TRAFFIC ADVISORY: Temporary Lane Closure on I-66 Ramp Start This Week

July 07, 2025
Map of construction area and road closures

DC CLEAN RIVERS – POTOMAC RIVER TUNNEL PROJECT 

Attention drivers. If you use the ramp from Ohio Drive Southwest to I-66, DC Water will be doing construction that requires the temporary closure of one northbound lane beginning as of today, weather permitting. Drivers will still be able to get onto the highway, and the lane will reopen before the evening rush.

The work is scheduled on weekdays during off-peak hours – 9:30 a.m. to 3:30 p.m. – to minimize the disruption during rush hour when traffic volumes are higher. The lane closure is expected to continue for approximately three weeks.

The temporary traffic change supports the Potomac River Tunnel Project, a major infrastructure initiative to improve water quality in the District. DC Water is preparing the site to store materials and equipment for construction of a tunnel system that will capture and redirect overflows of waste and stormwater away from the Potomac River.

When it’s done, this project is expected to reduce these overflows into the Potomac by 93% and transport it to the Blue Plains Advanced Wastewater Treatment Facility. That means cleaner water in the river and a healthier environment for the public and aquatic life.

What to Expect

  • Lane closures during off-peak hours (9:30 AM – 3:30 PM, Monday–Friday)
  • Rock Creek Trail remains open for pedestrians and cyclists
  • Signs and flaggers will help guide you safely through the area
  • Minor delays possible—plan ahead if you can

Near the Lincoln Memorial, DC Water is building an underground facility, as part of the project, that will connect to the existing sewer system and direct overflows into the new tunnel.

Expected to be completed in 2030, the project also ensures compliance 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.

Learn more at www.dcwater.com/prt.

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

 

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