Low tech makes cleaner water in Iowa; so what’s stopping it?

Apr 19, 2023, 10:04 PM

A worker shovels wood chips in a bioreactor trench in a farm field, Tuesday, March 28, 2023, near R...

A worker shovels wood chips in a bioreactor trench in a farm field, Tuesday, March 28, 2023, near Roland, Iowa. Simple systems called bioreactors and streamside buffers help filter nitrates from rainwater before it can reach streams and rivers. (AP Photo/Charlie Neibergall)

(AP Photo/Charlie Neibergall)

SLATER, Iowa (AP) — Nick Helland’s central Iowa farm looks much like every other nearby farm on this chilly March day, with corn stubble stretching from a gravel road up over a low hill to the northern horizon.

But look closely, and you can see patches of muddy ground where a few months ago crews buried low-tech systems called bioreactors and streamside buffers that filter fertilizer-borne nitrates from water as it drains from Helland’s field into nearby Big Creek and eventually the Des Moines River.

The underground devices work. The question is whether one Iowa county’s promising new approach to an old problem can be expanded enough to finally address nitrate pollution that, for years, has fueled a giant dead zone nearly 1,000 miles away in the Gulf of Mexico.

Polk County is doing it by making it painless for farmers — handling all the logistics and arrangements for the systems — and throwing in payments of $1,000 per site. Installations have exploded in the past two years, to 104, after only a handful were installed the eight years before that.

“They paid me and they paid the cost of all the installation,” Helland said. “That’s sort of a no-brainer to me that with very little lift, very little time, I can have this installed on my farm and it will ensure better water quality for everyone else downstream.”

The big challenge now is encouraging counties to launch and fund similar efforts to reduce runoff from Iowa’s 10 million acres of tile-drained farmland and combat the state’s multi-billion dollar problem with nitrogen pollution.

Nitrogen-based fertilizers and manure can lead to excessive nitrates in groundwater that can be toxic to livestock and humans. High levels have plagued waterways in Iowa and throughout the Midwest for decades from chemical fertilizers and animal manure sprayed on fields. Modern tractors let farmers assess their soil and apply only as much fertilizer as needed, but it’s still common to overspray.

It’s easy to see why. Yields of corn — the king crop in these parts, and planted on about 90 million acres nationwide — are at least doubled by fertilizer, and farmers want to be sure their crops have enough nutrients. Adding to the problem are the quick drainage systems that lie beneath so many fields — known as tiles, but actually plastic pipes — that whoosh excess water away and into streams.

Numerous studies have found the low-tech systems remove half the nitrate or more from runoff before it reaches waterways. In bioreactors, the water passes through a buried mound of wood chips that break down much of the nitrate. In the buffers, it moves through a grassy area parallel to a stream.

Too much nitrate and phosphorous in rivers and streams makes great food for algae and other plant growth that cuts oxygen in the water and blocks sunlight. Combined with industrial farming practices that have altered waterways by straightening streams and removing wetlands, that’s bad news for fish that need clear water and slower currents.

It hurts humans, too. Nitrate-contaminated drinking water can cause blue baby syndrome where an infant’s blood doesn’t have enough oxygen. More than half of Iowa’s rivers, streams and lakes are too polluted to properly support aquatic life or fishing and swimming, according to the state.

Iowa is among the largest contributors of nitrate runoff that flows to the Gulf, leading to the so-called dead zone by depleting oxygen necessary for marine life across several thousand square miles.

Pressure to reduce the dead zone led Iowa’s agriculture and natural resources departments to join in 2008 with Iowa State University for a strategy to address the problem. The effort has focused on voluntary actions; Iowa’s legislature has consistently rejected proposals to require farmers to reduce runoff.

Fifteen years into the program, Iowa hasn’t significantly reduced nitrogen runoff, according to a 2019 estimate. The problem in some ways has worsened as strong commodity prices encouraged farmers to plant corn and soybeans on more land. Meanwhile, Iowa’s giant hog industry has grown to about 24 million pigs — roughly triple the number in any other state — which means more manure gets spread over farmland.

In Polk County, exasperation with nitrate pollution came to a head in 2015, when the agency that provides drinking water to 600,000 people in the Des Moines area went to court over the millions of dollars it was being forced to spend to filter unsafe levels from drinking water taken from the Des Moines and Raccoon rivers. A judge ultimately dismissed the lawsuit against three northwest Iowa counties, ruling the issue was one for the Legislature to address.

Without hope of state mandates, local officials in Polk County sought to work cooperatively with agricultural groups. Part of that was studying why so few farmers were installing bioreactors and streamside buffers. They found an inefficient system for installation that made it expensive and bothersome for farmers, who had to arrange contractors and then seek reimbursement.

Polk County’s solution: Handle all the arrangements to make it easy for farmers, and group projects together for economies of scale. Even with the $1,000 inducement to get farmers to sign on, they found the new process was about 15% cheaper — less than $10,000 for a typical saturated buffer, and up to $15,000 for a bioreactor.

“Our success came from realizing we had been doing it wrong for like six years,” said John Swanson, Polk County’s water resources supervisor.

Iowa Agriculture Secretary Mike Naig, who has strongly opposed requiring farmers to filter runoff, has embraced Polk County’s effort and encouraged it elsewhere. In March, he promoted bioreactors and buffers at an event in Story County, north of Des Moines, where conservation officials have adopted the new program.

“We’re making it easy for a landowner to say yes, and then we bring the resources,” Naig said. “These are essentially 100% paid for. Either way, the work has to get done, and to have willing landowners and willing producers get involved, that will work much better.”

