About the Little Bear Creek Basin Plan

Our Study Area: Little Bear Creek

The Little Bear Creek basin in south Snohomish County was selected as the focus of this plan, with Department of Ecology approval. Key reasons for this selection were:

  • Location: The basin is located predominately in Snohomish County, with a relatively small southern extension into King County.
  • Current Land Use: The Snohomish County portion is predominately rural, covering 13 square miles and home to over 5,000 households.
  • Environmental Amenities: The basin is an important watershed for several species of salmon and trout, with good water quality and stream habitat.
  • Development Potential: Portions of this watershed are in areas adjacent to the cities of Bothell and Woodinville.

In the course of this study, the County identified a baseline for water quality conditions and options to manage future stormwater in a manner that will protect the basin’s water quality and habitat resources for the future.

Major Study Steps

  • In 2014 and 2015, the project team 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
  • In 2016, the project team:
    • Completed water quality and stream flow data collection
    • Conducted flow modeling, water quality modeling, hydrologic metric assessment, B-IBI analysis
    • Developed current future and fully-forested modeling forecasts for multiple parameters required by the NPDES permit
    • Completed the Current Conditions Report

The study found that dissolved copper and dissolved zinc would not present problems for future water quality. However, the other parameters (temperature, fecal coliform, and flow through a correlation with B-IBI) would require further mitigation to achieve water quality standards and targets in the future.

  • In 2017, the project team:
    • Completed the Watershed Modeling Report
    • Completed the Stormwater Strategies Report
    • Selected the proposed stormwater management strategies for inclusion in the basin plan.
    • Completed the draft Little Bear Creek Basin Plan
    • Conducted a public open house meeting on June 21, 2017, to receive public comments on the draft basin plan.
    • Reviewed comments and finalized the basin plan.

Next Steps

Following submittal of the final basin plan to the Department of Ecology, the County is committed to maintaining compliance with the Phase I Municipal Stormwater Permit. The information generated through this planning effort (assessment and basin plan) provides a valuable guide for the County’s ongoing projects and programs to improve water quality in the Little Bear Creek watershed. The permit itself does not require the implementation of this plan. However, the County will continue to work on projects in the Little Bear Creek Basin that are part of the Public Works Surface Water Management (SWM) capital improvement and education and outreach programs, incorporating the Plan guidance as projects are prioritized.