Assessment Comments
Assessment based on 2002 REMAP data: FIBI = 13 (Poor). FIBI BIC = 33.
Basis for Assessment
The 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 fish species that were collected in the stream sampling reach. The biological metrics were combined to make a fish community index of biotic integrity (FIBI). The indexes rank the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum). The 2002 FIBI score was 13 (poor). The aquatic life use support was assessed as not supporting (= NS), based on a comparison of the FIBI score with biological impairment criteria (BIC) established for previous Section 305(b) reports. The biological impairment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2004. The FIBI BIC for this ecoregion is 33.
As part of the 2002 REMAP project, stream physical habitat assessment found significant channel alterations that could contribute to the biological impairment. These include, bank instability, channel widening, shallow water depth, and excessive sediment bar development. Elevated summer water temperature (33.4C) and low D.O. levels at night (4.7 mg/L) were observed. Channel alterations, which have increased the stream width:depth ratio (38.4), probably have also contributed to adverse water quality conditions.
