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Predictions of barrier island berm evolution in a time-varying storm climatology

Journal of Geophysical Research F: Earth Surface

By:
, , , , , , , , ,
DOI: 10.1002/2013JF002871

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Abstract

Low-lying barrier islands are ubiquitous features of the world's coastlines, and the processes responsible for their formation, maintenance, and destruction are related to the evolution of smaller, superimposed features including sand dunes, beach berms, and sandbars. The barrier island and its superimposed features interact with oceanographic forces (e.g., overwash) and exchange sediment with each other and other parts of the barrier island system. These interactions are modulated by changes in storminess. An opportunity to study these interactions resulted from the placement and subsequent evolution of a 2 m high sand berm constructed along the northern Chandeleur Islands, LA. We show that observed berm length evolution is well predicted by a model that was fit to the observations by estimating two parameters describing the rate of berm length change. The model evaluates the probability and duration of berm overwash to predict episodic berm erosion. A constant berm length change rate is also predicted that persists even when there is no overwash. The analysis is extended to a 16 year time series that includes both intraannual and interannual variability of overwash events. This analysis predicts that as many as 10 or as few as 1 day of overwash conditions would be expected each year. And an increase in berm elevation from 2 m to 3.5 m above mean sea level would reduce the expected frequency of overwash events from 4 to just 0.5 event-days per year. This approach can be applied to understanding barrier island and berm evolution at other locations using past and future storm climatologies.

Geospatial Extents

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Predictions of barrier island berm evolution in a time-varying storm climatology
Series title:
Journal of Geophysical Research F: Earth Surface
DOI:
10.1002/2013JF002871
Volume
119
Issue:
2
Year Published:
2014
Language:
English
Publisher:
American Geophysical Union
Contributing office(s):
St. Petersburg Coastal and Marine Science Center
Description:
17 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
300
Last page:
316
Number of Pages:
17
Country:
United States
State:
Louisiana
Other Geospatial:
Chandeleur Islands