Dane County officials are down playing the recent manure spill from the Town of Vienna digester, noting that the resulting phosphorous amounts released into Six Mile Creek were less significant than amounts during snowmelts or rainstorms.
County officials have been able to quantify the runoff and volume by checking with the USGS preliminary data taken from a Six Mile Creek monitoring station at Hwy. M near Lake Mendota, said Josh Wescott, Dane County Executive Joe Parisi’s chief of staff.
On a normal week, during a three-day period, about 12 pounds of phosphorus is found at the creek’s monitoring station, Wescott said.
During the period of Nov. 26-28, after the Nov. 24 manure spill, 30 pounds of phosphorus was detected.
“For context, when an inch of rain fell March 10 through 12, 4,450 pounds went through that testing station,” Wescott said.
During a snowmelt March 28-30, 2,830 pounds of phosphorus was detected, according to data collected by the county.
“What we’re seeing is the basins at the base of the digester captured a good amount of volume, keeping it on the property,” Wescott said, adding that efforts to contain the spill were fairly successful.
“What this probably speaks to is a pretty successful remediation effort after a really unfortunate accident,” Wescott said.
During the nearly three years the digester has been online, it has processed 87,600,000 gallons of manure from the three farms it serves, according to Wescott.
A memo from the county’s Environment, Agriculture and Natural Resources committee notes that the digester has processed 73,000 pounds of phosphorus since it began operation three years ago.
“While we are optimistic that this event will not impact lake water quality, we would be remiss not to view this as an opportunity to identify and mitigate risks to water quality,” said Pat Downing, chair of the committee. “Manure digesters potentially play a critical role in our overall effort to restore the Yahara watershed because they allow us to address phosphorus in cooperation with an important industry and community in our county”
Wescott noted that more work is needed to help clean up the lakes. The participating farms generate between 80,000 and 100,000 gallons of manure every day without the digester, he added.
Still, Wescott said, county officials want to make sure precautions are in place to avoid the risk of any future incidents.
“The good news in an otherwise gloomy story was once the spill was detected, their fast work prevented an undesirable situation from becoming a real environmental problem,” Wescott said.
He added that the entire region’s runoff problem is evident after a rainstorm.
“It shows the real magnitude and challenge we all face to address manure management,” Wescott said.
The Nov. 24 spill just north of Waunakee occurred after a pipe ruptured at 11 p.m. and was discovered at 5 a.m. the following morning. Department of Natural Resources staff and area farmers worked to contain and clean up the spill, and Dane County conservationists helped to locate fields to spread the manure.
Another community manure digester is planned in the Town of Springfield. It is expected to be online before the first of the year, Wescott said.
The Milwaukee Journal Sentinel reported that farms in Wisconsin experienced the largest volume of manure spills in 2013 since 2007, resulting in 1 million pounds of leaked manure.
At their meeting last week, the Dane County Board asked the county’s zoning and natural resources committee to take a second look at a digester plan for the Town of Bristol before moving ahead with it.