On or about May 16, 2020, a drop structure (Drop 5) experienced a catastrophic failure resulting in the inability to deliver water from the St. Mary Facilities. This would effectively eliminate approximately 10% of Montana’s irrigated agricultural economy, devastate Hi-Line communities and likely have economic repercussions across the state. Failure of the canal, siphons or drop structures would also likely result in substantial environmental damage on the Blackfeet Reservation in southern Alberta. In addition, failure of the system would jeopardize the Fort Belknap and Blackfeet Federal Reserved Water Rights Compacts.
The Bureau of Reclamation, the State of Montana – Department of Natural Resource and Conservation, the Blackfeet Tribe, and the Milk River Joint Board of Control collaborated quickly on this project to restore valuable water. The Joint Board of Control hired HDR Engineering and Sletten Construction through emergency measures to proceed with replacement or repairs. The Construction and Engineering Teams conducted emergency site visits and provided quick geotechnical, design, and on-site support to re-establish water flow in the St. Mary Canal as soon as possible. In addition, while the canal was offline, the team moved forward with the replacement of the structure at Drop 2.
Just 22 weeks after the catastrophic collapse, dignitaries gathered to cut the ribbon on the new St. Mary Canal Drop 2 & 5 Replacement project — on budget and ahead of schedule. The project re-establishes water flow across the Hi-Line and provides reliable access to the thousands of irrigators, ranchers, communities, tribes and habitats that rely on it.
A Canal That Opened the Montana Prairie May Soon Dry Up
St. Mary Milk River Drop 2 & 5 Failure DNRC Document
May 17, 2020
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