(Spencer)– The Iowa Department of Natural Resources is investigating three more fish kills in northwest Iowa…all of them reported Thursday.
The agency says ammonia levels in Odebolt Creek near Arthur in Ida county ranged from 7.5 to 10 parts per million. Ammonia levels from three to five parts per million, depending on conditions, can be deadly to fish and other aquatic life. The DNR observed a small number of dead minnows and chubs. They estimate the kill happened Tuesday or Wednesday.
DNR investigators at Willow Creek, near Royal in Clay county, are working to identify a possible source of pollution that caused a fish kill there. Investigators found ammonia levels at 15 parts per million and very low dissolved oxygen levels, in addition to a strong manure smell. The kill affected bullheads, chubs and minnows.
The DNR is also investigating a fish kill on Mud Creek near Alvord in Lyon county.
The agency says heavy rains earlier this week likely washed manure and other contaminants into many northwest Iowa waterways that had been experiencing low flow conditions, resulting in low oxygen levels. The DNR says decomposing manure in a waterway releases ammonia and uses up available oxygen in the water, suffocating fish.
