Feeling increasingly in the crosshairs for fouling the rivers, farm groups have formed a coalition to tell their story. “All of us who live in the Minnesota River Valley have a stake in this,” said Warren Formo, executive director of the Minnesota Agricultural Water Resources Coalition.
The group was formed in 2008 by all of the state’s major farm-industry groups.
Formo argues that data linking drainage to much of the sediment problem are based on relatively new science. And he says there may never be enough proof to pinpoint ag drainage as the primary culprit.
“ The (river basin) system is continuing to change, so will we ever know? The need to do research on the system will never stop because the changes will never stop,” Formo said.
“Farming is a part of it, I’m not saying we shouldn’t look at agriculture. But we’ve changed the landscape with cities, roads and bridges. But it is all going toward one issue (agriculture).”
Formo said the public is not up to speed on changes that have been made in modern agriculture. “ We have such different starting points on the conversation, a different understanding of what’s ag today. We need to bring that out so we’re not arguing about what happened 40 years ago.”
He said the most dramatic change has been in using more conservation tillage.
“ Tillage is much less than 20 or 30 years ago. We’ve increased the water- holding capacity of the soil.”
Farm groups argue that getting water off the landscape through tile drainage allows farm fields to absorb more water after rains — in essence reducing the flow of water into rivers and limiting erosion. Farm advocates also point to a study done by University of Minnesota soil scientists Satish Gupta.
And Gupta said moisture- saturated soil — from increased precipitation — also is causing upper slopes of ravines to slough off into the river.
“ Some people believe that additional water from drained agricultural land is increasing river flows and contributing to sediment production,” Gupta said.
“ Our data indicate that’s probably not true.”
Many scientists who’ve studied the river basin accept some of Gupta’s observations but not his core analysis that farm drainage has had little effect.
“ The farm groups have come up with reasons why drainage is good. Some have merit and some are a stretch,” said Norman Senjem, who recently retired after many years with the Minnesota Pollution Control Agency.
Senjem said the MPCA did include Gupta’s views in agency studies.
And the latest comprehensive study, presented recently, analyzed 70 years of data and concluded that changes to the rural landscape and drainage are the primary drivers of increased river flows and sediment problems.
Dan Engstrom, a scientist with the St. Croix Research station, said much of the water now delivered to rivers via drainage used to lie across a landscape of vegetation and wetlands and slowly found its way into rivers or simply evaporated.
He said increased precipitation of about 8 percent since 1940 doesn’t account for the rate of flow increase in rivers. And, he said precipitation has not increased in May and June, but river flows have.
While farm groups are taking a more active role in the debate, there is little discussion by anyone of requiring farmers to alter drainage practices. The federal EPA does not regulate non-point sources such as farm drainage nor does the state.
“ I wonder sometimes why there’s so much concern by farm groups because there is no regulatory enforcement,” Senjem said.