Water quality efforts blossom in the Cedar Valley 

Eastern Iowa farmers, landowners add more “Batch and Build” projects, cover crops 

By Dan Looker 

Two workers set a large pipe into a deep, earthen trench. The hose is connected to a saturated buffer control unit aboveground, with an excavator in the background.
Dozens of new edge-of-field practices dot the Cedar Valley after the first round of Cedar River Source Water Partnership (CRSWP) Batch & Build projects this spring. SATURATED BUFFER INSTALL PHOTO: IOWA SOYBEAN ASSOCIATION/EVAN BREHM

CEDAR RAPIDS, Iowa (IAWA) – In 2008, the Cedar Rivernamesake of the city of Cedar Rapids – surged from its banks to leave more than a tenth of the city in muck and destruction. That disaster, among the worst in the state’s history, remains a fresh memory for the city’s residents and leaders 16 years later.

One of those leaders is Mary Beth Stevenson, who has her eyes uphill and upstream along the Cedar River. As the city’s Watersheds & Source Water Program Manager, she has helped farmers add more than 10,000 acres of cover crops to fields in the surrounding countryside. Among their other benefits, cover crops slow down runoff by improving rain infiltration into the soil. That slowed runoff helps lower flooding risks while also enhancing water quality.  

Right now, water quality is Stevenson’s main focus. Under her watch, new edge-of-field practices are springing up in the Cedar Valley thanks to cost share from the Cedar River Source Water Partnership (CRSWP) this spring. 

Edge-of-field practices include buried trenches of wood chips called bioreactors. The wood chips host microbes that feed on nitrates in runoff water. Saturated buffers – buried pipes that divert runoff from field drainage tiles toward grassy stream edges – are another common edge-of-field practice. Both can remove half or more of the nitrates that would otherwise flow toward the Cedar Rapids water treatment plant. 

“We’re wrapping up construction on 36 edge-of-field practices,” Stevenson said. This July we will let bids for a couple dozen practices that will be installed in late summer or early fall in Black Hawk and Grundy counties.” 

Planning for a second round of construction is in the works in each of those counties as well. 

 “We feel it’s important to normalize these practices and get them on the on the landscape to show they’re working,” Stevenson says.  

Nitrates come from both crop fertilizer and natural soil nutrients. They’ve become a well-publicized issue in the Des Moines metro, where the area drinking water treatment facility must sometimes filter water from the Raccoon River to bring levels below the EPA requirement of less than 10 parts per million (ppm). 

Unlike Des Moines, Stevenson says Cedar Rapids doesn’t source water directly from the river, but instead from 50 shallow wells in the Cedar’s flood plain. 

“That has kind of a buffering effect,” she says, adding that when nitrate levels rise to 6, 7, or even 8 ppm, the city can shift to other wells.  

Still, there is reason to be promoting more conservation. 

“We have seen nitrates steadily rising over the past couple of decades,” Stevenson says. “I guess the advantage we’ve had in Cedar Rapids is to be proactive.” 

There is time to head off a water quality crisis. That’s partly what the CRSWP, a USDA- Natural Resources Conservation Service Regional Conservation Partnership Program (RCPP), is about. 

Stevenson applied for and secured $7 million for the city to help fund the CRSWP in 2021. Another $11 million in support comes from partners that include the Iowa Agriculture Water Alliance (IAWA), the Iowa Department of Agriculture and Land Stewardship (IDALS), private co-ops, and other cities in the Cedar watershed. 

With money from USDA and IDALS, participating farmers are paid 100% of the cost of the edge-of-field practices they add. Stevenson doesn’t provide technical support – others do that but she does visit each farm to help with paperwork. She also lines up contractors who build several bioreactors and saturated buffers at a time. This “Batch and Build” approach speeds up construction and saves landowners from red tape. 

Edge-of-field practices take up little space, but construction can be an inconvenience. So, on top of covering the complete cost of the buffer or bioreactor, the CRSWP pays landowners a $1,000 temporary easement. 

This work will also help Iowa meet its goals of improving the quality of our water, which ends up in the Gulf of Mexico by way of the Mississippi River. The state’s voluntary Nutrient Reduction Strategy aims for a 45% cut in both nitrates and phosphorus. While some critics have called the process too slow, Stevenson empathizes with farmers who remain hesitant about new practices 

“I think a lot of people don’t understand the risk factors and the complexities that are involved,” Stevenson says. 

For example, she says cover crops can benefit farmers and are gaining a lot of traction – butthat doesn’t mean cover crops are an easy practice.” 

Among edgeoffield practices, saturated buffers are the most popular, Stevenson says. But for them to work, a stream must already have a vegetative buffer – such as grass, along its bank. And the slope must be just right. 

“I think there’s more hesitancy about bioreactors on the part of farmers,” she says, adding that farmers and landowners wonder how long the buried wood chips will last before needing to be replaced – a timeline currently estimated at about 10 years. 

In the bioreactor, microbes grow on the wood chips and remove nitrates as water flows through it. Eventually, the wood decomposes. How long it takes for that to happen is not certain – the best guess is about 10 years. 

Perhaps the most important need Stevenson sees is for even more conservation agronomists, experts who work with co-ops and ag suppliers to answer farmers’ questions.  

“If [farmers] can walk into their retailer where they’re already going, I think it makes things a lot easier,” Stevenson says. 

Evan Brehm, an enthusiastic Iowa Soybean Association conservation agronomist, is already filling such a role. While he works with farmers trying cover crops in northeast Iowa’s Clayton County, Brehm also points farmers toward cost share programs like the CRSWP. His passion for getting new water quality and soil health practices on the ground extends beyond his “9-to-5″ – he recently talked his dad into installing a bioreactor on his family’s farm near Van Horne, Iowa. 

“My goal is to go out in the countryside and talk to farmers about what’s available,” he says. “I don’t want anybody to miss out on an opportunity.” 

For instance, one grower Brehm worked with didn’t want to wait for a Batch and Build project to add a new saturated buffer. The farmer knew he could simply connect his existing drainage tile to the new buffer, so Brehm encouraged him to seek NRCS support, which also covers 100% of the cost.  

Like Stevenson, Brehm also encourages trying out cover crops, for which qualifying farmers can get up to $60 an acre through NRCS cost share. Those funds don’t cover the cost of cover crop seeds, but they greatly reduce the overall risk of getting started with a successful, beneficial new practice. 

In his role at ISA, Brehm is embedded with the team of agronomists at Linn Co-op, answering farmers-members’ questions about cover crop planting methods, seeding rates, seed mixes, and when to terminate the cover crop before planting corn or soybeans. 

Valuable as Brehm’s background in ag education and experience with ISA, Linn Co-op and Indigo Ag are, he says the real experts are early adopting famers who have been using cover crops for up to 10 years. 

“These guys wouldn’t be doing these programs if it wasn’t working … they’re the champions and I learn from them,” Brehm says. “And their neighbors are watching and seeing that it’s working.” 

Years from now, the beneficiaries of all this change in the Cedar Valley will be the residents of cities like Cedar Rapids, Waterloo and Cedar Falls, as well as those living in the small towns and farms in the surrounding countryside. and the farmers. That change is being made possible by folks like Mary Beth Stevenson, Evan Brehm, and the farmers and landowners they work with to improve water quality.

Published May 31, 2024