Des Moines Water Works sets nitrate removal record in 2015

Des Moines Water Works sets nitrate removal record in 2015

Utility says its nitrate removal equipment ran 177 days last year, compared to 106 days in 1999.

The Des Moines Water Works ended the year 2015 operating its nitrate removal facility for a record 177 days, eclipsing the previous record of 106 days set in 1999. It cost the utility $1.5 million to run the equipment that keeps the drinking water for 500,000 central Iowa customers below the federally mandated level of 10 milligrams per liter, according to information released January 4 by Water Works officials.

DES MOINES WATER WORKS: The utility filed a lawsuit in early 2015 against three counties in northwest Iowa. The suit alleges drainage districts in the counties allow nitrates to flow from field drainage tile to streams which enter the Raccoon River, a source for drinking water for 500,000 Des Moines area residents.

Water Works CEO Bill Stowe says farm drainage systems upstream are allowing nitrates to flow into drainage ditches and creeks and eventually into the Raccoon River, where the Des Moines Water Works gets its supply of water. He says farm fields are the largest contributors to high nitrate levels.

The Water Works has sued three upstream counties in northwest Iowa (Calhoun, Sac and Buena Vista), blaming them for the nitrate problem. The county boards of supervisors oversee the drainage districts in their counties. The counties say there is no proof that farm fields 200 miles upstream from Des Moines are causing the city's Water Works to have to remove nitrate from the river water.

Operational costs for denitrification in 2015 total $1.5 million 
Des Moines Water Works meets or exceeds regulatory requirements for drinking water established by the U.S. Environmental Protection Agency, including delivering drinking water to the 500,000 Central Iowa customers. The drinking water provided to Water Works customers has nitrate concentrations below 10 milligrams per liter or parts per million. "However, the costs and risks in removing the nitrate to meet the EPA's limits are increasingly high, as Iowa's surface waters demonstrate high and dangerous levels of pollutants," says Stowe.

The increase in river nitrate levels is attributable to upstream agricultural land uses, he says, with the largest contribution made by application of fertilizer to row crops, which is intensified by unregulated discharge of nitrate into the rivers through artificial subsurface drainage systems.

Water Works wants to build a new nitrate removal system
"Iowa's political leadership, with influence from industrial agriculture and commodity groups, continue to deny Iowa's water quality crisis," Stowe contends. "Defending the status quo, avoiding regulation of any form, and offering the illusion of progress and collaboration places the public health of our water consumers at the mercy of upstream agriculture and continues to cost our customers millions of dollars."

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Des Moines Water Works is seeking legal relief against the three upstream counties, and it wants agriculture held accountable for passing production costs downstream and endangering drinking water sources, says Stowe. "In addition, the Des Moines Water Works is actively planning for capital investments of $80 million, a cost funded by ratepayers, to build a new denitrification facility and equip it with the latest technology to remove nitrate and continue to provide safe drinking water to a growing population in central Iowa."

Des Moines Water Works filed the lawsuit about a year ago
The Des Moines Water Works filed the lawsuit almost a year ago. The lawsuit seeks federal oversight of drainage districts, which are currently exempt from complying with federal Clean Water Act regulations. The Water Works indirectly would regulate farmers whose tile drainage lines exceed the federal limits for nitrogen being discharged in the drainage water.

Iowa officials and farm organizations prefer a voluntary approach, enlisting the Iowa Nutrient Reduction Strategy. The state's strategy calls for the use of aggressive soil conservation practices, in its goals to cut nitrogen and phosphorus levels in Iowa's water by 45%. If more cover crops were planted, the state would get closer to that goal. Only about 500,000 acres of Iowa's 23 million corn and soybean acres are planted to cover crops.

Cover crops such as cereal rye, hairy vetch and winter triticale can cut nitrate loss about 30% in areas that rely on underground field tile, according to the nutrient reduction strategy. The plan is designed to cut nutrient losses that contribute to the dead zone in the Gulf of Mexico, an area about the size of Connecticut and Rhode Island that last summer was unable to support marine life. Iowa leaders believe the strategy will improve Iowa's water quality as well. But critics of the strategy, such as Stowe, say the voluntary strategy has no set deadlines for meeting its nitrate and phosphorus reduction goals. 

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