ADBNet

Assessment Comments

Assessment is based on results of IDNR/UHL biological (biocriteria) monitoring in1999: Fish IBI= 68 (good), BM-IBI= 77 (excellent).

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 1999.   This is the same assessment as that developed for the 2002 reporting cycle.

EXPLANATION:  This assessment was based on data collected in 1999 as part of the DNR/UHL stream biocriteria 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 1999 Fish IBI score was 68 (good) and the BM-IBI score was 77 (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.

This stream segment was also sampled as part of a 1995 ISU stream survey (A survey of fishes in unprotected tributaries of the Iowa River" by Kaminski et al.  (1995)).   Results of this sampling show that this reach Tipton Creek supports one of the most diverse fish communities of any Iowa stream:  species/families, dstr->upstr:  30/5, 27/5, and 22/5.   All, or nearly all of the expected fish taxa for streams in the Des Moines Lobe subecoregion (47b) were present (dstr->upstr:  11 of 11 (both DNR & ISU), 10 of 11, and 11 of 11).   In addition, Tipton Creek was rated as having the best habitat of the four streams examined in Kaminski et al.  (1995).