Dam overflow procedure doesn’t include calling nearby residentsWhen Minnesota Power opened dams on the Cloquet River in last month’s torrential rainfall, homes on Hunter and Bowman lakes flooded.
By: Jana Hollingsworth, Duluth News Tribune
When Minnesota Power opened dams on the Cloquet River in last month’s torrential rainfall, homes on Hunter and Bowman lakes flooded.
Hunter Lake resident Hazel Lafler, 100, said she wasn’t told to evacuate.
“Maybe they think we were bright enough with 9 inches of rain to take care of it on our own,” she joked, noting that no one was prepared for the amount of rain that came, notification or not.
But protocol for a situation like the one that faced the power company on June 19 and 20 doesn’t call for notifying residents individually.
Minnesota Power has three emergency classifications for certain situations, said Pat Mullen, vice president of marketing and corporate communications for the company.
Cases A and B involve failure of a dam and imminent failure of a dam. In those two circumstances, Minnesota Power would call eight downstream residences determined by Minnesota Power and the Federal Energy Regulatory Commission to be in the most imminent danger during a failure. Those eight residences are aware of their status, Mullen said. Minnesota Power has never had to use its call-out procedure.
Case C involves a high water flow through, around or over the dam — and that’s what happened June 19 and 20. Under that scenario, Minnesota Power calls the National Weather Service, which alerts the public via weather radio, television and its website that a high flow and potential flood condition exists.
The National Weather Service in Duluth issued this warning between 7:30 and 8 p.m. on June 19: “Below Island Lake and Fish Lake, the Cloquet River will rise rapidly with water being released from those reservoirs affecting residence (sic) around Bowman and Hunter Lakes.”
That information came from Minnesota Power, said National Weather Service meteorologist Dean Melde.
Lafler said she never heard the warning.
“There (was) no call-out procedure required and none done” the week of flooding, Minnesota Power spokesman Mullen said. “In that sort of storm situation, you have operators working the controls, making sure all of the procedures are followed. It’s usually OK. Obviously, in a situation like this, there was a lot of water in a short amount of time. I’m sure (residents) had a short amount of time to react.”
The lakes north of Duluth were made into reservoirs nearly a century ago to store water and regulate the flow along the St. Louis River — of which the Cloquet River is a tributary — to create steady hydroelectric power at the Fond du Lac, Thomson, Knife Falls and Scanlon dams downstream.
Though all the dams on the system held, the amount of water gushing through the system caused unprecedented flooding in many areas, from Island Lake to Duluth’s Fond du Lac neighborhood.