UPDATE: Piney Branch Parkway Temporary Closure & Relocation

DC Water has nearly completed the construction site setup (tree removal. fence, erosion & sediment controls, utilities, and trailers) in preparation for the upcoming shaft and tunnel construction. Site completion requires Piney Branch Parkway to be closed temporarily to relocate a section of the road between 17th Street NW and west of the 16th Street bridge before starting the shaft and tunnel work (See map below).

On or about May 12, 2026, Piney Branch Parkway will be closed between Arkansas Avenue NW and Beach Drive. Detour signs will be in place to notify and direct vehicles to alternate routes. The closure is anticipated to last twenty-seven days, weather permitting. The roadway will be returned to the original alignment at the end of the project.

The above image shows the relocation of Piney Branch Parkway in orange.

Traffic Impacts

•    Piney Branch Parkway will be closed from Arkansas Avenue NW to Beach Drive. NW for up to 27 days, weather permitting. 
•    17th Street NW between Newton Street NW and Piney Branch Parkway NW will only be open to local traffic and residents.
•    Detour signs and flaggers will be in place to direct traffic.
•    The pedestrian path along Piney Branch Parkway will be maintained for the duration of the project. Expect occasional short duration closures.

Piney Branch Parkway Detours

•    To Beach Drive south from Arkansas Avenue NW motorists will be detoured to 16th Street NW south, to Park Road NW to Klingle Road NW and onto Beach Drive. (Yellow)
•    To Beach Drive north from Arkansas Avenue NW motorists will be detoured to 16th Street NW south, to Park Road NW to Beach Drive. (Orange)
•    To Arkansas Ave. NW from Beach Drive south motorists will be detoured onto Park Road NW to Walbridge Pl. NW to Adams Mill Road NW to Irving St. and onto 16th Street north to Arkansas Ave. (Purple)
•    To Arkansas Ave. NW from Beach Drive north motorists will be detoured onto Porter Street NW to Klingle Road NW to Adams Road NW to Irving Street NW and onto 16th Street north. (Blue)
•    17th Street NW between Newton St. and Piney Branch Parkway NW will only be open to local traffic and residents. 

Additional Information

•    Project construction to continue through 2029.
•    Work hours: Monday through Saturday, 7:00 a.m. to 7:00 p.m. No work on federal holidays.
•    Noise and vibration monitors will be installed to monitor construction activity.

Piney Branch Tunnel Project

DC Water’s Clean Rivers Project is constructing the Piney Branch Tunnel Project within Rock Creek Park in northwest Washington, DC.  The tunnel will capture and store a minimum of 4.2-million gallons of sewage combined with stormwater, known as combined sewer overflow (CSO), that will otherwise overflow into Piney Branch when the capacity of the existing combined sewer system is exceeded during storms. The United States Environmental Protection Agency (USEPA) currently lists Piney Branch as an impaired waterbody under the Clean Water Act.

The Piney Branch Tunnel Project will comply with the 2005 Federal Consent Decree entered into by DC Water, the District, the USEPA, and the US Department of Justice, as amended January 2016, and modified December 2020. The project is designed to improve water quality in Piney Branch, Rock Creek, and ultimately the Potomac River and Chesapeake Bay by reducing untreated discharges to the sewer system and increasing sewer overflow storage and conveyance capacity.

Currently, an estimated 40 million gallons of untreated combined sewer discharge overflows into Piney Branch in a year of average rainfall during heavy storm events. This harms local waterways and wildlife. Once completed, the Piney Branch Tunnel will capture and store most of this overflow during storms, reducing these overflows by 96% and limit the frequency of overflow events from 25 to one in a year of average rainfall.