The Iowa Department of Natural Resources (DNR) has identified the material contaminating an unnamed tributary of the North Raccoon River in Greene County as hog manure. According to the DNR, state officials learned of a black liquid appearing in the creek just over a mile east of Cooper. Authorities say the manure entering the tributary is no longer flowing, but an investigation into its source is ongoing. DNR staff report checking tiles, tile intakes, and drainage tile outlets within District 37B but have not confirmed the contaminants’ source. Field tests show dissolved oxygen levels in the water at zero and ammonia concentrations at 300 parts per million, which is the maximum reading for the DNR’s standard mobile test kits. Water samples have been submitted to the State Hygienic Laboratory, and results are expected as early as the end of next week. The public is asked to avoid swimming or recreating in this area. The DNR also recommends that livestock using the tributary for watering be limited.
