DES MOINES (AP) — Last year's drought, combined with the wettest April in Iowa in more than 140 years, is significantly washing fertilizer out of farmland and into rivers used by many cities for drinking water.
The Des Moines and Raccoon Rivers this week reached record nitrate levels, forcing the Des Moines Water Works to switch on its $4 million nitrate removal equipment for the first time since 2007.
It costs the plant about $7,000 a day to strip nitrates out of the water to a level acceptable under federal regulations, Des Moines Water Works General Manager Bill Stowe said.
The U.S. Environmental Protection Agency allows up to 10 milligrams per liter of nitrate in drinking water.
Untreated Raccoon River water contained 24 milligrams per liter this week, above the previous record of 22, and the Des Moines River was just under 18, higher than the previous 14.2 milligrams per liter record.
“The real problem is it's the worst we've ever seen,” Stowe said. “Although the drinking water is safe, it's difficult to keep it that way.”
Drought-stunted crops absorbed less nitrogen fertilizer last fall, leaving it in the soil, and this spring's heavy rain washed the fertilizers into the rivers.
Stowe places the blame squarely on state policymakers. In November, state officials, including Gov. Terry Branstad and Secretary of Agriculture Bill Northey, released the state's new plan for improving water quality by reducing farm chemical runoff.
While the plan is designed to provide scientific data to farmers to help them more efficiently apply fertilizer and implement conservation practices, it largely relies on voluntarily compliance.
“One of our frustrations is that the governor and the Iowa Department of Agriculture and Land Stewardship have chosen not to regulate upstream use. It's made it all the worse. It's just an example of how volunteerism simply doesn't work,” Stowe said.
Ag Department spokesman Dustin Vande Hoef said criticism of the state's new policy is premature because the plan is not yet final.
But, he said, it's clear that the unusual weather patterns are significant factors in the high nitrate levels. Recently, Iowa Climatologist Harry Hillaker said the state experienced its wettest April in 141 years of records.
Northey continues to support the self-regulation approach, Vande Hoef said, and Branstad's spokesman said the Republican governor also continues to support the policy.
“The governor stands behind his bold, innovative new initiative and looks forward to working with Iowa farmers to protect our environment,” Tim Albrecht wrote in a statement.
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