Assessment Comments
Assessment based on 2000 biocriteria data: Fish IBI= 33 (fair), BM-IBI= 56 (good).
Basis for Assessment
[Note: For the 2002 report, the previous waterbody segment for the West Nishnabotna River (IA 05-NSH-0090-2), which extended 30 miles from the West Fork West Nishnabotna R. at Harlan to an unnamed tributary NE of Manning in Carroll Co., was split into three subsegments: (1) West Fork West Nishnabotna R. to Elk Creek at Irwin (IA 05-NSH-0090-2), (2) Elk Creek to the Crawford-Carroll county line (IA 05-NSH-0090-3), and (3) Crawford-Carroll county line to the unnamed tributary NE of Manning (IA 05-NSH-0090-4). See the assessment documentation for segment IA 05-NSH-0090-2 for previous Section 305(b) assessments for the original 30-mile stream segment.]
The assessment was based on data collected in 2000 as part of the DNR/UHL stream biocriteria project. The 2000 Fish IBI score was 33 (fair) and the BM-IBI score was 56 (good). The aquatic life use support was assessed as fully supporting/threatened (=FST), 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.
