City begins Tosh Creek Basin restoration project and is seeking residents’ input

The City of Redmond is in the very early stages of restoring the Tosh Creek Basin to improve the area’s water quality and ability to support wildlife.

In addition, the project’s goal is to improve stormwater infrastructure.

Covering about 200 acres just southwest of Marymoor Park, the basin is a combination of residential and commercial development.

Steve Hitch, the City of Redmond project manager for the restoration, said it is all of this development that has led them to making plans for improvements. He said before development, when the land was still forested 100 years ago, the natural environment would do its job in filtering and controlling the flow of the water. But with development, stormwater runoff just sits on the pavement, collecting whatever oils and pollutants are on the surface before returning to streams and other waterways.

Hitch said the goal of the restoration project is to make Tosh Creek, an urban stream, think there is a forest surrounding it by building projects that will help with flow control, stormwater treatment and infiltration.

With flow control, he said the city could possibly build a storage pond or vault to capture and store water and release it slowly back into the stream, which cuts down on erosion that would be caused if the water was released all at once. Hitch likened it to using a fire hose for your yard.

He said treatment facilities would capture any pollutants in the water before it is released and infiltration projects, such as rain gardens, would capture and remove water so the area is not overwhelmed.

While restoring Tosh Creek, the city will also repair or replace pipes, ponds and vaults to address many of the flooding, erosion, poor drainage or other issues within this area.

The restoration project is still in the planning phase and the City of Redmond is still seeking resident input to see which areas in the basin have drainage or other issues that would benefit most from the improvements.

The planning process for the project is funded by a state grant and it will still be about a year before any construction will be done. Hitch said the city will be looking into additional grants to help fund the project in addition to dollars from the city’s capital improvements budget.

For more information or to get involved in the project, visit

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