Project Links
Relieve pressure and sample pipe wall thickness on sections of Potomac Interceptor
Chesapeake and Ohio Canal National Historical Park » Relieve pressure and sample pipe wall thickness on sections of Potomac Interceptor
The Potomac Interceptor (PI) sanitary sewer system includes a significant portion of its length within the Chesapeake and Ohio Canal National Historical Park in Maryland and Washington, D.C. The system, managed and operated by DC Water, was constructed in the 1960s from reinforced concrete pipe ranging from 72 to 84 inches in diameter. This system, including the municipal sewer systems that feed it, transports sewage from a significant portion of Maryland, northern Virginia, and Washington, D.C. to the Blue Plains wastewater treatment facility. The sewer system enters the park as it crosses the Potomac River just south of Great Falls and parallels the canal, Clara Barton Parkway, and Canal Road until it reaches Georgetown, Washington, D.C.
DC Water has recently completed remote inspections of the pipeline within the park and in doing so has identified several sections that warrant additional investigation and action:
- Location 1: west of Interstate-495 bridge over the park. A small section of this pipe, approximately 15 by 50 feet in area, will be excavated to relieve overhead pressure from sediment and rock resting above the pipe. DC Water will then drill through the crown of the pipe to sample material and assess thickness and integrity of the pipe. Once complete, the area of the pipe coring will be repaired. Access to this area will be done from existing access routes off Clara Barton Parkway.
- Location 2: near Chain Bridge, along Canal Road. The pipe in this area is between 1 to 3 feet from the ground surface. The crown of the pipe will be excavated and a similar pipe coring sample will be taken. Access will be from road shoulder.
- Location 3: near Little Falls Creek. The pipe in this area is similarly close to the ground surface. Work will involve a small amount of excavation and pipe coring sample. Access will be from road shoulder.
These efforts will help inform future infrastructure repair and rehabilitation by DC Water. All excavation will be completed within the footprint of the existing pipeline so no new ground disturbance will occur. The project sites lie in the road shoulder and outside of traditional visitor use areas (e.g., the towpath), so no formal area closures will be necessary. The project will not cause any adverse effects to historic properties or historic resources, and the minor excavation and data collection efforts will not affect any endangered or threatened species. Further, proposed work will not necessitate removal of any vegetation except for some disturbance to mowed grass in the road shoulder. Grass will be re-seeded, as necessary.
All work will be performed by DC Water and/or its designee/contractor within the existing DC Water right-of-way. This work will be permitted under NPS Special Use Permit. Questions about the Potomac Interceptor system and planned repair work can be addressed by DC Water: https://www.dcwater.com/potomacinterceptor.
Work is expected to begin the week of Apr 6, 2026.
DC Water has recently completed remote inspections of the pipeline within the park and in doing so has identified several sections that warrant additional investigation and action:
- Location 1: west of Interstate-495 bridge over the park. A small section of this pipe, approximately 15 by 50 feet in area, will be excavated to relieve overhead pressure from sediment and rock resting above the pipe. DC Water will then drill through the crown of the pipe to sample material and assess thickness and integrity of the pipe. Once complete, the area of the pipe coring will be repaired. Access to this area will be done from existing access routes off Clara Barton Parkway.
- Location 2: near Chain Bridge, along Canal Road. The pipe in this area is between 1 to 3 feet from the ground surface. The crown of the pipe will be excavated and a similar pipe coring sample will be taken. Access will be from road shoulder.
- Location 3: near Little Falls Creek. The pipe in this area is similarly close to the ground surface. Work will involve a small amount of excavation and pipe coring sample. Access will be from road shoulder.
These efforts will help inform future infrastructure repair and rehabilitation by DC Water. All excavation will be completed within the footprint of the existing pipeline so no new ground disturbance will occur. The project sites lie in the road shoulder and outside of traditional visitor use areas (e.g., the towpath), so no formal area closures will be necessary. The project will not cause any adverse effects to historic properties or historic resources, and the minor excavation and data collection efforts will not affect any endangered or threatened species. Further, proposed work will not necessitate removal of any vegetation except for some disturbance to mowed grass in the road shoulder. Grass will be re-seeded, as necessary.
All work will be performed by DC Water and/or its designee/contractor within the existing DC Water right-of-way. This work will be permitted under NPS Special Use Permit. Questions about the Potomac Interceptor system and planned repair work can be addressed by DC Water: https://www.dcwater.com/potomacinterceptor.
Work is expected to begin the week of Apr 6, 2026.