Puget Sound nearshore

Stormwater Action Monitoring (SAM) conducts status and trend monitoring in Western Washington streams and nearshore marine waters.  

Study goals

Stakeholders — including municipal stormwater permittees — in Western Washington want to know the current status of Puget Sound nearshore health. They also want to know if stormwater management actions are collectively protecting and recovering nearshore habitat and wildlife.

Monitoring study design

Puget nearshore monitoring studies follow probabilistic survey design. Since first round monitoring in 2014-2019, a few adjustments to the study design were made to better answer regional status and trend questions and to improve monitoring efficiency. These new adjustments will be applied to studies starting in 2020:

  • Change the nearshore study frame from only the Urban Growth Area (UGA) to the whole Puget Sound nearshore area
  • Stratify the nearshore study areas by percent impervious surface of watershed, then select sampling sites from each stratified subgroup to better represent the full range of urban and urbanizing conditions in the region
  • Monitor bioaccumulation in mussels with a biannual schedule, and sediment chemistry less frequently (once every ten years), to be determined by Stormwater Work Group

Previous Puget Sound nearshore studies (2014-2019) focused on nearshore sediment quality, bioaccumulation of pollutants in mussels, and bacteria levels to evaluate the current status of nearshore conditions. 


SAM mussels study uses native blue mussels in cages anchored to Puget Sound beaches to filter water for three winter months.
SAM nearshore marine sediment study samples fine sediment at 6 feet below the mean low low water line in the Puget Sound nearshore.  

On-going long term studies

Completed studies list