Drainage remains an issue

By Tim Krohn
Free Press Staff Writer

July 16, 2008 12:51 am

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When talking to people who are closely tied to the Minnesota River, two topics invariably come up:
* Activity on, and interest in, the river has increased substantially the past decade, and the worst pollutants in the river have been reduced.
* The river is under horrendous pressure and threat because of extensive farm drainage in the millions of acres that drain into the river.
Farmland drainage has long been identified as a big contributor to erosion and pollution in the Minnesota. Before extensive tiling, the land drained slowly and dirt and pollutants were filtered out.
Today those fields drain quickly, sending water rapidly into drainage ditches and then to ravines and rivers, causing more extensive flooding and bringing more dirt and chemicals to the river. That drainage also has been blamed for the increased flooding on the Mississippi River.
Bob Zoet, a longtime canoeist from Mankato who often can be found on the Le Sueur River, said he’s seen big changes in recent years.
“On the Le Sueur, with an inch of rain now you see this fast jump in the river and it goes down fast. The banks of the river really get undermined from all that water flowing so fast.
“The banks and trees are just falling in. It’s not good.”
Dave Smiglewski, mayor of Granite Falls, said his city has been devastated by floods in recent years. Similar amounts of rainfall in the past wouldn’t have brought the same kind of damage, he said.
“The drainage tile is a big problem. When it rains upstream, the water comes up fast. It comes through town in three days instead of three weeks. We see the effects here.”
Patrick Moore, head of the CURE river-improvement group in Montevideo, said pattern tiling has become very efficient and widespread in the past decade.
“Turbidity is bad in the river. We’re losing topsoil and nutrients.”
Moore said counties also are failing to enforce laws on the books requiring buffer grass strips along drainage ditches.
One possible bright spot, Moore said, is that more tiling companies and farmers are starting to look at metered tiling systems that hold water in the fields longer and release it more gradually. The systems help farmers by holding more nutrients in the soil where the crops can use them.
Scott Kudelka, communications coordinator for the Minnesota River Watershed Alliance, said all conservation groups are particularly nervous about the effects of agriculture now because of record-high prices for grain.
“The biggest worry now is that a lot of the land in conservation programs is being pulled out. We’re going to lose a lot of that marginal conservation land. Farmers need to make a living and we have a big demand for corn,” Kudelka said.
In the Dakotas, land is being pulled out of grass cover and put back into crop production on a massive scale. “They’re losing 50,000 acres (of conservation land) in a lot of counties.”
More land in crops means more water moving quickly to the river. And with farmers planting more acres in corn — which needs more nitrogen fertilizer than other crops — there is more concern about nitrogen being carried into the rivers.
Kudelka said there has been a drop in phosphorus and fecal coliform levels in the river because of new city sewage treatment plants and upgrades to septic systems.
“Unfortunately, we haven’t seen much reduction in nitrates. They’re coming from nitrogen in farm fertilizers, and from cities and golf courses.”
Kudelka said it’s important not to blame farmers as being careless or unconcerned.
“Farmers are just trying to maximize their production and profits. They need nutrients. They are getting better. There’s a high cost to fertilizer now, and they don’t want to use any more than they have to.
“But with all the tile lines, nitrates are water soluble, and they go with the water.”

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