While Tropical Storm Arthur recently brought a temporary respite of cooler weather to the Southeast, its heavy rain provided an early reminder of the flooding and other tidal intrusions that South Carolina coastal communities face during each hurricane season.
On Isle of Palms, between 21st Avenue and 41st Avenue, work is underway on Phase 2 of the Waterway Boulevard Flood Barrier Project to not only combat the next round of coastal flooding but hopefully prove a long-term solution to the forces of Mother Nature.
“The project includes raising the pathway to an elevation of 7 feet to provide protection from extreme tides and long-term sea level rise,” said Hillary Aton, project manager with Thomas & Hutton engineering services in Mount Pleasant, the company in charge of the flood project. “For context, portions of the existing pathway were below 5 feet elevation, and in some areas, as low as 4.27 feet, where overtopping has occurred repeatedly during extreme tide events.”
Phases 1 and 1a were completed in fall 2025, which consisted of a new $1.5 million flood barrier within the Harbor Golf Course at Wild Dunes. Holes 9 and 10 that parallel the Intracoastal Waterway were raised in elevation to assist in seasonal tidal flooding.
Aton pointed out, however, that Phase II includes the installation of new, localized drainage systems to capture and convey stormwater runoff along Waterway Boulevard beneath the pathway and installation of “in-line check valves on all outfall pipes discharging to the Intracoastal Waterway.”
“These check valves are designed to prevent tidal backflow into the drainage system, reduce ‘sunny day’ flooding and preserve system capacity during storm events,” she said. “No changes, additions or expansions to the scope of work have been made.”
This portion of the project runs for approximately 1.68 miles and is scheduled for completion in fall 2026.
Funding for the project was approved in August 2024 for approximately $1.08 million. The federal cost share amounted to $979,931.70; the remaining cost of $108,881.30 either must come from IOP City or another funding source secured by the city.
“Localized flood reduction projects support risk reduction for the impacts from tropical systems and other flooding events,” said Tiffanie Barrett, chief of public information and external affairs with the South Carolina Emergency Management Division. “So they are an important tool for improving the resilience of coastal communities – as well as other communities.”
No one is sure yet how these improvements will stand up to future king tides or coastal storms because “the tidal protection components have not yet been tested by a major coastal storm or severe tidal event,” Aton said. She added though that early drainage improvements are already delivering benefits – an encouraging sign to safeguard the island from “increasing coastal flood risks in the years ahead.”
“Together, Phases 1 and 2 of the Pathway and Flood Protection Project represent a critical investment in the city’s long-term resilience,” Aton said. “The full completion of Phase 2 is expected to establish a continuous tidal barrier, reduce tidal intrusion from the Intracoastal Waterway and significantly mitigate coastal-driven flooding impacts.”
By L. C. Leach III
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