The Free Press, Mankato, MN

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January 19, 2014

Cross: New water control structure for Swan Lake

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Noting that muskrat populations are a good indicator of a healthy system, he said that trappers took an estimated 50,000 of the furbearers from the lake this past season.

“It’s just ideal out there right now,” he said.

To ensure it stays that way, work is underway to replace the previous water control structure that dated back to the late 1980s.

Key to the new structure, in addition to light-weight aluminum stop logs connected to a cranking system to facilitate easier removal for water level management, will be a fish barrier, something the previous structure lacked.

Innvaer said several designs including a velocity tube, a smooth-walled, inclined culvert that carp are unable to navigate through, and an electronic fish barrier were considered.

“It just wasn’t the right place for a velocity tube and you can imagine the expense of operating an electronic barrier,” he said.

Instead, the barrier will be of more conventional — closely spaced metal bars and a device called a “head knocker” to prevent fish from leaping over it — and designed to be easily cleaned of vegetation and debris.

Design and construction is being done by Ducks Unlimited staff and will be completed in the near future, well before any fish runs might begin.

The $125,000 project is being paid for with money raised from the 3/8 of 1 percent sales tax increase approved by voters in 2008 as the Clean Water, Land and Legacy Amendment.

John Cross is a Free Press staff writer. Contact him at (507) 344-6376 or by e-mail at jcross@mankatofreepress.com.

 

 

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