Assessment Comments
Assessment is based on results of an IDNR investigation of a fish kill in September 2003.
Basis for Assessment
SUMMARY: The general uses of this stream are assessed (monitored) as “partially supported” due to a fish kill in September 2003. The kill was caused by animal waste from an open feedlot. The party responsible for the kill was not identified. This impairment is appropriate for Category 5b of Iowa’s 2006 Integrated Report (=Section 303(d) list).
EXPLANATION: This kill occurred on or before September 15, 2003; the kill was attributed to animal waste from an open feedlot. Although comments from the investigation suggest than a number of fish were killed, the official estimate is one fish killed. The location point for the kill is Section 4 of T76N, R13W, Keokuk County. No estimate of stream length affected by the stream was provided; the party responsible for the kill was not identified. According to the IDNR investigation, a citizen reported seeing some dead fish in Coal Creek; he said the creek had an odor and was discolored. Ammonia levels a long the creek were over 3.0 ppm (i.e., greater than the limit of the Hach test kit). The creek water had a brown tint but suspended solids content didn't appear excessive. Odor wasn't particularly noticeable. A large beef lot appeared to be a source of the ammonia. Water discharging from two tile lines tested above 3 ppm ammonia. A well used to water the cattle in the feedlot was tested and it too showed significant ammonia contamination.
According to IDNR’s assessment/listing methodology, the occurrence of a single pollutant-caused fish kill, or a fish kill of unknown origin, on a waterbody or waterbody reach during the most recent assessment period (2002-2005) indicates a severe stress to the aquatic community and suggests that the aquatic life uses should be assessed as “impaired”. If a cause of the kill is identified, and the cause is either known, or suspected, to be a “pollutant”, the assessment type is considered “monitored” and the affected waterbody is a candidate for Section 303(d) listing. Fish kills attributed to a pollutant, but where a source of the pollutant was not identified and/or where enforcement actions were not taken against the responsible party, will be placed into Integrated Report subcategory 5b. The intent of placing these waterbodies into Category 5 is not to necessarily require a TMDL but to keep the impairment highlighted due to the potential for similar future kills from the unaddressed causes and/or sources.
