Tosh Creek Watershed Restoration

Project Update - 12/9/2015

In early 2015, Redmond was awarded grant funding from the Washington State Department of Ecology for the $6.5 million 159th Ave Vault project. In 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. In October, we applied for additional grant funding which, if awarded, will allow us to complete the design of the Onyx Pond and Prescott Vault projects.

We have completed the initial phase of fieldwork in the Tosh Creek Watershed. The fieldwork we gathered will be used to inform designs for the six Tosh Creek projects prioritized in the Tosh Creek Watershed Restoration Plan. We may conduct additional fieldwork in 2016 as needed to further inform project designs, and will be sure to notify nearby neighbors in advance. Thank you for your patience and cooperation as we conducted this work.

Please look for information in early 2016 regarding opportunities to learn more about the projects, including a public meeting and an online open house.

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 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

We considered a variety of projects for restoring Tosh Creek before deciding which ones to pursue. Feedback from Redmond residents played an important role in our decision-making by helping us understand where there are currently drainage, flooding and erosion problems. Along with public input, we evaluated proposed projects based on their feasibility, cost and the benefit they would provide.

There are six projects prioritized to address the main areas of focus identified above:

  • 50th Way Flood Reduction: NE 50th Way frequently floods when there is significant rain. We are funded to install new pipes to direct most stormwater away from the stream and reduce flooding while still maintaining normal flows.
  • 159th Avenue Vault: The current series of pipe vaults located under 159th Avenue NE are in poor condition and do not provide the capacity needed to manage Tosh Creek water flows and treat stormwater to improve water quality. Through this project, we plan to build a series of concrete vaults underneath the street to store more stormwater. We are funded to design and construct this project.
  • 156th Avenue Flow Splitter: This water control structure located on 156th Avenue NE directs some stormwater to a tributary of Tosh Creek. This project includes changes to the splitter to reduce the amount of water going to Tributary B. We are funded to design and construct this project.
  • Onyx Pond: Onyx Pond is too small to store the amount of water coming from the watershed. We are proposing to improve the pond to provide more efficient storage and water quality treatment. We have conducted initial fieldwork for this project and have applied for grant funding to complete design.
  • In-stream work: Over time, Tosh Creek tributaries have experienced erosion and the stream’s habitat has deteriorated. We are proposing to design and implement methods to reduce erosion, stabilize channels, and restore the stream’s habitat.
  • Prescott Vault: The Prescott Vault, located at the end of NE 43rd Court, directs water runoff into a tributary of Tosh Creek. We are proposing to expand the vault so that it can hold more stormwater. We have conducted initial fieldwork for this project, and have applied for grant funding to complete design.

Community Benefits


Completion of the projects identified by this plan will:
  • Reduce 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 proposed in the Tosh Creek Restoration Plan 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.

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

Funding Sources

City of Redmond Stormwater CIP
Washington State Department of Ecology Grant
King County Flood Control District

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

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