When nearly seven inches of rain fell on the River Falls area last June, it caused a powerful flood in the Kinnickinnic River. The St. Croix River tributary is renowned for its trout fishing, and has also been the focus of debate in recent years over removing two dams owned by the city.
The flash flood last summer was more than one of the dams could handle. The lower dam, Powell Dam, was significantly damaged. In October, the city drew down the reservoir behind the dam, called Lake Louise, so it could inspect the structure.
The inspection found the dam had lost about a foot of concrete on some abutments, while other parts showed cracking of the concrete.
“The inspection revealed that the dam is not in imminent danger of failing, though the cost of repairing it is high,” city utility director Kevin Westhuis told the city council at a January meeting.
Meanwhile, with the impoundment above the dam nearly drained, the river has already begun carving a new channel through accumulated sediment.
In 2018, the council decided it would remove Powell Falls Dam in 2026. The plan is to continue operating the dam for hydropower generation until 2023. While that would bring in approximately $70,000, the minimum cost to repair the structure for the next two years would be $100,000.
One option the city considered after the flood damage was moving up the timeline for removing the structure. Council members eventually decided to keep the dam open and the reservoir drawn down, but not adjust the removal timeline.
The complete removal and restoration is now expected to be completed in 2026.
The other city dam on the Kinnickinnic, upriver of Powell Falls, will likely remain intact and in operation until the mid-2030s and removed by 2040.