The cause of last week’s fish kill on the South Skunk River in Hamilton County is traced to a concrete manure holding structure at a hog confinement near Little Wall Lake. By Friday afternoon, the leak from the storage structure had been stopped, but approximately a half mile of tile line is still leaking manure into an unnamed tributary that flows to the South Skunk River.

The hog confinement unit consisting of four buildings with up to 4,800 animals combined is owned by Merlyn Hegland of Ellsworth. The fish kill was reported on Thursday afternoon by a citizen with D.N.R. staff on the scene until darkness Thursday evening.

On Friday, the DNR had environmental specialists at the site to find the source while fisheries biologists were doing an assessment of the fish kill. Field tests indicated high ammonia and low dissolved oxygen levels in the water.Dead fish were documented as far downstream as south of Story City, more than five stream miles.

The Iowa D.N.R. has recommended that the producer pump down the concrete manure holding structure and consider pumping contaminated water from the stream.

By Pat Powers, KQWC, Webster City