July 23 (Reuters) - Authorities are building a new containment boom to fight an oil spill in a major western Canadian river, officials said on Saturday, after the spill breached a previous barrier and threatened the drinking water of several communities along the coast.
The city of North Battleford, which draws its drinking water in part from the North Saskatchewan River, shut its supply intake on Friday and switched to using ground water, provincial officials said in a telephone conference with reporters.
Some 1,572 barrels of heavy oil and diluent leaked from Husky Energy Inc's Saskatchewan Gathering System pipeline on Thursday, flowing into the river. The company shut the line, stopping the leak, and has been working to contain the spill.
The Calgary-based Husky did not immediately respond to a request for further comment, but previously said it was expecting "minimal impact."
It is not immediately clear what caused the spill.
Water levels rose on Friday, pushing debris into the booms upstream from North Battleford, a city of 14,000, and the oil continued to moved downward.
The province of Saskatchewan has started building a new boom near the community of Maymont, about 50 km (31 miles) downstream from North Battleford, though it is not sure when the oil spill will reach it, Wes Kotyk, executive director of environment protection with the province of Saskatchewan, told reporters.
Water security is a concern as North Battleford's treatment capabilities for groundwater are limited, and water usage in summer is high, said Sam Ferris, Saskatchewan's executive director of environmental and municipal management services.
He said authorities are working on plans to deal with the issue for communities farther down the river, including several small communities and Prince Albert, a city with 35,000 people.
Kotyk said the federal environment agency is working on a "trajectory model" to determine the exact size and rate of movement of the oil plume, which officials don't yet know.
He said authorities are making plans for cleanup of the shoreline, parts of which had been polluted as the oil made its way downstream.
Bert West, in charge of petroleum and natural gas in Saskatchewan, said it is too early to talk about cleanup costs or how the incident could potentially affect the economy.
"We haven't have a spill like this, so we're not sure," he said. "As far as costs go, we're not worried about that at this point."
Reporting by Ethan Lou in Toronto; editing by Diane Craft