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

Invertebrate Program Statistics and Summary

Since the bioassessment program began in 1994, benthic macroinvertebrate surveys have been a critical component of the assessment process.

Total Invertebrates Collected
Unique Taxa
Total Surveys
BMIBI Assessments

Top 5 Most Collected Taxa

Taxa # Collected
Chironomidae 201,053
Cheumatopsyche 92,650
Baetis intercalaris 30,232
Simulium 29,631
Tricorythodes 28,800

Top 5 Most Common Taxa

Taxa % of all sites
Chironomidae 78.76%
Cheumatopsyche 67.03%
Hydropsychidae 59.73%
Oligochaeta 58.88%
Stenacron interpunctatum 52.93%

Valid Assessments

Assessment Type Count
Warm Water 1771
Cold Water 193
Rapid Assessment 188

BMIBI - Warm Water Scores

Stream Sample Date Score

BMIBI - Cold Water Scores

Stream Sample Date Score