Understanding the Processes that Govern Barrier Island Movement

Event Location: 
BCCMWS Room 100
Event Date: 
Thursday, November 6, 2014 - 3:00pm
Event Type: 
SCMSS Seminar Series

Presenter: Aundrea Dolan

Understanding the processes that govern barrier island movement will help to better predict impacts of future storm systems.  With South Carolina experiencing hurricanes on an average of once every seven years, monitoring these coastal zones becomes a highly important issue.  Hurricane Hugo is the largest storm to make landfall in South Carolina’s history, with storm surges reaching thirteen feet, wind velocities up to 138 mph, and mean high water storm surges topping twenty feet.  Sexton and Hayes used aerial photograph surveys, beach profiles, and sediment depth profiles to document storm impact and recovery over the course of 26 months.  Seven barrier islands with mesotidal ranges near Charleston, both transgressive and regressive, were monitored throughout this time frame.  Post-Hugo impact included 150 meters of dunes flattened, 18-25 meters of shoreline retreated, and many washover terraces were observed.  New inlets formed from the destruction of recurved spits on trangressive barrier islands, while regressive barrier islands saw mainly small return surge drainage channels.  Recovery on the regressive barriers occurred more slowly than on the trangressive barrier islands.  Trangressive barriers, being erosional in nature, continue to migrate landward post-storm yet show less erosional impact.  Many storm inlets closed up within one year of Hugo’s landfall, and previously exiting inlets did not show any major changes in depth.  Tidal range was found to be a good indicator of future storm impacts, with larger tidal areas experiencing less of a devastating impact.  

Sexton, W., & Hayes, M. (1991). The Geologic Impact of Hurricane Hugo and Post-Storm Shoreline Recovery Along the Undeveloped Coastline of South Carolina, Dewees Island to the Santee Delta. Journal of Coastal Research, Special Issue (8), 275-290.