Although record-high levels of nitrates in Iowa’s rivers were found during this past year, researchers say the Iowa Nutrient Reduction Strategy is making progress, albeit slowly.

The strategy, implemented in 2013, is attempting to reduce nutrient runoff by 45 percent from several sources, including agriculture.

It’s part of a larger initiative by the Environmental Protection Agency to reduce the amount of nitrogen and phosphorous draining into the Mississippi River and, ultimately, into the Gulf of Mexico. Iowa and the nine states bordering the Mississippi River are responsible for establishing their own strategies to meet this goal.

Several approaches and methods have been put in place around the state, but 2015 still showed some of the highest nitrate levels in history.

Keith Schilling, a research scientist in the University of Iowa IIHR-Hydroscience and Engineering department, said this record-breaking season is not a sign that the strategy has been unsuccessful: he attributed it to an unusually warm and wet year.

“There’s still a lot of nitrogen in the soil that needs to be flushed out, so it takes years for change to come,” Schilling said. “It takes time for water quality to change in the system, so for every one of these practices, there’s a lag time associated with it.”

IIHR research scientist Chris Jones said there are approximately 30 million acres of crops in Iowa, but there is less than $50 million available in state funding and farmer contributions that’s been put into the project.

“From a monetary perspective, that gives us an idea of how large and difficult this problem will be to solve,” he said.

Although there is no set timeframe yet on the strategy, Schilling said, he anticipates it will probably be at least 20 years before there are any significant improvements in nitrate levels.

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Despite these numbers, John Lawrence, an associate dean of the College of Agriculture and Life Sciences at Iowa State University, said the strategy has made progress on practices that will eventually have an effect.

Several strategies to reduce nutrient runoff were put in place this year across the state, he said.

“There are a number of practices that will ultimately lead to a reduction, but they can be overrun by weather,” Lawrence said. “If we had a normal weather year, we would have had less nitrogen in the water than we did five years ago, before we put these practices in place.”

Although these practices have been adopted widely around the state, it still is not nearly to the level that developers are hoping to reach, Jones said.