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7 Questions – and Answers – You Need to Know About Keeping Water Nutrient-Free

Bill Stowe and Bill Northey both want safe drinking water for people in the Des Moines, Iowa, metro area. 

They just disagree about some ways to achieve that. Stowe, general manager of the Des Moines Water Works, and Northey, Iowa secretary of agriculture, discussed water quality issues this week at a North American Agricultural Journalists program at the Meredith Corporation in Des Moines, home of Successful Farming magazine. Here are some questions and answers that surfaced during the dialogue. 

1. Why the fuss? 

Around 500,000 residents in the Des Moines metro area receive water from the Des Moines and Raccoon Rivers. During times of peak nitrate loads, Des Moines Water Works spends lots of money removing these nitrates that come from sources like cropland tile water that empties into these two rivers.

“For 70 days last year, nitrate concentrations on the Des Moines and Raccoon Rivers reached record heights,” says Stowe. Nitrate-reducing costs ran $7,000 to $8,000 daily to reduce these nitrate levels to safe ones, he says. 

Such levels pose significant public health dangers, says Stowe. He points to communities like Charleston, West Virginia, and Toledo, Ohio, which have had serious water contamination issues in the past year.

Cleaning costs for water are passed onto the customers of Des Moines Water Works, notes Stowe. There’s a wide broad demographic range of Des Moines Water Works customers, he says. 

“Within a few blocks, there are areas of great poverty and great wealth,” Stowe says. “Affluent or not, though, all customers share the costs of cleaning up the water.”

2. Why does agriculture get the blame for nitrates?

That’s because in this case, Stowe says 92% of the nitrate contribution is from non-point agricultural sources, with 8% coming from point-source pollution.

3. Won’t voluntary measures cut it?

Here’s where Stowe and Northey disagree. Stowe says the voluntary Iowa Nutrient Reduction Strategy in Iowa contains no time frame and metrics. 

“If I were to buy into that voluntary conservation practices and education were critical in improving water quality in this state, it would be important for me to rely on data to make that argument,” says Stowe. However, lack of metrics makes this difficult, he says. 

However, a mandatory approach would be a logistical nightmare, says Northey. Mandatory regulations spread across numerous farms would be akin to mandatory recycling. This would not only include mandatory home recycling, but also separating recycled material from trash at convenience stores. That’s not doable, he says.

“To me, that is the challenge of trying to regulate the system with millions of players, as opposed to a handful of players,” he says. That is the non-point equivalent.”

4. Would nutrient contamination of water cease if crop plants used all nutrients applied to them? 

No, says Northey. “We need to do a better job, and get more practices on the ground,” he says. Still, factors like leaves coming off trees to water flowing over last year’s cornstalks can cause nitrogen (N) and phosphorus (P) to flow into streams. In the case of P, one-half of it that leaves Iowa is due to bed and bank erosion in streams, says Northey. 

5. Will banning fall N applications help in Iowa?

No, says Northey. He cites Iowa State University research that shows it would have just a 3% impact on the amount of N lost off farms. This would create logistical problems by pushing all N applications into spring and summer. 

“We would have to get more N on in the spring, and we would have a shorter application window in the summer,” says Northey. “We would create a huge amount of storage needs, and we would have to have more equipment needs. This is one solution that looks like a solution, but one that does not fix the problem and creates more problems.” 

6. What will the courts say? 

Well, ultimately, litigation could intensify the environmental heat that farmers in the Mississippi River basin feel. That’s what’s happened in the Chesapeake Bay, where Maryland, Delaware, and Virginia famers have had to comply with rigorous nutrient management practices. 

 “Litigation is a final alternative,” says Stowe.  

Still, Des Moines Water Works keeps this in mind because Stowe says it encourages data collection for use in establishing metrics for water quality — something he says is lacking under the voluntary Iowa nutrient management program. 

7. Will technology help? 

Yes, and that’s the good news. “Nitrogen-modeling software will help us be more precise,” says Northey. 

Ditto for precision agriculture, says Stowe. “Precision agriculture has great potential for providing economic incentives for nutrient reduction at the farm site,” he says. 

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