Posted on September 9, 2024
The U.S. Army Corps of Engineers (USACE) has been performing maintenance on the Intracoastal Waterway, clearing out disposal areas to allow for more efficient disposal of dredged materials. As part of a beneficial use project, beach-compatible sand is being relocated to the Isle of Palms and Sullivan’s Island.
During the Sullivan’s Island Town Council meeting on Tuesday, Aug. 20, Steven Traynum of Coastal Science and Engineering and Dr. Nicole Elko of Elko Coastal Consultants provided an update on the project.
“This has never been done before in South Carolina; there are only one or two examples in the country of clearing out a disposal area and transferring it to the beach,” said Dr. Elko. “We all just need to be patient; understand that the contractor has no experience doing this, and the Corps has never designed something like this before. The next one will be a lot better.”
Traynum announced that sand placement is finally on the horizon after many delays. All equipment is ready, vegetation has been cleared, and the USACE is just waiting to create a large enough stockpile to allow for a continuous feed of sand before starting the placement.
Those delays have caused some confusion with Isle of Palms residents, some of whom have relied upon the schedule to regulate beach repair decisions and have looked at it as a renourishment project. However, the USACE has said that this is a disposal exercise to create space in the spoil area for their next dredge project and is not a renourishment project.
The sand placement will occur sequentially in three piles along the lower intertidal beach—the area exposed during low tide and submerged during high tide. Approximately 200,000 cubic yards of sand will be placed near Breach Inlet, with between 50,000 and 75,000 cubic yards in stockpile one, 75,000 cubic yards in stockpile two, and the remainder in stockpile three.
The Town of Sullivan’s Island is coordinating a supplemental project to move up to 71,000 cubic yards of sand from these stockpiles to desired areas on the island, focusing on restoring dunes, improving storm resilience, and expanding the recreational area around Thompson Park.
Additionally, the town plans to establish a 5,000-cubic-yard reserve stockpile on town property, which could be used locally in case of a storm or by individuals with permission from the town for dune nourishment on their property. This collaborative project with the U.S. Army Corps of Engineers is expected to cost between 10% and 20% of the typical expense of trucking in new sand for beach renourishment.
Although pumped sand from a sand source is less expensive than trucked sand, it is still costly. The quantity of sand, plus deployment cost, is estimated to be about $10 million. The Isle of Palm’s Beach Fund stood at $8.9 million at the end of June 2024. In addition, State Senator Chip Campsen was able to secure about $855,000 to help with the erosion control spending over the past year.
Some residents are concerned that this project, if successful, will provide just a fraction of the sand required on the beaches.
Traynum mentioned that it is very likely the sand will wash out into the Breach Inlet delta soon after placement, so the plan is to work closely with the USACE’s contractors to integrate these two projects. When the USACE finishes placing sand in stockpile one and moves to work on stockpile two, the town can begin its supplemental project, following behind the USACE and moving sand to higher elevations as quickly as possible.
Work will occur around the clock through mid-October on Sullivans Island before moving to Isle of Palms, with the USACE’s contractor aiming to minimize the closure zone to the immediate construction areas, allowing public access along the beach.
