South Fork Iowa River IA 02-IOW-748

Assessment Comments

Assessment based on (1) 1999 biocriteria data: Fish IBI= 73 (excellent), BM-IBI= 81 (excellent); also considered (1) 1995 biocriteria: Fish IBI=78 (excellent), BM-IBI=65 (good) and (2) 1995 SUAs: 28/13 (shock); 20/13 (shock);

Basis for Assessment

[Note:  For the 2002 report, the previous waterbody segment for South Fork Iowa River (IA 02-IOW-0280-1), which extended 18 miles from its confluence with Tipton Creek to an unnamed tributary in Section 19, T88N, R21W, Hardin County, was split into two subsegments:  (1) from Tipton Cr.  to tributary SE of Logsdon Park) (IA 02-IOW-0280-1) and (2) from tributary SE Logsdon Park to tributary E of Buckeye (IA 02-IOW-0280-2).   See assessment information for segment IA 02-IOW-0280-1 for previous Section 305(b) assessments for the previous 18-mile stream segment.]

The assessment was based on data collected in 1999 as part of the DNR/UHL stream biocriteria project.  The 1999 Fish IBI score was 73 (excellent) and the BM-IBI score was 81 (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.