COLLINS – A fish kill along Wolf Creek in Jasper County has been traced to high ammonia levels flowing out of an underground tile line about one mile southwest of Collins in Story County, the Iowa Department of Natural Resources (DNR) said Tuesday.
The most likely source of ammonia is fertilizer, manure or other sources like a cleaning product or industrial byproduct.
“We don’t know exactly where or how it got into the tile line,” said Bill Gibbons, environmental specialist at the DNR’s Des Moines area field office. “It could have been through a storm drain in town or a tile inlet in the country.”
The fish kill spanned more than nine miles of Wolf Creek, starting near Collins and running south to Jasper County. The DNR estimated more than 66,500 fish died, mostly minnows, shiners, stonerollers and chubs. Some bullheads, sunfish, and smallmouth and largemouth bass were also killed.
Wolf Creeks feeds into Indian Creek, which in turn empties into the South Skunk River in Jasper County
A farmer reported the Wolf Creek fish kill Sept. 3 after discovering dead fish on his property. When Gibbons investigated Saturday, he found elevated levels of ammonia and dead fish below where a county tile line empties into Wolf Creek, while live minnows swam above the area.
Gibbons said he visited with nearby livestock facilities and a local co-op but found no evidence of spills. The investigation is ongoing.
“Crops haven’t been harvested yet, so farmers haven’t started applying fertilizer or manure,” Gibbon said. “This is a good reminder that tile inlets and storm drains along the street carry water and pollutants directly to a nearby stream. People need to take care and dispose of unused chemicals and fertilizer properly.”
Lab results from water samples collected Sept. 3 show ammonia nitrogen levels that are toxic to fish – 9.9 and 40 milligrams per liter – below the tile outlet.
Gibbons said DNR fisheries staff determined the value of the fish killed was $7,082.19 and the cost of the fisheries investigation at $939.67.
The DNR is still seeking the responsible person. Anyone with information is asked to call the DNR’s Windsor Heights field office at 515-725-0268. Spills and fish kills can be reported to the DNR’s 24-hour spill line at 515-725-8694.
