As watershed coordinator for Iowa’s Floyd County Soil and Water Conservation District, Doug Johnson is no stranger to nitrate pollution and other water quality issues. He came to his current position after spending three decades with the Natural Resources Conservation Service, which is part of U.S. Department of Agriculture.

He has encouraged practices like planting cover crops and no-till farming to reduce nitrogen runoff. Recently, he has helped install bioreactors that help remove nitrate from soil. Those are 50-foot-long tubes filled with wood chips where the anaerobic bacteria that live on the wood chips turn the nitrate into nitrogen gas that evaporates.

So it’s not surprising that when Doug Johnson joined the Floyd County Chapter of the Izaak Walton League in 2015, it was because of their clean water projects. Johnson wanted his engagement with the League to be an extension of his career.

The Floyd County Chapter is located in Charles City, Iowa, which sits directly on the Cedar River, putting it squarely in the middle of the 35,000-acre watershed Johnson is responsible for. And when the League’s Nitrate Watch launched in early 2023, offering an easy way for clean water advocates to monitor streams for nitrate pollution, Johnson quickly signed up. He pledged to take action on his findings by communicating the testing results to local organizations and media.

Starting a Nitrate Watch team

Johnson made good on that promise right away. He raised the idea at a chapter meeting, inviting others to help monitor local waterways for nitrate, which is a carcinogen that forms in water when chemical nitrogen fertilizer and manure wash off agricultural fields.

As an experienced team leader, Johnson scoped out potential monitoring sites and verified that there was safe access to the water; the volunteers, most of whom were brand-new to water quality monitoring, just had to pick which sites they wanted. Johnson had also created a schedule for monitoring at the same time every month.

Soon, the team was gathering testing data, and Johnson entered each measurement into the League’s Clean Water Hub on behalf of the Chapter. Once the data is in the Hub, it’s available to the public, researchers and government agencies. But Johnson went one step further by actively bringing the findings back to the chapter. The data provided a window into local water quality and connected the chapter to a national effort to monitor and advocate for clean water.

Johnson’s team hasn’t yet found any alarming nitrate levels in their streams. That’s good news, because all the streams they’re monitoring contribute to the drinking water supplies for Cedar Rapids, a city of over 130,000 people. As a seasoned natural resources professional, though, Johnson is thinking about the reasons for the low nitrate levels and looking ahead to potential trouble.

Ready for action

When we talked in late February, Johnson knew that peaks of nitrate pollution tend to arrive in the spring, when farmers put down fresh fertilizer and rains wash all kinds of contaminants off the land. He also knew there was a lot of old fertilizer sitting on the soil, waiting to be washed away when Iowa’s ongoing drought finally ends.

If heavy rains return this year, Johnson reasoned, a double dose of nitrogen will get flushed through tile lines and into streams, spiking nitrate in waterways to levels well above what’s considered safe. If rainfall is about average, the much-needed precipitation will replenish moisture in the dry soil, and fertilizer will mostly stay put. And if the drought persists, nitrogen will continue to accumulate on fields, setting up an increasingly dangerous situation when the rain finally comes.

Johnson is ready for that too. When his team members start texting him test results with abnormally high nitrogen readings, he’ll activate the other half of his original pledge: alerting local media about the problem. He knows how to contact the key newspapers and radio stations in his region.

Volunteers contribute to science

After 40 years working as a professional for the organizations officially tasked with monitoring and protecting water quality, why organize volunteers for a community science project? Because volunteers can do science just as well as professionals can, Johnson replied. And because when they do, they free up professionals’ time for tasks that really require specialized resources and training. With those extra hours—and with the intel flowing in from volunteer monitors—agency staff can zero in on problems and resolve underlying causes.

“That local water monitoring…” Johnson said thoughtfully, “…can lead to focused technical and financial assistance to the smaller watersheds that show the greatest need.”

Johnson is well aware of the nitrogen pollution crisis in Des Moines, which sits west of Cedar Rapids in a different watershed. He didn’t want his community to have to take on the same battle of addressing the source of the pollution when the drinking water was already so contaminated that ratepayers had to put up the money to install specialized filtration equipment. He wanted to get ahead of the problem.

Nitrate pollution is a nationwide problem, and League staff are prepared to assist volunteers anywhere with monitoring and advocacy.

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Top photo: Ikes who monitor for nitrate are, left to right, Blair Redenius, Doug Johnson, Ryan Smith, Stan Pyratt. Not present are Dave Nehls and Mike Kruckenberg. Credit: Floyd County Chapter.