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Small watershed, big goals

By Staff | Jul 8, 2016

DIANE ERCSE, front left, gesturing, an Iowa Soybean Association watershed coordinator and resource management specialist, speaks to members of the public who witnessed the installation of a bioreactor north of Carroll on June 24. In the center is Roger Wolf, executive director of Agriculture’s Clean Water Alliance, which is leading the Elk Run Watershed water quality initiative.

CARROLL – As far as Iowa’s watersheds go, Elk Run Creek’s is hardly the biggest at 24,000 acres.

With its key location near the Raccoon River in parts of Sac, Calhoun and Carroll counties, however, it’s becoming the epicenter of innovative water-quality projects, from bioreactors to saturated buffers.

“The Elk Run Watershed is diverse, with livestock and approximately 87 percent of the watershed in cropland,” said Harry Ahrenholtz, chairman of Agriculture’s Clean Water Alliance, which is leading the Elk Run Watershed water quality initiative. “The area also has some of the highest nitrate concentrations the Raccoon River Watershed.”

“If we can make a positive difference in the Elk Run Watershed, we’re confident we can make improvements in larger watersheds.”

Finding solutions is important to ACWA, a group of 11 leading ag retailers in west central Iowa that have a dual mission – blend optimal crop yield and profitability with the best environmental performance possible.

WOOD CHIPS are being spread across the bottom of a bioreactor on June 24 during installation in the Elk Run Watershed, north of Carroll.

Formed in 1999, ACWA began focusing on water quality long before the Des Moines Water Works’ lawsuit brought the issue to the forefront, Ahrenholtz said.

ACWA is partnering with the Iowa Soybean Association, the Iowa Department of Agriculture and Land Stewardship and others to implement more conservation efforts to help protect Iowa’s water quality.

A grant of more than $350,000 has kick-started additional conservation efforts in the Elk Run Watershed, including the installation of a bioreactor in a farm field on June 24.

A bioreactor is essentially a buried trench filled with a carbon source (commonly wood chips), through which tile water is allowed to flow. The carbon source provides material upon which microorganisms can colonize. Using wood chips as a food source, the microorganisms begin breaking down nitrate in the water and expelling the nitrate as dinitrogen gas, N2, a primary atmospheric component.

While the bioreactors’ contribution to nitrate reduction varies with annual precipitation patterns, they can reduce nitrate loads up to 60 percent.

“Not every farm is going to offer a practical location for a bioreactor,” Ahrenholtz said, “but they can be extremely effective in the right places.”

A combination of in-field and edge-of-field practices are helping improve water quality in the Elk Run Watershed.

“We’re using tools that are based on science, approved by IDALS and the Natural Resources Conservation Service, and fit within the Environmental Protection Agency’s nutrient reduction strategy,” said Diane Ercse, an ISA watershed coordinator and resource management specialist who is working with ACWA. “We want to help farmers implement solutions that make agronomic sense and reduce nutrient loads going into Iowa’s waterways.”


Tests have shown that the average nitrate levels in water samples pulled from the Elk Run Watershed, from 1999 through 2016, are more than 19 parts per million, Ercse noted. That’s above current safe water quality standards of 10 ppm.

To address this issue, groups like ACWA and ISA are helping connect farmers with an array of educational resources, funding sources and conservation options that can fit their operations, including saturated buffers, cover crops, cost-share for nitrification inhibitors and confidential tile water monitoring.

Replicated strip trials, which are available through ISA’s On-Farm Network, encourage farmers to reduce the amount of nitrogen applied and monitor results through guided stalk nitrate testing and late-spring soil nitrate testing, according to Ercse.

“Putting practices in place is important, but so is monitoring results,” she said.

Some practices in the Elk Run Watershed are already paying dividends.

“A bioreactor installed this year has already led to a 90 percent reduction in nitrates from that area,” Ercse said.

Partnerships are also a key to protecting water quality in the Elk Run Watershed and beyond.

“The solutions to our water quality issues will rely on effective partnerships, both rural and urban.” Ahrenholtz said. “By working together, we can accomplish more than we could on our own.”

Various water quality improvement efforts are underway throughout the area, including Twin Lakes, Lohrville and Rockwell City.

Lohrville, for example, has installed new bioretention cells that work like natural filters, collecting storm water so it can flow through layers of sand and amended soil to remove sediments and pollutants before flowing into the North Raccoon River Watershed.

Native plants, including deep-rooting prairie grasses and flowers, will grow on top of the bioretention cells to further soak up pollutants and beautify the streetscape.

Financial assistance for this project was provided by the Iowa Water Quality Initiative’s Urban Conservation Demonstration Projects Program and the IDALS’ State Revolving Fund.

“When we hosted ag and urban guests in early June to tour some of these areas and see a bioreactor and saturated buffer being installed at Mark Schleisman’s farm in the Elk Run Watershed,” Ahrenholtz said, “many urban people said they had no idea all these conservation practices were going on. They were impressed by the ways farmers and small towns are making a positive impact for water quality.”

Interest grows

Interest in conservation and water quality improvement projects in the Elk Run Watershed continues to grow.

While there was a fair amount of skepticism and apprehension at first, approximately 70 people attended the kickoff meeting in December 2015.

About 40 farmers are currently engaged in the project, Ercse said.

The value of voluntary, rather than mandatory, participation, can’t be overstated, Ahrenholtz said.

“Voluntary works, because it spurs innovation,” he said. “The beauty of this system is that we’ll develop with new ideas we haven’t even come up with today.”

Although the current grant for the Elk Run Watershed project is slated for three years, Ahrenholtz expects more money, including private funding, to flow into the project to keep it going.

Improving Iowa’s water quality is a long-term process, Ercse added.

“We won’t see miracles happen in three years, but really good things are happening in the Elk Run Watershed,” she said. “Iowa farmers are intelligent and proactive, and it’s exciting to see progress.”

Ahrenholtz hopes the Elk Run Watershed project can create a model for water quality improvement that can be adapted to larger watersheds across Iowa.

“The Elk Run Watershed could be one of the most important projects ACWA has ever taken on,” he said. “There’s so much potential here.”

For more information on water quality improvement in the Elk Run Watershed, contact Ercse at (515) 314-3249, or dercse@iasoybeans.com.

To learn more about water quality improvement projects underway across Iowa, log onto www.cleanwateriowa.org/urban-demonstration-projects.aspx.

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