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Researcher works with rivers to heal erosion, create habitat

By Janet Kubat Willette
jkubat@agrinews.com

Date Modified: 10/03/2012 10:11 AM

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WINNEBAGO, Minn. — Joe Magner is leading a team research effort aimed at giving a stretch of Elm Creek time to heal itself.

Magner is a research professor in the University of Minnesota Department of Bioproducts and Biosystems Engineering who has a dual appointment as a researcher for the Minnesota Pollution Control Agency.

He led a Walk-n-Talk Sept. 13 focused on the research projects that have occurred along Elm Creek in Center Creek Township.

Work began on the property in fall 2007 with the goals of protecting the stream, reducing sediment, improving fish habitat and increasing water storage.

Elm Creek is a tributary to the Blue Earth River in the Minnesota River Basin and is located in western portion of Faribault County and northeastern portion of Martin County. It is impaired due to sediment and turbidity. The Elm Creek watershed covers about 20,000 acres.

The research projects used items available onsite as much as possible. Fallen ash, cottonwood, basswood and silver maple trees were used as log vanes designed to attract sediment and redirect stream flow toward the center of the stream.

They are angled at an upstream direction so as not to create a swirling current behind them that would further erode the bank, said landowner Dick Mair.

Mair has a 70-acre pasture along the creek with 50 acres on one side of the road and 20 acres on the other. His father acquired the land in the 1950s and its always been pasture to his knowledge. He grazes a 30-cow calf herd on the property.

Mair leads the way through a natural cow pass to the creek, telling the story of going to get the cattle on horseback and coming back wet to his waist.

Mair said he hasn't noticed a big change in the creek bank, much like anyone who sees the same landscape day after day.

He did however, have to move a fence back from a towering bluff around one bend in the creek for fear he would come out one day and find the fence dangling in midair.

The towering vertical bluff was eroding with high flow events.

Magner and his team, which includes the Martin County Soil and Water Conservation District and several graduate students, designed a fix called a bench where wood and rock are buried along the bluff and covered with soil from the bluff. He hopes the wood and rock will buy time for sandbar willows to become established on the bluff. The root balls of the willows will hold soil in place and prevent erosion. Sandbar willows are shrubs.

He hopes to dissipate some of the energy of the water that caused the bluff to collapse.

In another area, log vanes provide fish habitat, giving the fish an area deep enough to live in even during this low flow period.

The log vanes are anchored into sediment with cables, Magner said, and are placed according to information in the Natural Resources Conservation Service engineering handbook.

It is important to go further upstream and further downstream of what you think you need, Magner said.

They are also utilizing old oxbow channels on the property, sending water out of the main channel during high flow events to ease pressure on the banks. As the water level drops and loses energy, it will drop sediment in the old channel, where it will need to be cleared away.

Magner is confident that if the projects they utilized on the 2,000 linear feet in Center Creek Township were replicated, it would increase water storage within the valley walls.

The features they are installing are not permanent, Magner said, rather they are buying time. The also require management, such as keeping trees out of the oxbow, removing sediment and excluding cattle on a rotational basis.

"It's got to be managed," Magner said.

He emphasized that cattle need not be totally excluded from grazing along streams or creeks, but rather that grass along the streams needs time to grow and establish root balls. It is the root balls that hold soil in place.

"We have a great opportunity between the two valley walls to improve the environment," Magner said.

Upland management is essential, as is management of the riparian corridor. Investments in the riparian corridor will improve the health of rivers, streams and creeks.

Whatever the reason, the high flows in our water system are higher and the low flows lower. The challenge is to work with what exists and make it the best possible solution, he said.

The Walk-n-Talk was jointly sponsored by Rural Advantage and University of Minnesota Extension.