National Park Service’s seawall reconstruction at West Potomac Park and the Tidal Basin

Safeguarding a historic waterfront for future generations

West Potomac Park and the Tidal Basin in Washington, D.C. are home to some of the nation’s historic and world-famous landscapes, including the Thomas Jefferson Memorial, Franklin Delano Roosevelt Memorial, and D.C.’s annual Cherry Blossom Festival.

The century-old seawall was increasingly vulnerable to tidal flooding, saltwater intrusion, and sea-level rise, resulting in submerged walkways and deposited debris that impacted public safety.

With projected sea level rise of 2 to 4 feet by 2100, the National Park Service needed a solution that would improve resilience along the National Mall waterfront while preserving the historic and cultural identity of one of the most visited landscapes in the United States.

New raised seawalls to prevent flooding

Funded by the Great American Outdoors Act, the $113 million rehabilitation project includes three seawall segments: 1,200 linear feet (366 meters) at Tidal Basin East, 820 linear feet (250 meters) at Tidal Basin West, and 4,700 linear feet (1,433 meters) at West Potomac Park. The design covers 6,720 linear feet (2,048 meters) of shoreline upgrades.

Using a pile-supported system installed through existing riprap to bedrock, the team elevated and strengthened the seawall while minimizing disturbance to the surrounding environment. Precast components and stone-faced panels were integrated to maintain the historic character, while a cut-off wall and raised shoreline grades improve protection against tidal flooding. Designed for long-term climate resilience, the structure also includes built-in capacity for future height increases – allowing it to adapt as water levels rise and extending its service life.

Delivery in a complex urban environment

Construction took place within an active, high-profile urban setting, requiring close coordination with stakeholders and the public. The team worked around existing and future utilities while maintaining pedestrian access in a heavily visited area. Transparent communication with the National Park Service and stakeholders was critical to maintaining public trust.

A resilient future for a national treasure

The design-build approach enabled accelerated delivery by overlapping design and construction phases and incorporating modular components. Construction for the Tidal Basin began in 2024 and was fully completed in early 2026 – eight months early and $30 million under budget. The enhanced seawall design increases flood protection, improves visitor safety, reduces erosion, and allows for future height adjustments to accommodate projected climate change impacts for one of the nation’s most treasured waterfront landscapes.

Image credit: Cianbro