Tosh Creek Watershed Restoration

Project Update - 9/9/2015

Earlier this year, Redmond was awarded grant and loan funding from the Washington State Department of Ecology for the $6.5 million 159th Avenue Vault project. In early September the King County Flood Control District also awarded Redmond grant funding to complete the NE 50th Way Flood Reduction project. Both are shown in the proposed projects map. We have hired a consultant team to begin the design of this project in addition to other projects planned for restoring Tosh Creek. Take a look at the project information letter we sent to affected property owners.

Fieldwork in the Area

To inform the design of the Tosh Creek projects, we are continuing to conduct fieldwork investigations in your neighborhood. Crews will not enter private property without prior authorization or notification. Thank you for your patience as we conduct this work.

What is the purpose of the fieldwork?

We are conducting different types of fieldwork to identify and collect data. The data from this exploratory work will help us develop the project designs. The work we are doing includes:

  • Geotechnical investigation: To identify soil types and subsurface conditions by taking soil samples and testing the speed at which water enters the soil. Crews will use truck-mounted drills or handheld equipment depending on the location, the type of data they are gathering, and the depth of the sample needed. Crews may need to temporarily close sections of the sidewalk and run water from hydrants overnight.
  • Right-of-way survey: To identify the boundaries of City-owned land, or public right-of-way.
  • Topographic survey: To identify and map existing surface conditions, such as utilities, trees, and walkways, using handheld equipment.
  • Environmental reconnaissance: To assess terrain, plants and wildlife by visually surveying project areas.
  • Potholing: To identify utilities beneath the surface by using truck-mounted equipment to dig small holes. This work will not disrupt utility services.

Future fieldwork may include wetland delineations, to locate the boundaries of existing wetlands, and cultural resource surveys, to understand the potential for archaeological artifacts to exist in the area.

What is the status of the fieldwork near each project site?      

  • 159th Ave Vault: Geotechnical investigations will take place on 159th Ave NE the week of September 14. All geotechnical work will be on city-owned land. Right-of-way surveys will continue on 159th Ave NE until Friday, September 11.
  • 156th Ave Flow Splitter: Survey work and environmental reconnaissance will begin this month.
  • Onyx Pond and Prescott Vault: Crews have completed preliminary fieldwork.
  • Tosh Creek Trib. B: No fieldwork will be scheduled until we obtain permission from property owners.
  • NE 50th Way Flood Reduction: King County Flood Control District has awarded the City of Redmond grant funding to complete work on NE 50th Way. Survey work will begin soon.

What can neighbors expect?     

  • During geotechnical work: Noise similar to a truck engine running with brief periods of hammering, temporary sidewalk closures on 159th Ave NE and hoses running from hydrants overnight.
  • Crews working at the project sites during daytime hours.
  • Markings, such as paint, ribbons and small flags, left by survey crews.
  • Restoration of affected areas according to the City of Redmond standards.
  • Continued updates as the work progresses.

Purpose of the Plan

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 playTosh Creek 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 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 this 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

The proposed projects are summarized below. This plan proposes a sequence of projects that balances staffing and funding availability, grant cycles, property rights, and public support to sustain a program most likely to succeed.

The capital improvement plan is supported by a robust monitoring program and delays construction until that monitoring program has had the opportunity to develop baseline stream data that will be used to confirm modeling that has been done and develop project designs. Additionally, monitoring will be useful in evaluating the effectiveness of constructed projects. With continuous monitoring and periodic updates to this plan, a progression of improvements can be documented and the program can change course, if needed.

The initial phase of proposed projects includes:

  • 2015 – 2016             Stop flooding of the 50th Way stream
  • 2016 – 2017             Repair broken pipes, control structures, swales
  • 2017                        159th Vault and 156th Flow Splitter
  • 2017 – 2019             Stream stabilization and buffer restoration
  • 2019                        Onyx Pond and Prescott Vault expansion
  • 2020                        Update Tosh Creek Watershed Restoration Plan

Community Benefits

Completion of the projects identified by this plan will:
  • Eliminate flooding in the neighborhood
  • 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 will restore the ecological health of the stream, bringing 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.

If you wish to be on the project mailing list, contact the Program Manager as noted below.  

Funding Sources

City of Redmond Stormwater CIP and Washington State Department of Ecology Grant

Estimated Timeline

Development of Tosh Creek Watershed Restoration Plan:  2014
Design of 159th Vault Project:  Summer 2015 – Summer 2016
Seek Grant Funding for Additional Projects:  Fall 2015
Construction of Projects: 2016-2019
Plan Update:  2020

Tosh Creek Watershed Plan Program Manager:  Steve Hitch, 425-556-2891
159th Vault Construction Project Manager:  Joseph O'Leary, 425-556-2738