Project Links
2026 - Groundwater grouting to facilitate sewerline repairs at Pennyfield
Chesapeake & Ohio Canal NHP » 2026 - Groundwater grouting to facilitate sewerline repairs at Pennyfield
The National Park Service continues to coordinate with DC Water as the organization plans to complete critical infrastructure repairs on the Potomac Interceptor (PI) sanitary sewer system. DC Water had previously identified a critical section of the PI that required immediate repairs near Pennyfield Lock (Lock 22) in Potomac, MD (see https://parkplanning.nps.gov/projectHome.cfm?ProjectID=136861). As work on this section has progressed, DC Water has since identified a need to manage groundwater intrusion within the excavation areas in order to successfully access and work within the PI pipe.
DC Water will work with contractor Anchor Construction and sub-contractor CJGeo to complete this work, which will ultimately facilitate the long-term repair and rehabilitation of this section of PI as originally described. At the site of the excavation pits, DC Water will perform permeation grouting from the ground surface both up and downstream of the PI to prevent continued groundwater intrusion around work areas of the pipe. Grout will consist of a combination of single component and acrylate grouts. Dewatering wells, drilled adjacent to excavation areas, will also be in operation to reduce groundwater present at the pipe sections.
Upon completion of grouting work, DC Water will proceed with repair activities at each excavation area. Tubes and other infrastructure used for grouting and dewatering will be removed if feasible or cut and abandoned below grade. NPS, DC Water, and contractors will be monitoring the canal prism and adjacent areas to ensure operations do not 1) result in incidental migration and transport of grout, 2) affect groundwater flow or volume in the canal, and 3) result in inadvertent return of grout to the ground surface in the park.
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.
Updated project schedule has been delayed with an anticipated completion of January 2027.
DC Water will work with contractor Anchor Construction and sub-contractor CJGeo to complete this work, which will ultimately facilitate the long-term repair and rehabilitation of this section of PI as originally described. At the site of the excavation pits, DC Water will perform permeation grouting from the ground surface both up and downstream of the PI to prevent continued groundwater intrusion around work areas of the pipe. Grout will consist of a combination of single component and acrylate grouts. Dewatering wells, drilled adjacent to excavation areas, will also be in operation to reduce groundwater present at the pipe sections.
Upon completion of grouting work, DC Water will proceed with repair activities at each excavation area. Tubes and other infrastructure used for grouting and dewatering will be removed if feasible or cut and abandoned below grade. NPS, DC Water, and contractors will be monitoring the canal prism and adjacent areas to ensure operations do not 1) result in incidental migration and transport of grout, 2) affect groundwater flow or volume in the canal, and 3) result in inadvertent return of grout to the ground surface in the park.
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.
Updated project schedule has been delayed with an anticipated completion of January 2027.