Assessment Comments
Assessment is based on fish kill investigations in July and October of 2006 and in October 2012.
Basis for Assessment
[Note 1: 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, and due to completion and approval of a use attainability analysis, 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.]
[Note 2: Due to the completion and approval of a use attainability analysis, the lower portion of this assessment segment is now designated for Class A3 (children’s recreation) use; the upper potion remains presumptively designated for Class A1 (primary contact recreation) use. Because (1) the water quality criteria to protect Class A1 and A3 uses are identical and (2) incorporation of the new Class A3 designation would require a split in this assessment segment, the entire segment (IA 02-CED-0220_2) will be assessed as a Class A1 (primary contact recreation) segment for the 2012 305(b)/303(d) cycle.]
SUMMARY: The presumptive Class A1 (primary contact recreation) uses are "not assessed" (IR 3a) due to a lack of water quality information upon which to base an assessment. The Class B(WW-2) aquatic life uses remain assessed (monitored) as "not supported" (IR 4d) due to fish kills in July 2006, October 2006, and October 2012.
EXPLANATION: The first fish kill occurred on or before July 18, 2006 and was attributed to runoff from an open feedlot on a small tributary of Prairie Creek. Rainfall from the previous night washed manure and corn glucose from the feedlot into the tributary to Prairie Creek. Approximately 108,882 dead fish including carp, white suckers, smallmouth bass, and minnows were found up to 14 miles downstream of the tributary. The estimated value of the dead fish was $18,306.78. The party responsible for the kill was identified, and restitution was sought and received.
The second fish kill occurred on or before October 20, 2006 and was caused by hog manure that entered the creek when a coupler on an umbilical line failed while it was draining a hog facility. The kill occurred southeast of Keystone and affected 3.4 miles of the stream. Approximately 22,809 fish were killed. No information on types of fish was provided. The estimated value of the dead fish was $8,484.01. The party responsible for the kill was identified, and restitution was sought and received.
The third kill occurred on October 25, 2012 and was caused by manure runoff from on open cattle feedlot following a rainfall event. An estimated 20,800 fish were killed over approximately 3 miles of Prairie Creek near Blairstown. The value of the fish killed was estimated at $2,950. The party responsible for the kill was identified, and restitution has been sought by IDNR.
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, based on the two kills that occurred in 2006, 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. Due to the fish kill in October 2012, and due to the pending recovery of restitution of the value of the fish killed and the cost of the IDNR fish kill investigation, the aquatic life uses of this stream will remain assessed as impaired (not supporting) and placed in Category 4d of Iowa’s Integrated Report.
