Published July 15, 2008 11:51 pm - River activists say the biggest problem for the Minnesota is farm drainage.
Drainage remains an issue
Demand for cropland eats at conservation acreage
By Tim Krohn
Free Press Staff Writer
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.