Measuring river health

Five categories of river health were assessed to determine the health of the Willamette River, including Water Quality, Fish & Wildlife, Habitat, Flow, and People & the River. Important values and indicators of health were identified for each of these categories and analyzed by university and agency experts. Scores are based on the current status of each indicator as compared to a science-based goal or benchmark.

Overall Health Index

The Willamette River report card compares 15 indicators (water quality index, toxics, temperature, native fish, non-native fish, juvenile chinook, bald eagle, channel complexity, floodplain forest, flow targets, peak flows, fish consumption advisories, tribal fisheries, fecal bacteria, harmful algal blooms) to scientifically derived thresholds or goals. These individual indicators were averaged to calculate scores for each of the five categories, for the upper, middle, and lower Willamette. These five categories were then combined into an Overall Health Index for each reach of the river. The overall grade for the river is the average of these three reach scores.

Water Quality

  Water Quality Index | Water quality index (includes 8 water quality variables).

  Toxics | How often toxics are detected at unsafe levels.

  Temperature | Water temperature required for salmon and steelhead health.


Fish and Wildlife

  Native Fish | Number of native fish species present.

  Non-native Fish | Ratio of native to non-native fish species.

  Juvenile Chinook | Number of juvenile Chinook salmon.

  Bald Eagle | Bald eagles active during breeding season.



  Channel Complexity | In-stream habitat as measured by channel complexity.

  Floodplain Forest | Extent of intact floodplain forest.



  Flow Targets | Stream flow targets for salmon and steelhead.

  Peak Flows | Difference between current and historic peak flows.


People and the River

  Fish Consumption Advisories | Resident fish consumption advisories.

  Tribal Fisheries | Tribal fisheries for wild Chinook, steelhead and lamprey.

  Fecal Bacteria | Presence of fecal bacteria in the river.

  Harmful Algal Blooms | Occurrence of harmful algal blooms.