Abstract
Barrier island response to sea level rise depends on their ability to
transgress and move sediment to the back barrier, either through
flood-tidal delta deposition or via storm overwash. Our understanding of
these processes over decadal to centennial timescales, however, is
limited and poorly constrained. We have developed a new barrier inlet
environment (BRIE) model to better understand the interplay between
tidal dynamics, overwash fluxes, and sea-level rise on barrier
evolution. The BRIE model combines existing overwash and shoreface
formulations [Lorenzo-Trueba and Ashton, 2014] with alongshore sediment
transport, inlet stability [Escoffier, 1940], inlet migration and
flood-tidal delta deposition [Nienhuis and Ashton, 2016]. Within BRIE,
inlets can open, close, migrate, merge with other inlets, and build
flood-tidal delta deposits. The model accounts for feedbacks between
overwash and inlets through their mutual dependence on barrier geometry.
Model results suggest that when flood-tidal delta deposition is
sufficiently large, barriers require less storm overwash to transgress
and aggrade during sea level rise. In particular in micro-tidal
environments with asymmetric wave climates and high alongshore sediment
transport, tidal inlets are effective in depositing flood-tidal deltas
and constitute the majority of the transgressive sediment flux.
Additionally, we show that artificial inlet stabilization (via jetty
construction or maintenance dredging) can make barrier islands more
vulnerable to sea level rise. Escoffier, F. F. (1940), The Stability of
Tidal Inlets, Shore and Beach, 8(4), 114-115. Lorenzo-Trueba, J., and A.
D. Ashton (2014), Rollover, drowning, and discontinuous retreat:
Distinct modes of barrier response to sea-level rise arising from a
simple morphodynamic model, J. Geophys. Res. Earth Surf., 119(4),
779-801, doi:10.1002/2013JF002941. Nienhuis, J. H., and A. D. Ashton
(2016), Mechanics and rates of tidal inlet migration: Modeling and
application to natural examples, J. Geophys. Res. Earth Surf., 121(11),
2118-2139, doi:10.1002/2016JF004035.
Original language | English |
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Publication status | Published - 1 Dec 2017 |
Externally published | Yes |
Bibliographical note
American Geophysical Union, Fall Meeting 2017, abstract #EP21G-03Keywords
- 1926 Geospatial
- INFORMATICS
- 4217 Coastal processes
- OCEANOGRAPHY: GENERAL
- 4235 Estuarine processes
- 4275 Remote sensing and electromagnetic processes
- 4546 Nearshore processes
- OCEANOGRAPHY: PHYSICAL
- 4558 Sediment transport