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

Ashton Creek Washta (REMAP #209)

Analysis Summary for Series #896

Benthic Macroinvertebrate Index of Biotic Integrity (BMIBI)

Metric Name Value Score
MH Total Taxa 15 5.06
SH Total Taxa 6.67 5.86
MH EPT Taxa 2 1.42
SH EPT Taxa 2.33 3.08
MH Sensitive Taxa 0 0
SH Ephem % 8.98 1.15
SH EPT % 9.52 1
SH Chiron % 17.79 8.31
SH Scraper % 4.06 0.91
SH Top3Dom % 90.06 3.26
SH Dom FFG % 93.77 1.04
MHBI 7.69 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 7/6/2006
Sampling Series Series #896
Drainage Area (mi2) 6.495
Log(DA) 0.812579155409047
Calculation Last Updated 7/22/2025 3:34:22 PM
Sampling Gear Surb
BMIBI Score
26
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:

Northwest Iowa Loess Prairies

This site is in the Northwest Iowa Loess Prairies ecoregion.

Ecoregion Map
Max 88
75th Percentile 58
Median 51
25th Percentile 45
Min 10
This Session's Score 26
Total Reference Site Samples 45
Mean 50.91
Standard Deviation 13.26