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Stream biological monitoring

We collect biological data from stream sites around the state, evaluating multiple aquatic communities to assess river and stream health. Because stream-dwelling organisms respond to changes in the physical and chemical environment, the collection of organisms in a stream reach provides a comprehensive indication of the conditions experienced at a particular site.

We also collect data on habitat, and on chemical and physical parameters, to measure the response of biological communities to a variety of stressors.

Four studies with one goal

Our goal is to obtain estimates of biological health in our state's rivers and streams and to evaluate how conditions change through time, in the face of climate change and growing human influence. Armed with this information, we can focus on ways to protect and improve the condition of Washington's running waters. Scroll down for more information on all these studies.

Biological models evaluate macroinvertebrate communities

A thin insect with long wings, head, and antennae faces doward on a round gray granite rock on a streambank

Hesperoperla pacifica - Golden stonefly

We've conducted biological monitoring at a limited number of sites since the early 1990s. Starting in 2009, we intensified efforts to assess stream habitat conditions and biological integrity throughout the state.

Data are collected from sites ranging from targeted sites with relatively little human influence, also called "minimally impacted" or "reference" sites, to randomly selected sites from around the state.

While each study is designed to answer specific questions, each uses the same protocols for collecting data. Because data are collected in a consistent manner, the data can be used to help us answer two primary questions:

  • What is the state of biological conditions in streams and rivers throughout Washington?
  • Are things getting better or worse through time?

We can begin to answer these questions with bioassessment models evaluating stream macroinvertebrate communities, most notably the benthic index of biological integrity (B-IBI), a useful tool for assessing streams in the Puget Sound basin. Puget Sound Stream Benthos has more information on this tool. Additionally, bioassessment models are also being developed for periphyton (attached algae) communities.

Biological data

Data for raw taxa counts, as well as habitat metrics and various water chemistry and physical parameters, are contained in the Environmental Information Management (EIM) database. Individual study datasets are linked in study details, below.

Study details

Watershed Health Monitoring sites are sampled using a Generalized Random Tesselation Stratified (GRTS) or probabilistic sampling design, representing randomly sampled sites, while Sentinel and Ambient Biological Monitoring sites are targeted sites, representing "minimally impacted" or "reference" conditions. Effectiveness monitoring sites are targeted monitoring sites, evaluating the effectiveness of various restoration efforts throughout the state. All four studies employ a consistent methodology for collecting data.

Ambient biological stream monitoring

We currently sample over 100 targeted reference sites throughout Washington on a rotating basis. Each site is sampled approximately every 2-3 years. These sites help us understand what conditions are like at sites with minimal human impacts. We collect data for macroinvertebrate and periphyton communities, many measures of physical habitat, as well as various other chemical and physical parameters. Map showing where we have been

Find the data: Link to EIM database with results for Ambient Biological Monitoring, EIM Study ID = WHM_BIO.

Status and trends sentinel monitoring

We annually sample 16 targeted reference sites throughout Washington as baselines to spot trends. These sites also help us understand what conditions are like at sites with minimal human impacts. We collect data for fish, macroinvertebrate and periphyton communities, many measures of physical habitat, as well as various other chemical and physical parameters. Map showing where we have been.

Find the data: Link to EIM database with results for Status & Trends Sentinel Monitoring, EIM Study ID = WHM_SEN.

Watershed health monitoring

We randomly sampled almost 500 sites as part of the Watershed Health Monitoring study to provide a spatially-balanced, unbiased estimate of the biological health of the state's streams and rivers. Each summer, 50 sites are sampled in one of Washington's eight Salmon Recovery Regions. Data include those for fish, macroinvertebrate and periphyton communities, many measures of physical habitat, as well as various other chemical and physical parameters. Map showing where we have been.

Find the data: Link to EIM database with results for Watershed Health Monitoring, EIM Study ID = WHM_WAM0.

Effectiveness monitoring

As part of Water Quality Improvement Effectiveness Monitoring, targeted studies around the state evaluate the effectiveness of various restoration activities. We collect data for macroinvertebrate and periphyton communities and many measures of physical habitat, as well as various other chemical and physical parameters.

Find the data: Link to EIM database with results for Effectiveness Monitoring, EIM Study ID = WHM_EFF.