Tosh Creek Watershed Restoration

Project Updates

Welcome to the Tosh Creek Restoration Website!

Explore the links on the left side of the page to learn about why Tosh Creek Restoration is important to Redmond, how projects were selected, how this restoration program is being funded, and the status of each of the projects that are part of the plan. Come back to this page frequently to see the latest project updates.

Project Update - 7/28/2016

The City has reviewed the responses to the June 13th public meeting and has had follow up meetings with residents from Tamarack Lane. Within those communications was concern about the large temporary and permanent project impacts and a request for more information about the Tosh Creek Restoration Program. Specifically, the group is seeking response to the following questions:

  • Why restore Tosh Creek?
  • Are there fish in Tosh Creek?
  • What alternatives were considered in the restoration program?
  • How are alternatives evaluated? What temporary and permanent impacts will there be?
  • What will it cost, how will it be paid for, and can the City afford it?
  • What projects were (or will be) selected?
  • What is the design and construction schedule?

You can find responses to those questions on the left side of this website. The City is working on a community engagement program that will include a series of meetings where you can meet with City staff to learn more about these topics and provide your input as the City selects the preferred path forward.

In the meantime, the proposed construction of the 159th Vault project is on hold and will not occur in 2017. The City is reevaluating alternatives for projects near Tributary B with the goal of determining the path forward later this year.

Project Update - 7/14/2016

The Tosh Creek online open house is now closed!

To view materials from our June 13th public meeting and recent online open house, please visit our Project Resources page. 

The design team has completed preliminary engineering for the six projects shown in the project map below. These projects are proposed for construction from 2016-2022 as shown on the project schedule.

In May 2016, we distributed a project newsletter to residents and businesses within the watershed. Here are a few project updates that were included in the newsletter:

  • 159th Avenue Vault Project   
    We are reducing costs and construction impacts by moving the proposed vault from the street onto three adjacent properties. The City owns one of these properties and is negotiating the acquisition of the other two with the property owners.

  • 50th Way Flood Reduction Project   
    We have reached final design and are conducting outreach for the project. We will advertise the project to contractors in June and construction will start this summer.

If you are interested in receiving project emails and notifications, please sign-up for our mailing list: Tosh Creek Mailing List

Purpose of the Plan

Tosh Creek The City is committed to fully restoring Tosh Creek to make it healthy for aquatic life, and a valuable natural asset for the people who live, work, and play in Redmond. Using a watershed approach (as documented in the 2013 Redmond Watershed Plan) to achieve healthy aquatic habitat has been a long-standing policy detailed in the City's Comprehensive Plan and is recognized by stormwater and surface water restoration practitioners as the recommended approach to accommodate healthy streams in an urbanized landscape. The Tosh Creek Restoration Plan, completed in February 2015, identifies potential stormwater retrofit and in-stream projects that will improve the hydrology and water quality of the stream and also mitigate flood hazards.

There are five main areas of focus in this Restoration Plan:

  1. Flow Control - Slow down stormwater flows to protect the stream       
  2. Water Quality Treatment - Clean up stormwater runoff for cleaner water in the stream
  3. Low Impact Development Infiltration - Soak stormwater into the ground       
  4. Instream Work - Repair damaged sections of the stream and add plants       
  5. Stormwater Infrastructure Repairs - Repair or replace failing pipes

Projects described in the Tosh Creek Restoration Plan from each of these focus areas form a capital improvement program that lays out a sequence of projects tailored to the prioritized needs that have been identified for the Tosh Creek watershed.

Proposed Projects

Feedback from Redmond residents played an important role in our decision-making by helping us understand where there are drainage, flooding and erosion problems. Along with public input, we evaluated proposed projects based on their feasibility, cost and the perceived benefit to the watershed.

The projects we are moving forward with are shown on the map and table below.

Project Map


Project name

Current problem

Planned solution

Anticipated timeframe for construction

Funding status

50th Way Flood Reduction

The stream along NE 50th Way frequently floods when there is a lot of rain

Install new pipes under the street to direct most stormwater away from the stream, reducing flooding


Summer 2016 for approx. 3 months

Source: King County (KC) Flood Control District, Redmond Stormwater Capital Investment Program (CIP)

159th Avenue Vault

The current series of pipe vaults under 159th Ave NE are old and need to be replaced to ensure reliability and to meet current standards that protect the stream

Install a new stormwater vault on three adjacent properties: 4612 159th Ave NE, 4618 159th Ave NE, and the adjacent vacant City parcel

Spring 2017
for approx. 6-9 months

Sources: Washington State Dept of Ecology (Ecology), KC Flood Control District, and Redmond Stormwater CIP


156th Avenue Flow Splitter

The existing flow splitter directs too much water to one of Tosh Creek’s tributaries


Modify the flow splitter to reduce the amount of water going to the tributary

Summer 2017
for approx. 3 months

Sources: Redmond Stormwater CIP

Onyx Pond

Onyx Pond is too small to store and treat the amount of water coming from the Tosh Creek watershed


Improve Onyx Pond by removing sediment and trees in the pond; expand the pond

Summer 2020
for approx. 3-6 months


Preliminary funding received for fieldwork and early design; additional funding requested. Ecology grant award pending availability of state funding.

In-stream work

Tosh Creek tributaries are eroded and the stream’s habitat is deteriorated


Repair the stream to reduce erosion, stabilize channels, and restore habitat

Tributary B: Summer 2020
for approx. 3-6 months

Additional projects planned for the future

Preliminary funding received for fieldwork and early design; additional funding requested

Prescott Vault (NE 44th Court)

The existing vault is not large enough to hold the amount of stormwater needed

Expand the vault so that it can hold more stormwater, and add system to treat water before releasing it into the creek


Approx. 6 months in 2022

Preliminary funding received for fieldwork and early design; Ecology grant award pending availability of state funding.


Community Benefits

Completion of the projects identified by this plan will:

  • Reduce flooding in neighborhoods       
  • Prevent erosion in Tosh Creek
  • Reconstruct stream channel segments to improve fish habitat
  • Remove invasive vegetation and re-plant bare portions of the stream buffer
  • Repair damaged stormwater pipes to avoid future flooding problems 

Ultimately, the combined suite of projects proposed in the Tosh Creek Restoration Plan will restore the ecological health of the stream and bring back larger populations of Coho salmon, cutthroat trout, and other fish. This healthy stream will be a valuable asset for our community for generations to come!

How to Stay Informed

Please visit this website for the most up-to-date information on the project. Additional materials and project information will be posted on the site as the project develops.

Please join the Tosh Creek mailing and notification list:  Tosh Creek Mailing List

Tosh Creek Watershed Plan Program Manager:  Steve Hitch, 425-556-2891
159th Vault Construction Project Manager:  Joseph O'Leary, 425-556-2738
50th Way Flood Reduction Project Manager:  Bassam Al-Ali, 425-556-2743
Tosh Creek Project email: