Officials with the U.S. Bureau of Reclamation are conducting an environmental assessment on an estimated $200 million in upgrades to Hungry Horse Dam expected to take nearly a decade.
It’s the largest project undertaken on the dam since it opened in 1952 and will likely include the replacement of its four turbines.
If all goes smoothly, project manager Chris Vick said, the work could begin in 2017 and wrap up as early as 2025.
“The units are pretty much reaching the end of their expected life,” Vick said. “You want to get ahead of that before you start breaking down and you’re in repair mode constantly.”
The Bonneville Power Administration would cover the costs to modernize the facility.
The plans were first announced last December, and the pre-scoping period that followed brought just a handful of public comments.
Montana Fish, Wildlife and Parks, the U.S. Fish and Wildlife Service and Glacier National Park expressed support, but asked the bureau to consider any negative impacts to downstream aquatic life, including westslope cutthroat trout and threatened bull trout.
“I don’t believe our concerns are anything that would stop the project — it’s just a matter of doing things in the right sequence at the right time,” Brian Marotz, the state agency’s hydropower mitigation coordinator, said Wednesday.
The Flathead Valley chapter of Trout Unlimited echoed those concerns, writing that in the past, “peaking flows following dam construction and the release of very cold waters in the spring and summer were very detrimental to our native fishes.”
Vick said the bureau would avoid those negative impacts by timing the unit upgrades so that, at most, only one is offline at a time during the high-flow season. Otherwise, he said, water could back up and leave via the dam’s spillway, resulting in higher levels of dissolved oxygen than water passed through a generating unit.
The construction of Hungry Horse Dam took place from 1949 to 1952 after four years of pre-construction work that included clearing trees and building the facilities required for the massive undertaking.
When then-President Harry Truman threw the switch to start the flow of power from the new facility in 1952, Hungry Horse Dam was the third-largest in the United States and a state-of-the-art hydroelectric plant.
Since then, the 1950s-era mechanical controls have become outdated by more precise computer systems, which Vick said would be one of the first upgrades under the modernization project.
“The whole power train is all original,” he said. “You can imagine it’s outdated. There are no computers controlling anything. Now we can add much finer detail to the control of the units.”
The bureau would also replace the governor and excitation systems, which control the flow of water and create the magnetic field to generate electricity, respectively.
Five of the dam’s six cranes will be replaced early in the process so they can be used for replacing larger components later in the process. The other crane was replaced in 2000.
The task of replacing the turbines and rewinding the generator would take up half of the project’s total cost, Vick said.
As part of the ongoing environmental assessment, the bureau will install flow meters to test the current turbines’ efficiency and determine how much could be gained by replacing them.
The dam still houses the original 1950s cast-iron turbines, which require periodic repairs to add new layers of metal. The new turbines, if needed, would be stainless steel.
“Basically, air bubbles form due to the high pressure of the water, and that eats away at the metal,” a process called “cavitation,” Vick explained. “With stainless steel turbines, they’re pretty much cavitation-resistant. There wouldn’t be major repairs required.”
That will be the final phase of the upgrade, expected to begin in 2022 and finish in 2025.
Vick added that replacing the turbines could increase the generation capacity of the dam, but demand in the valley would be the limiting factor. The Bonneville Power Administration would need to upgrade its transmission lines to sell power outside the region.
Despite the project’s hefty price tag, its local economic footprint likely will be small.
Vick said he expects the bureau would hire between 15 and 20 workers, the bulk of whom will be mechanics and electricians.
“There’s just not that much space physically for people to fit into one place,” he said, adding that the federal agency usually hires as many local workers as possible, although some specialized positions may be filled from elsewhere.
Vick also floated the possibility of donating one or more of the old turbines — should they warrant replacing — to Hungry Horse or Kalispell.
“Typically we just scrap those, but if that’s something the community is interested in, I’d like to preserve that,” he said. “It just kills me, sending it to the junkyard, turning it into scrap metal, versus being on display to the community.”
Reporter Sam Wilson can be reached at 758-4407 or by email at firstname.lastname@example.org.