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

North Raccoon River Raccoon River Greenbelt- Sac City

Analysis Summary for Series #1837

Benthic Macroinvertebrate Index of Biotic Integrity (BMIBI)

Metric Name Value Score
MH Total Taxa 33 6.35
SH Total Taxa 12.67 5.58
MH EPT Taxa 19 7.04
SH EPT Taxa 10.33 7.03
MH Sensitive Taxa 11 10
SH Ephem % 16.4 2.1
SH EPT % 80.16 8.39
SH Chiron % 14.71 8.62
SH Scraper % 6.54 1.46
SH Top3Dom % 68.97 4.93
SH Dom FFG % 65.27 5.79
MHBI 5.1 7.04
*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 8/13/2015
Sampling Series Series #1837
Drainage Area (mi2) 328.119
Log(DA) 2.51603137929261
Calculation Last Updated 7/22/2025 3:31:16 PM
Sampling Gear Hess
BMIBI Score
62
Warm Water
Good

BMIBI Score Explained

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

Sites that score between 56 - 75 are considered good. A slight reduction in number (Ephemeroptera, Plecoptera, Trichoptera) of taxa; however, good numbers of taxa are present, including several sensitive species, EPT taxa are fairly diverse and dominate the community. The most sensitive taxa and some habitat specialists may not be present and/or are reduced in abundance. The community is balanced, with no taxon excessively dominating in abundance. One functional feeding group, often collector filterers or collector gatherers, may be somewhat dominant.

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:

Des Moines Lobe

This site is in the Des Moines Lobe ecoregion.

Ecoregion Map
Max 84
75th Percentile 68
Median 59
25th Percentile 51
Min 10
This Session's Score 62
Total Reference Site Samples 161
Mean 58.18
Standard Deviation 13.09