Walnut Creek IA 04-RAC-1120

Assessment Comments

Assessment is based on results of IDNR/UHL biological (biocriteria) sampling in 1998: FIBI = 48 (fair). FIBI BIC = 36.

Basis for Assessment

SUMMARY:  The Class A (primary contact recreation) uses remain "not assessed" due to the lack of information upon which to base an assessment.   The Class B(LR) aquatic life are assessed (evaluated) as "fully supported" based on results of biological monitoring conducted in 1998 as part of the IDNR/UHL stream biocriteria project.   These data are now too old for the assessment to be considered monitored; therefore, this is an evaluated assessment and has been upgraded from partial support to full support.

EXPLANATION:  The Class A uses remain "not assessed" due to lack of relevant water quality information upon which to base an assessment.   The aquatic life assessment was based on data collected in 1998 as part of the DNR/UHL stream biocriteria project.  The 1998 FIBI score was 48 (fair) and not enough data was available to calculate the BMIBI score.  The aquatic life use support was assessed as fully supporting (=FS), based on a comparison of the FIBI score 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 36.