Assessment Comments
Assessment is based on results of IDNR investigations of fish kills in August 2001 and August 2009 and on results of an IDNR fish kill follow-up investigation in July 2013.
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, 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 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 remain "not assessed" (IR 3a) due to the lack of information upon which to base an assessment. The presumptive Class B(WW1) aquatic life uses remain assessed (monitored) as "partially supported" (IR 5b) based on reports of fish kills in August 2001 and August 2009 and based on results of fish kill follow-up monitoring by IDNR staff on July 9, 2013.
EXPLANATION: The most recent fish kill on this stream segment occurred on August 7, 2009. Small numbers of dead minnows were observed in the 2 miles of this stream, sections 28 and 34 of Hazleton Township. The exact cause of the kill could not be determined. No ammonia was detected and the water appeared clear or slightly turbid. The operator of a local campground reported that the stream had become cloudy that afternoon following several inches of rain. Two farmers in the watershed noted that the ag chemical, Headline, had recently been applied to most of the surrounding crop fields. No dead fish were found in Otter Creek.
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. Thus, this assessment segment was placed in Category 5b of Iowa’s Integrated Report.
A fish kill also occurred on this stream segment on August 18, 2001. The kill affected 1 mile of this unnamed tributary to Otter Creek in sections 33 and 28 to T90N, R9W, Buchanan County approximately 3 miles south of Hazleton. The kill was caused by movement of land-applied hog manure and waste milk to this unnamed creek. This kill was not related to rainfall runoff. The responsible party was identified and restitution was sought.
This stream segment’s fish community was sampled on July 9, 2013, as part of the IDNR Watershed Improvement and Water Monitoring sections’ fishkill follow up monitoring program. Sampling methods described in IDNR’s fish kill follow-up protocol (Attachment 5 of Iowa’s 2014 assessment/listing methodology) were followed. Approximately 650 feet of stream were sampled using a single pass with two backpack electro fishing units. Results of this sampling show that this stream supports approximately 1,630 fish per mile compared to the Level IV ecoregion 47c average of approximately 1,710 fish per mile; 64% of the expected fish taxa for this ecoregion were sampled. For detailed results of this sampling, see https://programs.iowadnr.gov/bionet/Sites/966. The results from this follow-up sampling and comparison of these results to ecoregion averages suggest that the fish community of this stream segment fails to meet expectations for the non-fishkill impacted streams. These results suggest that the stream has not recovered from the previous fish kill event. Thus, this stream segment remains assessed as “impaired” and is remains in Category 5b of Iowa’s Integrated Report.
