A flash flood that destroyed homes in Baldwin, Wis., and killed a motorist in St. Croix County on June 29 ripped through the Rush River Valley with historic force, but fish experts say the river's esteemed trout population appears to be all right.
Newly born trout likely suffered high mortality rates, but juvenile fish and adult trout should have been able to find refuge near the bottom while top waters rose 10 to 12 feet above normal in some places, said officials from the Wisconsin Department of Natural Resources and Trout Unlimited.
"In general, adult fish can hang on really good," said Kasey Yallaly, a DNR senior fisheries biologist based in Baldwin. "They go to the closest stable cover until it recedes."
But trout hatched this spring, probably got hit as hard as they have in other historically bad floods in western Wisconsin's Driftless Area. But even at that, Yallaly conducted surveys this month on a few tributaries of the Rush River, and said she found good numbers of juvenile and baby fish.
The DNR also checked sites where conservation dollars have been spent over the past 20 years to fortify stream banks and make other trout stream habitat improvements. All those structures remained intact, she said.
The worst damage to stream banks happened in the lower reaches of the 35-mile river as it approaches the Mississippi River just north of Maiden Rock, Yallaly said. The river's headwaters are south of Baldwin and the best fishing is in the river's middle reaches.
"It looks like somebody set off dynamite," she said.
Even after the floodwaters receded, some high banks in the area along County Road A beside the lower Rush were actively eroding and dropping unwanted sand and silt into the river, she said, and fallen trees were everywhere. Some restoration work may be needed, Yallaly said, but the DNR doesn't have much in the way of easement rights to work in the affected area.
"We would like to for sure because there's a lot of trophy fish there," she said.
Del Brisson of Cottage Grove owns a parcel of recreational land along the Rush in the small town of El Paso, a place where the river breached high banks and rose another 6 to 8 feet in a matter of a couple of hours after sunrise June 29.