Assessment Comments
Assessment remains based on results of a fish kill investigation in July 2009.
Basis for Assessment
SUMMARY: The Class A1 (primary contact recreation) uses remain "not assessed" (IR 3a) due to a lack of information upon which to base an assessment. The Class B(WW-2) aquatic life uses remain assessed (monitored) as "partially supported" (IR 4d) due to a fish kill in July 2009.
EXPLANATION: The kill occurred on or before July 31, 2009 and was attributed to aerial spraying of the pesticides Cobalt and Laredo. Approximately 542 fish were killed along 1.6 miles of Flint Creek two miles northeast of New London. The value of the fish was estimated to be $7342.74. Updated information shows that IDNR sought and received restitution for this fish 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 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). IDNR feels that (1) TMDLs should not be required for kills caused by a one-time illegal or unauthorized release of manure or other toxic substance where enforcement actions were taken and (2) enforcement action is more appropriate, efficient, and effective for addressing a spill-related impairment than is the TMDL process. Thus, this assessment segment was placed in Category 4d of Iowa’s 2012 Integrated Report and remains in that IR category.
