By Sean McBride, USACE Charleston DistrictSeptember 19, 2018
Hurricane Florence barreled toward the east coast of the United States at a historically slow pace for weeks before making landfall on Wrightsville Beach, N.C. The coastline of South Carolina was spared the direct force of Hurricane Florence, however the exact extent of any impacts still needed to be determined by the U.S. Army Corps of Engineers, Charleston District.
The Charleston District has been working on coastal storm damage reduction projects at both Myrtle Beach and Folly Beach for several months in an effort to put sand back on the beach and reduce the risk of damage to infrastructure behind the dunes from storms like Hurricane Florence. With word that the storm may make a direct strike on either of these beaches, the projects were halted and all equipment removed from the beach.
The Charleston District's survey team was then tasked to conduct pre-storm assessments of each beach to determine location of the sand and how much sand was on the beach in each place. This data would then be used in comparison to post-storm assessments.
After Hurricane Florence crawled out of the Carolinas, the survey team quickly mobilized to conduct post-storm surveys. Surveys at Folly Beach were conducted with a real-time kinematic GPS receiver, which is rolled along the ground at 1,000 foot increments and uses GPS technology to collect data to determine the elevation and quantity of the sand every three feet.
At the much longer Myrtle Beach project, the survey team used the RAMbLr, or Rapid Assessment Mobile LiDAR, an ATV outfitted with the same detection equipment used at Folly Beach. This method allowed the survey team to conduct their assessment quicker over the longer span of beach.
"It's critical to conduct these assessments so that we can determine if there was any impact to the projects from Hurricane Florence," said Lt. Col. Jeff Palazzini, Charleston District commander. "It's also important to get the projects started again as quickly as possible so that they can finish on schedule. The contractor began remobilization as soon as was safe and are hoping to get started pumping sand again within a week."
The survey team will compare the post-storm data with the pre-storm data to determine if there was any sand loss or relocation from Hurricane Florence. During storm events such as these, sand isn't always washed away, just sometimes displaced to other areas. The results will determine if the Charleston District needs to request funding to redo these areas of the project.
The Folly Beach coastal storm damage reduction project is scheduled for completion in November, while the Myrtle Beach project is scheduled for completion in December. Regardless of the results of the survey, every cubic yard of sand that was placed on the beach as a result of these projects helped to reduce the risk of damage from Hurricane Florence to the infrastructure behind the dunes.