Little Bear Creek Basin Plan (Water Quality Study)

The Little Bear Creek basin in south Snohomish County supports several species of salmon and trout with good water quality and stream habitat. The basin starts in Snohomish County and extends into King County. Snohomish County’s portion covers 13 square miles and is home to nearly 4,000 households.

Why Study Little Bear Creek


To protect the stream’s valuable water quality and habitat resources for the future, Snohomish County is assessing its portion of Little Bear Creek to better understand how to manage stormwater.

This three-year project is required by the county’s National Pollutant Discharge Elimination System (NPDES) permit and is intended to reduce stormwater pollution.

What We Are Studying


Snohomish County Surface Water Management (SWM) is studying existing stream conditions within the basin and evaluating the impacts of stormwater on its water quality, stream flows, and aquatic health.

In 2015 we gathered data on:
  • Habitat conditions along Little Bear Creek and its tributaries including stream bank stability, sediment sources, vegetation, and channel dimensions.
  • Stream temperatures and pollutants such as dissolved copper, dissolved zinc, and fecal coliform bacteria.
  • Biological health of the stream including the aquatic insects that fish depend upon.
  • Stream flows during small and large storms. 
  • Existing stormwater infrastructure such as detention ponds.

How the Data is Being Used


The data is being input into a computer model of the Little Bear Creek basin to help determine whether water quality standards will continue to be met in the future as the area continues to develop and grow.

We will use the model findings to create a Little Bear Creek Basin Plan to protect future water quality and aquatic health. The plan will be available for public review and comment in 2017. A finalized plan is to be submitted to the Washington Department of Ecology by September 2017.

Where We Are in the Process


The timeline below shows what we’ve done, where we are, and what’s coming up. Click on timeline bullet items for more details
Little Bear Creek Timeline
Work-to-date
Upcoming Events
  • February 2017: Technical Workshop #2
  • May 2017: Draft Plan Compiled and Available for Review and Input (Public Meeting Date TBD)
  • September 2017: Final Plan Submitted to the Washington State Department of Ecology