Work at St. Mary Diversion nearing completion

The largest concrete pour to date took place last Friday on the St. Mary Diversion and Conveyance Works, where the drop near the end of the 29-mile system of dams, dikes, canals, gigantic metal siphons and concrete drop structures failed in May.

Work on Drop 2 was already planned for this year and is underway, and the work on Drop 5 was added after it failed May 17. Work also is being done on Drop 1.

“(Friday) morning started the biggest pour to date, with right under 200 yards on the Drop 5 … wall which wrapped up (Friday) afternoon,” Milk River Joint Board of Control Project Manager Jennifer Patrick said. “All went very well. I was a little worried (Thursday) as we had an emergency wind advisory in the area and those walls are high.”

The diversion was built more than 100 years ago by the Bureau of Reclamation as part of the irrigation system the Milk River Project, and also is used as a municipal water source by towns including Havre, Chinook and Harlem and provides recreation opportunities.

 Patrick said the concrete break tests are coming in great and they are losing in on completion on Drop 5. 

The forecast for this week looks good, she said, adding that they will plan to pour more next week and the cutoffs the following.  

“Drop 2 continues with site grading and rip-ap placement, but that structure is 100 percent complete,” Patrick said. “A lot of the dirt work remains, but we are prioritizing the south sides of both structures first because once we start running water, we cannot access them. Conversations with a company to hydroseed the south side this year are taking place, but that is on the low side of our priority list.

“We all want to see water this year in the structures and we can address the final touches after shutoff or next spring,” she added.

The diversion provides much of the water that flows through the Milk River, which typically ran dry by fall in 6-out-of-10 years before the diversion was built.

The diversion has been shut down since the drop collapsed May 17.

At the time, Fresno and Nelson reservoirs, part of the Milk River Project that use water from the diversion, were at very high levels, but have been drawn down for irrigation use.

Fresno and Nelson reservoirs had above-average storage levels and were used to provide continued irrigation deliveries up through July.

“Because we were having so much fun, we dug into Drop 1 when the Drop 2 crew finished (two weeks ago),” Patrick said. “The plan is to do an overlay on the walls and floors because the structure is 100-years old and we would like to avoid this scenario in the future.”

Drop 1 walls should be poured toward the end of next week and then the top of the walls will be the last pour, maybe on Oct. 7 or 8, she said.

“At (that) point we can turn on the water,” Patrick said.

After fixing Drop 2 and 5 and Drop 1 is shored up, the next step is to work on the dam that diverts water into the conveyance work that transports it to the Milk River, although no funding is set for that at the moment.

Under the original authorization at the start of the last century, most of the funding for the diversion and The Milk River Project comes from users, primarily the irrigators, who pay for about 75 percent of the costs with the federal government picking up about 25 percent.

The work being done now was declared an emergency project, so the federal government will pick up the first 35 percent with the remainder split between the users and the federal government. The total cost is estimated at about $8 million.

Sens. Jon Tester, D-Mont., Steve Daines R-Mont., and Rep. Greg Gianforte, R-Mont., are trying to shift the funding for the system from about 75 percent provided by the users and 25 percent by the federal government so the federal government picks up about 75 percent of the cost of operation and maintenance.

The St. Mary Rehabilitation Working Group, created in 2003 to plan for the system’s rehabilitation and how to fund that rehabilitation, is holding a meeting Thursday to discuss the funding and a legislative draft from the group to send to Tester’s office.

Patrick also said the crews have poured a new apron at the siphon and completed other maintenance while the diversion and conveyance work is shut down. 

 Two weeks ago, they built and installed fish screens at the diversion dam, she said.

Last year, the Alliance for the Wild Rockies filed a lawsuit over the protection of bull trout requesting fish screens to be put up.

The planning for the rehabilitation project included installing fish screens before the lawsuit was filed.

Alliance for the Wild Rockies Executive Director Mike Garrity said said he’s very happy that the government agreed with them and installed fish screens.

“Now, the request in the lawsuit for injunctive relief is moot, but we are still requesting declaratory relief to establish the fact that the government broke the law,” he said

Bureau of Reclamation Montana Area Manager Steve Davies said Reclamation has installed temporary adult fish screens at the St. Mary Canal headworks structure in anticipation of operating the canal in October, provided the ongoing efforts to replace Drop Structures 2 and 5 are complete.

This operation will allow them to partially replenish significantly depleted storage levels in Fresno Reservoir in advance of next year’s operating season, he said, and also facilitate replenishing.

These screens will hopefully aid in preventing the entrainment of adult bull trout to the system, Patrick said.

“We have been working with Fish and Wildlife Services and a late-season fish salvage has been scheduled at canal shutoff, first of November,” she said. “The St. Mary crew will start getting things ready (this week) for turning the system back on.”