After 10 inches of rain fell on Minnesota’s Sucker River over just 24 hours, a massive flood put a natural stream restoration there to the test.
John Lenczewski, executive director of Minnesota Trout Unlimited, said the flood definitely was a setback to their restoration, but without their work habitat damage likely would have been worse.
“The floodplain logs performed beautify,” Lenczewski said, referring to logs anchored to places on the shoreline to buffet flood waters and debris. “That’s a great logjam.”
Lenczewski shared this story with participants in a recent stream restoration webinar hosted by Sustain Our Great Lakes. Speakers focused on the use of natural structures, mainly large logs and rocks, to improve both flow and habitat with strategic placement.
Stream habitats in the Great Lakes region took historical blows from pollution and industrial activity and many now are in a fragile state. Now many organizations work to naturally restore these limping habitats while managing flow and erosion.
“Over the past 20 years there’s been a shift in channel design philosophy,” said Paige Baker, engineer and co-owner of Collins and Baker Engineering. “Channel design focuses more now on channel dimensions and profile.”
The concept sounds simple, but engineers do more than drop a boulder here and a fallen log there. Any kayaker who has ever traveled through a large stream may pass through natural stream restoration elements without even noticing. That fallen tree with exposed roots shooting into the water from a nearby bank may be there on purpose.
“We used a number of stabilization strategies,” said James Kettler, executive director of the Lakeshore Natural Resources Partnership, describing his experience restoring Centerville Creek in Cleveland, Wis. “(We) build riffles and use mats to stabilize banks.”
Stream restorations incorporate several design elements to optimize flow and sediment scour. For example, riffles composed of rocks grouted in place to form a small cascade can concentrate fast-flowing water in the center of the stream.
Mike Mlynarek of the U.S. Fish and Wildlife Service spoke about a restoration project that used logs to help restore streams in Wisconsin’s Whittlesey Creek National Wildlife Refuge near Lake Superior.
“A lot of this area was pretty much blown out by log drives,” Mlynarek said.
Logging runs left shallow wide stream sections full of sediment and without cover. It was a bad combination for native coaster brook trout.
Mlynarek said properly placed logs and root wads created an effect that scoured unwanted sediment, leaving only rocky stream beds and good cover for native fish.
Monitoring by local youth conservation corps revealed relatively quick removal of sediment. There was also a noticeable recovery of the trout population in just four months, Mlynarek said. They plan to install 400 logs in the Whittlesey Creek Watershed in 2013.
The webinar ended with presentations describing funding opportunities for Great Lakes stream restorations, including grants from the U.S. Fish and Wildlife Service, the National Oceanic and Atmospheric Administration and the National Fish and Wildlife Foundation. Click here to find more information on funding opportunities.
Top image: A natural logjam on Whittlesey Creek (Credit: USFWS)