Assessment Comments
Assessment remains based on results of an IDNR investigation of a fish kill in August 2005.
Basis for Assessment
Note: Prior to the 2008 Section 305(b) cycle, this stream segment was designated only for Class B(LR) 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. The stream remains designated for aquatic life uses (now termed Class B(WW2) aquatic life uses). Thus, for the current (2012) assessment, the available water quality monitoring data will be compared to the applicable Class A1 and Class B(WW2) water quality criteria.]
SUMMARY: The presumptive Class A1 (primary contact recreation) uses remain "not assessed" due to the lack of information upon which to base an assessment. The Class B(WW2) aquatic life uses of this stream remain assessed (monitored) as “partially supported” due to a fish kill in August 2005. The kill was caused by manure discharge from a dairy feeding operation. The party responsible for the kill was identified. This impairment qwas appropriate for Category 4d of Iowa’s 2006 through 2010 Integrated Reporting cycles and is now appropriate for IR Category 3b of Iowa’s 2012 Integrated Report.
EXPLANATION: This kill occurred on or before August 19, 2005, and was caused by manure discharged from a dairy feeding operation. The kill began in Section 36 of T93N, R4W and ended in Section 36 of T93N, R3W. Approximately 1.3 miles of stream were affected; South Cedar Creek, a trout stream, did not appear to have been impacted by the event. A total of 2,226 fish were killed with an estimated value of $660. The party responsible for the kill was identified, and IDNR is seeking restitution for the value of the fish killed and the costs incurred by IDNR in the investigation of the kill.
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 in Category 4d of Iowa’s 2006, 2008, and 2010 Integrated Reports. IDNR considers IR 4d fish kill waters with no subsequent kills in at least the five years subsequent to the kill as appropriate for movement to IR categories 2b or 3b (i.e., Iowa’s list of waters in need of further investigation). Thus, this 4d impairment will be moved to IR Category 3b of Iowa’s 2012 Integrated Report.
