D.C. Water crews are racing to build an emergency bypass system after a major section of a sewer line collapsed late Monday along Clara Barton Parkway in Montgomery County, triggering a significant sanitary sewer overflow into the C&O Canal National Historical Park.
D.C. Water and contractors are working to build a bypass system to carry 60 million gallons of wastewater daily from areas in Virginia out to Dulles as well as Montgomery County to the Blue Plains treatment plant.
The collapse involves a 72-inch section of the Potomac Interceptor, a 54-mile sewer line that carries roughly 60 million gallons of wastewater a day from communities near Dulles International Airport, Loudoun and Fairfax counties, the towns of Vienna and Herndon, and parts of Montgomery County, to the Blue Plains Advanced Wastewater Treatment Plant for treatment.
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To contain the overflow, D.C. Water is constructing a temporary bypass designed to divert wastewater upstream of the collapse.
On Wednesday, D.C. Water said crews were mobilized to clean up debris and install pipes in preparation for the bypass. In a news release, the utility company said pumps that will redirect the wastewater could be implemented as early as this weekend.
The plan says flow will be routed through a dry stretch of the C&O Canal — a temporary channel, then go back into the Potomac Interceptor downstream of the damaged section. Officials say the bypass is critical to stopping additional overflow and protecting the Potomac River and surrounding environment.
Once the bypass is operational and flows are under control, crews will excavate the damaged area to assess the extent of the collapse and determine how long permanent repairs will take.
On Thursday, D.C. Water and the National Park Service will begin to remove certain upper lock gates needed to accommodate the bypass.
D.C. Water stressed that the incident does not affect drinking water. The District’s drinking water system is completely separate from the wastewater system and water service remains safe and uninterrupted.
The overflow is located downstream from the Washington Aqueduct’s intakes at Great Falls, and intakes at Little Falls have also been closed as a precaution.
The collapse is located just east of the I-495 interchange along Clara Barton Parkway, forcing the closure of the right inbound lane.
As of Thursday morning, authorities said they’re making progress on repairing the watermain.
If you have additional questions or need information, you may contact DC Water’s Customer Care team at (202) 354-3600 (Monday-Friday, 8 a.m. to 5 p.m.) or the 24-Hour Command Center at 202-612-3400.
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