June 10, 2023

Constructed wetland doing its job

CULLOM, Ill. — A new constructed wetland was showcased during the recent Vermilion Headwaters Watershed field tour in Livingston County.

The constructed wetland was installed in August 2018 on Fulton Farms farmland and is designed to capture and remove nutrients from tile drainage. The wetland encompasses 4.6 acres, including a 1.1-acre water-holding pond and a 3.5-acre buffer that’s planted as a pollinator habitat.

“Wetlands are carefully engineered systems designed to capture tile drainage and naturally removed nitrates from agricultural runoff, which is a major contributor to the dead zone in the Gulf of Mexico,” said Jim Fulton.

“When it comes to conservation drainage practices, constructed wetlands are considered one of the most cost effective at reducing nutrient runoff. It can remain effective for 30 years or more with minimal maintenance and can generate additional benefits such as wildlife habitat.”

The wetland receives tile drainage water from 73 acres of cropland. The ratio of contributing drainage area to wetland treatment area is 1.5%, indicating that a relatively small area of cropland is out of production for the wetland, but enough to ensure adequate treatment.

“When it comes to conservation drainage practices, constructed wetlands are considered one of the most cost effective at reducing nutrient runoff.”

—  Jim Fulton, Fulton Farms

An inlet water control structure acts as an on/off switch to allow water to flow into the wetland or to bypass it and drain into the adjacent Five Mile Creek.

“It’s higher on one end and lower on the other end, so the water naturally flows through. We can control the amount of water that comes in. There are boards in the water control structures. If we need more water, we take out boards. If we need less water, we put in boards. On the other end, if we need to drain it, we can take all of the boards out and let the water out. If we need to fill it up, we can put boards back in,” Fulton added.

“The design standard is to get at least 1% of the drainage area that you are capturing. We’re taking very little land out of production, but getting 70% to 90% nitrate removal,” said Jill Kostel, The Wetlands Initiative’s senior environmental engineer.

Kostel provides technical assistance to farmers on the practice, working with the Illinois Corn Growers Association on outreach and collaboration with USDA Natural Resources Conservation Service on the wetland design.

The Wetlands Initiative assisted Fulton with the permitting process with the Army Corps of Engineers and Illinois Environmental Protection Agency, as well as enrolling in USDA’s Environmental Quality Incentives Program for funding.

Natural Process

Microbes and vegetation in the pond remove the nutrients through a natural process before the water moves on to the nearby creek that eventually flows into the Vermilion, Illinois and Mississippi rivers and eventually the Gulf of Mexico.

“This works best when it’s warm. We are very fortunate versus the other tile treatment practices. We have solar energy to heat the water up and make the microbes really happy. Tile water is cold,” Kostel explained.

“The microbes do a lot of production when it’s warm. During the winter they’re not doing as much. They’re removing a little bit, but aren’t as active and that’s why we really like to pair with cover crops. Cover crops can hold the nitrate in the field or any nitrogen left in the field over the winter.

“Technically I think this is designed to hold a 25- or 50-year event. Surface water is diverted around the wetland while tile water goes directly into the system.”

Fulton Farms began in 1893 when Jim’s grandfather purchased 480 acres. The family purchased an additional 80 acres in 1980 and added the 80 acres where the constructed wetland is located in 1993. They have a corn, soybeans, wheat, oats and hay rotation, along with a few head of cattle.

Conservation has been an important part of Fulton Farms and Jim is a member of the Vermilion Headwaters Watershed steering committee.

“We’re going away from the wheat and decided to invest that money in buying cover crop seed. We’ve been doing cover crops the last three or four years. Last year we did 60 acres and I hope to double that this year,” he said.

“We strip-till our corn and we no-till soybeans. I apply all of my nitrogen in-season using 32% and put some out with the chemicals and then sidedress the rest.”

Tom Doran

Tom Doran

Field Editor