Puget Small Streams study

Stormwater Action Monitoring (SAM) conducts status and trend monitoring in Western Washington streams to answer how stormwater runoff from a broad range of urban conditions affects the health of small wadable streams.

Study goals

Stakeholders, including municipal stormwater permittees in Western Washington, want to know how stream health changes over time in small streams as the area urbanizes and stormwater controls are implemented more broadly.

Study design

The Puget Small Streams (PSS) study collects water and sediment chemistry, in-stream and riparian habitat information, benthic macroinvertebrate, and periphyton samples. Continuous monitoring of stream water level and temperature are monitored at each site to cover a full water year. See sampling locations map below. 

The study design has been modified to improve monitoring efficiency and statistical power. Read more details about the design in the study design fact sheet

Read the Quality Assurance Project Plan (2020) for more detailed information such as study design, plans, and schedules.

Study findings 

Previous monitoring done in 2015 found that urban development negatively impacted nearly all of the stream health indicators. Key stressors driving poor B-IBI scores includes physical habitat characteristics, especially watershed-level canopy cover, urban development and sediment chemistry. See factsheet and completed studies list below for detail. 

Sampling locations 

33 randomly selected sites and two reference sites are monitored each year. The sites for 2020 summer sampling are a subset of past 2015 sampling sites that met the new study design criteria and grouped by the percent of impervious cover in contributing watershed. After that, 33 sites are combination of new and revisit sites.  

Site list: 2020 sampling sites, 2021 sampling sites

PSS study sampling locations. You can find detailed information for each site in the attribute tables. You can view the full size ArcGIS online map here

On-going study contracts 

Completed studies list