When John Sours shows up to rescue a trout stream, his first few days seem like an act of destruction.

Sours is a Wisconsin Department of Natural Resources habitat biologist who has restored trout streams for 30 years. He's often seated at the controls of a 23-ton excavator, where a reporter found him recently along the Kinnickinnic River near River Falls.

Earth-ripping work by Sours and others has helped restore more than 60 miles of trout streams in the past five years in western Wisconsin and southeast Minnesota. The big machines strip away thick layers of bank sediment that destroy trout habitat.

"You have so much stream bank erosion that you have 2 feet of silt in the bottom of the stream," Sours said. For anglers, "It's practically unwadable."

Minnesota and Wisconsin trout anglers often must walk along high, crumbling stream banks, thanks to reckless land-use practices decades ago that washed topsoil into valleys.

"I tell people they are standing on 5 or 6 feet of deposits from the ridge tops and it is hard for some people to believe," said Jeff Hastings, a project manager for the Driftless Area Restoration Effort, a regional initiative of the nonprofit Trout Unlimited.

These degraded streams are being revived, resulting in stable banks, deeper holes, plunge pools and undercut banks that hide more and bigger fish. Many angler-volunteers work on these efforts.

"If you walk a stream before habitat improvement, in a mile you might find some places with a deep pool and overhead cover where you are going to find some fish," said Hastings, a fly fisherman. "After we do a project, almost every bend is going to have overhead cover. Instead of six or seven places to fish on that mile, you are going to have 20 to 27."

Both states have done stream habitat projects for decades, but the techniques have evolved. Today, most projects aggressively flatten stream banks to reduce persistent siltation from high-water scouring.

"We need to re-create the flood plain for the stream," said Brian Nerbonne, who coordinates stream habitat restoration for the Minnesota Department of Natural Resources. "We do a lot of sloping of the banks and carving out new flood plain so that when the stream has higher flows, the water comes up and spreads out outcross the wide flood plain and doesn't cause a lot of erosion."

In Minnesota, $13 million from the Outdoor Heritage Fund has been committed to trout stream restoration since 2009. More than 30 streams have undergone work. Hay Creek, near Red Wing, is one of the largest efforts.

Wisconsin commits trout stamp receipts — about $1.5 million per year — to habitat restoration. The state's program, supplemented by volunteers, individual and corporate donors and federal grants, has accomplished significant work, including Pine Creek near Maiden Rock, Parker Creek, a tributary to the Kinnickinnic River and parts of Trimbelle Creek near Ellsworth.

Dirty piece of history

Trout streams' sediment problems can be traced to the late 19th and early 20th centuries, when settlers stripped trees and tilled soil on ridge slopes across southeast Minnesota, southwest Wisconsin and northeast Iowa. The hilly region, with more than 4,000 miles of trout streams, is called the Driftless Area because glaciers didn't drift through it during the Ice Age.

In southeast Minnesota, the former town of Beaver on the Whitewater River was abandoned after floods in the 1930s buried it in 15 feet of eroded soil. More recently, on Cady Creek in Pierce County, Wis., a DNR trout stream rehab crew uncovered a telling example of the problem. "Eight feet down we found a barbed-wire fence — buried in the ground," Sours said.

On a spring day along the upper Kinnickinnic River, Sours had just scraped back several feet of soil and was putting down a layer of rock that would be covered with soil and replanted to create a new, hardened — and lower — stream bank.

He and others also had removed some big trees, including their root wads, and piled them up. The logs will be embedded in the banks to create cover structure.

"What we are doing is very artificial, and it's controversial, but we are trying to almost lock the river into a certain, stable state and restore the trout habitat as much as possible so we have long-term sustainability," Sours said.

This project is on private land whose owner sold the DNR a fishing easement. Trout streams are public, but Minnesota and Wisconsin agencies won't improve them unless anglers have access.

Once completed, this stretch of the Kinnickinnic will have fewer trees and thorny bushes. That's because Randy Arnold, volunteer coordinator for the Hudson-based Kiap-TU-Wish Chapter of Trout Unlimited, assembled teams of volunteers to remove unwanted vegetation. Crews later will replant the banks with native species.

Focus on SE Minnesota

A surge in trout stream rehabilitation is happening in southeast Minnesota thanks to Outdoor Heritage funding.

Raymond Ricketts, a retired IBM project manager who has helped coordinate 21 stream projects as a Trout Unlimited volunteer, said chapters in the region have been awarded $1 million or more a year since 2009. Instead of doing one or two projects per year, the group oversees several, using local contractors to supplement DNR crews.

The work has ranged from Trout Run Creek south of St. Charles to Rush and Pine creeks north of Rushford and Camp Creek near Preston. Two tiny streams near Harmony have been preserved as habitat for native brook trout.

One upcoming project is on the South Branch of the Root River in Preston. "This river has seen so much damage," Ricketts said. "It's going to take a lot of work."

During trout stream restorations, shallow-rooted trees are cut down. This reduces shade, but the increased light nourishes aquatic insects that trout eat.

"I've heard people say that years ago they would get extremely good hatches," Ricketts said, referring to the emergence of stream-bred mayflies that produce exciting fly fishing. "This is our goal, not just to get the fish back, but also the food."

Workers will place boulders and embed logs in a 1.5-mile mile stretch of the South Branch of the Root, using flood-resistant designs. The presence of an adjacent bike trail means the high banks can't be flattened, but their slope will be reduced.

Another big southeast Minnesota project is Mill Creek, near Chatfield, where workers used heavy equipment to lower stream banks and install in-stream cover. One badly eroded section is being rechanneled to avoid a collapsing hillside.

Trout hiding spots are created beneath banks by installing wooden "lunker structures" — logs, root balls and boulders. Many projects also create habitat for nongame species, such as turtles and birds.

Trout numbers can increase up to tenfold after habitat improvement projects.

"The real value of this is if we can create something sustainable for the next generation," said Ricketts, who at 77 is wrapping up his last two stream projects in southeast Minnesota.

David Shaffer is a former Star Tribune staff writer. • dshaffer@outlook.com