KCCI Investigates: Water expert says warm temps, former drought upping nitrate levels
Nitrate levels in the Des Moines and Raccoon Rivers are unusually high for this time of year, causing Central Iowa Water Works to run its nitrate removal system in January for the second time ever. As of Friday, the nitrate levels in source water from the Raccoon River are 16.16 milligrams per liter. They’re at 12.41 milligrams per liter in the Des Moines River. The Environmental Protection Agency’s standard is 10 milligrams per liter or lower. The last time the nitrate removal system ran this early in the year was 11 years ago in 2015. If it runs at all, it typically does so in spring or summer. But it’s been running at partial capacity for 18 out of 23 days in January.”It’s not common.” John Lawrence, emeritus professor at Iowa State University, told KCCI. While it’s impossible to pinpoint exactly what could be causing the spike, he says it’s likely driven by several factors, like weather. “The ground is not completely frozen,” he said. “So that allowed for the moisture for some of the snowfalls we saw in December, and the rain, to infiltrate through the soil and leech out some of the nitrates.”Weather isn’t the only factor, though. Mineralization, which is when organic nitrogen in the soil is converted to nitrate, was high from warm temperatures last year. Plus, Iowa saw four years of drought until 2023, meaning more nitrogen remains in the soil, sinking deeper through the unfrozen ground.All of this could spell issues for the remainder of the year.”If we look at the 2010s, the 2015 time period, where it started early in the year, it continued at high levels throughout 2015,” Lawrence said. “So if we are in fact repeating history, we might expect to see high nitrate levels more often through this year.”That could mean higher costs for Central Iowa Water Works. It costs $16,000 a day to run the nitrate removal system at full capacity.But similarities to 2015’s data could provide a map of what to expect later this year, allowing central Iowans to make changes, like lessening fertilizer use or reducing lawn water, ahead of time”2015, we’ve done that. The last some we came through the summer without a lot of notice ahead of time and we’re able to do that. People will be paying more attention based on recent history. I don’t think this is something to panic about,” Lawrence said. It’s important to note that those high nitrate levels mentioned at the beginning of this story are pre-treatment levels.Central Iowa Water Works is able to dilute that concentration, meaning the treated water meets the EPA level of 10 milligrams per liter.
Nitrate levels in the Des Moines and Raccoon Rivers are unusually high for this time of year, causing Central Iowa Water Works to run its nitrate removal system in January for the second time ever.
As of Friday, the nitrate levels in source water from the Raccoon River are 16.16 milligrams per liter. They’re at 12.41 milligrams per liter in the Des Moines River.
The Environmental Protection Agency’s standard is 10 milligrams per liter or lower.
The last time the nitrate removal system ran this early in the year was 11 years ago in 2015. If it runs at all, it typically does so in spring or summer.
But it’s been running at partial capacity for 18 out of 23 days in January.
“It’s not common.” John Lawrence, emeritus professor at Iowa State University, told KCCI.
While it’s impossible to pinpoint exactly what could be causing the spike, he says it’s likely driven by several factors, like weather.
“The ground is not completely frozen,” he said. “So that allowed for the moisture for some of the snowfalls we saw in December, and the rain, to infiltrate through the soil and leech out some of the nitrates.”
Weather isn’t the only factor, though.
Mineralization, which is when organic nitrogen in the soil is converted to nitrate, was high from warm temperatures last year.
Plus, Iowa saw four years of drought until 2023, meaning more nitrogen remains in the soil, sinking deeper through the unfrozen ground.
All of this could spell issues for the remainder of the year.
“If we look at the 2010s, the 2015 time period, where it started early in the year, it continued at high levels throughout 2015,” Lawrence said. “So if we are in fact repeating history, we might expect to see high nitrate levels more often through this year.”
That could mean higher costs for Central Iowa Water Works. It costs $16,000 a day to run the nitrate removal system at full capacity.
But similarities to 2015’s data could provide a map of what to expect later this year, allowing central Iowans to make changes, like lessening fertilizer use or reducing lawn water, ahead of time
“2015, we’ve done that. The last some we came through the summer without a lot of notice ahead of time and we’re able to do that. People will be paying more attention based on recent history. I don’t think this is something to panic about,” Lawrence said.
It’s important to note that those high nitrate levels mentioned at the beginning of this story are pre-treatment levels.
Central Iowa Water Works is able to dilute that concentration, meaning the treated water meets the EPA level of 10 milligrams per liter.