Assessment Comments
Assessment is based on results of an IDNR investigation of a fish kill in April 2004.
Basis for Assessment
SUMMARY: The Class B(LR) aquatic life uses of this stream are assessed (monitored) as “partially supported” due to a fish kill in April 2004. The kill was caused by animal waste from a hog confinement operation. 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 April 27, 2004. The cause of the kill was identified as animal waste from hog confinement operation. Only 1 fish was reported killed*; no value estimate was provided. No location information for the kill was provided. According to the IDNR investigation, the spill of animal (swine) waste sent approximately 1,500 gallons of manure into David’s Creek. The umbilical line (hose that runs from the confinement building to the tractor applying the manure) ruptured, thus spilling manure onto the land and through a tile line before entering the creek. Dams were constructed to stop the flow of manure into the stream. The party responsible for the kill was not 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. Although documentation of this fish kill suggests that 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).
*Note: IDNR staff (JRO & TFW) surveyed Davids Creek in October 2001 as part of an IDNR stream use assessment. The fish community in the lower portion of this stream was found to be very productive and very diverse (15 species with eight species reported as "common"). Although field notes from that survey suggest that aquatic habitat in the upper reaches of this stream is limited, the report that only one fish was killed during the April 2004 kill should not be taken to imply that this stream is incapable of supporting an aquatic commuity.
