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

Upper Iowa River Dorchester

Analysis Summary for Series #2757

Benthic Macroinvertebrate Index of Biotic Integrity (BMIBI)

Metric Name Value Score
MH Total Taxa 59 10
SH Total Taxa 19 8.37
MH EPT Taxa 31 10
SH EPT Taxa 14 9.52
MH Sensitive Taxa 13 10
SH Ephem % 30.33 3.88
SH EPT % 54.59 5.72
SH Chiron % 6.71 9.43
SH Scraper % 11.34 2.54
SH Top3Dom % 56.32 6.93
SH Dom FFG % 60.63 6.56
MHBI 4.84 8
*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 7/31/2024
Sampling Series Series #2757
Drainage Area (mi2) 767.863
Log(DA) 2.88528374131866
Calculation Last Updated 7/22/2025 3:29:35 PM
Sampling Gear Hess
BMIBI Score
76
Warm Water
Excellent

BMIBI Score Explained

This site was analyzed using the BMIBI-Warm Water assessment methodology.

Sites that score between 76 - 100 are considered excellent. High numbers of taxa present, including sensitive species, EPT taxa are diverse and dominate the community in terms of abundance; habitat and trophic specialists (e.g., Scraper organisms) are present in good numbers, all of the major functional feeding groups (FFG) are represented, with no particular FFG that is excessively dominant. The community has good balance in terms of the abundance of organisms in each taxon.

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:

Paleozoic Plateau (Driftless Area)

This site is in the Paleozoic Plateau (Driftless Area) ecoregion.

Ecoregion Map
Max 87
75th Percentile 78
Median 70
25th Percentile 62
Min 52
This Session's Score 76
Total Reference Site Samples 55
Mean 70.55
Standard Deviation 9.41