If you've noticed the Missouri River looking unusually low in Great Falls, don't blame drought.
The lower water levels are part of a planned drawdown at Black Eagle Dam as NorthWestern Energy completes the final phase of a multi-year rehabilitation project aimed at strengthening the dam's spillway.
The drawdown began on July 31 and is expected to continue through approximately Sept. 16 while crews replace aging steel stanchions, install new steel panels and weld critical joints that couldn't be accessed while the reservoir was full.
"The last two years, we were able to work with a full reservoir. All that work has been completed," said Jerry Gray, superintendent of NorthWestern Energy's five Great Falls dams. "So the final part of it is to draw the water down to reinforce the spillway portion of Black Eagle Dam."
Gray said the project was driven by the need to better withstand the heavy ice that builds up on the Missouri River during Montana winters.
"The ice was the main driver of this project," Gray said. "So this is the last step. Early September it'll be back to full pool with a totally redesigned spillway."
To protect the riverbanks, NorthWestern Energy lowered the reservoir gradually — about one foot every 10 hours.
"We drain it slow intentionally to de-water the banks so that that water can kind of come out of the mud and silt, and it makes it a lot more stable," Gray explained. "If you do it too quickly, then you can get banks collapsing. So, we try to do it very slow."
While the work is taking place at the dam, the lower river level is also affecting several Great Falls Park and Recreation facilities that rely on Missouri River water for irrigation.
Those include Anaconda Hills Golf Course, Eagle Falls Golf Course, Montana Veterans Memorial Park, Voyagers Stadium, Gibson Park, Elks Riverside Park, Tourist Park and Electric City Water Park.
With less water available, city crews are adjusting irrigation schedules and focusing on high-priority areas.
"You might see some of the turf suffering a little bit. It's not dead. It'll bounce back," said Great Falls Park and Recreation Director Toby Hazelbaker. "We're watering whenever we can, as often as we can, so you may see some odd watering hours. And that's simply to keep up with the demand during the hot weather, but also because our capacity is diminished with the water level going down."
Residents may notice sprinklers running during the daytime and some grassy or landscaped areas appearing drier than usual over the next several weeks as crews prioritize high-use areas, trees and other critical landscaping.
Despite the lower water, Gray said recreational opportunities remain available upstream near the Sun River confluence above the 10th Avenue Bridge. However, he urges people to avoid the exposed muddy shoreline.
"We just encourage people to stay away from the banks because there are some muddy areas, and you could get stranded out there," Gray said.
NorthWestern Energy expects water levels to return to normal around Sept. 16, once the final repairs to Black Eagle Dam are complete.
