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.
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.