For the first time in nearly a month, nitrate levels in both the Des Moines and Raccoon rivers have dipped below the threshold that Central Iowa Water Works says it needs to sustain if it is to lift a first-ever ban on lawn watering for its 600,000 customers.
Meanwhile, some violators are receiving fines or even having their water cut off.
The Des Moines River measured 9.52 milligrams of nitrates per liter on Tuesday, July 8, and the Raccoon River tumbled to 7.93. Both readings were below the 10 milligrams-per-liter limit the U.S. Environmental Protection Agency requires for drinking water.
CIWW member utilities have strained since late April to maintain that level in their finished water as nitrate levels soared, and the agency imposed the watering ban June 12 to ensure seasonal demand wouldn’t outpace treatment capacity. The restriction remains in effect for now, CIWW leaders said at a press briefing Tuesday.
Most central Iowa residents are complying with the ban, but a few are getting tickets or losing water service for violations, officials said.
“Residents have been enormously patient, and we appreciate that,” Ted Corrigan, CEO of CIWW member Des Moines Water Works, told the Register. “We need them to be a little more patient. We’ll get there together.”
The ban needs to continue because the decline was the temporary result of heavy rainstorms in northern Iowa that dumped 3 to 5 inches in some areas over the July 4 weekend and diluted the nitrates in the rivers, Corrigan said.
As the large rush of runoff faded later Tuesday, nitrate levels were again beginning to climb, registering at 11.27 milligrams per liter in the Raccoon River and 10.09 in the Des Moines River on Wednesday.
The regional authority wants the nitrate levels in the rivers, the source of drinking water for the Des Moines metro, to stay consistently below 10 milligrams per liter before it lets watering resume.
What will have to happen to get Iowa watering ban lifted?
Lawn watering on hot, dry days can increase demand by 33% — or between 20 million and 40 million gallons a day — potentially outstripping the capacity of CIWW members’ nitrate removal equipment.
Since “we’re not seeing that sustained downward trend, we need to stay the course,” said Amy Kahler, who is set to become Des Moines Water Works’ CEO this month as Corrigan retires.
So, how long must nitrate levels remain below 10 milligrams per liter — the federal limit established to protect infants under 6 months and pregnant women from the negative effects of nitrates?
“We need hot, dry weather for days or a week,” Madsen said. “Not a day.”
Officials have said this year’s nitrate levels have been high in part due to drought conditions over the past couple of years that banked nitrogen fertilizer applied to farm fields. Large rainstorms upstream from Des Moines have flushed out the fertilizer, which is carried through drainage tiles beneath cropland into Iowa rivers, streams and lakes.
The regional authority has lifted some restrictions, allowing city splash pads and parks to operate and a dozen sod companies to install and water new lawns, a requirement before new homeowners can close on their mortgages.
Fines, water cutoffs handed imposed on some stubborn lawn waterers
During the update Tuesday, Clive Assistant City Manager Peter De Kock and West Des Moines Water Superintendent Lyle Hammes complimented residents on complying with the ban. But cities are taking action against a handful of scofflaws, they said.
De Kock said two Clive residents had been fined for breaking the ban. The first violation triggers a $100 fine, he said, with each offense afterward ticketed at $200. One person has received more than one ticket, he said.
“Overwhelmingly what we hear from customers in Clive is that we get it. We understand,” De Kock said. “They may not like it” and if lawns turn brown, “They may not like it a little bit more.”
Waukee posted notices at 56 residential and commercial properties, notifying occupants they were violating the ban, said Heather Behrens, a city spokesperson. In many cases, customers thought they had “shut off their automatic (sprinkler) system, but it was still running or in some cases” leaking, Behrens said.
The city did cut water to three townhome complexes’ irrigation systems because they continued violating the ban. The cutoff didn’t affect household water use, though, Behrens said. Another complex’s irrigation system was cut off because of a break in its system, she said.
Urbandale said it’s hung notices on 234 homes and businesses since the ban began, but all complied after receiving the alert, Derek Zarn, a city spokesperson, said in a text.
Hammes said West Des Moines has reached out to dozens of customers via texts and phone calls to encourage them to obey the ban. All have but one have, and the offender’s water will be cut off this week, he said.
Des Moines Water Works said it has left door tags at about 40 properties, warning of possible violations, but no one has lost their water service.
“We’ve had really good compliance,” Corrigan said.
Luckily, storms that swept across western Iowa Monday evening and into the Des Moines metro Tuesday have helped keep metro residents’ lawns green, Corrigan said.
Donnelle Eller covers agriculture, the environment and energy for the Register.
This article originally appeared on Des Moines Register: Nitrate levels drop in Des Moines, Raccoon rivers, but watering ban remains for now
Reporting by Donnelle Eller, Des Moines Register / Des Moines Register
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