Impact and cost of St. Mary Diversion failure still being assessed

As Milk River water users have been warning for decades will happen, the 100-year-old system that supplies much of the water in the river has suffered a catastrophic failure.

A concrete drop structure on the St. Mary Diversion and Conveyance work washed out and collapsed Sunday.

St. Mary Rehabilitation Working Group Co-Chair and Montana State University Phillips County Extension Agent Marko Manoukian said Drop 5, which is one of five drops on the St. Mary's project up near Babb and is the last full drop before water enters into the Milk River, failed Sunday afternoon.

"Water delivery from the St. Mary's  to the Milk River has ceased," he said. "And there will be no deliveries in the foreseeable like this year."

The conveyance, one of the first projects the Bureau of Reclamation was authorized to build and administer after the bureau was created at the start of the last century, provides water to irrigators, people recreating on the river and reservoirs and municipal water to Havre, Chinook and Harlem.

Before the diversion was built, the Milk River would dry up by the fall in about 6 out of 10 years.

The project was built to supply irrigators in the Milk River Valley with irrigation water.

Manoukian said the water supply will not run out in the near future. Water is available in Fresno and Nelson reservoirs, the two primary storage facilities for the irrigation and municipalities, he said.

He said the failure means irrigators will have only one irrigation this year.

"I think that Havre, Harlem, Chinook and, I think, Fort Belknap Agency, all use it as a water source. We're going to have to make sure that the reservoirs are drawn down significantly and we're going to have make sure that the municipal water there's enough left over because you'll need it for the rest of the winter," he said.

Hopefully it will be repaired by next irrigation season, he added.

Bureau of Reclamation Montana Area Manager Steve Davies said the cause of the collapse is unknown at this time as well as the costs to fix it.

He said he believes water likely breached the concrete slab, got underneath the slab and caused erosion underneath it and caused further collapse.

The upper end of the diversion is intact, he said, adding that the overflow section of the upper end structure is still intact as is the bottom drop structure.

"Sight conditions are being assessed," Davies said. "We have a large team gathered and we're evaluating options for temporary and permanent repairs, and as soon as that kind of information becomes available we'll certainly share it. We are collaborating not just with internally Reclamation, but with the (Milk River) Joint Board of Control which comprises irrigation districts, their engineering consultant and the state Department of Natural Resources and Conservation."

He said they are assessing water conditions for the Milk River Project irrigators in particular, adding that no decisions have been made relative to reducing water allotment.

"I think it's important to note that this canal provides the primary water source for the Milk River Project irrigators," he said. "In an average year, it represents over 60 percent of their water source. In a dry year, it's more than 80 percent of the entire water supply just conveyed through this canal. It's very impactful in particular to the irrigators, and we're going to be working with them, the Joint Board of Control, essentially daily to assess water supply conditions."

Fresno Reservoir and Nelson Reservoir are currently full, he said, and for the near-term that will be the primary water source for getting them through at least for the next six weeks.

U.S. Sens. Jon Tester, D-Mont., and Steve Daines, R-Mont., each sent letters to the Bureau of Reclamation asking what's the next step to fix this problem.

"The Milk River is a critical source of water on the Hi-Line, and I am deeply concerned how this crisis will impact the upcoming growing season for our farmers and ranchers," Daines said in his letter. "I have long been working on legislation in Congress to complete this water project, and with yesterday's news it is urgent we get this done as soon as possible."

"A wide variety of users rely on the Milk River Project, including eight irrigation districts, three municipalities, and two tribal communities," Tester said in his letter. "The Bureau of Reclamation must take immediate action to assess the full extent of the damage at Drop 5. Understanding the damage will help chart a path towards the work necessary to restore functionality at Drop 5, and secure a reliable water supply for those that rely on this system."

He said this is a cost the BOR will have to shoulder or the irrigators will have have to choose between breaking the bank on emergency repairs or not receiving enough water this season, adding that he will stand ready to work with BOR on any effort to secure the needed funding or authorization to see the work done rapidly and safely.

Rep. Greg Gianforte R-Mont., wrote a letter Monday to President Donald Trump asking him to act quickly to fix the situation.

"I encourage you to take swift action to engage with the Milk River Joint Control Board to fix Drop 5 as quickly as possible," Gianforte said in the letter. "This project is over 100 years old and in dire need of a full upgrade. Fixing this drop structure will allow the project to continue moving water for the upcoming irrigation season. Without this repair, Montanans across the Hi-Line will soon turn on their faucets and no water will come out."

At the start of the last century, the U.S. Bureau of Reclamations was created primarily to address water scarcity in the West. One of the first projects authorized for the BOR was the Milk River Project to provide irrigation water to Milk River Valley farmers and ranchers.

Using construction equipment often drawn by horses, a 29-mile system of dams, dykes, canals and 8-foot tall metal siphons that suck water over the Hudson Bay-Missouri River divide was completed, transferring water into the north fork of the Milk River which runs into Canada and then back down into Montana. The Milk River Project also includes Fresno Reservoir, Nelson Reservoir by Malta and other dams, dykes and reservoirs.

Patchwork repairs have been done to the system over the years, paid for primarily by the users.

Milk River water users began campaigning at the start of the last decade to find funding to rehabilitate the system to prevent catastrophic failure, which led to the state establishing the St. Mary Rehabilitation Working Group in 2003. The group has been working to plan and find funding for rehabilitation ever since.