St. Mary River siphon failure floods Blackfeet Tribe lands

UPDATE: Tuesday, June 18 at 2:14 p.m.

The following is a press release from the Bureau of Reclamation:

On June 17, 2024, both St. Mary River siphons experienced structural failures outside Babb, Montana. The breach caused substantial water discharge, affecting the surrounding areas. The breach led to severe erosion, resulting in washout areas at the breach site, impacting the hill and concrete footings holding the pipes. Water flows are expected to continue throughout the day. They are anticipated to subside sometime this afternoon as the canal drains.

The majority of the damage is located on lands administered by the Blackfeet Tribe. The flooding caused road closures and disruptions to utilities such as water and electricity. The community, which relies heavily on this water for agriculture, will be significantly impacted for the rest of the season. Though the Fresno and Nelson dams are nearly full, the water supply is expected to be depleted over the next several weeks.

The incident primarily impacted residents and tribal land. Hooks Hideaway, a facility in close proximity to the breach, has been affected, and livestock has been successfully relocated from the site. No injuries have been reported. The Bureau of Reclamation and Emergency Services, including local law enforcement, are actively involved in the response efforts. The Bureau of Reclamation is coordinating with local services to bring bulldozers to restore access to flooded areas. The Bureau of Reclamation’s primary concern is the safety of people and property. When the flooding subsides, Reclamation will evaluate any available short-term solutions, along with long-term rebuild options.

Ryan Newman, Reclamation’s Montana Area Office Manager, stated, “Our primary concern is the safety and well-being of the community. We are committed to supporting those affected and are finding solutions to restore water availability to the affected area.”

Planning activities for the replacement of the St. Mary siphon were funded through the Bipartisan Infrastructure Law and were initiated in 2023.  The plans for replacement of the St. Mary Siphon are currently at a 60% design stage.  Geotechnical and cultural investigations were underway before winter weather set in.

The St. Mary siphon is a critical component of the Milk River Project, designed to transport water from the St. Mary River across the valley. It consists of two 90-inch riveted steel barrels traverse the valley from the inlet, transition to an 84-inch diameter at the river crossing, and then back to 90 inches in diameter as they ascend the valley slope to the outlet. The siphon has a maximum head of 165 feet and was constructed in two phases, with the downstream barrel completed between 1912-15 and the upstream barrel after 1925.

The siphon has undergone extensive repairs due to seepage, corrosion, and buckling. A cathodic protection system was installed in the 1950s to address these problems. However, unstable valley sidewalls have caused further movement of the steel barrels and concrete supports, leading to additional damage.

UPDATE 8:50 p.m., 6/17/24:

Both Senator Jon Tester and Senator Steve Daines have issued statements following the St. Mary Canal flood.

Sen. Tester called on the Biden Administration for more immediate support for the local community. 

“The timing of this failure could not be worse because hundreds of farmers and ranchers are currently depending on the Milk River Project to irrigate their crops,” Tester wrote in a letter to Secretary of the Interior Deb Haaland and Secretary of Agriculture Tom Vilsack. “This is a disaster that requires the immediate and full attention of the Department of Interior and the Department of Agriculture. I ask that you swiftly work to ensure that the local community and the irrigators have the resources they need to confront the challenges that lay ahead.”

Sen. Daines said he has been in contact with both local irrigators and the Bureau of Reclamation. 

“The damage is serious, and I’m standing by to help local authorities in any way necessary,” Sen. Daines tweeted. “With the second siphon failure at St. Mary’s today I’m keep close contact with authorities on the ground. Stay vigilant and stay away from the affected areas.”

The following is a news release from the Bureau of Reclamation on Monday, June 17, 2024. 

BABB, Mont. – The St. Mary Canal Siphon breached just outside Babb, Montana, at approximately 8:45 a.m. today, resulting in isolated flooding in the surrounding area. The breach caused local flooding and erosion, with some areas resulting in washout areas estimated to be 30 to 50 feet deep. Diversions to the canal were 600 cubic feet per second (cfs) at the time of failure, diversions have been stopped however flows are expected to continue for as long as 24 to 36 hours while the canal drains.

This breach has affected residents and surrounding communities directly or indirectly. Emergency response teams, and local law enforcement are involved in the response efforts. The Bureau of Reclamation is coordinating with the Gallatin County Sheriff’s Department, Blackfeet Tribe, National Park Service, Glacier County Sheriff’s Department, and Glacier Electric to limit the impacts of the breach and ensure people remain safe.

“Emergency response teams have been deployed to contain and evaluate the damage,” said Ryan Newman, Reclamation’s Montana Area Office Manager. “Water flows were naturally diverted back to the St. Mary River and helped mitigate the potential for additional flooding in the surrounding area.”

 The flooding has caused localized property damage in direct proximity to the breach, impacted local infrastructure, and may pose risks to public safety. Roads are closed, and utilities may potentially be disrupted in the affected areas. Traffic cones and caution tape have been placed to limit access to potentially dangerous areas.

Reclamation and local authorities responded quickly to the breach and will be conducting damage assessments to the St Mary system, local property, and surrounding areas. Residents are advised to avoid the area and follow evacuation or safety orders from local authorities.

The Bureau of Reclamation is coordinating assets and experts to assess the damage and potential cause of the failure and will be evaluating both short term solutions, if any, along with long-term rebuild options. Detailed inspections will commence as soon as the water empties from the line and surrounding ground is determined to be stable. 

The St Mary Canal, completed in 1915, diverts water from the St. Mary River to the North Fork of the Milk River in Montana., is a critical infrastructure component for water management in the region and serves 120,000 acres of irrigated land and approximately 14,000 municipal users. The Bipartisan Infrastructure Law was designed to mitigate events like this by allocating $8.3 billion for the Bureau of Reclamation to repair aging water delivery systems, secure dams, complete rural water projects, and protect aquatic ecosystems.