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

Elk Creek Elk Creek Marsh SWMA - Kensett

Analysis Summary for Series #1266

Benthic Macroinvertebrate Index of Biotic Integrity (BMIBI)

Metric Name Value Score
MH Total Taxa 38 8.1
SH Total Taxa 6.33 3.4
MH EPT Taxa 3 1.36
SH EPT Taxa 1 0.79
MH Sensitive Taxa 0 0
SH Ephem % 0.83 0.11
SH EPT % 0.83 0.09
SH Chiron % 48.91 5.16
SH Scraper % 0 0
SH Top3Dom % 95.56 0.8
SH Dom FFG % 96.64 0.56
MHBI 7.13 0
*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 9/26/2012
Sampling Series Series #1266
Drainage Area (mi2) 40.745
Log(DA) 1.61007432214005
Calculation Last Updated 7/22/2025 3:28:02 PM
Sampling Gear ArtSub
BMIBI Score
17
Warm Water
Poor
Series Analysis Notes

Little to no flow throughout the reach.

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 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:

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 17
Total Reference Site Samples 161
Mean 58.18
Standard Deviation 13.09