CHARLESTON, S.C. -- The U.S. Army Corps of Engineers, Charleston District, and the City of Charleston have partnered together to rehabilitate the city’s historic brick arch stormwater drainage system on the Charleston Peninsula and to support the design of the next phase of the Dupont-Wappoo Watershed Master Plan in West Ashley. This effort, authorized under a federal environmental infrastructure program, aims to improve stormwater management, enhance public safety, and strengthen the reliability of critical drainage systems in two of the city’s most flood-prone areas.
Authorized under Section 219(f) (391) of the Water Resources Development Act of 1992, as amended, federal funding of $7,625,000 was appropriated through the Construction – Environmental Infrastructure Work Plan of the Disaster Relief Supplemental Appropriations Act of 2025 (Public Law 118-158). The brick arches rehabilitation project is structured as a 75% federal and 25% non-federal cost share, with the Corps contributing $5,625,000 and the City of Charleston providing $1,875,000. The remaining $2,000,000 in federal funding will support the design of the Dupont-Wappoo project and will follow the same 75% federal and 25% non-federal cost-share structure.
“This project represents a critical investment in one of Charleston’s oldest and most important underground infrastructure systems,” said Major Patrick Ripton, acting district commander, U.S. Army Corps of Engineers, Charleston District. “Through this partnership with the City of Charleston, we are enhancing the resilience of the Peninsula’s stormwater system while preserving its historic legacy.”
The underground brick arch system, constructed between 1850 and 1870, was originally built to control wastewater and stormwater in a time when flooding and public health concerns were escalating. Over time, development pressures, sedimentation, and utility conflicts have caused substantial degradation to the system, resulting in structural instability and reduced stormwater capacity.
The rehabilitation effort will focus on structurally repairing and lining the brick tunnels, addressing penetrations from improperly installed utilities, and improving the capacity of the drainage network. The work will extend the service life of the existing system, minimize emergency repairs, and support long-term maintenance by the city.
A pilot rehabilitation project completed by the city in 2021 beneath Limehouse Street demonstrated the potential to significantly improve stormwater conveyance. Building on that success, the current project will target additional high-priority segments across the Peninsula.
Design activities will begin in 2025 and be overseen by USACE. Construction is scheduled to begin in summer 2026 and will be completed in late 2027. Upon completion, the system will be returned to the City of Charleston for operation and maintenance in accordance with the Section 219 agreement.
In addition to the Brick Arches rehabilitation, the agreement also enables the Charleston District to partner with the City of Charleston on the design of the next phase of the Dupont-Wappoo (DuWap) Watershed Master Plan in West Ashley. The DuWap neighborhood, located near the Citadel Mall and named for Dupont and Wappoo Streets, has experienced worsening flooding over the years due to continued development and aging infrastructure. This next phase of design work will support long-term efforts to alleviate flood risk in vulnerable residential, commercial, and roadway areas.