by Jared Strong, Iowa Capital Dispatch
September 8, 2023
More than 500,000 gallons of manure-contaminated water has been pumped from a creek in Greene County because an aging storage basin began to leak, according to the Iowa Department of Natural Resources.
The DNR received a report Aug. 18 that a creek southeast of Jefferson had discolored water, and initial tests of the water showed an elevated concentration of ammonia, which can be indicative of manure contamination.
There was no immediate, obvious source of that contamination — which was flowing from a underground tile outlet — so DNR staff scoured maps of tile lines for clues. Contaminated water flowed from a tile outlet into the Greene County creek. (Photo courtesy of Alison Manz/Iowa DNR)
There is a vast amount of field tiling in western Iowa, used to drain cropland that might otherwise be too soggy for ideal production. Those systems of tubes move groundwater away from fields into creeks and other waterways.
A DNR examination of tile maps for that area showed that one of the tile lines goes very close to an open-air, earthen manure basin that was constructed about 1990, according to DNR records. It holds manure from a hog confinement with about 2,200 animals and lies about two miles away from the contaminated creek.
“It took a lot of time,” said Alison Manz, a senior environmental specialist for the DNR who investigated the incident. “This was definitely a team effort.”
It took about three days to identify the potential source of the contamination, and Manz said she was able to persuade the confinement owner — Eric Crosman, who bought the facility about five years ago — to excavate nearby. The digging confirmed that the basin was leaking into the ground, she said.
The basin has a clay liner that apparently failed. An engineering firm is attempting to determine what happened.
The soil around the basin has had problems with erosion in recent years, DNR records show.
The contaminated creek flows to the North Raccoon River. But because of low creek flow and beaver dams in the area, none of the manure reached the river, Manz said.
At least 550,000 gallons of contaminated water have been pumped from the creek onto nearby land. The leak did not kill fish.
There are no state regulations that prevent animal confinements from being located near underground tiling.
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