COMPARING LONG-TERM & SHORT-TERM SHORELINE CHANGE AND THE EFFECT OF HURRICANE IRENE AT CURRITUCK BEACH, NORTH CAROLINA

The barrier islands of North Carolina are particularly vulnerable to erosive processes due to low elevation, limited sand supply, sea level change, and frequent storms (USGS Open File Report 99-593). Barrier island morphology may change rapidly during high-energy, episodic storm events or gradually during more common low-energy wave conditions. Short-term data sets focusing on specific storm events and long-term data sets spanning the last 154 years were compared to identify the dominant process controlling morphologic change in this area. Within that time range, Currituck Beach has regressed landward by 256 meters. Episodic storm events such as Hurricane Irene have the potential to cause significant erosion to the shoreline in just a few days.

Long-term erosion rates were calculated from the shoreline data with the USGS Digital Shoreline Analysis System extension for ArcGIS 10. Preliminary analysis of the erosion data at Currituck Beach indicates an average shoreline regression of 1.5 meters/year. In addition to field collected GPS shorelines and beach profile data from June 2011 to January 2012, data sets used include historical shorelines from 1857, digital orthophotos, and LiDAR images.

On August 27, 2011 Hurricane Irene made landfall 183 km south of the study area and tracked through eastern North Carolina. Post-Irene beach profile data were collected on September 3, 2011 and showed an average loss of 18 meters from the shoreline due to the storm event. Erosion associated with these episodic events must affect the long-term regression rates.