National Mall and Memorial Parks Seawalls and Shoreline Rehabilitation

The rehabilitation of 6,800 linear feet of seawall mitigates soil erosion into the Potomac River, protects the surrounding landscape, and enhances visitor safety.

In the late 19th century, the U.S. Army Corps of Engineers built the West Potomac Park and Tidal Basin Seawalls to retain material dredged from the Potomac River. Since construction, the stone seawalls in the National Mall and Memorial Parks in Washington, D.C. have settled significantly, contributing to the erosion that exacerbates daily high tide flooding and landslides, further damaging the seawall’s integrity. As part of the National Capital Seawall Rehabilitation IDIQ for the National Park Service (NPS), Moffat & Nichol and HDR led the restoration of 6,800 LF of seawall to reestablish the structures’ historic functional height and adapt to future climate conditions.

Biohabitats provided the project team with natural resources investigation, analysis and documentation for the environmental assessment of the site, and engineering and design services for the rehabilitation of major portions of both seawalls. The site analysis included geotechnical and hydrologic studies, climate analysis, utility identification, a vegetation survey, and topographic/bathymetric surveys.

This project helped protect visitors’ safety and habitat integrity in multiple busy D.C. parks by protecting against future seawall settlement, preventing flooding, and adapting to future climate conditions.

TAGS

• Analysis+Planning