Ioway Creek IA 03-SSK-954

Assessment Comments

Assessment based on 2002 REMAP data: Fish IBI= 45 (fair), BM-IBI= 79 (excellent) and on 2000 biocriteria data: Fish IBI= 51 (good), 43 (fair); BM-IBI= 73 (good), 72 (good).

Basis for Assessment

SUMMARY:  The Class B(LR) aquatic life uses are assessed (monitored) as "fully supported" based on results of (1) IDNR/UHL biological (biocriteria) sampling in 2000 and (2) IDNR/UHL biological (REMAP) sampling in 2002.  

EXPLANATION:  The assessment was based on data collected in 2000 as part of the DNR/UHL stream biocriteria project and in 2002 as part of the DNR/UHL REMAP project.   A series of biological metrics which 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 that were collected in the stream sampling reach.   The biological metrics were combined to make a fish community index of biotic integrity (F-IBI) and a benthic macroinvertebrate index (BM-IBI).   The indexes rank the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum).   The 2000 Fish IBI scores were 51 (good), 43 (fair) and the BM-IBI scores were 73 (good), 72 (good).  The 2002 Fish IBI score was 45 (fair) and the BM-IBI score was 79 (excellent).   The aquatic life use support was assessed as fully supporting (=FS), based on a comparison of the F-IBI and BM-IBI scores with biological assessment criteria established specifically for the 2002 Section 305(b) report.  The biological assessment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2001.