Lower Pilchuck River Assessment


The Pilchuck River is home to approximately 1,000 riverside residents, several species of salmon, and countless other birds and animals. Over the past several years, this region has experienced some of its highest floods on record, causing property damage from flooding and erosion. Additionally, salmon numbers in the river have declined from historical levels. Three species of local salmon – Chinook, steelhead, and bull trout – are now listed as “threatened” on the Endangered Species List.

To learn more about how the recent high flows have affected the river, Snohomish County Public Works Surface Water Management (SWM) is studying the changing conditions of the Pilchuck River.

The goals of the river assessment are to:

  • Assess the health of the Lower Pilchuck River
  • Identify potential projects to address flooding and erosion concerns for landowners, and to improve fish habitat

Study Area

The Lower Pilchuck River Assessment will cover approximately 8.6 miles of the river between OK Mill Road and the end of the Pilchuck River where it connects with the Snohomish River.

SWM completed an assessment of Middle Pilchuck River – from the City of Snohomish Diversion dam to the OK Mill Road bridge – in 2011.


Assessment work will take several days, and will occur sometime between May and September 2016. This work is very dependent on weather and river conditions.


The Lower Pilchuck River Assessment will be conducted in a similar manner as the Middle Pilchuck River Assessment. Data collection will include:

  • Areas of recent bank erosion
  • Width and depth of the river channel
  • Sediment size and location
  • Frequency and depth of pools
  • Location and abundance of large woody debris jams
  • Condition of vegetation along the banks
  • Water temperature

This data, coupled with historic data on channel location and movement, should enable SWM to take a look at how sediment is moving through the system, what changes have occurred in the river, and where potential restoration opportunities could potentially be feasible.


You Can Help Together we can make the Pilchuck River a healthier place for future generations of people and wildlife.

Please contact Lisa Tario via email if you have ideas or information about locations for potential habitat improvement projects. If you are interested in planting trees or eradicating invasive species, such as knotweed, along the Pilchuck River, assistance and resources are available to help fund this work.