Clean Water Solutions for Iowa
Is More Better? Projects Expand Ag Drainage and Wetlands
Report: Give Iowa Pilot Projects Time to Show Results

CONTACT: Mike Owen (319) 338-0773, ipp(at)

Read full report or download 15-pg PDF, including executive summary)
Executive summary below (2-pg PDF)

IOWA CITY, Iowa — A state initiative to determine the value of a combined strategy of expanded tiling and constructed wetlands needs a chance to show results, Iowa researchers say.

"There is much speculation about the impacts of tiling on floods and water pollution in Iowa and downstream," said Will Hoyer, research associate for the nonpartisan Iowa Policy Project (IPP) and author of a new report. "And there certainly are concerns if Iowa farmers just keep putting in more and larger tiles.

"But what if combining greater drainage systems with the creation of new wetlands can serve not only farmers' pocketbooks but better water quality as well? That's what is under study — and nobody should be drawing premature conclusions.”

In a new report, Hoyer noted the Iowa Department of Agriculture and Land Stewardship (IDALS) has pilot projects focused on the Des Moines Lobe, to see whether the combination of strategies could produce tandem benefits of greater yields for farmers and less surface runoff.

"The theory is largely untested and there are several pilot studies under way. Are there benefits? Are there unforeseen consequences? The study needs to be done carefully," Hoyer said.

"The implications are serious," Hoyer added. "The ‘Dead Zone” in the Gulf of Mexico this year is expected to be the largest ever because of all the nitrates sent south by flooding. But the impacts of nitrogen pollution not only show up in the Gulf. They also have an impact in Iowa cities, which must remove nitrate from drinking water because excess nitrate is a health hazard."

Hoyer also said the implications are important to farmers, who may invest large sums into tiling and they should have an assurance that the practice will work better than existing alternatives that are underfunded.

His report noted that the project has provoked concerns from many angles — whether water monitoring in the project is transparent, how Iowa water quality is changing as new drainage systems are installed, whether wetlands will remove nitrates as many believe.

"The many unanswered questions cannot be answered without on-the-ground trials, such as those that IDALS has proposed. With these pilots, enough time, and adequate monitoring, scientists may start to understand the costs and benefits of such an approach. Iowa must not develop any programs linking enhanced drainage and wetlands until there are credible answers to the many questions," the report's executive summary stated.

Hoyer's report pointed to the potential for the combined economic and environmental benefits.

"To know if those economic and environmental benefits materialize, the pilot projects should be constructed and given enough time to determine what the results, expected or unexpected, are and what impact broader implementation across much of Iowa would have on farmers, fish, fields and flows," the summary stated.

The report, “Agricultural Drainage and Wetlands: Can They Co-exist?” is available at The Iowa Policy Project is a nonpartisan, nonprofit public policy research organization based in Iowa City.

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