By NANCY MADSEN firstname.lastname@example.org
August 20, 2016
Water quality improvement projects are difficult to get done and may not show the expected benefits to all involved, locals told state legislators on a recent visit.
Karen Galles, who works on Seven Mile Creek Watershed projects for Great River Greening and the Nicollet County Soil and Water Conservation District, told a group of state legislators Aug. 17 that the system is “very flawed.
“To get stuff like this done is nearly impossible,” she said at a farm west of St. Peter on Hwy. 13. “The system for getting these projects done is maddening for landowners.”
The Legislative Water Commission, a group of 12 legislators from both parties and houses, took a one-day tour of site in southern Minnesota, getting an in-depth look at water issues.
Agricultural drainage management
They headed to a farm field owned by Jerry and Shirley Payne to look at a series of drainage management improvements made to their property and a neighbor’s.
A controlled drainage system was installed on neighbor Chuck Peters’ land, similar to a terrace that helps stop erosion. The level of water held back in a field can be adjusted based on crops or conditions. Typical drainage systems are set at about four feet deep and always drain to that depth, which gives farmers dry and easy access to fields. But now, Peters said he’s generally held the water at two feet, ideal for growing crops.
“We had already cut nitrogen (fertilizer) rates because of multiple treatments instead of one in the fall,” Peters told the legislators. “We built the structure to help hold moisture and if there’s a bonus of holding nitrates, surely we had to do that.”
Excessive nitrogen in field runoff can stimulate plant and algae growth in streams, which can lead to algal blooms and less oxygen for fish and invertebrates. It leads to poorer water quality.
On the Payne property, they built a woodchip bioreactor to take nitrates out of the water coming out of agricultural fields. The bioreactor is 6 feet deep, 8 feet wide and 120 feet long, covered with dirt. The water drains through the wood chips and the organisms living on the chips consume the nitrates. The water should take six to eight hours to drain through. On each end, there are water control structures to regulate the flow. The water, scrubbed of nitrates, flows into a county ditch.
The Paynes also saw their ditch to the west of the bioreactor widened and flattened to make it easier to control for weeks. But the solution wasn’t a perfect one. The water from Highway 13 flows freely into the farm field on the Payne side of the road. County officials wouldn’t allow the project to include grading a ditch near the road to direct the flow toward the private ditch. And while county officials allowed the Paynes to move a field access, a culvert through the new field access was not permitted. That, again, would help direct water to the private ditch, which has a water control measure and a biomass crop at its end.
“The cooperation we receive in the watershed in spite of all that is inspiring,” Galles said. “There’s a lot of bad talk about the voluntary approach and yet, we still get this level of cooperation.”
Rep. Clark Johnson, D-North Mankato, said the cooperative work in the Seven Mile Creek Watershed is a model that others can follow.
“The closer we can get it to the economics of farming, the better,” he said. “We need long-term sustainability.”
And that could come through savings on fertilizer or markets for biomass fuels, he said.
Drinking water protection
In St. Peter, they heard about drinking water protection and treatment, which included a tour of the city’s Broadway Avenue Water Treatment Plant.
Bruce Montgomery, from the state Department of Agriculture, said the city’s were one of the first water sources they sought to improve. The city draws from aquifers at three levels; each has their own contaminants.
In the shallow aquifer, nitrates are at high levels due to agricultural runoff from west of the city. The middle-depth aquifer has high iron and manganese levels while the deep aquifer has sulfates and chlorides.
“Twenty-five to 30 public water supplies in Minnesota are threatened because of nitrates,” Montgomery said. “It comes from heavier tile-drained areas.”
St. Peter blends the three water sources and then uses reverse osmosis, a more expensive process, to treat the drinking water in order to take out nitrates
The main source of water that sinks into the shallow aquifer is the end of a county ditch that runs into a ravine perpendicular to County Road 40. There is no governmental authority that can force improvements in the ravine and the city alone can’t pay for improvements on the private property that would come with high regulations, Public Works Director Pete Moulton said.
“We tried 20 years ago and, so far, we’ve had to take a hands-off approach,” he said.