Little Rock River IA 06-BSR-1799
from confluence with Otter Cr. (NW 1/4 S21 T98N R44W Lyon Co.) to confluence with Argo Slough in S17 T99N R43W Lyon Co.
Assessment Comments
Assessment is based on results of 1996 Biocriteria sampling: Fish IBI=40 (fair).
Basis for Assessment
The assessment was based on data collected in 1996 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).
Only the Fish-IBI was calculated for this assessment. The F-IBI score was 40 (fair). The aquatic life use support was assessed as fully supported / threatened (=FST), based on a comparison of the F-IBI score 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.
Assessment Key Dates
| 9/5/1996 | Biological Monitoring |
Methods
| 220 | Non-fixed station physical/chemical monitoring (conventional pollutant only) |
| 315 | Regional reference site approach |
| 330 | Fish surveys |
| 380 | Quan. measurements of instream parms-- channel morphology-- floodplain-- 1-2 seasons-- by prof |
Monitoring Levels
| Biological | 3 |
| Habitat | 4 |
| Physical Chemistry | 1 |
| Toxic | 0 |
| Pathogen Indicators | 0 |
| Other Health Indicators | 0 |
| Other Aquatic Life Indicators | 0 |
| # of Bio Sites | 1 |
| BioIntegrity | Fair |