Photo By Marcy Sanchez | The U.S. Army Corps of Engineers, Walla Walla District, McNary Lock and Dam’s intake...... read more read more
Seventy years ago, the 34th President of the United States Dwight D. Eisenhower, performed the dedication ceremony on the 1.4-mile long, concrete gravity, McNary Lock and Dam on the Columbia River, the first project assigned to the U.S. Army Corps of Engineers’ (USACE) newest district, the Walla Walla District.
Rising approximately 183 feet above the streambed, the dam’s 14 70,000-kilowatt hydroelectric generator units can supply enough power for about 686,000 homes at full capacity. There’s little doubt if McNary Lock and Dam plays a significant role in the Pacific Northwest. However, no significant investments have been made to the project since Ike spoke to a crowd of approximately 40,000 during its dedication ceremony, prompting much needed modernization efforts across the project. One effort was the replacement and modernization of the project’s tailrace and intake cranes, which have been in service since 1953 at McNary Lock and Dam.
“This project was developed and funded as this crane is original to the McNary plant and had numerous safety and reliability issues,” said Samantha Handcox, project manager for the crane replacement project. “The updated design incorporated improved efficiencies and industry innovation while balancing the unique requirements of operating on a hydropower facility.”
The cranes serve vital roles at the project, with the tailrace crane, also referred to as “Crane 4,” purposed to deploy tailrace stop logs, needed to dewater a main unit when maintenance or repairs are necessary. The Intake Crane, or “Crane 5,” is a multipurpose crane which includes deploying head gates, fish screens and removal of debris from the forebay.
The modernization effort aims to enhance hydropower production, improve safety, and boost operational efficiency. Upgrades also meet current and future operational needs. The upgrades are crucial for handling the heavy loads required for hydropower production and maintenance tasks at McNary.
“The most significant change to the physical structure was a complete redesign of the hoisting system which allowed the removal of the “hammer head” located at the very top of the original crane. The new hoisting system also increases the efficiency of fish screen deployment and removal, reducing operational costs for that job by a factor of 2,” said Handcox. “The main hoist capacity was increased by 10 tons to 150 tons, improving the ability to pull head gates and fish screens in and out of water with ease without overloading the crane.”
The updated Crane 5’s auxiliary hoist was also designed for easier placement of debris into trailers during clearing of the forebay, added Handcox.
Additionally, the new cranes feature advanced hoist systems, state-of-the-art control mechanisms, and programmable logic controllers (PLCs) integrated with variable frequency drives (VFDs). These technological improvements will significantly enhance precision and operational reliability. The project also emphasizes safety protocols, incorporating modern safety features to ensure the well-being of the workforce and surrounding environment.
“Prior to redesign, accessing the main hoist trolly as well as the hammer-head machinery housing (located at the crest of the crane) for maintenance, posed a major fall hazard. Now all machinery is easily and safely accessible,” added Handcox.
With the Cranes expected to last upwards of 50 years, the $9.3 million project not only strengthens the infrastructure but also supports the region by enhancing hydropower production, enhancing fish passage through more efficient deployment of the fish screens which redirect fish away from turbines, and protecting the lock and dam infrastructure itself, through more efficient debris removal, ensuring operations aren’t jeopardized.
The project, completed in November 2023, was not without challenges. During the replacement, staff noticed cracks in the concrete beams which support the rails the crane trolleys on, requiring the strengthening of all 48 concrete beams before the new crane was erected. The challenge demonstrated the value of partnerships for USACE as design teams were expecting a three-sided reinforcement of the beams, while the contractor provided a one-sided enlargement solution which would surpass the required load capacity and was finished two weeks ahead of schedule. Collaboration between the Walla Walla District, HDC, and Structural Technology, an industry-leading contractor, was imperative to success.
More than 120 Walla Walla District employees work at the McNary project. They serve as electricians, lock operators, painters, welders, riggers, utility workers, mechanics, biologists, environmental resource specialists, park rangers, heavy equipment operators, administrative staff, engineers, and maintenance workers. Together, they ensure the safe and continuous operation of the project. More than 5.5 million tons of commodities pass through the navigation lock annually.
In 2018, the Walla Walla District awarded a $321.3 million contract to design, manufacture and install 14 new turbines at McNary Lock and Dam, part of modernizing hydropower along the Columbia and Snake rivers. McNary is one of eight dams along the river highway between the mouth of the Columbia River and Lewiston, Idaho.
| Date Taken: | 09.03.2024 |
| Date Posted: | 09.03.2024 14:48 |
| Story ID: | 479981 |
| Location: | UMATILLA, OREGON, US |
| Web Views: | 40 |
| Downloads: | 0 |
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