Combined Sewer Overflow (CSO) 028 Construction Site Announcement 
Georgetown: Capital Crescent Trail west of the Aqueduct

This notice provides important information about mobilizing the combined sewer overflow (CSO) 028 construction site, a part of DC Water’s Potomac River Tunnel (PRT) project. Beginning on or about the week of March 10, 2025, DC Water’s contractors will start setting the site up for the first construction phase. The site is located along the bank of the Potomac River, near the trailhead of the Georgetown Capital Crescent Trail. DC Water will construct a diversion facility that will include a diversion chamber, an approach channel, a drop shaft, and other structures to convey flow from CSO 028 to the tunnel, and an overflow structure. Initial site setup activities will involve installing fences and signage, clearing the site area, and setting up operations. 

Throughout construction, the Capital Crescent Trail will remain accessible to all users. However, multiple phases of trail shifts will be in place to direct trail users around the work zones. Advance notice of changes will be provided. Please send your email address to dcpotomacrivertunnel@dcwater.com if you would like to receive updates.  Thank you for your patience and cooperation as we work to complete this major infrastructure improvement project.

Site Mobilization – CSO 028 
Capital Crescent Trail trailhead – Water St, NW  

During the CSO 028 site mobilization initial phase, the contractor will establish a safe and efficient work zone. Work includes placing signs along the Capital Crescent Trail and Water Street NW and flaggers directing traffic during working hours. The primary work area will be on the west side of the aqueduct and enclosed by fencing. The current traffic pattern under the aqueduct will remain for approximately two to three weeks.

Additional site preparations will include setting up chain-link fences around work zones, installing erosion controls, removing trees, and placing protections around remaining trees.  The contractor will grade the site and set up equipment and facilities to support the next stages of construction. The site will be restored at the end of the project. 

Construction Activities During Mobilization
The contractor will construct the following during mobilization. 

• A new trail on the west side of the aqueduct to direct trail users around the construction site area. 
• A path on the north side of Water Street to direct pedestrians and bicyclists under the aqueduct. 
• Two lanes under the aqueduct: one for trail users and the Washington Canoe Club and another for accessing the construction site. 

Traffic Pattern Changes and Pedestrian and Bicycle Detours

• Pedestrians and bicyclists will be detoured around work zones. Please follow the detour signs.
• Parking restrictions on the south side of Water Street NW in front of the Potomac Boat Club.

Construction hours are 7:00 am – 7:00 pm, Monday through Friday. Temporary, short-term detours may occur periodically; road signs and/or flagging personnel will direct you around the work site. You may notice noise associated with construction during this phase. The contractor will install noise and vibration instruments to monitor construction noise.

Link: CSO 028 Construction Site Fact Sheet

What is the Potomac River Tunnel Project?
 

The Potomac River Tunnel is the next major phase of the DC Clean Rivers Project. The project consists of constructing a large-diameter deep sewer tunnel, diversion facilities, drop shafts, and support structures to capture potential combined sewer overflows (CSOs) from existing outfalls along the Potomac River and convey them to the Blue Plains Advanced Wastewater Treatment Plant. The project is required to reduce CSOs that contribute to water quality impairment of the Potomac River and ultimately Chesapeake Bay; and to comply with the 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. 

During large rain events, CSOs are released untreated into the Potomac River from CSO outfalls when the system's capacity is exceeded. CSOs impair water quality by increasing water bacteria levels, contributing to low dissolved oxygen impacting aquatic life, and increasing the amount of trash in waterways.  An estimated 654 million gallons of CSOs currently enter the Potomac River in a year of average rainfall. The proposed controls are estimated to reduce the volume of CSOs to the Potomac River by 93% and reduce their frequency from approximately 74 events to 4 events in a year of average rainfall. 

Additional Information  

• The work at this site will commence on or about the week of March 10, 2025. Workdays are Monday-Friday. Work hours are 7:00 AM – 7:00 PM. Work is expected through early 2030.
• Commuters, pedestrians, and cyclists will notice additional construction equipment, personnel, and noise associated with construction activities.
• Commuters and pedestrians will notice road signs and/or flagging personnel directing them safely around the work site.
• Signage and project information signage will be posted throughout the project site.
• The site layout and impacts will change as the work progresses. Updates will be provided in additional notices.
• The site will be fully restored once construction is complete. 

For more information 
Project Email: dcpotomacrivertunnel@dcwater.com 
Project Website: www.dcwater.com/prt 
Dedicated Project Hotline: 202-972-1388 
DC Water 24-hour Emergency: 202-612-3400 

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