That ended on Friday sometime shortly after noon.
Over the course of an hour or so, Scarbrough and fellow NorthWestern Energy dam operator Mike Haenke flipped switches, turned dials and tracked meters while forever shutting down the four operating turbines and generators inside the dam's powerhouse.
The shutdown was timed to take place just ahead of the effective date of a consent decree that officially sets the Milltown Dam removal project in motion.
On Monday, authority over the dam will shift from the Federal Energy Regulatory Commission to the Environmental Protection Agency. NorthWestern remains the dam's owner.
EPA is the lead agency in a $100 million project to dismantle the dam and remove about one-third of the 6.6 million cubic yards of contaminated mud that filled Milltown Reservoir during a flood the same year the dam began producing electricity.
The dam was constructed by William Andrews Clark, one of Butte's Copper Kings. It began producing electricity on Jan. 9, 1908.
The three original turbines and generators that generated power for Clark's timber mill and Missoula's new electric street railway system were still operating Friday.
Another pair of turbines and generators was added to the powerhouse in 1927 - one of those was still operating when Scarbrough and Haenke started powering down the plant shortly after 11 a.m.
It was about a 10-minute process to shut down each turbine and generator.
The process began with Scarbrough flipping a switch that would slowly close the head gate to each turbine. As the turbine slowed, the pair of dam operators watched a gauge monitoring the kilowatts being produced by the generator. Once that hit zero, additional breakers were tripped and the huge red spoke wheels of the generators would slowly spin to a stop.
Bill Thompson, a NorthWestern senior engineer, had the honor of flipping the first breaker as the No. 3 generator came off-line.
Over the course of an hour, the rumble inside the power plant faded slowly as each turbine spun to a stop. Finally, only a single high-pitched whine of the DC exciter generators remained. With a ceremonial tug at a pair of long copper knife-blade switches by Scarbrough and Haenke, that sound disappeared as well.
With all the turbines shut down, the temperature inside the concrete power plant began to drop noticeably.
“It's going to get cold in here,” said Scarbrough, nodding toward the now still generators. “That's where the heat came from.”
Before the generators started to come off-line, the dam was generating 2.1 megawatts Friday morning, said Thompson. The power plant was rated at 3.2 megawatts, but over the past few years it maxed out somewhere between 2.4 and 2.5, he said.
One megawatt is typically considered enough to power about 650 homes.
Taking the dam off the grid won't have much of an impact for NorthWestern, but there will certainly be some employees feeling a bit sad to see it go.
“It's been such a long process to get to this point,” said Claudia Rapkoch, NorthWestern's director of corporate communications. “The feelings are a little mixed. Obviously, we've worked hard to get to this point ... but what gets lost, especially from the employee's standpoint, is there's a history here and a bit of sentimental value. It's a little bit bittersweet.”
The company has agreed to donate one of the turbine/generator units to the Milltown Citizens Redevelopment Working Group for its proposed interpretive center. The group also took audio and video recordings of the final power generation for possible inclusion in the center.
NorthWestern will try to sell the remaining generators.
“It's kind of an historic day,” said Peter Nielsen of the Missoula City-County Health Department. “There's no going back now, it appears.”
The next stage in the eventual dam removal calls for drawing down Milltown Reservoir 10 feet during the summer. It won't be until later this fall or early winter that work will actually begin with construction of the bypass channel, a rail spur and other infrastructure.
“That's when people are really going to see things start to happen,” Nielsen said. “All of it appears to be on track right now ... but there's still a lot of work to do and a possibility something might trip it up.”
Back at the dam, Scarbrough and Haenke had just climbed the long stairway up to the top of the structure. There was one last thing to do. A heavy head gate needed to be lowered into place.
The two spent a few minutes getting the gears spinning and then slowly the metal structure began to slide into place. Rugged metal gears came to a stop and the gate settled in.
“That be that,” Scarbrough said. “Milltown Dam is now dead in the water.”
Reporter Perry Backus can be reached at 523-5259 or at pbackus@missoulian.com
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