Assessment Comments
Assessment is based on results of an IDNR fish kill investigation in October 2011.
Basis for Assessment
[Note 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 (see http://www.iowadnr.gov/Portals/idnr/uploads/water/standards/files/swcdoc2.pdf), 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 assessment, the available water quality monitoring data will be compared to the applicable Class A1 and Class B(WW2) water quality criteria.]
SUMMARY: The preumptive Class A1 (primary contact recreation) uses remain "not assessed" (IR 3a) due to the lack of information upon which to base an assessment. The Class B(WW-2) (aquatic life) uses are assessed (monitored) as "partially supported" (IR 4d) due to the occurrence of a pollutant-caused fish kill in October 2011.
EXPLANATION: The Class B(WW-2) (aquatic life) uses are assessed (monitored) as "partially supported" due to the occurrence of a fish kill in October 2011. The kill occurred on or before October 8, 2011; the kill was located near Terrace Hills Golf Course east of Altoona. Approximately 1,000 fish were killed over 0.9 miles of stream. The value of the fish was reported as $6,292.94. Cost of the IDNR investigation was $361.78. The cause of the kill was identified as a release of wastewater. According to the IDNR fish kill investigation report, there was a wastewater release at a pumping station in the 1300 block of Eighth St. in Altoona. An estimated 170,000 gallons of untreated wastewater were released. DNR staff found dead and struggling fish along a 0.75 mile stretch of Mud Creek following the kill. The fish were mostly minnows, chubs and suckers with a few game fish. DNR staff also found elevated levels of ammonia in the same areas as the dead fish and for about two miles downstream.
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. Fish kills attributed to a pollutant, but where a source of the pollutant was not identified and/or where enforcement actions were not taken against the responsible party, will be placed into Integrated Report subcategory 5b. The intent of placing these waterbodies into Category 5 is not to necessarily require a TMDL but to keep the impairment highlighted due to the potential for similar future kills from the unaddressed causes and/or sources. 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 records show that the party responsible for the kill was identified, and IDNR sought and received restitution for the value of the fish killed and the costs incurred by IDNR during investigation of the kill. Thus, this assessment segment was placed in Category 4d of Iowa’s 2014 Integrated Report.
