Drainage districts, one of the lowest tiers of Iowa government, could play a big role in addressing ag-sourced nitrate pollution that threatens well water, aquifers and the growing “dead zone” in the Gulf of Mexico, according to a new report from an Iowa think tank.
Drainage districts “probably have the power and the obligation” to address nitrate pollution, according to David Osterberg, co-founder of the Iowa City-based Iowa Policy Project and its lead staff researcher on energy and environment.
Historically, drainage districts have not been held accountable for ag-sourced nitrate pollution, according to a paper by Osterberg and colleagues Sarah Garvin, an IPP research associate, and Michael Burkart, a 34-year career researcher with the USDA before joining the Iowa State University faculty.
Although earlier this year the Iowa Supreme Court dismissed the Des Moines Water Works case against three northwest Iowa county boards of supervisors -- Sac, Buena Vista and Calhoun -- for nitrate contamination in the Raccoon and Des Moines Rivers, the researchers suggested that should not prevent drainage districts and county supervisors from taking action.
“If we’re going to start somewhere, we might as well start somewhere where we have the infrastructure in place to do something about it,” Garvin said. “It’s necessary. We’re past the tipping point.”
About two-thirds of Iowa land is used for row-crop agriculture, primarily corn and soybeans. Much of that land is heavily tiled for drainage to remove excess water in areas that otherwise have poor drainage and crop potential.
Osterberg believes drainage district managers “have the power and the obligation” to take action on their own. Existing statutory authority gives drainage districts the power to level fees and to use eminent domain, powers that could be used to clean up Iowa waters and the Mississippi River.
If they don’t, Garvin said, they could be vulnerable to legal action.
“Just because this last case failed, it still leaves the door open for another group or another entity to come and approach it from another direction,” she said.
Referring to drainage pipes emptying into open ditches that run into streams, rivers and lakes, Osterberg said if those pipes “were any other entity doing any other kind of business, they would be regulated.”
Burkart argued the convergence of low commodity prices, an emerging plant breeding and seeding industry, and the “perennialization” of commodity crops makes the timing right for new approaches by drainage districts.
One of the causes of nitrate pollution is that seasonal crops such as corn and beans go dormant in the winter. The use of perennial cover crops that would continue to draw water and nitrates out of the ground year-round would help alleviate the problem, Burkart said.