Traffic Advisory: Lane Closure on Ramp from Ohio Drive Southwest to I-66

May 13, 2025
Map showing lane closure from Ohio  Drive to I-66 ramp
Map A: The blue rectangle marks the work zone. A portion of the northbound lane to I-66 is closed near the work zone.

Beginning on or about May 13, 2025, DC Water will temporarily close one lane of the ramp from Ohio Drive Southwest to I-66. Crews will be working to locate and mark underground utilities in the park area west of the Lincoln Memorial as part of the Potomac River Tunnel Project. The lane closure will occur after the morning rush hour and reopen before the evening rush hour begins.

The utility investigation requires drilling a series of small holes to identify underground utilities, including water, gas, electrical, and fiber-optic lines. This work is expected to take 3 to 4 weeks, from 9:30 a.m. until 3:30 p.m., weather permitting. During this time, drivers should expect minor delays and follow all posted directional signs. The area will be restored when the utility investigation work is completed.

Access to I-66 will remain available via one lane which will remain open. Please use caution when traveling through the area.

Next year, DC Water will begin constructing a facility at the site to divert excess sewage and stormwater to the Potomac River Tunnel. The tunnel will convey the overflow to the Blue Plains Advanced Wastewater Treatment Plant.

Ohio Drive Southwest at Rock Creek and Potomac Parkway (Map A) 

  • Start Date: May 13, 2025, weather permitting.
  • Time: Monday–Friday from 9:30 a.m. – 3:30 p.m.
  • Location: Ramp from Ohio Drive Southwest to I-66
  • Traffic Pattern Changes and Pedestrian/Bicycle Detours:
    • Traffic: Temporary lane closure during non-peak hours.
    • Bicycle Trail: The trail will remain open during the utility investigation work.
  • Be aware of road signs directing traffic through the temporary closures.
  • Plan your travel routes accordingly and anticipate potential delays. Traffic control measures will be in place to guide motorists safely through the area.


 Project Details

The Potomac River Tunnel is the next major phase of DC Water’s Clean Rivers Project. The 5.5 mile tunnel system, including diversion facilities, drop shafts, and support structures, will capture combined sewer and stormwater and divert it to the Blue Plains Advanced Wastewater Treatment Plant. Each year about 650 million gallons of untreated sewer overflows enter the Potomac River, and ultimately, Chesapeake Bay, releasing trash and increasing bacteria levels harmful to aquatic life.

The tunnel will reduce this volume by 93% and reduce the frequency of events from 74 to four in a year of average rainfall, ensuring 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.

For more information

Project Email: dcpotomacrivertunnel@dcwater.com

Project Website: www.dcwater.com/prt

Project Hotline: 202-972-1388

DC Water 24-hour Emergency: 202-612-3400

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View of Mary at bottom of shaft inside tunnel shown from above

First turn of cutterhead signals the start of excavation for the Potomac River Tunnel Project

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Board of Directors Meeting

April 24, 2023

Monday 9:00 AM

Announcement

View of Mary at bottom of shaft inside tunnel shown from above
DC Water Launches Tunnel Boring Machine Mary, Marking Important Step for Potomac River Tunnel Project

First turn of cutterhead signals the start of excavation for the Potomac River Tunnel Project

In a defining moment for one of the District’s largest infrastructure investments, DC Water has marked its next major milestone in the Potomac River Tunnel Project. The first tunnel boring machine, Mary, has launched her northbound journey breaking through the soil to signal the start of excavation.

With the first turn of Mary’s drill-like cutterhead underground, the machine pushed forward to begin tunneling, representing the transition from years of planning and preparation to active tunnel construction on the $819 million project.

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Wednesday, 9:30 AM

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