Mill Creek Larrabee
Analysis Summary for Series #2154
Benthic Macroinvertebrate Index of Biotic Integrity (BMIBI)
| Metric Name | Value | Score |
|---|---|---|
| MH Total Taxa | 25 | 4.81 |
| SH Total Taxa | 15 | 6.61 |
| MH EPT Taxa | 10 | 3.7 |
| SH EPT Taxa | 7.33 | 4.99 |
| MH Sensitive Taxa | 1 | 0.91 |
| SH Ephem % | 18.28 | 2.34 |
| SH EPT % | 44.15 | 4.62 |
| SH Chiron % | 41.27 | 5.93 |
| SH Scraper % | 5.45 | 1.22 |
| SH Top3Dom % | 66.66 | 5.29 |
| SH Dom FFG % | 66.85 | 5.53 |
| MHBI | 5.66 | 4.96 |
| *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 | 9/19/2017 |
| Sampling Series | Series #2154 |
| Drainage Area (mi2) | 259.008 |
| Log(DA) | 2.41331317837545 |
| Calculation Last Updated | 7/22/2025 3:26:53 PM |
| Sampling Gear | Hess |
Sessions used in this analysis
Warm Water
Fair
BMIBI Score Explained
This site was analyzed using the BMIBI-Warm Water assessment methodology.
Sites that score between 31 - 55 are considered fair. Total taxa richness and EPT (Ephemeroptera, Plecoptera, Trichoptera) taxa richness are noticeably reduced from optimum levels; sensitive species and habitat specialists are rare; EPT taxa are still dominant in abundance; however, the most-sensitive EPT taxa have been replaced by ept taxa that are more tolerant of organic enrichment; the community is not well-balanced; a few taxa clearly dominate in abundance, collector-gatherers or collector-filterers often comprise more than 50% of the community.
This location has been classified as a Reference Site. Reference sites represent natural stream qualities that are least disturbed by human activities within the watershed. These sites are then grouped by ecoregion to establish a benchmark against which other streams in the same ecoregion are compared.
EcoRegion Comparison
Scores for a sampling session are compared against reference sites within the same ecoregion:
| Max | 88 |
| 75th Percentile | 56 |
| Median | 51 |
| 25th Percentile | 45 |
| Min | 10 |
| This Session's Score | 42 |
| Total Reference Site Samples | 49 |
| Mean | 50.82 |
| Standard Deviation | 12.75 |