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The flood caused streams and rivers to cut new channels through the landscape, something that happens all the time, but not usually to the extent seen Aug. 18 and 19, 2007, said Bill Huber, a Minnesota Department of Natural Resources hydrologist.
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Derek Casper, an equipment operator with the Lanesboro fisheries, adjusts a lunker structure Wednesday in the Pickwick Creek. Casper is working on a project to restore about 1,800 feet of the creek by installing 28 lunker structures and sky hooks, which provide safe areas for trout. It will also improve the banks along the stretch of creek which, along with the trout boxes, will help maintain the creek. (photo by Katie Derus/Winona Daily News)
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The water flowed with so much energy it was able to lift and carry huge amounts of sediment as well as large boulders. As the water flowed down the bluffs, it lost that energy and deposited the debris, clogging old channels. The water then split out into new territory.
“This happens on a much smaller scale,” Huber said. “I’ve never witnessed a flood of this magnitude and haven’t seen this phenomenon so widespread.”
Rather than follow the meanderings of the Whitewater River, rushing waters blew through Whitewater State Park, sweeping away trees and 15 of 17 trail crossings, park naturalist Dave Palmquist said.
Once the waters receded, most existing channels were wider and shallower than before and a brand new channel formed, leaving an abandoned crescent-shaped lake behind. Rock bars and islands disappeared while new ones sprang up, dramatically changing the look of the river.
Camping numbers are down for the state park, Palmquist said, but that could be attributed as much to “flood hangovers” and worries about what’s open and to weekends of bad weather in the early spring. Several projects are in the works to repair about $5 million in damages, Palmquist said. The park is about three-quarters restored.
The projects include restoring two traffic bridges, two pedestrian bridges and stepping-stone crossings over the river. River banks are being reshaped and seeded with native plants to bolster growth where trees and plants were stripped away and to discourage exotic, aggressive plants introduced to the area by the floodwaters, Palmquist said.
Rush Creek cut a new path within the confines of Farmer’s Park near Lewiston, reducing the once beautiful spot for family picnics and social gatherings to rubble and mud. Carolyn Dingfelder, co-chairwoman of the Farmer’s Park Board, said some pavilions, picnic tables and playground equipment disappeared when the stream was redirected to flow through the front gates.
With the OK from several agencies, including the Minnesota DNR and the U.S. Fish and Wildlife Service, the board is commissioning a project to reroute the creek back to its original path while revamping its banks and floodplains to avoid similar damage in possible future high-water events, Dingfelder said.
The rerouting project is expected to cost between $60,000 and $80,000 and the rebuilding of the park as a whole is expected to top out at about $200,000, she said. Dingfelder hopes the park will reopen to the public by spring.
Although the projects in Whitewater and Farmer’s Park are designed to fight back against floodwaters while improving aesthetics, trying to prevent the kind of havoc wreaked by a flood in the future may not be feasible, Huber said.
He said there are several ideas out there to handle a similar flood, but none are failsafe. The high cost of these projects coupled with the rarity of the flood — far less than a 1 percent chance of it happening even once — and the severity of its damage make Huber think it isn’t worth trying to prevent another August 2007 flood.
“It’s extremely unlikely you could build structural components to address this degree of flooding,” he said. “Minimizing damage from an event this big is a futile effort.”
Fish are still biting
With “tons and tons” of rock tumbling through the area’s streams, it’s to be expected that a few trout get crushed during the flood. But the youngest of the trout, those that hatched in spring 2007, were hit the hardest because they aren’t as strong, quick or able to hide as well as their older relatives, said Vaughn Snook, a fisheries specialist with the Minnesota DNR fisheries office in Lanesboro, Minn.
The lasting effect the flood had on trout is still largely invisible. Anglers haven’t noticed the dip in population because they’re still happily catching 12 to 14-inch trout, Snook said. In the next couple years, they’ll see a hiccup in trout that size because the class of newly hatched trout from the spring of 2007 was largely destroyed.
Organisms that act as food for trout, like amphipods (also called freshwater shrimp), were entirely wiped out in smaller streams by the flood, according to research done in the spring by Neal Mundahl, a biology professor at Winona State University. In larger streams, there was nothing left but a few handfuls of the invertebrate species.
Palmquist said they brought Mundahl back to the state park in June, and he found the amphipods were back in abundance. It’s still a mystery as to how they repopulated so quickly, Palmquist said, but they’re there and that’s what counts.
The effect on land animals in the area seemed to be temporary at best. Palmquist said there was some worry about Pickerel frogs and timber rattlesnakes. Immediately after the floods, those animals were nowhere to be seen. The frogs have since returned, and Palmquist said he’s gotten several calls about rattlesnake sightings.
Moles, chipmunks, mice and shrews that lived in the floodplain were largely drowned in the raging waters, but their abundance in the lower hills allowed them to repopulate quickly, Palmquist said.
He said he was walking through the Whitewater floodplain right after the flood and came across a doe and two fawns. The startled deer tried to run away but trees and debris fallen over familiar paths muddled the doe’s escape route. She ran back and forth, confused.
“She had the same look on her face that we had,” Palmquist said. “Stunned and getting used to a new reality.”
