Barrier island breach evolution: Alongshore transport and bay-ocean pressure gradient interactions

Journal of Geophysical Research: Oceans
By: , and 

Links

Abstract

Physical processes controlling repeated openings and closures of a barrier island breach between a bay and the open ocean are studied using aerial photographs and atmospheric and hydrodynamic observations. The breach site is located on Pea Island along the Outer Banks, separating Pamlico Sound from the Atlantic Ocean. Wind direction was a major control on the pressure gradients between the bay and the ocean to drive flows that initiate or maintain the breach opening. Alongshore sediment flux was found to be a major contributor to breach closure. During the analysis period from 2011 to 2016, three hurricanes had major impacts on the breach. First, Hurricane Irene opened the breach with wind-driven flow from bay to ocean in August 2011. Hurricane Sandy in October 2012 quadrupled the channel width from pressure gradient flows due to water levels that were first higher on the ocean side and then higher on the bay side. The breach closed sometime in Spring 2013, most likely due to an event associated with strong alongshore sediment flux but minimal ocean-bay pressure gradients. Then, in July 2014, Hurricane Arthur briefly opened the breach again from the bay side, in a similar fashion to Irene. In summary, opening and closure of breaches are shown to follow a dynamic and episodic balance between along-channel pressure gradient driven flows and alongshore sediment fluxes.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Barrier island breach evolution: Alongshore transport and bay-ocean pressure gradient interactions
Series title Journal of Geophysical Research: Oceans
DOI 10.1002/2016JC012029
Volume 121
Issue 12
Year Published 2016
Language English
Publisher American Geophysical Union
Publisher location Washington, D.C.
Contributing office(s) Woods Hole Coastal and Marine Science Center
Description 11 p.
First page 8720
Last page 8730
Country United States
Other Geospatial Pea Island