By Emily Haavik
Government officials across the Midwest face pressure to address high levels of nitrate pollution in water, which researchers have linked to illnesses including cancer, birth defects and thyroid disease.
In Des Moines, the water utility has spent millions keeping levels just below the federal limit.
In Cedar Rapids, the water is creeping toward that limit, and the city doesn’t have the technology to clean it.
In Iowa, the powerful Farm Bureau and other ag industry groups oppose regulations that limit fertilizer application or require farmers to clean up the pollution coming off their land.
Instead, the state must coax farmers to use voluntary conservation tools. But many of those threaten crop output, reduce field acreage or require changes in farming practices.
One taxpayer-funded tool the state is promoting doesn’t cause farmers any of those headaches: saturated buffers.
Iowa State researchers invented saturated buffers to capture nitrate from fertilizer, which would otherwise flow through farmers’ underground drainage pipes into streams and rivers.
The devices work by rerouting polluted water to a perforated pipe, which is buried along a stream or ditch. The water seeps out slowly, and the microorganisms in the soil break down the nitrate.
But research and records show Iowa’s saturated buffers aren’t as effective as promised. And even if the buffers met advertised standards, the state would need to increase installations exponentially to make even a marginal difference in water quality.
The Iowa Department of Agriculture and Land Stewardship, or IDALS, has dubbed its program to install the devices “Batch and Build.” The state pays farmers to allow it to install saturated buffers on the edges of their fields.
The state’s top agricultural interests back the initiative. The Iowa Farm Bureau has published articles promoting it, the Iowa Pork Producers Association invested in the program, and the Iowa Seed Association has received state money to help implement it.
Iowa Secretary of Agriculture Mike Naig has called Batch and Build a success and used it as a talking point before federal regulators concerned about Iowa’s contributions to the polluted “dead zone” in the Gulf of Mexico. Naig has also boasted about the model spreading to other states.
But APM Reports reviewed more than half of the designs for Batch and Build’s saturated buffers in Iowa and found most installed under the statewide initiative fall short of the original federal standard meant to ensure a “minimum level of acceptable quality.” The federal government signed off on the water treatment devices after lowering its standard, allowing Iowa to increase installations.
“This is such a huge rip-off of public money,” retired University of Iowa researcher Chris Jones said. Jones, a critic of the Batch and Build program, called the findings “scandalous.”
Jones is one of few who spoke out publicly against the state’s efforts.
Many researchers and local officials who spoke with APM Reports refused to openly criticize Batch and Build, or to discuss fertilizer regulation. One scientist whose research is publicly funded said the Iowa Farm Bureau and IDALS “discourage monitoring” water quality. He then asked for anonymity, citing fears that the Farm Bureau and state officials would try to defund his research.
Polk County, Iowa, administrator John Norris said he’s not surprised people didn’t speak candidly about these topics.
“It’s because of primarily the incredible political force of agricultural interests in the state,” he said. “Everyone’s thought that you can’t talk about regulation of these issues. Or you face the backlash of the Farm Bureau, Corn Growers, Pork Producers, you name it.”
The Iowa Farm Bureau and Iowa Pork Producers Association did not respond to invitations to comment. The Iowa Corn Growers Association confirmed its opposition to regulation but said it supports conservation practices.
IDALS declined multiple requests for interviews, but said in a statement that saturated buffers are part of a broader effort to reduce farm pollution.
Don McDowell, the communications director for IDALS, said that in recent years, Iowa has increased the money it spends on conservation tools, put in more nitrate-capturing wetlands, and seen “unprecedented demand” for cover crops that mitigate pollution.
“Saturated buffers are just one of many proven practices in our toolbox, and our team always works with landowners and partners to find the most effective combination of in-field and edge-of-field practices that will be successful on a particular landscape,” he said.
IDALS does not monitor most devices installed through Batch and Build, despite the Legislature recommending it monitor such initiatives.
Even supporters of the program question the lack of data.
“We probably owe the taxpayer some results,” said Lee Tesdell, a farmer, landowner, and early adopter of saturated buffers and other conservation technologies. “What good are they doing, if we don't know the data?”
Push to ‘get them done’
Reducing nitrate in Iowa’s drinking water has grown more critical as researchers link even small amounts of the nutrient to serious effects on human health.
In the 1990s, the Environmental Protection Agency set the maximum concentration of nitrate allowed in public drinking water at 10 parts per million. Since then, research has shown an increased risk of cancer, thyroid disease and birth defects at nitrate levels far below that.
Iowa, which has some of the country’s highest nitrate pollution, also has the second-highest cancer rate in the United States.
Instead of taking more aggressive steps to address the roughly 600 million pounds of nitrogen pollution flowing past its borders every year, Iowa has chosen to rely on saturated buffers and other industry-friendly solutions.
But saturated buffers aren’t living up to expectations.
While the state claims saturated buffers remove at least 40% of nitrogen runoff, research shows that figure is in the single digits. And the buffers aren’t measuring up to the federal standard originally set for them.
