McMillen has collaborated with Chelan PUD on several contracts to upgrade or rehabilitate hydroelectric facilities. Our work has included design and specifications development and close coordination with their staff to prioritize capital improvements at the Rocky Reach (1,300 MW) and Rock Island (629 MW) Dams. Since 2019 we have been assigned four Master Services Agreements. Tasks have included root cause analysis for failures, permitting support, feasibility of environmentally acceptable lubricants, oil accountability assessment, turbine upgrades, and a vulnerability assessment for invasive quagga and zebra mussels.
Example task orders include:
Rocky Reach Tainter Gate Hoist Design:
McMillen inspected the 200-ton hoists, made recommendations, and is responsible for the design of the hoist replacement. The new hoist system simplifies the existing drivetrain, eliminates open gearing, improves maintenance and safety, and updates the controls. Our design shortens onsite installation time, minimizes oils impacting the environment, enables personnel access, and provides capacity for future needs.
Rocky Reach Trash Rack Rehabilitation:
McMillen assisted Chelan PUD with refurbishing trash racks at 11 turbines. The trash racks ranged from 50 to 70 years old and reached the end of their useful life. Work included extracting the trash racks, sandblasting them, analyzing the structural integrity, and reinstalling them.
Rock Island Powerhouse 1 Equipment Upgrades:
McMillen provided oversight of a prime contractor’s work in the disassembly, inspection, analysis, modification, design, construction, and commissioning of six vertical Kaplan and four vertical propeller turbine/generator main units (25MW each) at Powerhouse 1. The project’s purpose was to reset the usable life of each main unit to 40 years and increase unit efficiency. The upgrades required complete teardown, rehabilitation or modification of parts, and new manufacturing of select components.
Rock Island Spillway Gate Design Improvements:
After a comprehensive alternatives analysis on the spillway configuration, McMillen provided a 30% design to upgrade or repair 40 gates in 7 different configurations (vertical lift gates up to 55 feet tall, over-under gates, and notch gates for fish passage) to accommodate 31 spillway bays. The design improves spillway performance, reliability, safety, and function and includes gate operators, storage mechanisms, latching and connections, and enhanced dogging components. Work also includes seismic retrofits and concrete repairs. We are also completing the final design for two options that will be used as prototypes for other gates on the spillway.
Rock Island Program Management:
McMillen provides program management services to integrate several initiatives to improve dam safety and enhance operational efficiency. Our team prioritizes needed improvements, coordinates projects, develops and maintains comprehensive cost-loaded schedules and cost estimates, communicates with the respective stakeholders and Chelan PUD’s FERC relicensing team, and advises on contract execution.
Additional tasks include:
- Chinook Broodstock collection trap
- Seismic retrofits and concrete repairs
- Assessments to optimize operations
- Oil accountability program and lubricant assessments
- Mussel vulnerability assessment
