Dissolved Oxygen measures the availability of oxygen for aquatic animals. From eutrophication to warmer temperatures, a number of threats can reduce oxygen availability and harm aquatic ecosystems. We used thresholds established by the U.S. Environmental Protection Agency (EPA) to assess dissolved oxygen levels.
How is it scored?
Sampling events were scored pass/fail based on the EPA threshold of 5 mg/L. Samples above the threshold passed (100%), while samples below thresholds failed (0%). An average score was calculated for survey sites that were sampled multiple times. Site scores were averaged to calculate a watershed score. Watershed scores were area-weighted to calculate an overall region score.
Data sources: National water quality monitoring council water quality portal (waterqualitydata.us), Huron River Watershed Council, and River Raisin Watershed Council.