26 Barrier Island and Backbarrier Sediment Dynamics (Posters)

Saturday, 18 March 2023
8:00 AM - 12:00 PM
Grand Ballroom A–D

BATHYMETRY-DERIVED STRATIGRAPHIC MODELING OF BOGUE INLET, NC

Paper number: 26-3
Program: Theme Sessions
Time: 8:00 AM – 12:00 PM

Authors

Abstract

Tidal inlets are highly dynamic features of sandy barrier coasts, giving rise to coastal management concerns like navigational safety and controlling erosion of adjacent shorelines. Bogue Inlet, North Carolina is a microtidal inlet on the Atlantic coast of the United States which is regularly exposed to hurricanes (e.g., Hurricane Florence in 2018). A new channel was dredged in 2005 to maintain navigability but has since migrated several hundred meters to the east. High resolution semi-annual to annual multibeam bathymetric surveys acquired around Bogue Inlet between 2005-2022 permit a detailed examination of its morphological evolution. Using the approach of Pearson et al. (2022), we create a stratigraphic model of Bogue Inlet derived from the bathymetric data. During the monitoring period, the main channel migrated laterally and incised, which is clearly visible from dipping structures and channel-fill deposits in the stratigraphy. The progradation and attachment of ebb-tidal delta shoals to the adjacent coast are also observed. The utility of this approach spans several timescales: (1) Sub-annual, as we can relate the observed patterns to ambient processes and major storms and hurricanes or eventful storm seasons; (2) Sub-decadal, as we can use the knowledge of persistent sediment deposits to infer dredging needs, and identify the impact of longer-term developments in the backbarrier basin (e.g. changes to the prism); (3) Decadal to Centennial, as knowledge of decadal-scale morphodynamics will help us to better understand the implications for longer term preservation of sediment within barrier island systems, which is essential for managing climate-sensitive barrier coasts in the future; (4) Millennial and beyond, as understanding contemporary inlet dynamics provides a valuable analogue for recognizing similar processes and stratigraphy in ancient coastal sedimentary deposits.

Geological Society of America Abstracts with Programs. Vol. 55, No. 2

doi: 10.1130/abs/2023SE-385906

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