Watersheds
We collect long-term data to assess ecological condition of rivers and streams throughout the state and build a record of how watersheds are changing over time. Our data inform salmon recovery and habitat restoration efforts. Healthy watersheds protect water quality and support stronger, more resilient salmon populations.
Our work answers three questions:
- What is the relative health of streams and rivers throughout Washington?
- Are conditions improving, stable or declining over time?
- What factors drive healthy and unhealthy stream conditions?
Statewide monitoring
Through the watershed health monitoring program, we collect data at randomly selected sites from around the state to generate a representative snapshot of watershed health at both regional and statewide scales. Since 2009, we have sampled over 700 randomly selected sites and have over 100 comparative reference sites. The reference sites are sites that are minimally impacted by humans and helps us determine what conditions are healthy.
We rate the overall stream condition as good, fair or poor by using biological and habitat data from the randomly selected and regional reference sites.
Randomly selected sites and reference sites sampled between 2009 and 2025.
Biological data
At each site, we collect and document organisms that live within the stream — including fish, algae, and tiny bottom-dwelling critters called benthic macroinvertebrates. The composition of biological communities within a stream can tell us about the recent health of the stream.
Habitat data
Data collection at each site also includes measuring the suitability of the stream habitat. Hundreds of habitat data points are collected, including availability of fish habitat, streambed stability, human influence, and streamside vegetation cover. These data help us understand the underlying causes of the stream’s condition.
A scientist scrubbing stream rocks into a net to collect bottom-dwelling macroinvertabrates.
A captured stonefly, which is a type of benthic macroinvertebrate often found in cool, healthy streams.
A rainbow trout being measured and recorded before returning to Hamma Hamma River.
A densiometer device, used to measure canopy cover at stream sites.
Measuring the width of a stream channel helps us understand streambed morphology.
Measuring pool depth within a stream is important in determining if there is adequate salmon habitat available.
Want to learn more?
Find out how watersheds are doing in your region. To download data and read our reports, methods and study design, visit the watershed health studies page.
To view our preliminary reports from our project thus far, visit our statewide report and regional reports webpages.
Find out how watersheds are doing in your region!
To learn more about how we collect this data, please visit our monitoring methods page.
Contact information
Edward M. Krynak
Watershed Health Monitoring Lead
edward.krynak@ecy.wa.gov
360-742-1581