Assessment Comments
Assessment is based on results of a fish kill investigation in March 2009.
Basis for Assessment
[NOTE: Prior to the 2008 Section 305(b) cycle, this stream segment was classified only for general uses. Due to changes in Iowa’s surface water classification that were approved by U.S. EPA in February 2008 (see http://www.iowadnr.com/water/standards/files/06mar_swc.pdf), this segment is now presumptively designated for Class A1 (primary contact recreation) uses and for Class B(WW1) aquatic life uses. According to the Iowa Water Quality Standards, all perennial rivers and streams and all intermittent streams with perennial pools that are not specifically listed in the Iowa surface water classification are designated as Class A1 and Class B(WW1) waters. Thus, for the current (2010) assessment, perennial flow is presumed, and the available water quality monitoring data will be compared to the applicable Class A1 and Class B(WW1) water quality criteria.]
SUMMARY: The presumptive Class A1 (primary contact recreation) uses are "not assessed" due to a lack of information upon which to base an assessment. The presumptive Class B(WW-1) aquatic life uses of this stream are assessed (monitored) as "partially supported" due to a fish kill in March 2009.
EXPLANATION: The kill occurred on or before March 18, 2009 and was attributed to manure contaminated water from a truck wash facility that was released into a ditch that flows into Rose Creek. Approximately 1230 fish were killed with an estimated value of $110.70. The fish kill began near the center of Section 28 (T74N R36W) Noble Township in Cass County and extended 3 miles to the confluence with Seven-Mile Creek in Section 5 (T73N R36W) of Douglas Township in Montgomery County. Updated information shows that IDNR sought and received restitution for this fish kill.
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 (2009-2011) 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 will be placed in Category 4d of Iowa’s 2012 Integrated Report.
