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Slip-line repairs of Potomac Interceptor - Lock 14 to Lock 10
Chesapeake and Ohio Canal National Historical Park » Slip-line repairs of Potomac Interceptor - Lock 14 to Lock 10
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 proposes to immediately repair a portion of the PI pipeline generally falling between Lock 10 and Lock 14, which has been identified as the highest priority for repairs. Portions of this pipe will be slip-lined with a smaller pipe comprised of fiberglass-reinforced pipe (FRP) or centrifugally cast fiberglass reinforced polymer mortar (CCFRPM).
Around Manhole 20, DC Water will install suction piping, powered by a number of pumps, to establish a sewage bypass around the area. Four 30-inch diameter HOBAS pipes will convey sewage from the suction chamber at Manhole 20, along the road shoulder of Clara Barton Parkway, and back into the PI system at Manhole 15. Pipes will be staged in an open property adjacent to the I-495 bridge. DC Water will install timber or similar stabilized matting to avoid any rutting or ground disturbance.
Trees, shrubs, and understory plants will be removed where necessary to complete repairs, including for bypass pumping and piping. Vegetation material will be cut and removed from the park. Based on consultation with the US Fish and Wildlife Service, the timing of tree removal associated with this project avoided impacting habitats associated with federally listed and proposed listed bat species, including Myotis septentrionalis and Perimyotis subflavus. Upon project completion, the park will work with DC Water to regrade, restore, and revegetate the site.
All excavation will be completed within the footprint of the existing pipeline so no new ground disturbance will occur. The project site lies 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.
Work is expected to begin with equipment staging during the week of May 11, 2026.
DC Water proposes to immediately repair a portion of the PI pipeline generally falling between Lock 10 and Lock 14, which has been identified as the highest priority for repairs. Portions of this pipe will be slip-lined with a smaller pipe comprised of fiberglass-reinforced pipe (FRP) or centrifugally cast fiberglass reinforced polymer mortar (CCFRPM).
Around Manhole 20, DC Water will install suction piping, powered by a number of pumps, to establish a sewage bypass around the area. Four 30-inch diameter HOBAS pipes will convey sewage from the suction chamber at Manhole 20, along the road shoulder of Clara Barton Parkway, and back into the PI system at Manhole 15. Pipes will be staged in an open property adjacent to the I-495 bridge. DC Water will install timber or similar stabilized matting to avoid any rutting or ground disturbance.
Trees, shrubs, and understory plants will be removed where necessary to complete repairs, including for bypass pumping and piping. Vegetation material will be cut and removed from the park. Based on consultation with the US Fish and Wildlife Service, the timing of tree removal associated with this project avoided impacting habitats associated with federally listed and proposed listed bat species, including Myotis septentrionalis and Perimyotis subflavus. Upon project completion, the park will work with DC Water to regrade, restore, and revegetate the site.
All excavation will be completed within the footprint of the existing pipeline so no new ground disturbance will occur. The project site lies 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.
Work is expected to begin with equipment staging during the week of May 11, 2026.