But clean water advocates note that Iowa needs thousands of the systems added each year, not hundreds, and question whether voluntary efforts can reach even a small percentage of the state’s farms — let alone those in other states.

“There’s a lot of people who are doing really good work,” said Alicia Vasto, the water program director at the Iowa Environmental Council. “The fact of the matter is that it’s just not at the pace and scale that’s necessary to fix the problem.”

The projected cost of scaling up is staggering. To significantly reduce nitrogen and phosphate runoff, a 2017 analysis found that upfront costs could be as high as $4 billion. That would include more than 100,000 bioreactors to deal with runoff on two-thirds of tile-drained farmland, as well as other solutions, like cover crops.

Swanson, the Polk County official, is now working with state officials to build more wetlands, which cost more and require more land but can filter much more runoff than the bioreactors and buffers. Helland wants such a wetland on his property and wants farmers to do more, but he thinks efforts should remain voluntary. Each farm is different, he said, and if governments try to require action, it could cause more problems and ultimately not be effective.

Jerry Hill, who has farmed for 52 years, attended the Story County meeting with other farmers and is leaning toward installing a bioreactor along a creek that borders his property. He liked the idea of filtering the water at little cost to his bottom line.

“We’re going to have to do a better job of keeping things clean,” Hill said. “From what I’ve heard, what they have going now is as good as it gets.”


Follow Scott McFetridge on Twitter: https://twitter.com/smcfetridge


The Associated Press receives support from the Walton Family Foundation for coverage of water and environmental policy. The AP is solely responsible for all content. For all of AP’s environmental coverage, visit https://apnews.com/hub/climate-and-environment

United States News

Protestors gather in the atrium of Atlanta City Hall to protest the proposed police training center...

Associated Press

Atlanta project decried as ‘Cop City’ gets funding approval from City Council

ATLANTA (AP) — Atlanta City Council on Tuesday approved funding for the construction of a proposed police and firefighter training center, rejecting the pleas of hundreds of activists who packed City Hall and spoke for hours in fierce opposition to the project they decry as “Cop City.” The 11-4 vote is a significant victory for […]

4 hours ago

President Joe Biden listens as he meets with Denmark's Prime Minister Mette Frederiksen in the Oval...

Associated Press

White House website highlights infrastructure as Biden pushes policy wins

WASHINGTON (AP) — The White House on Tuesday is launching a website to map and track tens of thousands of manufacturing investments, an effort by the administration to show the positive impact of its policies on the U.S. economy to a skeptical public. The site, Invest.gov, documents roughly 32,000 infrastructure projects and more than $470 […]

4 hours ago

FILE - Nevada Gov.-elect Joe Lombardo speaks with supporters at Rancho High School in Las Vegas, Mo...

Associated Press

Oakland Athletics move to Las Vegas in flux as Nevada Legislature adjourns

CARSON CITY, Nev. (AP) — A plan to help build a stadium for the Oakland Athletics in Las Vegas is in flux after Nevada lawmakers adjourned their four-month legislative session. The future of the contentious bill is now uncertain after the Democratic-controlled Legislature did not advance it before the midnight deadline as Monday turned to […]

4 hours ago

Associated Press

California investigating whether DeSantis involved in flying asylum-seekers from Texas to Sacramento

SACRAMENTO, Calif. (AP) — Officials were investigating Tuesday whether Florida’s Gov. Ron DeSantis was behind a flight that picked up asylum-seekers on the Texas border and flew them — apparently without their knowledge — to California’s capital, even as faith-based groups scrambled to find housing and food for them. About 20 people ranging in age […]

1 day ago

Former New Jersey Gov. Chris Christie, center, poses for a selfie after a town hall style meeting a...

Associated Press

Former New Jersey Gov. Chris Christie set to launch 2024 presidential bid at New Hampshire town hall

NEW YORK (AP) — Former New Jersey Gov. Chris Christie is set to launch his bid for the Republican nomination for president at a town hall in New Hampshire on Tuesday evening. The campaign will be the second for Christie, who lost to Trump in 2016 and went on to become a close on-and-off adviser […]

1 day ago

This booking photo provided by the Missouri Department of Corrections shows Michael Tisius. Tisius ...

Associated Press

Missouri man facing execution for killing 2 jailers in failed bid to help inmate escape in 2000

A man who shot and killed two rural Missouri jailers nearly 23 years ago during a failed bid to help an inmate escape is set to be executed Tuesday evening. for killing Leon Egley and Jason Acton at the small Randolph County Jail on June 22, 2000. Tisius’ lawyers have urged the U.S. Supreme Court […]

1 day ago

Sponsored Articles


OCD & Anxiety Treatment Center

5 mental health myths you didn’t know were made up

Helping individuals understand mental health diagnoses like obsessive compulsive spectrum disorder or generalized anxiety disorder isn’t always an easy undertaking. After all, our society tends to spread misconceptions about mental health like wildfire. This is why being mindful about how we talk about mental health is so important. We can either perpetuate misinformation about already […]



Why drug-free weight loss still matters

Wanting to lose weight is a common goal for many people as they progress throughout life, but choosing between a holistic approach or to take medicine can be a tough decision.

(Photo: OCD & Anxiety Treatment Center)...

OCD & Anxiety Treatment Center

Here’s what you need to know about OCD and where to find help

It's fair to say that most people know what obsessive-compulsive spectrum disorders generally are, but there's a lot more information than meets the eye about a mental health diagnosis that affects about one in every 100 adults in the United States.

Low tech makes cleaner water in Iowa; so what’s stopping it?