Minnesota Power diversion canal washed out near Thomson DamA portion of embankment along a man-made diversion canal has washed out into the water above the Thomson Dam, Minnesota Power officials said Thursday.
By: John Myers, Duluth News Tribune
A portion of embankment along a man-made diversion canal has washed out into the water above the Thomson Dam, Minnesota Power officials said Thursday.
The problem poses no threat to the dam and doesn’t affect water flow in the raging river, said Amy Rutledge, spokeswoman for the Duluth-based utility.
The move sent more water through the river at Jay Cooke State Park, which is closed because of the high water.
The canal diverts water from the main river into the electrical generating station that’s part of the system of dams along the lower
St. Louis River. Utility officials said there are no problems with any of the four dams along the lower river — including the Fond du Lac, Thomson, Scanlon and Knife Falls dams between Cloquet and Duluth.
“The integrity of Thomson Dam was not impacted by this event. No homes were affected and public safety was not at risk when the released water flowed back into the St. Louis River,” Rutledge said.
Stream flow on the St. Louis River at the Fond du Lac dam rocketed tenfold from the usual 2,000 to 5,000 cubic feet per second to a gushing 47,000 cubic feet per second Wednesday morning, Rutledge said, as more dam gates were opened to relieve flooding behind them.
Minnesota Power did have to shut down electrical generators at its Scanlon generating station because water had risen to flood the floor of the building, said Bonnie Carlson, hydropower operations manager for Minnesota Power.
The utility’s dams at all five reservoir lakes north of Duluth also were holding well, although some areas below the lakes are flooding along the Cloquet River because so much water is flowing through, such as at Hunter Lake.
The utility’s hydro operations went into emergency operations mode early Wednesday and began to open gates in the dams to allow more water to pass through and prevent floods upstream. That caused the St. Louis River to rise rapidly in the Fond du Lac neighborhood, as it has often in the past, and inundate riverfront areas there.
Rutledge said company officials have not determined when the diversion canal will be repaired. The utility’s hydro system is shut down, in an ironic twist, because there is too much water moving down the river.