THAYER, Iowa—Officials with the Iowa Department of Natural Resources report DNR staff, Tuesday, investigated cleanup of a manure spill about six miles south of Thayer, in Union County. Iowa Select Farms had reported the spill Monday night, after pumping manure into a nearly full manure storage tank at one of their sow facilities. Their staff said the manure was supposed to be pumped into a different tank, but someone left a valve closed. Iowa Select estimated between 10,000 and 20,000 gallons spilled over the side of the tank into a small tributary of the Grand River. Tuesday, they updated the amount to about 10,000 gallons.

DNR staff confirmed Iowa Select had dammed the tributary, trapping pooled liquid behind the dam, preventing a fish kill in the Grand River. Iowa Select is working with DNR to pump manure from the pool and land apply it at fertilizer rates. DNR field tests showed elevated ammonia levels behind Iowa Select’s dam. Field tests also indicated there was no impact to the Grand River.

The tributary was too small to support fish and DNR staff found no dead fish in the Grand River. They will continue to monitor cleanup activities. DNR will consider appropriate enforcement action.