DC Water will initiate the next phase of construction at the Capital Crescent Trail site near the Aqueduct by opening a temporary trail around the work zone. The new trail will open on or about May 6, 2026. Safety features will include rumble strips, traffic mirrors, and overhead protection. The following week, DC Water will resume preparing for deep excavation by drilling reinforced steel columns into the ground. The columns, known as secant piles, will act as a retaining wall holding soil in place and preventing groundwater from entering the excavation area.

Secant pile work is expected to continue for approximately four months. Residents and trail users may experience increased construction noise during permitted work hours, and all activities will be monitored to ensure compliance with the District’s noise standards.

What to Expect

• The work zone will be shifted south, extending closer to the Potomac River. 
• Access to the trail under the Aqueduct will be shifted north. 
• All work will occur within the construction site; flaggers may be present to assist trucks entering and exiting the site.
• A large drill rig will be used to install secant pile columns.
• Additional truck traffic will occur to remove excavated material and debris from the site.
• Residents and trail users may notice increased noise from drilling and material removal during permitted work hours.

This work is part of the ongoing Potomac River Tunnel Project, which is designed to reduce combined sewer and stormwater discharges during heavy rainfall by conveying flows through the tunnel to the Blue Plains Advanced Wastewater Treatment Plant.

New Trail Opening 

• Start Date: May 6, 2026, weather permitting.
• Work Hours: 7:00 am – 7:00 pm
• Location: 3500 block of Water St NW & Capital Crescent Trail trailhead
• Traffic Pattern Changes and Pedestrian/Bicycle Detours: 
  • Parking restrictions on the south side of the 3500 block of Water Street, NW 
  • Pedestrian and Bicyclist Detours: Signage will direct trail and roadway users around the work zone. Please adhere to the flaggers’ directions and construction signage.  

Project Details
DC Water is constructing the Potomac River Tunnel and support structures to capture combined sewer overflows (CSOs), a mixture of sewage and stormwater, and redirect it to DC Water's Blue Plains Advanced Wastewater Treatment Plant. The tunnel will begin operating in 2030.  At the Capital Crescent Trail site location, DC Water is constructing an underground facility to connect to the sewer outfall and direct the overflows to the tunnel.

The project will reduce overflows polluting the Potomac River and, ultimately, Chesapeake Bay. The tunnel also ensures compliance with the 2005 Federal Consent Decree entered by DC Water, the District of Columbia, the U.S. Environmental Protection Agency, and the US Department of Justice, as amended in January 2016. The tunnel will reduce the volume of these overflows to the Potomac River by 93% and their frequency from approximately 74 events to four events in a year of average rainfall. 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