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

South Fork Iowa River Logsdon County Park- Iowa Falls

Analysis Summary for Series #1269

Benthic Macroinvertebrate Index of Biotic Integrity (BMIBI)

Metric Name Value Score
MH Total Taxa 28 5.38
SH Total Taxa 8.67 3.82
MH EPT Taxa 7 2.62
SH EPT Taxa 3 2.04
MH Sensitive Taxa 4 3.64
SH Ephem % 4.61 0.59
SH EPT % 14.9 1.56
SH Chiron % 37.93 6.27
SH Scraper % 20.28 4.54
SH Top3Dom % 72.67 4.34
SH Dom FFG % 67.11 5.48
MHBI 5.89 4.11
*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 8/2/2012
Sampling Series Series #1269
Drainage Area (mi2) 120.775
Log(DA) 2.08197704615856
Calculation Last Updated 7/22/2025 3:28:13 PM
Sampling Gear Hess
BMIBI Score
37
Warm Water
Fair

BMIBI Score Explained

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

Sites that score between 31 - 55 are considered fair. Total taxa richness and EPT (Ephemeroptera, Plecoptera, Trichoptera) taxa richness are noticeably reduced from optimum levels; sensitive species and habitat specialists are rare; EPT taxa are still dominant in abundance; however, the most-sensitive EPT taxa have been replaced by ept taxa that are more tolerant of organic enrichment; the community is not well-balanced; a few taxa clearly dominate in abundance, collector-gatherers or collector-filterers often comprise more than 50% of the community.

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 37
Total Reference Site Samples 161
Mean 58.18
Standard Deviation 13.09