Benthic macroinvertebrates are small freshwater organisms that live in streams and on river bottoms. The abundance and diversity of these organisms are good indicators of local stream health because they have more limited movement than fish and they respond quickly to environmental stressors.

How is it measured?

We considered surveys of stream benthic macroinvertebrate species taken since 1992. From these results an Index of Biotic Integrity (IBI), an quantiative measure of community health, was calculated by the Arizona Department of Environmental Quality for each survey site. These IBI values were rescaled to meet the standard 0-100 Report Card scoring methodology. Based on data availability, the observation period from to 2013 to present was selected.