Additional Potomac Interceptor pipe core sampling to inform repairs

DC Water proposes to complete additional pipe core sampling of the Potomac Interceptor sewer system following the same means and methods as previously described and completed under a previous project (see https://parkplanning.nps.gov/projectHome.cfm?ProjectID=135554). Additional sampling work is needed to inform future infrastructure repair and rehabilitation efforts by DC Water.

- - Location 1: two sections at Little Falls pumping station, with one upstream and one downstream of the building. Access via mini excavator from DC Water access road
- - Location 2: adjacent to parking area by Lock 6, adjacent to road shoulder
- - Location 3: near Chain bridge, along Canal Road in road shoulder (same as previously sampled)
- - Location 4: near Little Falls Creek at the DC line, next to canal in grass shoulder (same as previously sampled)

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 on or after Apr 28, 2026.