East Branch West Nishnabotna River IA 05-NSH-1823

Assessment Comments

Assessment is based on results of IDNR/UHL biological (biocriteria) monitoring in 2000: FIBI = 35 (fair); BMIBI = 46 (fair). FIBI BIC = 31, BMIBI BIC = 54.

Basis for Assessment

SUMMARY:  The Class B(LR) aquatic life uses are assessed (monitored) as "fully supported"  based on results of IDNR/UHL biological (biocriteria) sampling in 2000.   This is an upgrade to the assessment that was developed for the 2002 reporting cycle (partially supported).

EXPLANATION:  This assessment was based on data collected in 2000 approximately 4.5 miles northeast of Avoca as part of the DNR/UHL stream biocriteria project.  The 2000 FIBI score was 35 (fair) and the BMIBI score was 46 (fair).   The aquatic life use support was assessed as fully supporting (= FS), based on a comparison of the FIBI and BMIBI scores with biological impairment criteria (BIC) established for previous Section 305(b) reports.  The biological impairment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2004.   The FIBI BIC for this ecoregion is 31 and the BMIBI BIC for this ecoregion is 54.   The FIBI score was higher than the FIBI BIC and the BMIBI score plus the UAV (8) was equal to the BMIBI BIC.