2018 journal article

Observation and modeling of the evolution of an ephemeral storm-induced inlet: Pea Island Breach, North Carolina, USA


By: L. Montoya n, E. Sciaudone n, H. Mitasova n & M. Overton n

co-author countries: United States of America 🇺🇸
author keywords: Coastal morphodynamics; Outer Banks; Numerical modeling; Barrier island breaching; Aerial photography; Albemarle-Pamlico Sound; Inlet dynamics
Source: Web Of Science
Added: August 6, 2018

The Outer Banks of North Carolina is a wave-dominated barrier island system that has experienced the opening and closure of numerous inlets in the last four centuries. The most recent of those inlets formed after the breaching of Pea Island during Hurricane Irene in 2011. The Pea Island Breach experienced a rapid evolution including episodic curvature of the main channel, rotation of the ebb channel, shoaling, widening by Hurricane Sandy in 2012, and finally closing before the summer of 2013. Studying the life cycle of Pea Island Breach contributes to understanding the behavior of ephemeral inlets in breaching-prone regions. This topic has gained relevance due to rising sea levels, a phenomenon that increases the chances of ephemeral inlet formation during extreme events. This study explores the spatiotemporal effects of tides, waves, and storms on flow velocities and morphology of the breach by means of remotely sensed data, geospatial metrics, and a numerical model. The combined use of observations and results from modeling experiments allowed building a conceptual model to explain the life cycle of Pea Island Breach. Wave seasonality dominated the morphological evolution of the inlet by controlling the magnitude and direction of the longshore current that continuously built transient spits at both sides of the breach. Sensitivity analysis to external forcings indicates that ocean waves can modify water levels and velocities in the back barrier. Sound-side storm surge regulates overall growth rate, duration, and decay of peak water levels entering the inlet during extreme events.