Oak Grove Frog Lake Flowline Repair and Construction

We were the prime contractor for this project to reinforce the flowline from a slow moving landslide that has been occurring in the area for years and recover power generation capacity lost due to damage from the 2020 wildfires.

Frog Lake’s earth and dam was successfully excavated, maintained, and restored to its existing condition with additional filter material. Even with record rainfall and weather conditions, we successfully dewatered and maintained the excavation site for the duration of construction. Additionally, the existing flowline encased in concrete at the toe of the Frog Lake dam was reinforced with new grout ports, an engineered EPDM seal, and 212 CY of new concrete extending 44 LF to protect the flowline from seismic activity. Also, four piezometers (water-measuring devices) were installed for real-time water monitoring. We completed the project to specification and within time constraints, allowing PGE to recommission their Oak Grove Powerhouse before the salmon spawning deadline upstream of Frog Lake.