Assessment Comments
Assessment remains based on results of an IDNR investigation of a fish kill in November 2004.
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 the lack of information upon which to base an assessment. The presumptive Class B(WW1) aquatic life uses of this stream remain assessed (monitored) as “partially supported” due to a fish kill in November 2004. The kill was caused by a spill of ammonia fertilizer. The party responsible for the kill was identified, and IDNR has sought restitution for the value of the fish killed and the costs incurred by IDNR during investigation of the kill. This impairment is appropriate for Category 4d of Iowa’s Integrated Report.
EXPLANATION: This kill occurred on or before November 10, 2004 in Section 20 of T80N, R41W of Harrison County. The cause of the kill was attributed to fertilizer. A truck pulling an anhydrous ammonia tank rolled over and spilled its contents near South Picayune Creek. An undetermined amount of anhydrous ammonia traveled into the creek. The kill traveled approximately 700 feet from where Picayune Creek empties from a road culvert through County Road F 32 east of Woodbine and stopped at an emergency dam constructed downstream of road culvert. Following the spill, ammonia levels in the contained area of the creek were between 75 and 150 parts per million (ppm), while levels downstream were between zero and 2.5 ppm. Ammonia levels of about 8 to 10 ppm can cause a fish kill, depending on stream temperature and pH. An estimated 93 fish were killed with an estimated value of $768. The responsible party was identified and restitution was sought.
According to the IDNR 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 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). Thus, this assessment segment was placed in Category 4d of Iowa’s 2006 Integrated Report. 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 2010 Integrated Report.
