On May 17, a concrete drop structure failed on the St. Mary Canal, which is located in northern Montana and owned by the U.S. Bureau of Reclamation. The canal diverts water from the St. Mary River to the Milk River. Permanent repairs to the canal will begin immediately, with completion scheduled for September. Repairs will be paid for by U.S. officials.
“We recognize the severity of the situation and the importance of the Milk River basin to surrounding communities and the local economy. Environment and Parks is supporting Alberta water users and working with our federal and U.S. counterparts to keep water users informed as work to repair the canal progresses.”
“I want to assure my constituents in Taber-Warner that we are taking the situation along the Milk River very seriously. I will continue to meet with the local mayors, reeves and irrigators over the coming weeks and months as this situation continues to evolve.”
Environment and Parks will support Alberta water users in the Milk River basin with an updated water supply outlook, updates on infrastructure repairs south of the border, details on allotments and water use by each country and support for water conservation planning, as necessary.
With no canal in place, water licence holders in Alberta should be prepared for only natural flows on the Milk River throughout the summer and should proactively explore options for water conservation.
Recreational users will also be impacted. Without diverted water via the St. Mary Canal, Milk River water levels will likely be too low this summer for activities like canoeing or kayaking.
No impacts to drinking water or household use are expected. The province provided the Town of Milk River with funding to increase water storage. The town’s current stored water supply would support four months of water use in the event the town was unable to draw any more water from the river.
- Water use on both the St. Mary River and the Milk River are governed by the Boundary Waters Treaty of 1909.
- The accredited officers for the St. Mary and Milk rivers calculate natural flows and water usage by each country semi-monthly during the irrigation season, ensure deficits are balanced by Oct. 31, and resolve disputes, if necessary.
- During the irrigation season (April 1 to Oct. 31), Canada is entitled to 25 per cent of the natural flow of the Milk River, up to a natural flow of 18.9 cubic metres per second, and 50 per cent of natural flows above this threshold.
- On the St. Mary River, from which the St. Mary Canal diverts water, Canada is entitled to 75 per cent of natural flows up to 18.9 cubic metres per second during the irrigation season and 50 per cent of natural flows above this threshold. Natural flows are shared equally with the United States from Nov. 1 to March 31.
- The United States may accumulate a deficit on the St. Mary River from March 1 to May 31, which would be equalized through a Canadian entitlement to water on the Milk River transferred via the St. Mary Canal.
- The St. Mary Canal was constructed between 1907 and 1915.