The manure discharge happened in April 2021 when a worker at Rock Bottom Dairy, near Lester, neglected one night to shut off an irrigator that spreads manure onto a nearby field.
An overrun of about 200,000 gallons of manure into Mud Creek and its tributary was discovered early the next morning. Signs of contamination stretched 13 miles downstream, with elevated concentrations of E. coli bacteria and ammonia, the DNR reported.
The dairy has about 3,800 cattle, and the DNR has documented four other manure releases there in the past two decades.
One of them, in 2009, similarly polluted the waterways with about 100,000 gallons of manure and killed about 1,400 fish. That spill was caused by a clamp that came loose from a hose that was used to transfer manure from one location to another on the site, DNR records show. The dairy was fined $6,000.
The causes of the spills were different in each case, said Scott Wilson, supervisor of the DNR field office in that area.
“This is unfortunate,” Wilson said of the most-recent spill. “It was clearly a mistake, and we expect them to come up with procedures, some sort of remedy that would prevent this from happening in the future.”
The dairy’s owner Bernard Bakker agreed to pay a $10,000 fine for the most-recent spill — the maximum administrative penalty the DNR can levy. He must also pay restitution to the state for the estimated 96,168 fish that were killed along with the costs for the DNR investigation into the fish kill. That totaled about $26,100.
