The Iowa Department of Natural Resource has identified hog manure as the black liquid in an unnamed tributary approximately 1-1/5 miles from the North Raccoon River in Franklin Township.
Although the manure is no longer actively flowing, an unknown amount of manure continues to be pooled in numerous areas in the tributary and in Drainage District 37B.
The public is asked to continue to avoid swimming or recreating in the area. Additionally, it is recommended that livestock using the tributary for watering be limited as well.
The manure spill was first discovered last Friday by Bob Rye, a certified tester for the Raccoon River Watershed Association’s (RRWA) Save Our Streams program. That group has been testing tributaries to the Raccoon River since June 2022 to have baseline information about water quality.
Chris Henning, Franklin Township farmer and chair of the RRWA, has also done water testing at the stream. She described it as “pristine” prior to the manure spill. She had seen heron, wood ducks, and even a beaver floating on its back in the stream. She said it was reputed to have Topeka shiners, although she hadn’t seen any. Water transparency had scored 60, the maximum, in late May; after the spill it scored 3.
DNR staff this week has investigated the area by checking tiles, tile intakes, and drainage tile outlets. Local officials and multiple landowners provided information.
Field tests show dissolved oxygen at zero (it had been 8-10, according to Henning), and ammonia concentrations greater than 300 ppm, which is as high as the field tests read.
Water samples have been collected and sent to the State Hygienic Lab for further analysis and are expected within the next 7-10 business days.
