Assessment Comments
Assessment is based on (1) a 2006 summary of trout reproduction in Iowa streams prepared by the DNR Fisheries Bureau and (2) results of an IDNR investigation of a fish kill in May 2003.
Basis for Assessment
SUMMARY: The Class B(CW) coldwater aquatic life uses of this stream are assessed (monitored) as “partially supported” due to a fish kill in May 2003. The kill was caused by manure-contaminated storm water runoff. 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 2006 Integrated Report. Fish consumption uses remain "not assessed."
EXPLANATION: This kill occurred on or before May 2, 2003; the kill was attributed to manure-contaminated storm water runoff from an open (cattle) feedlot. Twenty-nine fish (rainbow trout and brown trout) were killed. The fish kill occurred in Sections 15 and 16 of T90N, R4W in Delaware County and affected approximately 0.25 miles of stream. Fountain Springs is one of the state’s most heavily used put and take trout streams and also has a naturally-reproducing brown trout population. Based on the value of the fish killed and the value of the days of angling opportunity lost, an estimated value of the kill was set at $2,325. The party responsible for the kill was identified; restitution for the fish killed and for costs incurred during the investigation was sought and received by IDNR.
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 (2002-2005) 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.
The assessment of impairment is in contrast to that suggested by a summary of trout reproduction in Iowa's coldwater streams. Based on the updated summary of trout reproduction in Iowa streams prepared by the DNR Fisheries Bureau in May 2006, the Class B(CW) uses of Fountain Spring Creek are assessed as "fully supported". According to the updated summary, this stream is in the group of Iowa coldwater streams that supports natural reproduction of trout. In previous IDNR summaries of trout reproduction, this stream was placed in the category of Iowa trout streams that have fairly consistent natural reproduction and that are capable of maintaining a viable population for the target trout species without any stocking. Based on results of surveys by the IDNR Fisheries Bureau, however, this stream is now placed in the category of Iowa trout streams that exhibit recent, but inconsistent reproductive success and that are generally not capable of maintaining a viable population for the resident trout species at this time. The influence of the May 2003 fish kill on the ability of this stream to support natural reproduction of trout is not known.
Fish consumption uses remain "not assessed" due to lack of fish tissue monitoring in this stream reach.
