(Radio Iowa) – A group of researchers drew strong reactions from a large crowd in Des Moines as they reviewed their report on water quality in the Raccoon and Des Moines Rivers. Jerald Schnorr is a long time professor in the University of Iowa’s College of Engineering. He says data from 2000 U-S rivers indicates these two Iowa rivers are in the top one percent when it comes to nitrate levels.

“You might ask: Well, where’s all the nitrate coming from? It’s a good question,” Schnoor said and the crowd laughed. “Most of it is from agricultural land, roughly 80% and, of that, 40% is coming from fertilizers applied directly to the land; about 20% is coming from manure that’s applied onto the land.” Soybeans also produce nitrates that wind up in ag drainage tiles and that accounts for the remaining nitrate levels connected to agland runoff. About 18 percent of nitrates in the Raccoon and Des Moines Rivers comes from rain and snow according to the report.

Elliot Anderson, a civil and environmental engineering professor at the University of Iowa, says each year about 50-thousand tons of nitrogen winds up in the Raccoon and Des Moines Rivers. “About 10 years ago or so, the state government decided to fund one of the most extensive, world-renowned nitrate monitoring networks that’s ever been in existence…Starting in the next year, we’re set to contract this network from about 80 sensors that we’ve had down to about 20,” he said and the crowd booed. “With this there’s a lot less that we can say about nitrate in the state.”

Last (Monday) night’s event was hosted by the Harkin Institute and by Polk County, which paid 16 researchers who published the 277-page assessment of central Iowa water quality. Adam Shriver of the Harkin Institute says the report is the best objective, factual information about Iowa’s water quality that is available to the public. “Even if those facts contain bad news or are uncomfortable for certain groups,” he said, to extended cheers from the crowd. When a moderator asked if nitrate problems had reached a point where regulations were needed, the crowd and the researchers on stage joined in shouting “yes.”

Matt Helmers, director of the Iowa Nutrient Research Center at Iowa State University, told Axios the main cause of the Des Moines metro’s nitrate problems this year has been persistent wet weather that increased leaching from farm fields into rivers.