Assessment Comments
Assessment is based on results of (1) 1997 DNR Fisheries Bureau survey in DeWitt city park and (2) DNR 1998 Biocriteria sampling: Fish IBI= 40(fair), BM-IBI= 55(fairly good). See attached document for details.
Basis for Assessment
SUMMARY: The Class B(LR) aquatic life uses remain assessed as "fully supported / threatened" (minor impacts). EXPLANATION: Continue to use the assessment of the Class B(LR) uses developed for the 1998 report (above). This assessment was based on (1) results of the a stream survey conducted in August 1997 by the DNR Fisheries Bureau and (2) on data collected in 1998 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 F-IBI score was 40 (fair) and the BM-IBI score was 55 (fairly good). The aquatic life use support was assessed as fully supported/threatened (=FST), based on a comparison of the F-IBI and BM-IBI scores with biological assessment criteria established specifically for the 2000 Section 305(b) report. The biological assessment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-1998.
