Cougar Dam Spillway Gate 2 Rehabilitation

Prime Contractor: Advanced American Construction
Owner: U.S Army Corps of Engineers
Location: Blue River, OR | September 2022 – April 2025

Advanced American Construction (AAC) rehabilitated Spillway Gate 2 at Cougar Dam, a remote flood-control facility 60 miles east of Eugene. Built in the 1960s, the gate required full restoration to ensure safe, reliable flood management, hydroelectric operations, and environmental protection across the Willamette River Basin. AAC’s scope included structural steel reconstruction, installation of new operating machinery, corrosion-resistant coatings, and a major upgrade of the electrical power distribution system serving the spillway gates.

The project involved precision work under challenging conditions: crews performed fracture-critical welding to AWS D1.5 standards, replaced trunnion bearings with alignment tolerances within fractions of an inch using advanced surveying, and installed line shafts with tolerances as tight as one-thousandth of an inch. The rehabilitated gate was commissioned with a wire-rope balancing process, achieving just 2.5% tension variance across all lift lines.

Working 2,000 feet above sea level, crews faced narrow single-lane access roads, steep drop-offs, and confined workspaces over the spillway and visitor areas. Environmental and weather extremes, including sleet, heat, rain, and wildfire risk, required flexible planning and adaptive field operations. Portions of the original gate contained red-lead primer, which necessitated full containment and specialized safety protocols to protect workers and the surrounding forest.

AAC completed the rehabilitation safely, meeting all structural, electrical, mechanical, and environmental requirements, restoring the gate’s reliable operation for flood control.