(Winfield, Iowa) — The Iowa Department of Natural Resources is investigating a hog manure spill into a Louisa County creek near Winfield, following a pumping incident. According to a DNR news release, a crew from the manure application business Catnip Ridge was applying manure to a field Thursday when a break in a line caused an unknown amount of manure to spill into a tributary of Roff Creek.

Iowa Department of Natural Resources is investigating a hog manure spill into an unnamed tributary in Louisa County. (Photo courtesy of Iowa DNR)

DNR said the applicator team took “immediate action” to stop pumping and to clamp the line once the tear, which DNR later discovered was from friction against an iron fence post hidden in some vegetation, was discovered. The spill occurred in a road ditch northeast of Winfield at the intersection of Q Avenue and 65th Street. The Catnip Ridge crew placed dams in several areas along the tributary and plugged a nearby culvert to keep the manure from entering the creek, DNR reported.

Fresh water was added to the spilled area to help the crew flush the tributary and pump out the spilled manure. When DNR staff assessed the scene Thursday, initial water monitoring tests showed elevated levels of  ammonia, but staff did not observe any dead fish.

According to the release, when staff returned Friday morning to the site, “a small number of dead fish were observed” in the tributary, but the plugged culvert had prevented further downstream migration of the manure. The DNR said it will continue to monitor the cleanup efforts and investigate the incident to determine if further enforcement action is necessary.

It was the second manure spill reported the DNR reported last week, the first was also contained to an unnamed tributary in Carroll County.