Dennis Anderson
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– Irony surfaced like a trout rising to a fly on a recent morning as Dr. Michael Osterholm of the University of Minnesota held forth in the neatly kept garage of his hideaway near this picturesque northeast Iowa village.

One of the world’s leading authorities on infectious diseases and biosecurity, and a U regents professor, Osterholm, 64, had himself been afflicted since childhood by a bug for which there is no cure.

Which was fine by him.

Because the malady in this case is a deep affection for stream trout and the cold, flowing water and multitudinous insects these fish require to survive.

A native of Waukon, Iowa, about a 20-minute drive from Dorchester, Osterholm was explaining to a small cadre of similarly stricken trout enthusiasts that he had first fished Waterloo Creek “on this property” as a child.

“Then in 2002, I bought it,” Osterholm said, referring to a 98-acre parcel on Dorchester’s edge that divides two steep bluffs, through which not only Waterloo Creek flows, but also Duck Creek and Brook Creek.

In the years since, Osterholm, former Minnesota state epidemiologist, has refurbished Waterloo and Duck creeks, and completely re-established Brook Creek, with the same scientific discipline and fervor that have earned him a reputation worldwide as a germ sleuth par excellence.

“When I bought this property, the owner was growing corn on it,” Osterholm said, his finger on a laptop that threw PowerPoint images, data and charts onto a screen.

Cold-water fisheries managers and advocates from Wisconsin, Minnesota and Iowa listened attentively as Osterholm recounted a decade and a half of stream restoration completed at a cost of more than $1 million, the end result of which argues that some traditional ways of breathing life into cold-water rivers might be outmoded.

“This is especially true in the Midwest’s ‘driftless’ area,” Osterholm said.

Challenging geography

Blanketing up to 24,000 square miles of Minnesota, Wisconsin, Illinois and Iowa, the driftless region is so named because it was spared the scarring retreat of the most recent glacier. As a result, a latticework of limestone spring creeks courses the area, totaling more than 3,600 miles in length.

But gone are the tall grass prairies and oak savanna that once bordered the streams. Farming, logging and drainage played roles in these losses. But the cessation of wildfires was perhaps most responsible, Osterholm said.

“You look at land in this part of the Midwest, whether in my hometown of Waukon or near the Twin Cities, and there were not many trees here historically, due to grassfires,” he said. “Some fires were wild, but many were set by Native Americans to clear the areas they traveled.”

As farmlands replaced prairies, the loss of deep-rooted grasses contributed to massive erosion and mudslides that buried some stream valleys with up to 30 feet of sediment.

The result: Streams that for thousands of years were home to brook trout were lost or severely degraded.

“Only in about the past 25 years did natural trout reproduction occur again in many of these streams,” Osterholm said. “Primarily the streams recovered because, over time, water moving through these valleys exposed the original streambeds.”

From the moment he purchased his property, Osterholm began improving it. He did so, he said, in ways that at the time were widely practiced — hauling in multiple semi-loads of huge boulders, for example, to shore up stream banks.

Then came the first 1,000-year flood, in 2008 — followed by three more “1,000-year” floods, in 2008, 2013 and 2017. Add to these two 500-year floods in 2012 and 2014 and, Osterholm said, more 100-year floods than he could count, and much of his early work proved untenable.

“Two things I learned,” he said. “One is that there is not enough review of stream habitat work completed in the driftless area to see whether it’s effective. And two, because climate change is real and big rain events are happening more often, stream habitat projects must be undertaken with these downpours in mind.”

Attentive students

His presentation finished, Osterholm led the trout aficionados along a mowed path through a blanket of prairie cordgrass, prairie dropseed, sideoats gramma and other native sedges and grasses.

Among the group were Mark Johnson and John Lenczewski. Johnson is the vice chairman of Trout Unlimited (TU) Minnesota, and Lenczewski the group’s executive director. Both have been closely involved with TU’s accelerated stream habitat work in Minnesota’s portion of the driftless area.

“This is a learning experience and we appreciate Mike sharing his knowledge with us,” Johnson said.

At the path’s end was Waterloo Creek, which presented itself as a crystalline ribbon bending and flowing over a hard bottom.

Unlike some similar restoration projects, none of the river’s banks were buttressed with large boulders. “Early on I had multiple semi loads of rocks brought in,” Osterholm said. “But it was a costly mistake, because I had to take them out.”

The rocks proved disastrous during major floods because rushing water bounced off them and shot to the next bend, eroding it wildly and sloughing soil into the stream.

TU’s Lenczewski was among those in attendance who at the end of Osterholm’s report pieced together a fly rod to cast to brook, brown, rainbow and tiger trout (tiger trout are sterile crosses between brown and brook trout).

“On our TU projects we work with cooperating landowners and we can’t always get access to do what Mike has done on his property,” Lenczewski said. “But he’s right: Connecting a stream with its floodplain is important.”

As Lenczewski tied on a Hare’s Ear, or underwater fly that can imitate scuds, caddis larvae and other bugs, Osterholm, the professional pursuer of bugs, and carrier of one that has afflicted him since childhood, looked on.

Not with irony, but pleasure.

Dennis Anderson • 612-673-4424