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

West Fork Little Sioux River Hornick

Analysis Summary for Series #1354

Benthic Macroinvertebrate Index of Biotic Integrity (BMIBI)

Metric Name Value Score
MH Total Taxa 23 4.42
SH Total Taxa 7.67 3.38
MH EPT Taxa 7 2.59
SH EPT Taxa 5 3.4
MH Sensitive Taxa 2 1.82
SH Ephem % 3.67 0.47
SH EPT % 32.22 3.37
SH Chiron % 65.04 3.53
SH Scraper % 0 0
SH Top3Dom % 89.43 1.68
SH Dom FFG % 69.59 5.07
MHBI 5.76 4.59
*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 9/5/2012
Sampling Series Series #1354
Drainage Area (mi2) 399
Log(DA) 2.60097289568675
Calculation Last Updated 7/22/2025 3:35:25 PM
Sampling Gear ArtSub
BMIBI Score
29
Warm Water
Poor

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:

There are not enough sampling sessions collected at reference sites in this ecoregion to generate a meaningful comparison.