A cross-border water dispute with Montana threatens Alberta’s plans to boost water supplies and expand the irrigation farming business in the south of the province.
Montana Gov. Judy Martz says Alberta irrigators have been unfairly taking too much water for more than 80 years from the St. Mary and Milk rivers.
The headwaters of both rivers are in Glacier National Park in Montana, and they both flow north into Alberta.
Martz has asked the International Joint Commission, which oversees international waterways, to revisit a 1921 water-sharing agreement between Canada and the U.S. to ensure the state receives its allotted share of the water.
Alberta insists it has abided by the agreement, which the province says has worked well and is as fair as possible given the unpredictable supply of water in both rivers.
“It would be a different issue if we were not meeting the requirements under the agreement. But as far as I know, we are,” said Val Mellesmoen, a spokeswoman for Alberta Environment.
At stake on either side of the border are potential multimillion-dollar projects to capture, store and use more of the water in the rivers to support irrigation.
Richard Moy, chief of the water management bureau in Montana’s Department of Natural Resources and Conservation, says the state plans to spend up to $100 million US to repair and expand a canal and related irrigation infrastructure on its side of the Milk River basin, which spans the border.
“We want the (1921 agreement) to be opened up and we want to ensure that we get our fair share of the water,” Moy said in an interview.
But Mellesmoen said that Montana’s plans “obviously would have a significant impact on the water coming into Alberta.”
An accounting firm hired by the province is just wrapping up its review of a consultant’s $237,000 feasibility study that looked at the economics and environmental effects of capturing and storing more water from the Milk River as it flows through Alberta.
Options include building a dam and reservoir directly on the river or constructing off-stream storage reservoirs.
Alberta and Montana have to respect each other’s water needs, Mellesmoen said.
“But at the same time, we have to respect the reality that the water isn’t flowing the way it was 80 years ago,” due to a warming climate.
Alberta, which also has launched a long-term water-management strategy that focuses on conserving water, is already under pressure from rural landowners to stop the oil and gas industry’s practice of pumping freshwater down wells to push more oil to the surface.
The oilpatch is licensed to use about 180 million cubic metres a year of water, or 4.6 per cent of all water allocated in the province.
Alberta’s irrigation sector receives by far the lion’s share of water – 4.2 billion cubic metres a year, or about 45 per cent.
Southern Alberta’s three largest irrigation districts – the St. Mary River, Raymond and Taber – have a total of more than 500,000 acres under irrigation. And the St. Mary River district is looking at expanding by 20,000 acres.
In comparison, the Milk River basin in Montana consists of 140,000 irrigated acres and there are no plans to expand, Moy said.
The dispute has been simmering ever since Canada and the U.S. agreed, in the 1909 International Boundary Waters Treaty, to share the waters of the St. Mary and Milk rivers.
The north fork of the Milk River flows into Alberta, past the town of Milk River, before it re-enters the U.S. south of Manyberries and flows into Montana’s Fresno Reservoir.
The St. Mary River flows almost directly north into Alberta and into the province’s St. Mary Reservoir.
Moy said that the 1909 treaty stipulates that both rivers are supposed to be considered as one waterway and their flows split 50-50.
But the state’s study found that Montana farmers have been receiving on average about 90,000 acre-feet of water less than half the flow from the two rivers. One acre foot of water is enough to cover an acre of land to a depth of one foot.
The analysis shows that Montana farmers have been averaging only about 43 per cent of the water while Alberta farmers have been getting more than 56 per cent.
In dry years, Montana farmers get only 37 per cent and Albertans take about 63 per cent, Moy said.
The water in the Milk River, which he called “the lifeblood” of Montana’s irrigation-based agriculture industry, sustains crops that make up about eight per cent of the state’s agricultural economy.
Yet in six or seven years out of every 10, he noted, Montana farmers experience water shortages on their side of the Milk River basin.
Moy said the problem is a 1921 agreement between both countries that was used to implement the 1909 water-sharing treaty.
Under the agreement, the U.S. is allowed access to up to 75 per cent of the Milk River’s flow between April 1 and Oct. 31 each year. Canada is allowed the same volume of water during the same period from the St. Mary River.
However, the Milk River frequently runs dry during the summer. The St. Mary River, which supplies southern Alberta’s irrigation farmers, rarely does.
The natural variations in the river flows, combined with the procedures used under the 1921 agreement, have prevented Montana from receiving its full 50-per-cent share of water under the treaty, Moy said.
But Mellesmoen insists that Alberta every year passes along to Montana at least half of the river water flowing from the U.S. through the province and back across the border.
Alberta will continue to pass along Montana’s share of the water, even if the province proceeds with a new water-storage project on the Milk River, she said.
Cheryl Bradley, of the Southern Alberta Environmental Group, says the so-called southern tributaries in Alberta – the St. Mary, Belly and Waterton rivers – are already under stress from over-allocation of water and successive years of drought.
The new water storage and irrigation projects planned on both sides of the border will cause even more diversion and degradation of the rivers, Bradley warned.
The International Joint Commission (IJC), which includes three Canadians and three Americans, plans to hold meetings this summer in communities in both Alberta and Montana.
The IJC wants to hear from stakeholders whether the 1921 water-sharing agreement is still working or needs to be changed.
