

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