Silver Creek IA 01-TRK-192
mouth (S16 T94N R5W Clayton Co.) to confluence with unnamed tributary in S32 T95N R5W Clayton Co.
Assessment Comments
2000 Biocriteria: Fish IBI= 41(fair); BM-IBI=46(fair).
Basis for Assessment
The assessment was based on data collected in 2000 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 2000 Fish IBI score was 41 (fair) and the BM-IBI score was 46 (fair). The aquatic life use support was assessed as not supporting (=NS), 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.
Assessment Key Dates
| 8/2/2000 | Fixed Monitoring Start Date |
| 8/2/2000 | Fixed Monitoring End Date |
| 8/2/2000 | Biological Monitoring |
Methods
| 220 | Non-fixed station physical/chemical monitoring (conventional pollutant only) |
| 315 | Regional reference site approach |
| 320 | Benthic macroinvertebrate surveys |
| 330 | Fish surveys |
| 380 | Quan. measurements of instream parms-- channel morphology-- floodplain-- 1-2 seasons-- by prof |
Monitoring Levels
| Biological | 4 |
| 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 |
| Causes | Use Support | Cause Magnitude | Sources | Source Magnitude |
|---|---|---|---|---|
| Organic enrichment/Low DO | Overall Use Support | Moderate |
|
|
| Organic enrichment/Low DO | Aquatic Life Support | Moderate |
|
|
| Other habitat alterations | Overall Use Support | Moderate |
|
|
| Other habitat alterations | Aquatic Life Support | Moderate |
|
|
| Siltation | Overall Use Support | Moderate |
|
|
| Siltation | Aquatic Life Support | Moderate |
|
|