Assessment Comments
Assessment remains based on results of an IDNR investigation of a fish kill in August 2004.
Basis for Assessment
Note: Prior to the 2008 Section 305(b) cycle, this stream segment was classified only for Class B(CW1) coldwater aquatic life uses. Due to changes in Iowa’s surface water classification that were approved by U.S. EPA in February 2008, this segment is now presumptively designated for Class A1 (primary contact recreation) uses and for Class A2 (secondary contact recreation) uses. Thus, for the current (2012) assessment, perennial flow is presumed, and the available water quality monitoring data will be compared to the applicable Class A1, Class A2, and Class B(CW1) water quality criteria.]
SUMMARY: The presumptive Class A1 (primary contact recreation) and Class A2 (secondary contact recreation) uses remain "not assessed" due to the lack of information upon which to base an assessment. The presumptive Class B(CW1) aquatic life uses of this stream remain assessed (monitored) as “partially supported” due to a fish kill in August 2004. The kill was caused by animal waste from an open feedlot. The party responsible for the kill was identified and IDNR sought restitution for the value of the fish killed and costs incurred by DNR during the investigation of the kill. Thus, this impairment is appropriate for Category 4d of Iowa’s Integrated Report. NOTE: This impairment was placed in Category 5b of the 2008 Integrated Report due to a lack of information on whether or not IDNR sought restitution for this fish kill. This information was updated for the 2010 assessment/listing cycle and indicated that IDNR has sought restitution for this fish kill; thus this impairment was moved to IR Category 4d. Fish consumption uses are not assessed due to the lack of fish contaminant monitoring upon which to base an assessment.
EXPLANATION: Regarding support of aquatic life uses, the fish kill occurred on or before August 3, 2004, and occurred two miles north of Luxemburg on Highway 52 in Section 9 of T90N, R2W, Dubuque County; approximately 0.8 miles of stream was affected by the kill. The kill was attributed to animal wastes from an open (swine) feedlot. An estimated 6,574 fish were killed with an estimated value of $628. Fish killed were non-game species, primarily minnows (including creek chubs, stonerollers, blacknose dace, and southern redbelly dace). The party responsible for the kill was identified and restitution has been sought.
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 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. If, however, a consent order has been issued to the party responsible for the kill and monetary restitution has been sought for the fish killed, the affected waterbody will be placed in IR Category 4d (impaired but TMDL not required). IDNR feels that (1) TMDLs should not be required for kills caused by a one-time illegal or unauthorized release of manure or other toxic substance where enforcement actions were taken and (2) enforcement action is more appropriate, efficient, and effective for addressing a spill-related impairment than is the TMDL process. Thus, this assessment segment was moved to Category 4d of Iowa’s 2010 Integrated Report from Category 5b due to the recent information regarding restitution being sought. This impairment remains in IR Category 4d of Iowa’s 2012 IR.
