Assessment Comments
Assessment based on results of IDNR/UHL biological (REMAP) monitoring in 2002: Fish IBI= 23 (poor), BM-IBI= 38 (fair).
Basis for Assessment
[Note: For the 2002 report, the previous waterbody segment for Bear Creek (IA 02-IOW-0180-2), which extended 21 miles from Little Bear Creek to Highway 146 in Poweshiek County, was split into two subsegments: (1) from L. Bear Cr. (S16, T80N, R13W, Poweshiek Co.) to confluence with unnamed tributary in SW 1/4, S9, T80N, R14W, Poweshiek Co. (IA 02-IOW-0180-2) and (2) unnamed tributary (SW 1/4, S9, T80N, R14W, Poweshiek Co.) to confluence with unnamed tributary at Hwy 146 crossing at west line, S21, T81N, R16W, Poweshiek Co. (IA 02-IOW-0180-3).]
SUMMARY: The Class B(LR) aquatic life uses are assessed (monitored) as "not supported" based on results of IDNR/UHL biological (REMAP) sampling in 2002.
EXPLANATION: This assessment was based on data collected 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 2002 Fish IBI score was 23 (poor) and the BM-IBI score was 38 (fair). The aquatic life use support was assessed as Not Supporting (=NS), based on a comparison of the F-IBI and BM-IBI scores with biological assessment criteria established for previous Section 305(b) reports. The biological assessment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2001.
