Round Butte Dam Dump Tunnel Aerator
Madras, Ore.
Merit Award
Presented by Syblon Reid
Owner/Engineer/Project Manager Portland General Electric
Leading design company Schnabel Engineering
General Contractor Syblon Reid
Subcontractors Condon-Johnson & Associates Inc.; Northwest Scaffold Service Inc.; M2 Integration LLC; Smith Monroe Gray Engineers Inc. (SMG); Eastern Oregon Iron Co.; Manufacturing Products Inc.; CEI Forms Inc.
This critical dam infrastructure upgrade, located 200 feet down a spillway tunnel on a sustained 52-degree slope within Round Butte Dam, is only the fifth retrofit concrete tunnel aerator constructed in the US.
The project was commissioned during a turbine intake valve replacement design analysis to mitigate potential cavitation damage during spills, making this the first retrofit installed proactively to prevent damage rather than respond to failure.
The access system designed by the contractor was critical to the success of the project. Engineered scaffolding and a custom rolling platform powered by dual hydraulic winches span the entire perimeter and slope of the tunnel, allowing safe access throughout construction.
After drilling and FERC-approved chemical grouting to stabilize the substrate and control seepage, the team began demolition of the tunnel using a remotely controlled Brokk 170 hydraulic breaker. Despite encountering unexpected sandstone geology that extended drilling operations and required field adaptations, the team maintained the stability and safety of the tunnel.
