Knife River modified at Second Falls

Jason Radzak with RJS Construction in Superior guides a heavy rock into place on below the Second Falls on the Knife River Wednesday afternoon. Two rocks were placed below the falls so that migrating rainbow trout can ascend the falls more easily during low flows. (Sam Cook photo)

A construction crew using a large excavator lowered two stones, each weighing about 24,000 pounds into the Knife River Thursday afternoon to improve the stream for migrating rainbow trout. The stones were placed just below the Second Falls on the river to form a deeper “jumping pool” to help trout leap the falls.

“During low flows, the fish are not able to get over the Second Falls because the jumping pool isn’t deep enough,” said Scott Kuiti, vice-president of the Lake Superior Steelhead Association.

Placing the rocks in the river forms a deeper pool during low flows, Kuiti said. The fish likely will be able to simply swim up the falls rather than having to leap, he said.

With two rocks in place below the Second Falls on the Knife River, a deep pool is formed upstream of the rocks. The rocks were placed there Wednesday to replace a concrete barrier that had been washed out of the river several years ago. (Scott Kuiti photo)

The rocks replace a concrete barrier that had served the same purpose until it was washed out several years ago. DNR officials originally had opposed the project, saying that enough steelhead were clearing the falls to spawn. But the agency changed its mind and let the project go forward.

“We’re just happy to see everybody moving on, so the focus can be squarely on improving the habitat upriver,” said John Lenczewski, executive director of Minnesota Trout Unlimited.

The steelhead association is paying for the project with part of a $380,000 Legacy grant it received, although the stream improvement portion likely will cost less than $50,000, Kuiti said. The work was done by RJS Construction in Superior. The DNR designed the project and provided a permit for the work. The rock was donated by Cliffs Natural Resources, Kuiti said.

 

 

2 thoughts on “Knife River modified at Second Falls

  1. Won’t this just allow weaker trout to make the jump and hurt the gene pool in the long run? Why do we continue to mess with natural created order of things?

    • These boulders are an effort to restore the falls to conditions more consistent with the original unaltered pool depth before MN DNR
      past alterations to the falls. Movement of anadromous fish up the river at this falls, including coaster brook trout, will find conditions which will match more closely those found before previous alterations. This “modification” will still provide
      challenging conditions to migrating fish while not preventing movement of anadromous fish in low water flows we have been experiencing some years. Healthy fish prevented from yearly migrations over this falls had little chance of successful natural reproduction in the river as low flows and high temps combined to create less than optimal spawning and rearing of young of year and pre-smolt trout.

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