09-07-2025
Southern Albertans still feeling the effects of Montana's St. Mary Siphon failure
For over a century, a diversion plan in Montana has sent additional water flowing down the Milk River into Canada.
However, in June of last year, a catastrophic structural failure at the St. Mary Siphon occurred, eventually halting flow downstream.
While the primary use of the water is on the American side of the border, Canadians were still affected.
'During the diversion failure, our natural flow was only hovering around one cubic metre per second and it did hit zero flow in early June, which caused a cessation order for our irrigators on the Canadian side,' said Tim Romanow, executive director of the Milk River Watershed Council of Canada.
Immediately following the failure, American crews began working to repair the St. Mary Siphon. They managed to complete their job well ahead of schedule, turning the taps on again on June 25.
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In a news release the same day, the U.S. Bureau of Reclamation said the repair was crucial for farmers.
'Completing the St. Mary Siphon is the first step to restoring critical water supply to more than 110,000 acres of farmland and multiple municipalities across north-central Montana.'
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Romanow says the Milk River, which was nearly empty and dry, began seeing a significant boost in water near the town of Milk River, Alta., by Canada Day. Unfortunately, due to water-use agreements, Canadian farmers are still unable to use irrigation on their crops for the remainder of 2025.
'I always say it's Montana licence-plated water. This is Montana-only water that we see flowing past us. The way the boundary water treaty works, we're only entitled to 25 per cent of the natural flow of the Milk River,' he said.
'We're able to use less than 1/15th of the water that's flowing past us right now as that's what we're legally entitled to.'
To add to the headache, repairs south of the border aren't totally complete yet, either.
'Right now, what we're seeing for the river flows will be sustaining until Aug. 15, at which time there will be a scheduled shutdown to allow for more construction on the Halls Coulee Siphon, which is part of the infrastructure in Montana as well,' said Romanow.
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The U.S. Bureau of Reclamation says the repairs are vital for the future of the entire canal system.
'The Halls Coulee replacement will build on the same modern design standards, further strengthening the reliability of the entire St. Mary Canal system for future generations.'
While Romanow says this work is good and required to ensure sustainable flow next spring, he says there is still a lot more to do before confidence is fully restored.
'There are still three drop structures and over 20 miles of canals that need rehabilitation work before we feel like we've actually got long-term water security in this system.'
While the St. Mary Siphon repairs evidently affected farmers, they weren't the only ones feeling the impact.
'A lot of the large body fish species were lost last year and some species like Western Silvery Minnow was a full loss of the spawn and they probably weren't going to be found,' said Romanow.
He says, for better or worse, they've learned a lot about the ecosystem of the past year as wildlife has also had to deal with the sudden loss of water.
