MWH provided comprehensive engineering, design and services during construction for the award-winning Arrow Lakes Hydroelectric Project, a design-build project that included a 170 MW powerhouse in southern British Columbia, Canada.
Located on the Columbia River, the project was constructed on the north side of the existing Hugh Keenleyside Dam, which was completed in 1969 without power facilities. The dam, built to control flooding and flow to downstream hydroelectric facilities, impounds 8.8 billion cubic meters of water, forming the Arrow Lakes Reservoir. Existing facilities included a navigational lock, gated concrete spillway, debris boom, an earth-fill dam, and a concrete gravity dam with outlets.
The project included a new, single-monolith, powerhouse 400 meters downstream of the existing dam with two 85 MW vertical axis Kaplan turbines. The integral intake, surface-type powerhouse forms the water retaining structure at the downstream end of the approach channel and incorporates post-tensioned anchors in the intake structure. Water to the new powerhouse is conveyed via a 1.4-kilometer-long channel excavated through overburden and rock on the north side of the existing dam. A new concrete face rock-fill dam was constructed downstream of the existing dam to connect the existing dam with the new powerhouse.
As a partner on the design-build team, MWH provided civil, structural, geotechnical, geological, hydraulic, electrical, mechanical, and architectural engineering services and services during construction. The project was honored for innovative application of project delivery and unique solutions.
MWH developed an innovative and cost-effective design that provided the Owner an economically viable and technically sound project.
Design and support during construction enabled early completion of the project, namely the first unit was put into operation approximately seven months ahead of schedule.
The Consulting Engineers of British Columbia honored the project with the Lieutenant-Governor’s Award for overall excellence and the Award of Excellence for the category of Resource, Energy, Industry and Environmental Engineering.
The Design-Build Institute of America honored the project with the Design-Build Excellence Award in the category of Industrial/Process Sector over $25 million for advanced and innovative application of total integrated project delivery and finding unique solutions to project challenges.