Assessment Comments
Assessment based on 2003 REMAP data: FIBI = 69 (good), BMIBI = 24 (poor). FIBI BIC = 65; BMIBI BIC = 52.
Basis for Assessment
SUMMARY: This evaluated biological assessment was based on data collected in 2003 as part of the DNR/UHL stream REMAP project. A series of biological metrics that reflect stream water quality and habitat integrity were calculated from the biocriteria 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 2003 FIBI score was 69 (good) and the BMIBI score was 24 (poor). 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 from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2004. The FIBI BIC for this ecoregion is 65 and the BMIBI BIC for this ecoregion is 52. This assessment is considered evaluated because the drainage area (1211 mi2) above this sampling site was greater than the maximum limit (500 mi2) that was used to calibrate the Iowa wadeable stream impairment criteria. Even though this site passed the FIBI BIC and failed to meet the BMIBI BIC, it is uncertain as to whether or not this segment is meeting the aquatic life criteria because it doesn’t fall in the calibrated watershed size.
