Snaking and Winding Again
The human alteration of Wilson Creek began in the 1700s. Now a team of U of L scientists and others have the rare opportunity to radically restore the stream to its original state.
When Michelangelo carved a statue, he said he was merely releasing the form that God had already placed inside the slab of stone.
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Engineers, biologists, arborists, landowners and others find the restored Wilson Creek in Bullit County, Ky., to be a treasure trove of information.
Now U of L engineers, biologists and colleagues are similarly releasing a stream in the Bernheim Arboretum and Research Forest that had been filled in, plowed over and moved by farmers long ago.
The restoration of Wilson Creek in rural Bullitt County, Ky., is being hailed as an unprecedented opportunity for engineers, biologists, arborists and landowners to see what happens when a stream is rebuilt virtually from scratch.
The demonstration project should provide how-to information to landowners and others across the country on effective ways to restore stream beds altered by human activities. Such restorations could reduce soil erosion and downstream pollution as well as increase biological diversity.
Bernheim Forest is managing the project with technical assistance from U of L, the University of Kentucky School of Forestry and others. The project is funded with $500,000, mostly from the U.S. Environmental Protection Agency (EPA).
Wilson Creek is just one example of how streams across America have been altered from the very beginning of the nation’s history.
“Virtually every flat piece of land has been farmed, and farmers can’t tolerate streams interacting with the plain, so they straighten and move the streams so that the water flows quickly from the property,” says Art Parola, professor of civil and environmental engineering (CEE) in U of L’s Speed School of Engineering and lead designer of the Wilson Creek restoration.
The same thing happened to Wilson Creek.
Between 1770 and 1790 settlers surveyed the Bernheim Forest area for agricultural and other uses. For more than a century the land in and around Wilson Creek was intensively logged, cleared, farmed and mined for salt and iron ore. As a result, the meandering stream was straightened and set along a hillside to increase the amount of farmable land in the valley.
Even after Bernheim’s founding in 1929, the forest managers used the Wilson Creek valley land for agriculture, says Margaret Shea. Shea is natural areas director at Bernheim and manager of the restoration project.
When the park’s administrators decided five years ago to restore the creek, Shea says, they had no idea of the project’s magnitude.
“We were interested in the creek’s revegetation and went to the Kentucky Division of Water for a grant. They suggested we talk to Art Parola,” Shea says. “What he told us really opened our eyes.”
Parola revealed that the creek had been “channelized,” or straightened and moved from its original course.
“Parola told us we’d have to do a lot more than just revegetation,” Shea adds.
“When we first walked the creek,” Parola explains, “it was obvious to me that it had been straightened. I said it would be better to first move the creek to the middle of the valley where it belongs rather than revegetate it in the position it was in.”
Paul Bukaveckas, a U of L associate professor of biology studying water quality and stream ecosystems, says many people are surprised when told that a creek has been substantially altered.
“Most people look at it with all the vegetation around it and think it looks just fine,” he says. “But no natural stream looks like that, with a straightened channel.
“It’s amazing but you could still see where the creek originally was by looking at the topography, even though it has been plowed for more than a hundred years.
“When you straighten a stream,” Bukaveckas continues, “you have a problem with bank erosion. There’s no place for the water to overflow when it rises and the fast action of the moving water erodes the bottom. Parts of Wilson Creek had eroded down to the bedrock.”
As a result, algae and other life forms needed for stream health are reduced.
A Creek Rises from the Dirt
Parola has spent years researchingwaterway-related engineering problems. He and colleagues studied the topography and ecosystems of Wilson Creek and other streams for five years before the first rock was moved from the site.
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U of L associate professor of biology Paul Bukaveckas, right, works with students and others to chart the renewal of nutrients and life forms in Wilson Creek. At center is Randall Kelley, a U of L field techniciann.
The restoration team, including graduate students Bill Vesely and Mike Croasdaile, surveyed the area and dug test pits to find the old stream bottom. Vesely was construction manager as well as co-principal designer of the site with Parola. CEE professor Donald J. Hagerty examined soils at the site while department chair Mark French examined the area’s hydrology.
“The complexity,” Parola says, “is in the details, such as how sharp a bend is and how deep the channel should be.”
Bulldozers and crews moved in during summer 2003 and scraped the valley floor bare before carving out the new stream channel. The restored creek merges at various points with its previous incarnation, since those areas were part of its original course. Water was diverted into the new stream, and the unused portions of the old stream are being turned into wildlife-friendly wetlands.
