Iowa DNR
BioNet
River & Stream Biological Monitoring
Fish and Benthic Macroinvertebrate Surveys
Physical Habitat Assessments

Unnamed Tributary to Little Volga Maynard

Analysis Summary for Series #1420

Benthic Macroinvertebrate Index of Biotic Integrity (BMIBI)

Metric Name Value Score
MH Total Taxa 30 9.73
SH Total Taxa 8.33 7.01
MH EPT Taxa 11 7.53
SH EPT Taxa 2.33 2.94
MH Sensitive Taxa 6 9.31
SH Ephem % 1.61 0.21
SH EPT % 2.5 0.26
SH Chiron % 83.94 1.62
SH Scraper % 1.56 0.35
SH Top3Dom % 92.27 2.4
SH Dom FFG % 91.93 1.34
MHBI 6.04 3.56
*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 9/20/2012
Sampling Series Series #1420
Drainage Area (mi2) 7.371
Log(DA) 0.867526411199743
Calculation Last Updated 7/22/2025 3:39:24 PM
Sampling Gear ArtSub
BMIBI Score
39
Warm Water
Fair
Series Analysis Notes

gear comparison

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and habitat specialists are rare; EPT taxa are still dominant in abundance; however, the most-sensitive EPT taxa have been replaced by ept taxa that are more tolerant of organic enrichment; the community is not well-balanced; a few taxa clearly dominate in abundance, collector-gatherers or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:

Iowan Surface

This site is in the Iowan Surface ecoregion.

Ecoregion Map
Max 91
75th Percentile 75
Median 66
25th Percentile 57
Min 23
This Session's Score 39
Total Reference Site Samples 162
Mean 65.27
Standard Deviation 12.31