NuFlow Services of St. Louis successfully repaired leaking conduits at the Barkley Dam Power Plant using trenchless NuDrain CIPP technology. By addressing both groundwater intrusion and an unexpected tunnel wall leak, the team delivered a cost-effective solution that met the high standards of the U.S. Army Corps of Engineers (USACE).
Groundwater Intrusion Threatens Barkley Dam Power Plant Operations
The Barkley Dam Power Plant in Grand Rivers, Kentucky, faced a serious issue when groundwater began leaking into the powerhouse tunnel through eight rigid steel conduits. These conduits had been installed by an electrical contractor, but the steel couplings became compromised, allowing water to seep into the conduits and the tunnel. This posed a significant risk to the power plant’s operations, requiring an immediate and effective solution to stop further water intrusion.
Narrow, Remote Conduits Create Major Repair Challenges
Several factors added complexity to the repair. The conduits in question were extremely narrow, with diameters ranging from only 1 to 2 inches. This small size made accessing and lining the pipes extremely challenging. Additionally, the conduits were located 350 feet from the tunnel entrance, complicating access and debris removal during cleaning. The project also had to contend with high moisture levels and tight spatial constraints, which made working conditions more difficult. Given that the contractor was dealing with a warranty issue, there was also considerable pressure to resolve the situation swiftly.
NuDrain CIPP Technology Provides a Trenchless, Watertight Solution
To resolve the issue, NuFlow Services of St. Louis utilized NuDrain CIPP technology, which involved lining the conduits to create a watertight barrier. The conduits were first cleaned using high-pressure air abrasive blasting with a silica carbide aggregate. Evacuating the debris posed a challenge due to the 350-foot distance from the tunnel entrance, but a 2-inch suction hose was used to successfully remove the debris.
Once the cleaning was complete, eight NuDrain liners were consecutively installed within the leaking conduits. This application tested the limits of NuDrain’s small-diameter solutions, as the conduits included multiple bends and diameters as narrow as 1 inch. To successfully rehabilitate the pipes, the application and curing pressures exceeded 100 psi, ensuring a durable, watertight seal despite the challenging pipe configuration.
Shortly after inflating the final liner, water began leaking through the tunnel wall—a new problem outside the original scope of work. To address this, Prime Resin’s “Prime Flex 920 HydroPhobic Polyurethane Injection Resin” was ordered and shipped overnight. A method of drilling holes into the affected penetrations was implemented, followed by injecting the grout to fill the voids. As the process progressed, one penetration began leaking significantly, but the team managed to successfully seal the tunnel wall by continuing the grouting process and using the NuDrain liners in combination.
Successful Repair Passes USACE Inspection and Restores Confidence
Despite the challenging conditions, the project was successfully completed. All conduit lines were fully lined, and the tunnel wall was sealed effectively, addressing both the initial groundwater intrusion and the unexpected tunnel wall leak. The electrical contractor was highly satisfied with the innovative and swift solution provided by NuFlow Services. The final inspection by the U.S. Army Corps of Engineers confirmed the repair met all standards, with no wrinkling in the conduit bends and minimal loss of internal diameter, ensuring the cables had sufficient space to pass through. This project highlights how NuFlow’s trenchless technology excels in adapting to complex, demanding conditions, delivering durable and cost-effective solutions.
This project was completed by NuFlow Services of St. Louis for the U.S. Army Corps of Engineers (USACE). The mention of USACE in this case study is for informational purposes only and does not imply or constitute an endorsement or recommendation of NuFlow Services, its products, or services by USACE or the Department of the Army. All statements made here are solely related to the work performed and are not intended to convey any government endorsement.
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