Watershed health sampling schedules

To obtain statewide trends, we rotate between eight Status and Trends Regions. Within each region, randomly selected sites are used to represent the selected area of the state.

New focus sheet for Mid-Columbia 2024

Rocky-bottom stream Teanaway river near Cle Elum

This summer, our crews will sample 50 randomly selected sites in the Mid-Columbia Region. To learn more about our 2024 sampling plans, take a look at our focus sheet: Watershed Health Monitoring 2024 — Mid-Columbia Region.

Regional rotation

Each year we sample randomly selected sites in one of the eight Status and Trends Regions.  This rotation allows us to complete an extensive protocol for the required number of sites in each region.  We are looking forward to completing the third round of sampling in 2028 and reviewing data from three statewide rotations!

The regional rotation schedule is shown below.

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


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 region.

Three people walking on a trail carrying backpacks, nets, and rods

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 our protocols.

This is a multi-step process that starts with screening out sites on federal lands and tribal reservations. Crews sample 50 sites in most regions and only 30 sites in the Unlisted Region.

So far in 2024, we've narrowed a candidate site list to the 449 sites mapped on this page. These are organized by Strahler stream order size, a method based on how many tributaries enter a stream. We seek to sample 50 sites in 2024, 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.