Big Sioux River Westfield (TMDL)
Analysis Summary for Series #821
Benthic Macroinvertebrate Index of Biotic Integrity (BMIBI)
| Metric Name | Value | Score |
|---|---|---|
| MH Total Taxa | 20 | 3.85 |
| SH Total Taxa | 9.67 | 4.26 |
| MH EPT Taxa | 14 | 5.19 |
| SH EPT Taxa | 7.67 | 5.22 |
| MH Sensitive Taxa | 4 | 3.64 |
| SH Ephem % | 12.91 | 1.65 |
| SH EPT % | 97.9 | 10 |
| SH Chiron % | 1.19 | 9.98 |
| SH Scraper % | 4.48 | 1 |
| SH Top3Dom % | 76.34 | 3.76 |
| SH Dom FFG % | 84.98 | 2.5 |
| MHBI | 5.37 | 6.04 |
| *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 | 9/8/2005 |
| Sampling Series | Series #821 |
| Drainage Area (mi2) | 7805.7 |
| Log(DA) | 3.89241185582965 |
| Calculation Last Updated | 7/22/2025 3:38:38 PM |
| Sampling Gear | ArtSub |
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and habitat specialists are rare; EPT taxa are still dominant in abundance; however, the most-sensitive EPT taxa have been replaced by ept taxa that are more tolerant of organic enrichment; the community is not well-balanced; a few taxa clearly dominate in abundance, collector-gatherers or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 survey site. Survey sites are compared to reference sites within the same ecoregion. A reference site represents natural stream qualities that are least disturbed by human activities within the watershed. Reference sites are grouped by ecoregion to establish a benchmark against which these survey streams are compared.
EcoRegion Comparison
Scores for a sampling session are compared against reference sites within the same ecoregion:
There are not enough sampling sessions collected at reference sites in this ecoregion to generate a meaningful comparison.