CHARLES CITY — For Charles City farmers Dean and Linda Tjaden, constructing a Conservation Reserve Enhancement Program wetland is partly about heritage.

Dean’s father, Leonard, was a founder of the Washington School Watershed project in the 1970s. He and other landowners undertook major conservation projects to prevent flooding and soil erosion.

Now Dean and his brother, Larry, use no-till, strip-till and minimum-till, and participate in the CRP, CSP and EQIP to improve their environmental footprint.

In early August, Dean and Linda’s nitrate-reducing wetland was completed. Research by Iowa State University shows that strategically sited and designed CREP wetlands remove 40 to 90 percent of nitrates from cropland drainage waters.

Mehmert Construction of Saratoga created an earthen berm, built a steel sheet pile weir and a grouted riprap stilling basin and installed a water level control structure. The Tjadens’ wetland pool hasn’t completely filled yet. The water level will remain low so wetland plants can establish. The berm will be seeded with an oats cover crop and later this fall native grasses and flowers will be planted.

Dean said much of the land where the wetland was built was prone to flooding and they had mostly used it for hay.

CREP invitation

The process started more than four years ago when the couple received a letter from an Iowa CREP representative asking if they would be willing to meet about building a wetland.

“At first I wasn’t that excited about it, but Linda said this is something we need to look at,” Dean said. “The more we looked at it, the more I thought, 'This is all right.'"

Throughout the building process, Linda, a Floyd County supervisor, used her campaign Facebook page to post updates with photos on the wetland’s progress.

“This is something we can do,” Linda said. “We are happy to help communicate the importance of these sites in providing nitrogen reduction.”

“We feel like we took ownership in it and it worked out well,” Dean said.

The CREP wetland adjoins a smaller pond and getaway cabin. The Tjadens enjoy watching the deer, waterfowl and birds and fishing in the pond.

Removing nitrogen

The 6.2-acre wetland, which receives tile drainage from 695 crop acres above it, will remove an estimated 11,700 pounds of nitrogen each year, said Brandon Dittman, CREP field coordinator with the Iowa Department of Agriculture and Land Stewardship. Nitrogen reduction is achieved through denitrifying bacteria that occur naturally in wetlands.

If the Tjadens’ wetland is 40 percent efficient at removing nitrogen from the water flowing through it, the land retirement equivalent amount for an equal reduction of nitrogen runoff is 327 row-cropped acres. At 70 percent efficiency, it would be 572 row-cropped acres.

Joint effort

A joint effort of IDALS and USDA in cooperation with local soil and water conservation districts, Iowa CREP provides incentives to landowners who voluntarily establish wetlands for water quality improvement in the state’s heavily tile-drained regions.

Landowners receive 15 years of annual rental payments from USDA for all enrolled acres. They receive 100 percent cost-share for wetland restoration and buffer establishment with 90 percent of construction cost paid by USDA and 10 percent paid by the state. They also receive a one-time payment from the state to enter into either a 30-year or perpetual conservation easement.

The Nature Conservancy and The Coca-Cola Foundation also contributed to the Tjadens’ project.

“There are multiple benefits with a project like this,” said Dennis Sande, NRCS district conservationist in Floyd County.

Many wetlands in county

The Tjadens’ wetland is the 11th in Floyd County, which has far more than any other county in the state.

“It’s multiple things,” said Sande when asked why Floyd County has more CREP wetlands.

“There has always been an atmosphere of 'What can we do?' in this county. Once the first one took shape in 2006, farmers, staff and CREP field specialists got excited about it. It made an impression on me.”

“A lot of it is because of Dennis,” Dittman said. “He does a really good job of telling people about CREP and it benefits.”

Dittman sees CREP wetlands as nitrogen removal infrastructure for the Gulf of Mexico just like the county road system is infrastructure.

“Forty years ago, everyone got together to fix the flooding problem in Charles City,” Dittman said. “As we’ve learned more about the dead zone in the Gulf of Mexico, we’re impacting people further downstream, now the same family is continuing the legacy to impact a different priority, removing nitrogen in tile water. I think that’s really neat.”


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