Assessment Comments
Assessment based on SHL special project biological sampling: FIBI = 18 (poor), BMIBI = 53 (fair). FIBI BIC = 31, BMIBI BIC = 54.
Basis for Assessment
SUMMARY/EXPLANATION: The Class A1 (primary contact recreation) and Class HH (human health/fish consumption) uses remain "not assessed" (IR 3a) due to the lack of water quality information upon which to base an assessment.
The Class B(WW1) aquatic life uses are assessed (evaluated) as “partially supported” (IR 3b-c) based on biological data collected in 2011 as part of an SHL stream special project. 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 2011 FIBI score was 18 (poor) and the BMIBI score was 53 (fair). 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 31 and the BMIBI BIC for this ecoregion is 54. This site failed the FIBI BIC and passed the BMIBI BIC with the use of the BMIBI UAV of 8 points applied to single samples. The biological impairment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2008.
This aquatic life assessment is considered "evaluated" because there were not two or more samples collected from this segment in multiple years over a five-year period. 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).
