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- Permanent Link:
- http://dpanther.fiu.edu/dpService/dpPurlService/purl/FI15061861/00001
Notes
- Abstract:
- Using a morphological‐behavior model to conduct sensitivity experiments, we
investigate the sea level rise response of a complex coastal environment to changes in
a variety of factors. Experiments reveal that substrate composition, followed in rank
order by substrate slope, sea level rise rate, and sediment supply rate, are the most
important factors in determining barrier island response to sea level rise. We find that
geomorphic threshold crossing, defined as a change in state (e.g., from landward migrating
to drowning) that is irreversible over decadal to millennial time scales, is most likely to
occur in muddy coastal systems where the combination of substrate composition, depthdependent
limitations on shoreface response rates, and substrate erodibility may
prevent sand from being liberated rapidly enough, or in sufficient quantity, to maintain a
subaerial barrier. Analyses indicate that factors affecting sediment availability such as
low substrate sand proportions and high sediment loss rates cause a barrier to migrate
landward along a trajectory having a lower slope than average barrier island slope, thereby
defining an “effective” barrier island slope. Other factors being equal, such barriers
will tend to be smaller and associated with a more deeply incised shoreface, thereby
requiring less migration per sea level rise increment to liberate sufficient sand to maintain
subaerial exposure than larger, less incised barriers. As a result, the evolution of larger/less
incised barriers is more likely to be limited by shoreface erosion rates or substrate
erodibility making them more prone to disintegration related to increasing sea level rise
rates than smaller/more incised barriers. Thus, the small/deeply incised North Carolina
barriers are likely to persist in the near term (although their long‐term fate is less certain
because of the low substrate slopes that will soon be encountered). In aggregate,
results point to the importance of system history (e.g., previous slopes, sediment budgets,
etc.) in determining migration trajectories and therefore how a barrier island will respond
to sea level rise. Although simple analytical calculations may predict barrier response
in simplified coastal environments (e.g., constant slope, constant sea level rise rate, etc.),
our model experiments demonstrate that morphological‐behavior modeling is necessary to
provide critical insights regarding changes that may occur in environments having
complex geometries, especially when multiple parameters change simultaneously. ( English )
Record Information
- Source Institution:
- Florida International University
- Rights Management:
- Please contact the owning institution for licensing and permissions. It is the user's responsibility to ensure use does not violate any third party rights.
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