BABB, Mont. — After a year of urgent construction and collaboration, the Bureau of Reclamation has completed the replacement of the failed St. Mary Canal Siphon and successfully resumed water deliveries into the Milk River. The completion of the $70 million project marks a major milestone in restoring critical water supplies to more than 110,000 acres of farmland and multiple municipalities across north-central Montana.
The St. Mary Siphon failure occurred on June 17, 2024, about eight miles north of Babb, Montana. Both 90-inch siphon barrels catastrophically breached, causing significant flooding, erosion, and an immediate disruption to irrigation and municipal water deliveries. Emergency responders, including local law enforcement and tribal officials, quickly mobilized to mitigate damage and ensure public safety, with water flows naturally diverting back to the St. Mary River to reduce further flooding.
Within days, the Bureau of Reclamation made an emergency determination that allowed for expedited design, permitting, and construction. Reclamation, in partnership with the Milk River Joint Board of Control, the Blackfeet Nation, the State of Montana, and private contractors including NW Construction, Sletten Construction, and Pro-Pipe, began immediate efforts to rebuild.
“Getting this siphon back online within a year is a remarkable accomplishment and a reflection of our commitment to the people who rely on this water every day,” said Montana Area Office Manager Ryan Newman.
The new siphon system replaces deteriorating early-20th-century infrastructure with reinforced concrete and modern steel piping to address long-standing issues like corrosion, seepage, and ground instability. Water is now flowing again through the canal, helping to stabilize agriculture operations, support tribal and municipal needs, and recharge reservoirs like Fresno and Nelson.
With the St. Mary Siphon complete, attention now turns to the Halls Coulee Siphon, located six miles downstream. Crews have already mobilized to begin construction on that replacement, using the same modernized design standards. Importantly, water delivery will continue through the new St. Mary system during much of this next construction phase.
Reclamation estimates the total cost for replacing both siphons at approximately $70 million—$51.6 million for the St. Mary Siphon and $18.4 million for Halls Coulee. Funding has come from the Aging Infrastructure Account, Disaster Supplemental appropriations, and grants from NRCS and Montana DNRC.
“This milestone wouldn’t have been possible without the exceptional work of our contractors and support from the Blackfeet Tribal Employment Rights Office,” said Jennifer Patrick, Project Manager for the Milk River Joint Board of Control. “These crews worked tirelessly under intense pressure and challenging conditions to get water flowing again.”
The Milk River Project is a trans-basin diversion system that moves water from the St. Mary River into the Missouri River Basin. It supplies 60% to 80% of the region’s water annually, serving 18,000 municipal users and irrigating over 120,000 acres. As of now, irrigation projections for 2025 suggest about 0.4 acre-feet of water per acre, with deliveries beginning May 20. Natural runoff from the Milk River Basin will play a key role in meeting these targets.
Water stored in Fresno Reservoir will be prioritized for municipal users, maintaining a minimum release of 40 cubic feet per second. Additional storage will support irrigation and tribal water rights, including the Fort Belknap Indian Irrigation Project.
“Reclamation’s mission is to reliably deliver water to western communities, and this project is a shining example of that mission in action,” said Acting Reclamation Commissioner David Palumbo. “The success here is a result of strong partnerships and shared commitment to resilient infrastructure.”
As work continues on the broader St. Mary Canal system, the region is celebrating the return of a lifeline that sustains both livelihoods and communities across Montana’s Hi-Line.
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Bureau of Reclamation, Milk River Joint Board of Control – 2025
