CASWELL BEACH STORMWATER MANAGEMENT & DUNE INFILTRATION SYSTEM

Ardurra implemented an innovative Dune Infiltration System (DIS) to resolve critical flooding on Caswell Beach Road, the sole access route for 240 residents, Duke Energy Progress Nuclear Pumping Station, U.S. Coast Guard Station, and NC Baptist Assembly grounds. The road frequently became impassable for 8+ hours during moderate rainfall events, creating emergency response hazards and community isolation.

As only the second DIS installation in North Carolina, this groundbreaking project adapted technology originally developed for water quality to address localized flooding and public safety. The system collects stormwater from low-lying areas through pumping and directs it via stormwater piping to infiltration chambers embedded within beach dunes, utilizing existing sand as natural filtration media.

Key Project Highlights

• Reduced street flooding duration to 2-4 hours following storm events, enabling safe vehicular traffic

• Designed innovative mobile pumping system with standpipes at key low points and trailer-mounted pump array for town operation

• Achieved dual environmental benefits removing 75-95% of pollutants including pathogens, hydrocarbons, and excess nutrients

• Protected tourism economy by reducing bacterial levels that cause beach closings and swimming advisories

• Utilized natural sand filtration for pollutant removal through absorption and bacterial desiccation

• Optimized single-location design on town-owned property near public beach access after evaluating four potential sites