The restorers say that for awhile the results will look like a construction site. But that will change with time as vegetation and wildlife return and slight modifications are made to the stream.
The 4,000-foot section of restored creek with its twists is about 15 to 20 percent longer than the old one, Parola says.
The researchers say the snaking pattern is essential to a healthy stream’s ecosystem because it allows the stream to slow down and harbor life. It also permits occasional overflows that deposit nutrients into the surrounding soil.
“Loose materials on the bed act as biofilters that retain nutrients for life and maintain water quality,” Bukaveckas says. But in a fast-moving altered stream natural debris can’t accumulate on the bottom.
During the dry season, it was easy to see Wilson Creek’s problems. “The bottom should have been like walking on a pea gravel path, but instead it was like a concrete sidewalk,” Bukaveckas explains.
Parola says that the stream’s design was key to ensuring it would function properly and allow for a diverse habitat to develop.
“Interaction with the floodplain is key,” Parola says. “Streams undergo constant change—they change course, erode their banks and overflow and deposit sediment onto the floodplain.”
The creek’s revegetation will take years as newly planted trees such as sycamore, sugar maples, poplars as well as grasses and shrubs regrow. UK assistant forestry professor Chris Barton and contractor Adam Dattilo are overseeing the replanting.
“This is a long-running work-in-progress,” Parola adds. “We will monitor the physical conditions and entire environment of the valley, including upstream and downstream. We’ll do additional physical modifications this spring and into summer.
“It will be a four- to five-year project to see how the channel physically changes.”
A Natural Lab
What’s unique about the Wilson Creek project, say its restorers, is its comprehensiveness. Streams have been modified or enhanced before, but not fully restored.
“Traditional conservation efforts focused on particular species—reestablishing bass or trout or ducks to a stream or wetland, for instance,” Bukaveckas says.
Institute to Study Stream Restorations
The Wilson Creek project and the restoration of part of Obion Creek in Hickman County are two projects dovetailing into the creation of a new U of L research center.
Art Parola
© Courier Journal
U of L’s Interdisciplinary Stream Restoration Institute is being created with a $1.35 million federal earmark secured in February 2003 by U.S. Sen. Mitch McConnell.
The institute will bring together faculty and students from U of L schools, colleges and centers to study the restoration of streams affected by agriculture and development.
Professor Art Parola will be its director. The institute’s administrative structure still is being developed.
“Here, we’re looking at the whole ecosystem. The idea is that if you restore the ecosystem, then the species will follow. That’s what makes this project different.”
t also will give biologists, students and others a rare chance to study how life reestablishes itself in a stream ecosystem.
In one study under way, Bukaveckas wants to find out how well nutrients are retained to support life in the newly restored creek.
Before the restoration, he found that Wilson Creek had half the nutrient retention capacity than two nearby natural streams.
Nutrients can come from many sources, including decomposed vegetation, animals and insects as well as nitrogen from agricultural runoff. In a natural stream, those nutrients should remain closer to their source and settle rather than be whisked away.
In his experiments, Bukaveckas measures how quickly nutrients in the stream disappear, indicating retention of the nutrient by biofilms. Greater nutrient retention means healthier ecosytems downstream.
“We hope to show that nutrient retention will double in the restored stream,” he says.
Preliminary observation shows that Wilson Creek is biologically on the right course.
Jeff Jack, a U of L assistant biology professor who is studying and identifying returning life in the restored creek, says insects such as caddis flies and mayflies already are appearing, as are small fish including darters and sunfish.
Jack and his students also want to observe the growth of algae on rocks and microscopic invertebrates such as nematodes and rotifers on the stream bed that provide prey for larger organisms. Biology students Wes Daniel and Randall Kelley are studying the creek’s life forms.
Students Amy Gentry and David Word, working with Jack, are studying the rate of leaf decomposition. Early indications are that the stream is breaking down and processing leaf matter at the same rate as comparison streams in the park.
“So far, so good,” Jack says.
Margaret Shea agrees.
“It will take several years to get a sense of how successful this project is. We need to plant trees for shading and see the native vegetation reestablish itself,” she says.
Bukaveckas says Wilson Creek’s restoration could have wide implications.
“Wilson Creek was part of a broader problem throughout the Mississippi River Valley with all its tributaries carrying nitrogen pollution from agriculture to the Gulf of Mexico where it has created a dead zone.
“If you can get these smaller streams upriver to retain the nutrients, it will benefit the Salt, Ohio and Mississippi rivers.
“It’s an exciting start.”
