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

Raccoon River Upstream of Des Moines

Analysis Summary for Series #1263

Benthic Macroinvertebrate Index of Biotic Integrity (BMIBI)

Metric Name Value Score
MH Total Taxa 40 7.69
SH Total Taxa 3 1.32
MH EPT Taxa 21 7.78
SH EPT Taxa 1.33 0.9
MH Sensitive Taxa 7 6.36
SH Ephem % 0.75 0.1
SH EPT % 1.2 0.13
SH Chiron % 98.35 0.17
SH Scraper % 0.52 0.12
SH Top3Dom % 99.55 0.07
SH Dom FFG % 98.8 0.2
MHBI 6 3.7
*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 8/8/2012
Sampling Series Series #1263
Drainage Area (mi2) 3424.997
Log(DA) 3.53466019542435
Calculation Last Updated 7/22/2025 3:27:52 PM
Sampling Gear ArtSub
BMIBI Score
24
Warm Water
Poor
Series Analysis Notes

Water level very low. Anaerobic smell in sediment, pools, runs, and riffles. Fisherman stated flow was the lowest he had seen in 55 years. Velocity in area the art subs were deployed was less than optimal.

BMIBI Score Explained

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

Sites that score between 0 - 30 are considered poor. Severely impaired macroinvertebrate community. Low numbers of taxa present, sensitive species not present, EPT taxa are rare or not present; community extremely unbalanced; dominated by a few pollution tolerant organisms; some trophic functional feeding groups are not represented. Total numbers of organisms may be low. Total taxa richness and EPT taxa richness are noticeably reduced from optimum levels; sensitive species and habitat specialists are rare; EPT taxa no longer dominate the macroinvertebrate community. Taxa that are tolerant of organic enrichment and/or excessive sediment loads are dominant; the community is unbalanced; a few generalist taxa make up a high percentage of the organisms present; collector-gatherers or collector-filterers are very dominant.

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:

Rolling Loess Prairies

This site is in the Rolling Loess Prairies ecoregion.

Ecoregion Map
Max 86
75th Percentile 69
Median 61
25th Percentile 54
Min 20
This Session's Score 24
Total Reference Site Samples 127
Mean 61.08
Standard Deviation 10.7