Assessment Comments
Assessment remains based on results of an IDNR investigation of a fish kill that occurred on a tributary of Steeles Branch in August 2002.
Basis for Assessment
Note: Prior to the 2008 Section 305(b) cycle, this stream segment was designated only for Class B(CW) aquatic life uses. Due to changes in Iowa’s surface water classification that were approved by U.S. EPA in February 2008, this segment is also now presumptively designated for Class A1 (primary contact recreation) and Class A2 (secondary contact recreation) uses. This segment remains designated for coldwater aquatic life use (now termed Class B(CW1) uses), and for fish consumption uses (now termed Class HH (human health/fish consumption) uses.
SUMMARY: The presumptive Class A1 (primary contact recreation) uses and the Class A2 (secondary contact recreation) uses remain "not assessed" due to the lack of information upon which to base an assessment. The Class B(CW1) aquatic life uses remain assessed (evaluated) as "partially supported" due to occurrence of a fish kill on a tributary of Steeles Branch in August 2002. This kill was caused by a spill. Fish consumption uses are "not assessed" due to the lack of fish contaminant monitoring in this stream reach.
EXPLANATION: The fish kill occurred on August 2, 2002, and resulted from the spillage from a 500 gallon tank containing liquid animal feed containing molasses; the tank slid off a flatbed truck into a road ditch; an undetermined amount of liquid feed was spilled. Approximately 0.5 miles of this tributary was affected; a total of 153 fish was killed. The party responsible for this kill was identified. Steeles Branch was not affected by this kill.
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 placed into Category 4d of Iowa's 2004 Integrated Report. IDNR considers IR 4d fish kill waters with no subsequent kills reported in at least five year subsequent to the kill as appropriate for movement from IR Category 4d to either categories 2b or 3b (i.e., Iowa’s list of waters in need of further investigation). Thus, this assessment segment was be moved to Category 3b of Iowa’s 2010 Integrated Report and remains in IR Category 3b of the 2012 Integrated Report.
Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this stream reach.