The Natural Resources Conservation Service, part of the U.S. Department of Agriculture, has created a federal standard to ensure saturated buffer quality. It includes a minimum on how much water a saturated buffer should treat — measured as a percentage of the entire field’s drainage capacity.
But instead of enforcing the standard, the NRCS loosened it, allowing buffers to be built in places where they are less effective.
NRCS engineer Jeff Lutz said the message from his supervisors and “those who are in influence” in state government is to “get them done, do them out here, even though some of the treatment levels will vary.”
In a statement, the NRCS said Lutz’s account does not reflect “NRCS policy and procedures” and said the department lowered the standard to give “additional flexibility for site-specific needs.”
The NRCS also distanced itself from Iowa’s Batch and Build program.
“While a number of these state projects have received minor technical assistance from NRCS, funding and oversight falls under the Iowa Department of Agriculture and Land Stewardship and local counties,” the spokesperson said, and the $8 million NRCS has committed for saturated buffers and other conservation projects in Iowa has not yet been spent.
The NRCS also said saturated buffers are one of many tools it offers. Another device called a bioreactor is also funded through Batch and Build. It makes up about one in four installations. APM Reports did not review bioreactor designs.
If saturated buffers are going to make a difference, Iowa must aggressively accelerate installations. In the right landscapes, it would take more than 11,000 saturated buffers to remove just 1% of the state’s annual nitrate load. The state has installed fewer than 200.
Laura Krouse, a soil and water commissioner in Linn County, Iowa, said she fears the point of the program is to make the state look like it’s addressing water pollution without fundamentally changing farming practices.
“My main criticism of the Batch and Build program is that it’s being used for somebody to look good,” said Krouse, adding that it allows IDALS to “look like they’re doing something far more than they actually are to improve water quality.”
There are more effective ways to clean up pollution, Krouse said, including addressing it directly at the source. Farmers can use less fertilizer, she pointed out, and limit tilling so nitrate seeps through the soil less easily.
Rotating other crops with corn and soybeans is also an effective practice, though it would challenge Iowa’s dominant corn-soy economy.
“There’s lots of things you could do to keep the nitrate out of the water, but they’re all hard,” Krouse said. “Because they all require change from this perfectly tuned system that we have in Iowa to grow a lot of corn.”
‘I don’t think there’s any ill intent in any of this’
Iowa State University professor Tom Isenhart co-invented the saturated buffer, and his research helped establish an oft-cited figure that IDALS and prominent Batch and Build supporters use to justify the initiative. Namely, saturated buffers remove, on average, nearly half of a drainage system’s nitrate pollution.
When Isenhart reviewed the data APM Reports collected on the saturated buffers, though, he acknowledged they are likely capturing less nitrate than his research indicates.
But he maintains the devices are worthwhile. “I think that we’re doing OK,” Isenhart said. “I don't think there’s any ill intent in any of this. I think it is just a natural — you know, this is a brand new practice.”
Isenhart also said the federal government is using the wrong criteria altogether when it comes to evaluating the devices.
He shared comments he sent to the NRCS in 2022 calling its main design criteria, the capacity percentage, “arbitrary.” Instead the government should measure the total amount of water treated, he wrote.
NRCS is currently reviewing the standard and has proposed minor changes. To date, the agency has not taken Isenhart’s suggestion.
Industry influenced research, helped shape policy around its own product
One of the architects of Batch and Build is a businessman who profits from it.
Charlie Schafer co-founded two companies that produce and engineer saturated buffers. For years, Schafer and his companies have influenced government policy around the devices.
Schafer described Batch and Build as “carpet bombing” Iowa watersheds with taxpayer-funded saturated buffers. Now, he said, he’s working with the federal government to bring similar initiatives to other Midwestern states including Minnesota, Ohio, Illinois, Indiana and Michigan.
Schafer said the idea for Batch and Build was born over coffee around 2019, when local officials in Polk County asked him for advice selling farmers on conservation tools. Schafer said the county had been overwhelming farmers with options. By the end of the meeting, Schafer said, they decided to focus on one of the easiest interventions: saturated buffers.
Schafer’s influence extends across government agencies.
An engineer from one of his companies helped NRCS write the federal standard. Since then, a drainage industry coalition Schafer co-founded has promoted the devices before Congress.
When asked about his financial interest in saturated buffers, Schafer likened himself to a medical professional making money off a surgical device.
“It’s a shame if folks in the water management industry don’t take an active role in looking at how to make it better,” he said.
Lack of monitoring can ‘mask the problem’
The best way to know if saturated buffers “make it better” is to monitor the water they’ve treated. But the state is trying to accelerate their adoption without testing most of the devices.
The lack of water-quality monitoring is part of a larger trend in Iowa.
Over the past decade, Iowa’s Legislature closed or defunded several environmental research centers.
In 2023, state lawmakers redirected money that funded water sensors in Iowa’s streams and rivers to help pay for Batch and Build.
This year, IDALS backed a bill that would limit local water management authorities’ ability to assess water quality in their watersheds.
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