Canada studies damming the Milk River

Renewed interest by the Alberta provincial government in building a dam across the Milk River has caused some Montana irrigators to question the project.

"Without the ability to receive the water due to us from the St. Mary River, it will just hurt us," said Randy Reed of Blaine County, who irrigates with Milk River water.

Kay Blatter, chair of the Milk River Board of Control, the organization that oversees the irrigation boards on the Milk River, isn't so sure.

"There's good and bad about it," he said.

The Milk River, which originates in Montana, crosses into Canada and returns to Montana about 80 miles farther east. The U.S. Bureau of Reclamation oversees a system that releases water from Lake Sherburne into the St. Mary River and diverts it to the Milk River for irrigation.

Sherri-Dawn Annett, a spokeswoman for the Alberta Department of Environment, said building a dam is just one of several alternatives the department is looking into.

"Right now we're in the process of doing a preliminary study," she said. "What it really translates into is fact- finding."

The preliminary study will be completed June 30. Then the Department of Environment will decide whether to pursue any of the options identified, Annett said.

The study was commissioned because the Alberta towns of Milk River and Coutts, north of Sunburst, have suffered from low water supplies from the Milk, especially in the drought years from 1999 to 2001, she said.

Issues the study will examine include the cost, benefits and environmental impacts of several alternatives, including building a dam on the river and creating or expanding offstream storage, Annett said. No alternative will be recommended in the study.

"It's an all-encompassing, nonbiased study," she added.

Increasing the water supply for the towns is one reason the department commissioned the study, but it also could translate into additional irrigation and recreation use, Annett said.

Once the best alternative has been identified, another study will be done to examine it more closely, she said.

Reed said that if a new dam is built on the Milk River, people in Montana will lose surplus water that flows down the Milk now.

Water-use agreements between the United States and Canada give an advantage to Canada, he said.

During the irrigation season from April 1 to Oct. 31, Canada receives 75 percent of the water in the St. Mary River up to a certain rate of flow, with any surplus split with the United States, said Tim Felchle, hydrologist with the Bureau of Reclamation.

The United States receives 75 percent of the Milk River up to a certain rate of flow, with any surplus split evenly with Canada, he said.

Because the storage at Sherburne and the capacity of the diversion from the St. Mary River is not sufficient, Felchle said, some of the water the United States is entitled to flows into Canada during the highest runoff time."During the irrigation season we're diverting as much as we can," he said.

Meanwhile, the Canadians aren't able to store all of the water from the Milk River they are entitled to and that water flows to Montana, Felchle said.

Dick Long of the Bureau of Reclamation said a dam could keep up to 40,000 acre-feet of water from coming into Montana that Canada is entitled to under current agreements.

"We would lose that surplus water," he said.

Felchle said losing 40,000 acre-feet that comes down the Milk would translate to a reduction in irrigation allotments by about 20 percent.

While losing the surplus might not impact water use in cities much, it might require a little more conservative use, especially in the winter, he said.

"I don't think we'd try to short (towns), but we'd try to protect the water supply," he said.

Long said an alternative would be for the state to enter an agreement with Alberta to build a bigger reservoir that could store some water for Montana as well as for Alberta.

Rich Moy of the Montana Department of Natural Resources and Conservation said the state is considering that as one option in managing the Milk River water supply, but it's too early to talk about any possible benefits or drawbacks.

The Bureau of Reclamation is conducting a study on the entire Milk River basin, which includes looking at the need to rebuild the St. Mary Diversion, which was first constructed some 90 years ago. Moy said that study could identify many ways to improve the water supply, including a Canadian dam.

"What we'd do is look at this as one option to possibly pursue," he said.

Blatter said extra storage could be a benefit to Montana for a couple of reasons. The runoff from snowmelt often comes too fast and at a time when the irrigators can't use it, he said.

Another possible benefit would be reducing the amount of silt running into Fresno Reservoir west of Havre, Blatter said, although how much it would help hasn't been determined. The reservoir, which has 90,180 acre-feet of storage, loses about 500 acre-feet every year from silt settling on the bottom, he said.

"That, I think, needs to be a consideration too," Blatter said.

Reed said he opposes that idea too. The surplus water Montana would lose outweighs any possible benefit, he said.