Water Quality Improvement Projects (TMDLs) > WRIA 8 > Bear-Evans Watershed Area Multi-parameter Project

Water Quality Improvement Project
Bear-Evans Watershed Area:
Multi-parameter

Introduction

The Bear-Evans watershed is located in Washington State, in Water Resource Inventory Area (WRIA) 8. It is situated west of the Cascades mountain range and east of Lake Washington, in the Puget Sound lowlands within northern King and southern Snohomish counties. The watershed drains approximately 51 square miles of land area. It includes the cities of Redmond, Sammamish, and Woodinville. Bear Creek is the major stream of the system, with Cottage Lake Creek and Evans Creek as its main tributaries. Bear Creek flows southerly for 12 miles through rural and suburban neighborhoods before joining the Sammamish River in the commercial district of Redmond. (See Study Area map)

Water quality issues

Too Much Bacteria

Warm Temperatures and Low Oxygen in the Water

Parts of Bear, Evans, and Cottage Lake Creeks exhibit unhealthy temperature and oxygen conditions that cause them to fail Washington State water quality standards. Fish breathe oxygen in the water (dissolved oxygen). Cooler water holds more oxygen. Warmer water results in less oxygen for fish and other aquatic organisms. When water has too little oxygen or is too warm, local fish can face thermal stress and harm. These streams serve as important migration corridors and spawning and rearing areas for several salmon species -- Puget Sound Chinook, coho, sockeye, kokanee, steelhead/rainbow, cutthroat trout -- that all need cold water for optimum health during various stages of their lives.

What is being done

To address the water quality issues, in 2006 Ecology initiated the Water Quality Improvement (TMDL) Projects for fecal coliform, temperature, and dissolved oxygen in the Bear-Evans Watershed. Ecology, King County, City of Redmond, and others cooperated in a summer field study to collect data for the temperature and dissolved oxygen TMDL studies. To coincide with this TMDL effort, Ecology initiated the fecal coliform bacteria TMDL study that same year.

As part of the TMDL study, Ecology identifies the pollution problems and specifies how much pollution needs to be reduced to achieve clean water. As a follow-up to the TMDL study, Ecology works with the local community to prepare a Water Quality Implementation Plan that details the specific actions needed to improve water quality in the basin. The plan describes management roles, activities, and schedules for partners.

Many local partners are involved in these projects, including the Muckleshoot Indian Tribe; King County; City of Redmond; Northeast Sammamish Sewer and Water District; King and Snohomish Conservation Districts; and Water Tenders. Most importantly, watershed residents, local businesses, and public citizens play an important role as well in improving water quality.

Status of the project

Fecal Coliform Bacteria TMDL Project Timeline:

Temperature and Dissolved Oxygen TMDL Project Timeline:

April 6, 2011:  Ecology sent the final multi-parameter water quality implementation plan (WQIP) to EPA.

Technical information

Fecal Coliform:

Bear-Evans Watershed Fecal Coliform Bacteria TMDL Water Quality Improvement Report (Ecology publication)
www.ecy.wa.gov/biblio/0810026.html

Temperature and Dissolved Oxygen:

Bear-Evans Watershed Temperature and Dissolved Oxygen Total Maximum Daily Load: Water Quality Improvement Report (Ecology publication)
www.ecy.wa.gov/biblio/0810058.html

Quality Assurance Project Plan for the Temperature and Dissolved Oxygen TMDL in Bear-Evans Watershed (Ecology publication)
www.ecy.wa.gov/biblio/0603107.html

Focus on temperature and dissolved oxygen in Bear-Evans Watershed (Ecology publication)
www.ecy.wa.gov/biblio/0610060.html

Related information

Bacteria:

Focus on Bacteria in Bear-Evans Watershed (Ecology publication)
www.ecy.wa.gov/biblio/0810047.html

"Let’s Talk About Bacteria in the Bear-Evans Watershed" presentation (PDF, ~11mb)
www.ecy.wa.gov/programs/wq/tmdl/BearEvans/BearEvansFCPresentation052708.pdf

WRIA 8: Cedar-Sammamish-Lake Washington Watershed Information (Environmental Assessment Program website)
www.ecy.wa.gov/apps/watersheds/wriapages/08.html

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