USGS Study: East Coast Can Expect Significant Coastline Changes Due to Minor Hurricanes

Posted by on July 2, 2013 in Blog, Coastal Resilience | 0 comments

In two new reports, the U.S. Geological Survey has assessed the probabilities of hurricane-induced coastal changes from Florida to New York. Looking at wave heights, storm surge potential, dune heights, and dune continuity, the USGS found that 89 percent of dune-backed beaches would experience significant dune erosion in even a minor hurricane.  A year ago, in a similar study, the USGS found that some 70 percent of the Gulf coast was similarly vulnerable. 

As the USGS press release points out: “Beaches serve as a natural buffer between the ocean and inland communities, ecosystems, and natural resources.  However, these dynamic environments move and change in response to winds, waves, and currents.  During extreme storms, changes to beaches can be large, and the results are sometimes catastrophic.  Lives may be lost, communities destroyed, and millions of dollars spent on rebuilding.”

According to the new studies, South Carolina has some of the most significant challenges. “The South Carolina coast, where average dune elevations are only 2.9 meters (9.5 feet), is the most vulnerable to overwash of the beaches studied. Ninety-six percent of coastal locations in the state are likely to overwash if a category 1 hurricane makes landfall there.”

It’s not just the height but also the continuity of the dunes that protect communities. According to one of the researchers, “Large areas of the South Carolina coast are very likely to erode during hurricanes due to long, continuous stretches of low dunes.” The study shows that if a category 1 storm makes landfall on the South Carolina coast, 34 percent of the beaches and dune systems there are very likely to be completely submerged, compared to an overall average of 9 percent for the rest of the east coast study area.

This has obvious and immediate implications for coastal communities and their emergency planners. We’d simply point out that this vulnerability exists today, not some 50 years into a climate-changed future. With a rising sea level, the mild hurricanes of the future are going to be worse than the mild hurricanes of today.

 

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