Old Mans Creek Williamstown
Analysis Summary for Series #23
Benthic Macroinvertebrate Index of Biotic Integrity (BMIBI)
| Metric Name | Value | Score |
|---|---|---|
| MH Total Taxa | 21 | 4.04 |
| SH Total Taxa | 13.5 | 5.95 |
| MH EPT Taxa | 11 | 4.07 |
| SH EPT Taxa | 11.5 | 7.82 |
| MH Sensitive Taxa | 3 | 2.73 |
| SH Ephem % | 71.58 | 9.15 |
| SH EPT % | 91.9 | 9.62 |
| SH Chiron % | 7.24 | 9.37 |
| SH Scraper % | 21.07 | 4.71 |
| SH Top3Dom % | 46.75 | 8.45 |
| SH Dom FFG % | 48.1 | 8.65 |
| MHBI | 4.91 | 7.74 |
| *Mouse-over metric for full name | ||
| **Final IBI is sum of scores multiplied by 0.8333 | ||
Analysis Factors
| Factor | Value |
|---|---|
| BMIBI Type | Warm Water |
| Sample Date | 8/3/1994 |
| Sampling Series | Series #23 |
| Drainage Area (mi2) | 137.824 |
| Log(DA) | 2.13932485008251 |
| Calculation Last Updated | 7/22/2025 3:34:15 PM |
| Sampling Gear | ArtSub |
Sessions used in this analysis
Warm Water
Good
BMIBI Score Explained
This site was analyzed using the BMIBI-Warm Water assessment methodology.
Sites that score between 56 - 75 are considered good. A slight reduction in number (Ephemeroptera, Plecoptera, Trichoptera) of taxa; however, good numbers of taxa are present, including several sensitive species, EPT taxa are fairly diverse and dominate the community. The most sensitive taxa and some habitat specialists may not be present and/or are reduced in abundance. The community is balanced, with no taxon excessively dominating in abundance. One functional feeding group, often collector filterers or collector gatherers, may be somewhat dominant.
This location has been classified as a Candidate Reference Site. Further study is required to determine if this site represents natural stream qualities that are least disturbed by human activities within the watershed.
EcoRegion Comparison
Scores for a sampling session are compared against reference sites within the same ecoregion:
| Max | 86 |
| 75th Percentile | 69 |
| Median | 61 |
| 25th Percentile | 54 |
| Min | 20 |
| This Session's Score | 69 |
| Total Reference Site Samples | 127 |
| Mean | 61.08 |
| Standard Deviation | 10.7 |