Nitrates Persist in Iowa Water

Study Shows High Nitrate Levels Present in Samples

Todd Neeley
By  Todd Neeley , DTN Staff Reporter
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Agriculture's Clean Water Alliance, an Iowa-based group, reported Thursday the results of some 2,500 water testing samples from across the Raccoon and Boone watersheds during 2015. (Courtesy graphic)

OMAHA (DTN) -- Though the trial for the Des Moines Water Works' nutrient runoff lawsuit against government entities in Iowa's Raccoon River and Boone River watersheds is set for later next year, a clean water interest group in the state is acknowledging there's more to be done to reduce runoff and improve water quality.

Agriculture's Clean Water Alliance, an Iowa-based group, reported Thursday the results of some 2,500 water testing samples from across the Raccoon and Boone watersheds during 2015. The ACWA-funded tests found more than half of the 45 Raccoon River water monitoring sites reported their highest average nitrate levels this past year in some 10 years' worth of data collection. The tests also showed the Boone River experienced high nitrate concentrations across 30 sample sites.

In a news release Thursday, the ACWA said, "The results are not surprising, considering weather patterns during the past decade."

Roger Wolf, ACWA executive director, said in a news release agriculture understands its role in nutrient runoff.

"We acknowledge that water quality across the state needs to improve," he said. "Many factors influence water quality, but weather is a particular driving force."

In its 2014 lawsuit, the Des Moines Water Works claimed that drainage districts in counties across the watersheds should be subject to federal regulation and be required to implement conservation methods to cut nutrient runoff. DMWW claims those districts should be responsible for the clean-up of source waters used to serve some 500,000 drinking water customers.

ACWA said that "large shifts in water movement" have allowed nitrate that has moved below root zones and accumulated in dry times to be "rapidly transported" during wet periods.

Ag industry officials say fertilizer use is declining across Iowa. United States Census of Agriculture data on the counties named in the lawsuit -- Sac, Buena Vista and Calhoun -- show commercial fertilizer use has increased since 1997. Overall, fertilizer use in Iowa increased from about 3.2 million tons in 2001 to about 4.8 million tons in 2013, according to the Iowa Department of Agriculture and Land Stewardship. Total tonnage peaked at about 5 million tons in 2011.

The census reveals an increase in the use of virtually all fertilizers and chemicals in those counties from 2007 to 2012. What's more, when comparing census data from 1997, commercial fertilizer use in those counties increased dramatically by 2012 -- in some cases by at least 50% overall.

"Data allows us to pinpoint where we should be focusing our efforts and dollars to have the biggest impact for water quality at a local level and across the state," Wolf said.

Since 1999, the ACWA has invested $1.5 million in monitoring, according to the news release, as part of a commitment to improving water quality.

ACWA has recently focused some of its research efforts in the Elk Run Watershed -- a sub-watershed of the North Raccoon River. In March, ACWA and 15 commodity groups and other conservation partners were awarded a $354,000 Water Quality Initiative grant from the Iowa Department of Agriculture and Land Stewardship for work to be conducted in the Elk Run watershed.

That project centers on working with farmers in parts of Sac, Calhoun and Carroll counties, all three named in the DMWW lawsuit. Buena Vista also is named in the suit.

The Elk Run project is designed to generate awareness and adoption of water quality conservation practices outlined in the Iowa nutrient reduction strategy. The project will evaluate current practices, collect water samples and implement the voluntary conservation strategy including working with urban and other state partners.

In addition, ACWA is working with farmers to improve water quality in the headwaters of the North Raccoon River, the Boone River Watershed Nutrient Management Initiative and the Riverside Stormwater Wetlands in Webster City.

ACWA Chairman Harry Ahrenholtz said in a news release the ongoing water quality efforts will require continued and expanded water quality monitoring.

"We are excited to see the positive progress these partners can achieve by working together," he said. "For our part, ACWA members will help farmers identify and implement practices beneficial to the environment and water quality. Our water monitoring program will be a valuable tool for documenting future successes."

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Todd Neeley