Assessment Comments
Assessment is based on results of a fish kill investigation in March 2007.
Basis for Assessment
[Note: Prior to the current (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 (2008) 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 water quality information upon which to base an assessment. The presumptive Class B(WW1) aquatic life uses are assessed (monitored) as "partially supported" due to a fish kill in March 2007.
EXPLANATION: The kill occurred on or before March 21, 2007 and was attributed to a spill of hog manure into the stream. The spill occurred when an underground pipe broke causing manure from a 20,080 head swine finishing confinement to enter Elk Creek. The kill affected 3.1 miles of the stream near Woodbine. Approximately 378 fish were killed. The estimated value of the fish was $ 42.23. At the time of this assessment there are no records that IDNR has sought/received restitution for this 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 (2005-2007) 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. Fish kills attributed to a pollutant, but where a source of the pollutant was not identified and/or where enforcement actions were not taken against the responsible party, will be placed into Integrated Report subcategory 5b. The intent of placing these waterbodies into Category 5 is not to necessarily require a TMDL but to keep the impairment highlighted due to the potential for similar future kills from the unaddressed causes and/or sources. Thus, this assessment segment will be placed in Category 5b of Iowa’s 2008 Integrated Report.
