Ted Peterson, an environmental program supervisor with the Iowa DNR, says more than 66,000 fish were wiped out along nine miles of Wolf Creek in Jasper County in the incident that was reported on September 3rd.
“Our specialist was able to track it back using a field test kit for ammonia and was able to track that back to a tile outlet,” Petersen says. “This was a larger diameter tile outlet which indicates it’s draining a large watershed of land upstream.” The underground tile line stretched into Story County near the town of Collins. He says the lethal amounts of ammonia could have come from any of several sources.
“Some of those include agricultural sources but it could also be failing septic tanks, it could be household products,” Petersen says. “People don’t always think of this but it also could be the lawn fertilizer you might use on your own property. If there’s a number of those in one area and you have a significant runoff event, those could contribute as well.”
While the ammonia may have come from a manure spill or an industrial byproduct, the investigation is now at a stand-still. “We don’t have any leads,” Petersen says. “We checked out the mostly likely areas based off of land use in that immediate watershed and there was no indications anything had been dumped or released in those areas that we checked out.”
DNR investigators visited livestock facilities and a local coop, but found no evidence of spills. Crops haven’t been harvested yet, so farmers haven’t started applying fertilizer or manure. Residents in Story and Jasper counties are urged to help out.
“If anybody in the area might suspect something or saw something in the area that might lead them to believe it contributed to the fish kill, yes, we’d like to know about it,” Petersen says. DNR fisheries staff determined the value of the fish killed exceeds 7,000 dollars, while the fisheries investigation cost almost another thousand.
Tips can be directed to the DNR’s Windsor Heights field office at 515-725-0268.