Tosh Creek Watershed Restoration Plan

Project Update - 2/27/2015

The Tosh Creek Watershed Restoration Plan is now available and may be viewed under the Project Data-Tosh Creek listing located at the bottom of this page.

The Washington State Department of Ecology has announced the intent to award Redmond grant and loan funding to fund the $6.5 million 159th Avenue Vault project.

The Ecology draft offer list can be found here:  State Fiscal Year 2016 Draft Water Quality Funding Offer List and Intended Use Plan   

Project Background

In December 2013, City Council adopted the Redmond Watershed Management Plan which evaluates and prioritizes Redmond's watershed basins and identifies priority basins for stormwater retrofitting and habitat restoration. The plan identified Tosh Creek as a high priority basin for retrofit.

As a result of this designation, the Washington State Department of Ecology is partnering with Redmond to fund development of the Tosh Creek Watershed Restoration Plan (Restoration Plan). 

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 play in Redmond. Using a watershed approachTosh Creek 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 know of any flooding, erosion, or other drainage problems in and around Tosh Creek (see Vicinity Map below), let us know. This kind of information can influence the types and locations of future projects. Call, email, or complete the Report a Stormwater/Drainage Concern to report your drainage concerns.

Our next mailing is scheduled for late summer of 2015.

Project Data - Tosh Creek

Tosh Creek Watershed Restoration Plan (February 27, 2015)
Vicinity Map  (September 24, 2014)
Quality Assurance Project Plan  (November 2013)
Existing Conditions  (April 14, 2014)
Geomorphology  (April 14, 2014)
LID Feasibility  (April 14, 2014)
Drainage Issues Map  (September 24, 2014)
Stormwater Infrastructure Conditions Assessment  (September 24, 2014)
In-Stream Work Recommendations  (April 14, 2014)
Stormwater Retrofit Recommendations   (September 24, 2014)
Tosh Creek Projects Predesign Report
159th Vault Predesign Report
Prescott Vault Predesign Report
Watershed Restoration Projects - Five Year Plan 
2014 Winter Focus Article:  What's Next for Tosh Creek?

Project Phase: Design

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