Assessment Comments
Assessment is based on results of an IDNR investigation of a fish kill in June 2004.
Basis for Assessment
SUMMARY: The general uses of this stream are assessed (monitored) as “partially supported” due to a fish kill in June 2004. The kill was caused by a spill of an industrial chemical (sulfuric acid). Although the party responsible for the kill was identified, IDNR records do not indicate that IDNR sought restitution for the value of the fish killed or for the costs incurred by DNR during the investigation of the kill. Thus, this impairment is appropriate for Category 5b of Iowa’s 2006 Integrated Report (=Section 303(d) list).
EXPLANATION: This kill occurred on or before June 17, 2004. The cause of the kill was identified as a spill of an industrial chemical (sulfuric acid). An estimated 1,736 fish were killed, including a number of non-game and game fish species. The estimated value of the fish killed was $3,570. The kill occurred in sections 28, 33, and 32 of T72N, R13W, Wapello County; approximately 0.9 miles of this stream was affected. The kill began at the Highway 34 bridge east of Ottumwa and extended 1546 yards downstream to the confluence with the Des Moines River. According to the IDNR investigation, approximately 2,500 gallons of sulfuric acid spilled from an overturned transport truck at the Highway 34 bridge over Sugar Creek. The party responsible for the kill was identified.
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.
