Drainage Ditch 81 Nevada (Mixed HWCRS)
Analysis Summary for Series #946
Benthic Macroinvertebrate Index of Biotic Integrity (BMIBI)
| Metric Name | Value | Score |
|---|---|---|
| MH Total Taxa | 23 | 6.71 |
| SH Total Taxa | 8 | 6 |
| MH EPT Taxa | 3 | 1.85 |
| SH EPT Taxa | 1.67 | 1.87 |
| MH Sensitive Taxa | 2 | 2.78 |
| SH Ephem % | 8.31 | 1.06 |
| SH EPT % | 8.66 | 0.91 |
| SH Chiron % | 41.13 | 5.95 |
| SH Scraper % | 4.32 | 0.97 |
| SH Top3Dom % | 85.35 | 3.94 |
| SH Dom FFG % | 91.15 | 1.47 |
| MHBI | 5.99 | 3.74 |
| *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 | 8/29/2007 |
| Sampling Series | Series #946 |
| Drainage Area (mi2) | 10.66 |
| Log(DA) | 1.02775720469055 |
| Calculation Last Updated | 7/22/2025 3:37:28 PM |
| Sampling Gear | Surb |
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and habitat specialists are rare; EPT taxa are still dominant in abundance; however, the most-sensitive EPT taxa have been replaced by ept taxa that are more tolerant of organic enrichment; the community is not well-balanced; a few taxa clearly dominate in abundance, collector-gatherers or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 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 | 84 |
| 75th Percentile | 68 |
| Median | 59 |
| 25th Percentile | 51 |
| Min | 10 |
| This Session's Score | 31 |
| Total Reference Site Samples | 162 |
| Mean | 58.11 |
| Standard Deviation | 13.08 |