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. This impairment was appropriate for Category 4d of Iowa’s Integrated Report. Due to the age of the kill (greater than five years), however, this assessment is moved from IR Category 4d to 3b for the 2014 Integrated Report. Fish consumption uses remain 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 DNR's assessment methodology for Section 305(b) reporting, occurrence of a single pollution-caused fish kill during an assessment period indicates "partial support" of the aquatic life uses. 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 should be placed in IR Category 4d (impaired but TMDL not required). Thus, this assessment segment was placed into Category 4d of Iowa's Integrated Report. If no additional fish kills have occurred over at least a five-year period, the assessment of impairment should be considered “evaluated” (i.e., of lower confidence), and the waterbody segment should be moved from IR Category 4d to IR Category 3b (list of waters in need of further investigation). Thus, this assessment is moved from Category 4d to Category 3b of the 2014 Integrated Report.
