Ballard Creek IA 03-SSK-952

A fish kill occurred on Ballard Creek on August 24, 2002, near the intersection of 255th Avenue and 310th Street; the kill was localized to an approximately 40-meter segment of stream; approximately 100 fish were killed. The kill was believed to be caused by manure.  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.  DNR records show no evidence that restitution was sought by DNR for the value of the fish killed or costs of investigation.  Thus, this assessment will remain in IR Category 5b.  

The results of the IDNR/SHL follow-up biological monitoring in 2007 and 2013 suggest that the Class B(WW2) aquatic life uses should be assessed (evaluated) as “partially supporting.” A series of biological metrics which reflect stream water quality and habitat integrity were calculated from the biological sampling data. The biological metrics are based on the numbers and types of benthic macroinvertebrate taxa and fish species collected in the stream sampling reach. The biological metrics were combined to make a fish community index of biotic integrity (FIBI) and a benthic macroinvertebrate index (BMIBI). The indexes rank the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum). The 2007 FIBI score was 43 (fair) and the BMIBI scores were 65, 61 (good). The 2013 FIBI score was 26 (fair) and the BMIBI score was unavailable.  The aquatic life use support was assessed (evaluated) as partially supporting (=PS), based on a comparison of the FIBI and BMIBI scores with biological impairment criteria (BIC) established for previous Section 305(b) reports. The non-riffle habitat FIBI BIC for this ecoregion is 32 and the BMIBI BIC for this ecoregion is 62. This segment passed the FIBI BIC 1/2 times and passed the BMIBI BIC 2/2 times in the last eight years. One of the BMIBI samples (61) was an artificial substrate sample where the samples quality was poor due to exposed plates on the artificial substrates. Even though the BMIBI score of 61 is lower than the BMIBI BIC of 62, due to the actual score being 61.43 and sampling conditions, IDNR considers it a passing score. The biological impairment criteria were determined from a statistical analysis of biological data collected at stream ecoregion reference sites from 1994-2008.

This aquatic life assessment is now considered "evaluated" based on a change in the 2010 IDNR assessment methodology. IDNR now requires a segment have two or more biological samples collected from the segment in multiple years over a recent five-year period to be considered “monitored”. This segment had multiple BMIBI samples collected in 2007 and multiple FIBI samples in the last eight years.  According to IDNR’s assessment/listing methodology, impairments based on “evaluated” assessments are of lesser confidence and are thus not appropriate for Section 303(d) listing (Category 5 of the Integrated Report). IDNR does, however, consider these impairments as appropriate for listing under either Category 2b or 3b of the Integrated Report (waters potentially impaired and in need of further investigation). However, despite this change in assessment methodology and type, this waterbody remains in IR Category 5b-t and remains on Iowa’s Section 303(d) list of impaired waters.