Water Quality Improvement Project
Bear-Evans Watershed Area:


The Bear-Evans watershed is located in Washington State, in the Cedar-Sammamish watershed, 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 and includes parts of 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 major tributaries. Bear Creek flows southerly for 12 miles through rural and suburban neighborhoods before joining the Sammamish River near downtown Redmond. (See Study Area map)


Water quality issues

Too Much Bacteria

Bear, Evans, and Cottage Lake Creeks have too much fecal coliform bacteria. Stream samples show bacteria levels beyond what Washington State standards allow in our freshwaters. Excess fecal coliform bacteria are a common water quality problem in our state. Fecal coliform belong to a mostly harmless group of bacteria commonly found in large numbers in the feces of people and warm-blooded animals such as pets, livestock, and wildlife. However, they indicate that more serious disease-causing organisms, called pathogens, may be present in the water. Stormwater runoff and other discharges can carry these small organisms into streams where they pollute the water.

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. The Bear-Evans system served 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.

Looking and planning for fixes

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 field studies to collect data for the fecal coliform, temperature, and dissolved oxygen TMDL modeling and target setting.

As part of the TMDL study, Ecology identifieD the pollution problems and specified how much pollution needs to be reduced to achieve clean water. As a follow-up to the TMDL study, Ecology worked with the local community to prepare a Water Quality Implementation Plan detailing 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; Adopt-a-Stream Foundation; and Water Tenders. Most importantly, watershed residents, local businesses, and public citizens play an important role as well in improving water quality.

As a last step in this process Ecology sent the TMDLs to the Environmental Protection Agency (EPA) for approval. EPA approved the TMDLs in August and September 2008. TMDL implementation is currently underway.

Status of the project

Fecal Coliform, Temperature and Dissolved Oxygen TMDL Project Timeline:

August 2008 EPA approved TMDL study on fecal coliform bacteria in the Bear-Evans watershed.
September 2008 EPA approved TMDL for temperature and dissolved oxygen in the Bear-Evans watershed.
April 2011 Ecology sent final multi-parameter water quality implementation plan (WQIP) to EPA.

What is being done now

Ecology and other watershed stakeholders are working on projects that are consistent with the Water Quality Implementation Plan. Many are completed and others are underway.

Since 2011 the city of Redmond has received over three and a half million dollars from Ecology’s Water Quality financial assistance programs for installation of bioretention cells, pervious pavement, a stormwater trunk line, a stormwater wetpond, decant bays, and an on-site stormwater management systems designed to reduce quantity of heavy industrial runoff. Since 2009 Ecology has also funded over half a million dollars in activity projects for riparian restoration and educational efforts aimed at actions to reduce pollution runoff, such as having people reduce fertilizer use and pick up pet waste.

The Washington State Salmon Recovery Fund is sponsoring many millions of dollars of riparian restoration in the Bear-Evans watersheds, including instream work, riparian restoration, and even the reconfiguration of the confluence of Evans Creek. This is not an exhaustive list, and Ecology anticipates more funding and as well as other stakeholders to come forward to work on watershed improvements.

Technical information

Unless otherwise specified, the following documents are Ecology publications.

Bear-Evans Watershed Fecal Coliform Bacteria TMDL Water Quality Improvement Report

Bear-Evans Watershed Temperature, Dissolved Oxygen and Fecal Coliform Bacteria TMDL - Water Quality Implementation Plan

Bear-Evans Watershed Temperature and Dissolved Oxygen Total Maximum Daily Load: Water Quality Improvement Report

Quality Assurance Project Plan for the Temperature and Dissolved Oxygen TMDL in Bear-Evans Watershed

Focus on temperature and dissolved oxygen in Bear-Evans Watershed

Related information

Unless otherwise specified, the following documents are Ecology publications.


Focus on Bacteria in Bear-Evans Watershed

"Let’s Talk About Bacteria in the Bear-Evans Watershed" presentation (PDF, ~11mb)

WRIA 8: Cedar-Sammamish-Lake Washington Watershed Information (Environmental Assessment Program website)

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Last updated March 2014
  Water resource inventory area (WRIA) 8 map, Washington State.


WRIA: #8 (Cedar-Sammamish)

Water-body Names:
Bear Creek
Cottage Lake Creek
Evans Creek

Dissolved Oxygen
Fecal Coliform

# of TMDLs:
Fecal Coliform - 4
Temperature and Dissolved Oxygen - 4

TMDLs approved by EPA
Has an implementation plan

Contact Info:
Joan Nolan
Phone: 425-649-4425
Email: Joan.Nolan@ecy.wa.gov

Northwest Region
Department of Ecology
3190 160th Ave. SE
Bellevue, WA 98008-5452