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 scored?
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.
Macroinvertebrates are excellent indicators of water quality, with some types of macroinvertebrates only present in clean water. The methodology for this indicator is based on the last five years of survey data from ADEQ. However, due to staff shortages, COVID-19, and other efforts outside the Verde Watershed, the only surveys completed within the five years assessed here (2019–2024) occurred in 2019. Those surveys were very few and no surveys were conducted in regions 2, 4, 5, and 6, therefore no scores are available for those regions. ADEQ is planning to develop a long term statewide sampling plan.