Assessment Comments
Assessment remains based on results of a fish kill investigation in October 2007.
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, 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 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 remain "not assessed" (IR 3a) due to a lack of water quality information upon which to base an assessment. The Class B(WW1) aquatic life uses remain assessed (monitored) as "partially supported" (IR 4d) based on results of a fish kill investigation in October 2007. This is the same assessment as that developed for the previous (2012) IR cycle.
EXPLANATION: The kill occurred on or before October 8, 2007 and was attributed to a manure spill from a hog confinement. The spill occurred when a pit under a hog confinement building overflowed with manure. The kill affected 7.43 miles of Otter Creek near Morning Sun. Approximately 9,321 fish were killed. The value of the fish was estimated to be $3,850.74. The party responsible for the kill was identified, and restitution was sought. NOTE: This assessment was placed in Category 5b of the 2008 Integrated Report due to a lack of information on whether or not restitution was sought for this fish kill. Due to updated information regarding legal action this assessment was placed in Category 4d of Iowa's 2010 Integrated Report.
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 moved from Category 5b of Iowa's 2008 Integrated Report to Category 4d of Iowa’s 2010 Integrated Report based on updated information regarding restitution for this fish kill. 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). Because, however, this fish kill occurred within the most recent five years, this assessment segment will remain in Category 4d of Iowa’s Integrated Report.
