FAIRFIELD – The Iowa Department of Natural Resources investigated a manure spill last week that occurred about 7 miles northeast of Fairfield.
The manure applicator, John Widmer of Maynard Manure Management, estimated that between 800 and 1,000 gallons may have spilled, but because of a quick action to plug the tile inlet the manure was running into, little of the manure reached North Walnut Creek.
Terry Jones, Iowa DNR senior environmental specialist, took water samples downstream and did not find elevated ammonia levels or dead fish. He noted that an 800-gallon spill is “significant,” and said his office tries to test far enough downstream to get ahead of the plume of manure. In this case, he said DNR officials did not identify a plume or impact downstream.
“The bigger the release, the bigger the impact, and the further we test,” he said. “Dead fish, foul odor and discoloration can all be indicators [of a manure spill], but if the stream is high flowing and turbid, you may not see anything out of the ordinary, which is why we conduct field sampling.”
Jones said manure spills can disrupt aquatic ecosystems in the short term, but once the source is eliminated and water quality returns to normal, the system typically recovers. He said there’s little reason to worry about manure seeping into underground aquifers in southeast Iowa, but that could be a problem in other places with what he called “Karst topography,” characterized by underground caves and sinkholes.