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.
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.
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 sediemnt chemistry. See factsheet and completed studies list below for detail.
33 randomly selected sites and two reference sites are monitored each year. The map has been updated regularly to include completed sampling sites every 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.