Starting on or about Aug. 7, 2026, weather permitting, drivers can expect a temporary lane closure southbound on Rock Creek and Potomac Parkway NW near the intersection of Virginia Avenue NW and F Street NW. The closure will allow DC Water crews to pour a large concrete foundation for the Potomac River Tunnel Project. The foundation will provide a strong base for the tunnel shaft, supporting the next phase of tunnel construction.

The concrete pour is scheduled to begin at approximately 11 p.m. on Friday, August 7, and continue through approximately 3 p.m. on Saturday, August 8. Once the concrete pour begins, crews must keep working until it is finished. Stopping before the job is complete could affect the strength of the foundation. As a result, concrete trucks will be continuously coming in and out of the work area throughout the operation.

This work is part of the Potomac River Tunnel Project, which will help prevent combined sewage and wastewater from overflowing into the river during heavy rain by capturing the untreated water and sending it to the Blue Plains Advanced Wastewater Treatment Plant for treatment.

Southbound Lane Closure

• Dates: Aug. 7-8, 2026, weather permitting
• Hours: 11 p.m. Friday to 3 p.m. Saturday
• Location: Rock Creek and Potomac Parkway NW between F Street NW and Virginia Avenue NW
• Traffic impacts: 
  • Temporary southbound lane closure 
  • Frequent truck traffic in and out of the work zone during the concrete pour

Project Details
The Potomac River Tunnel is part of DC Water’s Clean Rivers Project, which is helping to reduce pollution in the Potomac River and Chesapeake Bay. The 5.5-mile tunnel system will capture combined wastewater and stormwater that can overflow during heavy rain and redirect it to the Blue Plains Advanced Wastewater Treatment Plant. Each year, about 650 million gallons of untreated sewer overflows enter the Potomac. When completed, the tunnel is expected to reduce these overflows by 93% and the number of times this occurs from 74 to 4 in a typical year.

This work is being completed in compliance with a 2005 Federal Consent Decree entered by DC Water, the District of Columbia, the US Environmental Protection Agency, and the US Department of Justice, as amended in January 2016.

Learn more at dcwater.com/prt.

Contact Us
Project Email: dcpotomacrivertunnel@dcwater.com 
Project Hotline: 202-972-1388 
DC Water 24-hour Emergency: 202-612-3400