Assessment Comments
Assessment is based on results of IDNR/UHL biological (biocriteria) sampling in 1996: Fish IBI=30 (fair), BM-IBI=50 (fair).
Basis for Assessment
SUMMARY: The Class B(LR) aquatic life uses remain assessed (evaluated) as "fully supported / threatened" (minor impacts) based on results of biological monitoring and habitat assessment conducted as part of the 1996 IDNR/UHL biocriteria sampling. Due to the age of these data, the assessment category is changed from "monitored" (higher-confidence assessment) to "evaluated" (lower-confidence assessment).
EXPLANATION: Continue to use the assessment developed for the 1998 and 2000 reporting cycles that was based on results of the 1996 IDNR biocriteria assessment. As stated in the assessment developed for the 2000 report: the F-IBI score was 30 (fair), and the BM-IBI score was 50 (fair). The aquatic life use support status was assessed as fully supporting/threatened (=FS/T), based on a comparison of the F-IBI and BM-IBI scores with biological assessment criteria established specifically for the 2000 Section 305b report (IDNR 2000). The biological assessment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-1998. Previous stream use assessment data sheets suggest that channelization, fluctuation in stream flow, and riparian grazing impacts are the primary threats to the aquatic biological community.
Because these data are now considered too old (greater than five years) to accurately characterize current water quality conditions, the assessment category is changed from "monitored" (indicating an assessment with relatively high confidence) to "evaluated" (indicating an assessment with relatively low confidence).
