Halls Coulee Siphon construction begins
Crews perform work at the site of the newly completed St. Mary Canal Siphons near Babb, MT.
BILLINGS, Mont. – The construction to replace the failed St. Mary Canal Siphon is complete and the Bureau of Reclamation has started operations to resume water deliveries into the Milk River. 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.
"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. "Reclamation, working shoulder to shoulder with the Joint Board, the Blackfeet Nation, and the State of Montana, ensured this project remained on track under extraordinary circumstances."
The effort follows the catastrophic failure of both 90-inch siphon barrels on June 17, 2024, located approximately eight miles north of Babb, Montana. The breach caused extensive erosion and disrupted irrigation water deliveries throughout the region. Reclamation made an emergency determination for both the St. Mary Siphon and the Halls Coulee Siphon, enabling expedited design, environmental review, and construction, allowing construction activities to begin almost immediately.
The new siphon system replaces the early-20th-century infrastructure with modernized steel piping and reinforced concrete structures. It is designed to address the historic issues of seepage, corrosion, and instability caused by landslides. With the system again operational, water is moving through the canal to support agricultural operations, municipal systems, and tribal water uses.
Following the completion of the St. Mary Siphon, construction crews have mobilized approximately six miles downstream to begin work on replacing the Halls Coulee Siphon. This next phase of the project can proceed while the St. Mary system is operational, ensuring continued water delivery during a portion of the construction period. 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.
"The completion of this replacement project underscores Reclamation's mission to reliably deliver water and meet our obligations to western communities," said Acting Reclamation Commissioner David Palumbo. "Our success here is the result of strong collaboration with local, Tribal, and state partners, and it reinforces our ongoing investment in resilient infrastructure."
"This milestone wouldn't have been possible without the exceptional work of our contractors—NW Construction, Sletten Construction, and Pro-Pipe—and the critical support provided by the Blackfeet Tribal Employment Rights Office," said Project Manager for the Milk River Joint Board of Control Jennifer Patrick. "These crews worked tirelessly under intense pressure and challenging conditions to get water flowing again. Their commitment to quality, safety, and collaboration made all the difference for the Milk River Project and the communities that depend on it.”
The Milk River Project, a trans-basin diversion from the St. Mary River to the Missouri River watershed, provides 60% to 80% of the water used annually in the region. Reclamation will continue monitoring canal flows and infrastructure performance and coordinating closely with stakeholders to ensure operational stability through the 2025 irrigation season and beyond.
