Watershed health sampling schedules

We've scheduled watershed surveys in eight regions across the state to obtain a consistent, objective picture of biological, chemical, and physical conditions and to track trends. The program is designed to answer questions about the overall stream condition of Washington and each its eight regions. It is also intended to show how these conditions might be changing.

During 2020, we will observe the health of aquatic biological communities and their habitat among 50 randomly selected streams and rivers in the Puget Status & Trends Region between July 1 and Oct. 15. We previously surveyed this region in 2009 and 2013. 


Tracking biological trends of watershed regions

We monitor watershed health by studying various indicators, including those that describe biological communities and their habitat. The biological communities are fish and amphibians, bottom-dwelling invertebrates, and the algae/diatoms of the streambed. The habitat includes chemistry and the physical characteristics of the stream, riparian zone, and surrounding landscape. 

This table details the schedule of past and future sampling rounds. 

Status and Trends Monitoring Regions Round 1 Round 2 Round 3
Puget Sound 2009 2013 2020
Coastal 2010 2014 2021
Lower Columbia River 2010 2014 2022
Mid Columbia 2011 2015 2023
Snake River 2011 2016 2024
Upper Columbia 2012 2017 2025
Northeast Washington 2012 2018 2026
Unlisted Washington 2010 2019 2027

Watershed Health Monitoring 2020 is a two-page focus sheet describing this year's sampling project.

Candidate sampling sites

We use a "master sample" of 409,867 statistically selected sites in Washington that can be used for conducting unbiased surveys at various scales, including statewide or by status and trends region. Each year, we evaluate the master sample within the next scheduled region. Using maps and other research, we evaluate each site on the list and reject sites that do not fit sample-design criteria as described in the protocols. This is a multi-step process that starts with screening out sites on federal lands and tribal reservations. Crews sample 50 sites in each of seven STRs per round and 30 sites in the Unlisted STR. 

In 2020 so far, we have narrowed a candidate site list to the 348 sites mapped on this page. These are organized by Strahler stream order size, a method that is based on how many tributaries enter a stream. We seek to sample 50 sites in 2020, with 10 sites in each of five size classes. The ORD1 sites are on first-order streams (headwaters). The ORD2 sites are on second-order streams, etc. The largest class, ORD5, includes fifth-order or larger rivers.

Sites are only accessed with permission of the landowners.