Major Milestone Paves Way for Potomac River Tunnel Construction at the Site

DC Water has completed its slope stabilization project along Canal Road, a critical step in order to move forward with construction for the Potomac River Tunnel Project. Originally scheduled to end in February, the project finished about two months ahead of schedule, minimizing additional impacts to commuters and residents. 

With all major construction activities now finalized, the sidewalk adjacent to the slope is expected to reopen tomorrow, December 23, after the safety fencing and barriers are removed. An ADA-accessible shuttle which had been operating during the sidewalk closure will end service on Wednesday, December 24. Signage will be posted at the two stops - Georgetown University and Foxhall Road NW - to notify shuttle users the service is ending.

Additional work will continue on a few outstanding items to ensure the site is fully restored and ready for the next phase of construction.

Work on the slope began in September and required extensive coordination due to the complexity of the project, high traffic volumes, and the ongoing need to maintain safe access for both pedestrians and vehicles.  

Input from local residents, commuters, and stakeholders—including ongoing communication with the District Department of Transportation (DDOT)—helped to develop a revised plan to mitigate traffic and minimize disruption to the community.

During the course of work, crews removed trees and loose materials, drilling approximately 725 steel dowels into the slope and installing mesh to to ensure long-term slope stability. Crews also installed 9,300 linear feet of steel soil nails, applied 36,000 square feet of shotcrete facing, and constructed advanced draining systems. Over the past week, crews seeded the slope to allow new vegetation to grow, the final step in the process.

The instability of the slope has been a safety issue, previously identified by DDOT, after repeated shallow landslides and rockfalls over the years that posed a risk to motorists and pedestrians.

Without stabilizing the slope, DC Water could not advance construction to meet the aggressive schedule for the 5.5 mile tunnel project which will connect to DC Water’s existing system via seven shafts, including the site near Georgetown University.

Construction began on the Potomac River Tunnel in 2024 and is scheduled to finish in 2030. Once operational, the tunnel will reduce the amount of stormwater runoff and untreated sewage released into the Potomac River by approximately 93% and decrease the amount of times this happens from about 75 each year to only four in a typical year.

The project is a core component of DC Water’s Clean Rivers initiative and is being delivered under a Federal Consent Decree with the District of Columbia, the US Environmental Protection Agency (EPA), and the US Department of Justice.

For more information and updates on the Potomac River Tunnel Project, visit dcwater.com/PRT.