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 conditions of Washington and each of its eight regions. It's also intended to show how these conditions might be changing.

During 2023, we'll observe the health of aquatic biological communities and their habitat among 50 randomly selected streams and rivers in the Lower Columbia region between July 1 and Oct. 15. We previously surveyed this region in 2010 and 2014. 

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 physical characteristics of the stream and riparian zone, plus chemsitry of water and sediment. 

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 2021
Coastal 2010 2014 2022
Lower Columbia River 2010 2014 2023
Mid Columbia 2011 2015 2024
Snake River 2011 2016 2025
Upper Columbia 2012 2017 2026
Northeast Washington 2012 2018 2027
Unlisted Washington 2010 2019 2028

Watershed Health Monitoring 2023 is a two-page focus sheet describing this year's sampling project.

Candidate sampling sites

We use a  "master sample" of 547,877 statistically selected points from the Pacific Northwest Hydrologic Region. These can be used for conducting unbiased surveys at various scales, including statewide or by status and trends region (STR). 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 or external to the STR being surveyed. Crews sample 50 sites in each of seven STRs per round and 30 sites in the Unlisted STR. 

So far in 2023, we've narrowed a candidate site list to the 511 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 2023, with 10 sites in each of five size classes. Streams are ordered by size, ranging from category one, small headwater streams, to category five, large streams and rivers. 

Sites are only accessed with permission of the landowners.