Frequently Asked Questions

Where is Tosh Creek located?

Tosh Creek and the Tosh Creek Watershed are located in the Overlake neighborhood of Redmond, just west of Marymoor Park. The watershed includes the Microsoft campus. A map of the project area (outlined in pink) may be viewed here:  Tosh Creek Watershed Restoration Project Area.  Tosh Creek flows from Redmond's Overlake neighborhood into the Sammamish River.

What is the Tosh Creek Watershed Plan?

The Tosh Creek Watershed Restoration Plan (the Plan) will be a detailed plan on how to best retrofit existing and install new stormwater treatment infrastructure to help control the flow of polluted runoff into Tosh Creek and surrounding bodies of water. The Plan will include the design and siting of treatment facilities that could potentially be in your neighborhood, on your street, or in front of your property.

How will this project benefit Tosh Creek?

Like most areas in Redmond, the Tosh Creek Watershed was developed with stormwater infrastructure that was deemed adequate for that time, but which does not meet the water quality and salmon needs of today. This has resulted in high velocity flows, unnatural creek channels, and the frequent flooding of roads.

The Tosh Creek Watershed Restoration Plan and the treatment projects outlined within the Plan provide an opportunity to resolve these problems. Stormwater treatment facilities remove pollutants from stormwater runoff so the water is cleaner for fish and other wildlife once it enters the river. 

Why is this Plan being proposed in my neighborhood?

The Plan is being proposed in the Tosh Creek neighborhood because the Creek is special and has the opportunity to support fish and wildlife with relatively minimal investment. In 2013, Redmond identified the Tosh Creek Watershed as one of the six priority watersheds, meaning the Creek will likely become healthy after investments in stormwater treatment facilities and programmatic actions to address water quality issues in the Creek. The Tosh Creek Watershed Plan will determine the location and design of the treatment facilities across the entire Tosh Creek Watershed.

I thought Redmond already addressed this by improving the culvert under West Lake Sammamish Parkway. Why are additional projects needed?

West Lake Sammamish Parkway has flooded in the past, largely due to culverts (a structure that allows water to flow under a road, trail, or other obstruction) getting plugged up with debris. Redmond has completed two projects in the last 10 years to address the flooding issue at this location. Redmond replaced the culverts at NE 48th Street (2004/2005) and replaced the main West Lake Sammamish Parkway culvert last year (2013). Realigned Creek

The culvert replacement projects allow for less debris to get caught in the culverts, and as a result, have reduced flooding of West Lake Sammamish Parkway. However, Redmond needs to continue to work in the stream to reduce the velocity of peak flows and high-flow durations that cause erosion and degrade salmon and other aquatic habitat, as well as complete in-stream stabilization projects to address the debris sources. 

How will Redmond be deciding which projects to pursue?

Redmond is currently in the process of deciding which treatment facilities to include in the Tosh Creek Watershed Restoration Plan. Redmond is considering a variety of projects, including the expansion of existing storage ponds, constructing underground stormwater storage vaults, and others. Importantly, Redmond wants to hear from you where you’ve seen flooding, erosion, or drainage problems in the neighborhood to help ensure that the City is addressing the most pressing and long-term problems. Along with public input, Redmond is using a set of criteria that includes multiple considerations dealing with feasibility, cost, benefit, and community acceptance to decide which treatment facilities to prioritize. 

Are you considering rain gardens? I heard that some rain garden pilot projects in other jurisdictions have had a lot of problems.

Rain gardens help control polluted runoff by collecting stormwater from roofs, streets, and other impervious surfaces, instead of having the polluted runoff flow straight into Tosh Creek. Redmond is looking to see if rain gardens are a good option in the Tosh Creek Watershed. If it is determined that rain gardens are an effective solution, Redmond will take the lessons learned from other jurisdictions attempts to install rain gardens to help ensure that the gardens are built successfully and with community acceptance. 

How is this project being funded?

For this planning effort, Redmond received a $250,000 grant from the U.S. National Estuaries Program, administered through the Washington State Department of Ecology, to develop the Tosh Creek Watershed Plan. Redmond Stormwater Utility has also contributed $135,547.

Previous culvert replacement projects at West Lake Sammamish Parkway were funded by Redmond’s Stormwater CIP, with grants from King Conservation District and King County Flood Control District. Future capital projects will be funded by Redmond’s Stormwater CIP and we are hopeful to be awarded significant grants for these important projects. 

When do you expect the project will be completed?

Redmond is in the preliminary stages of the Tosh Creek Watershed Restoration Plan. The City is currently on track to identify a suite of preferred treatment projects to include in the Tosh Creek Watershed Plan in fall 2014. However, this is only the first step in recovering Tosh Creek. After the treatment facilities are identified, they need to be built, which is expected to begin in 2015. Redmond expects to complete restoration efforts in the Tosh Creek Watershed by 2025. 

Potential Impacts to Neighborhoods and Residents

How will I be impacted? Will there be construction projects in my neighborhood?

Redmond will have a better sense of how the neighborhood will be affected once the priority treatment facilities are identified. Once this occurs, Redmond will focus on reaching out to impacted members of the community.

I don’t have any flooding on my property. How will this help me?

This is an opportunity to restore Tosh Creek to a healthy, functioning ecosystem, which could potentially bring back salmon and other wildlife to the area for you and your kids to enjoy for the foreseeable future. Tosh Creek is unique and we have the opportunity to protect it. These treatment facilities will also control the flow of water throughout the watershed, which will help reduce street flooding and make it safer to drive and walk during and after large rain events.

Public Process

How will the public be consulted?

Your involvement is critical in this process. Redmond is reaching out to key community leaders to determine where they’ve seen drainage problems, and has also sent out a postcard that easily allows community members to provide comments to the City on where they’ve seen issues.

How will our input be used?

If you know of any flooding, erosion, or other drainage problems in and around Tosh Creek, please let the City know! This kind of information can influence the types and locations of future projects.

How can I help?

You can call, email, or complete a comment form on the project’s website to report your drainage concerns. Most importantly, fill out the postcard from the City! Redmond is using your input to help decide which stormwater treatment facilities it should prioritize. 


Steve Hitch, Project Manager
425-556-2891 or