Wave Dissipation System
The Board of the South Carolina Department of Health and Environmental Control (DHEC) recently approved the continued use of the controversial Wave Dissipation System (WDS) along South Carolina beachfronts. This approval follows a year-long pilot study by the Citadel, third party review by GEL Engineering, and request for removal of WDS and termination of the pilot study by SCDHEC staff.
The Coastal Conservation League understands concerns about increasing erosion along our beachfronts. However, we firmly oppose the use of hard structures that adversely impact the natural ecosystem and do not actually protect against the long-term issue of coastal erosion near development. Our Beachfront Management Act includes a 40-year policy of retreat that we must begin not only understanding, but enforcing, as we continue to face extreme impacts along our coastline.
History and Timeline of WDS Study
In March 2015, the Citadel originally submitted a request to perform a one year-long study of WDS technology along various parts of South Carolina’s coastline. The WDS are located at four sites, some of which have multiple rows of walls called tiers:
- Ocean Club Villas on Isle of Palms, 256 feet long; triple tier
- Seascape Villas on Isle of Palms, 120 feet long; double tier
- Beachwood East on Isle of Palms, 850 feet long; single tier
- Harbor Island on St. Helena, 400 feet long; single tier
In July 2016, DHEC staff notified The Citadel that the year-long study of WDS would end on July 28th and ordered removal of all WDS devices at that time.
DHEC staff concluded that the WDS present several problems: the devices do not hold the scarp line position–a steep drop on the beach caused by erosion–unless sandbags are also used; there was loss of sand volume landward of the WDS; and net accretion of sand only occurred seaward of the WDS because they block the natural accretion of sand on the shoreline. Staff also found that the WDS has negative effects similar to those associated with seawalls, including trenching and scouring around the WDS, impacts requiring periodic excavations to adjust the systems, and impacts to adjacent properties. Negative impacts on lateral public beach access and potential harmful impacts on sea turtles were also noted. Anecdotal and photo evidence by local turtle patrols and residents has shown that numerous false crawls have occurred around the WDS.
Several parties, including homeowners who installed the WDS, requested final review of the staff decision by the DHEC Board. The Board conducted the review in September 2016 and reversed the staff decision to remove the WDS. This allowed WDS structures to remain in place pending the continued analysis of the pilot study.
In August 2016, The Citadel submitted a final report for their study. Thereafter, DHEC staff contracted with GEL engineering to provide a third-party evaluation of the findings in the report.
Upon review of Citadel and GEL Engineering reports, DHEC staff again recommended at their December meeting that the WDS be removed. The Board published the staff recommendation of findings and their conclusion of removal and hosted a 60-day comment period. During this time, the League and many others submitted written comments, totaling 486 altogether. Following the comment period, a public hearing was held in March 2017. In June 2017, The Board released their official decision that the WDS pilot study would be allowed to continue for an additional year with certain conditions that stipulate that each WDS:
- is placed mostly parallel to the shoreline;
- is designed to dissipate wave energy;
- is designed to minimize scouring seaward of and adjacent to the device by permitting sand to move landward and seaward through the device;
- the horizontal panels designed to dissipate wave energy can be deployed within one-hundred twenty hours or less and can be removed within one hundred twenty hours or less;
- does not negatively impact or inhibit sea turtle nesting or other fauna;
- can be adjusted after initial deployment in response to fluctuation in beach elevations; and
- otherwise prevents down-coast erosion, protects property, and limits negative impacts to public safety and welfare, beach access, and the health of the beach dune system. The Citadel is also required to improve the methodology used to assess the effectiveness of the WDS.
Represented by the South Carolina Environmental Law Project, we, alongside the South Carolina Sierra Club, have requested a contested case hearing to review the DHEC Board’s decision. DHEC’s Board has blatantly disregarded sound analysis by their staff and GEL engineering. We challenge the Board’s decision that the study be allowed to continue when the WDS has clearly demonstrated to be ineffective against erosion, harmful to sea turtles, and a barrier to public access. Please stay tuned for updates!
Emily Cedzo is the lead in our Charleston office, but if you are in the Harbor Island area, please contact Kate Schaefer, South Coast Office Director, at 843.522.1800 for more information.