Fox River IA 04-FOX-994

The presumptive Class A1 (primary contact recreation) uses are assessed (evaluated) as "partially supported" due to identification of an impairment for indicator bacteria (E. coli) in the adjacent downstream segment in Missouri by the Missouri Department of Natural Resources.

The Class B(WW2) aquatic life uses are assessed (evaluated) as “partially supporting” based on biological data collected in 2005 and 2013 as part of the DNR/SHL stream sampling projects. 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 2005 FIBI score was 18 (poor) and the BMIBI score was 58 (good). The 2013 FIBI score was 24 (poor) and the BMIBI score was 56 (good). The aquatic life use support was assessed 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 FIBI BIC for this ecoregion is 33 and the BMIBI BIC for this ecoregion is 41. The biological impairment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2008. This segment passed the FIBI BIC 0/2 times and passed the BMIBI BIC 2/2 times in the last 12years.

This aquatic life assessment is considered "evaluated" because there were not two or more samples collected from this segment in multiple years over a recent five-year period. According to DNR’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). DNR 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 due to this segment’s previous Section 303(d) listings.