Tosh Creek Watershed Restoration

Project Update - 7/28/2015

Redmond has been awarded grant and loan funding from the Washington State Department of Ecology for the $6.5 million 159th Avenue Vault project, 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.

Before we can get started on the design of these projects, we need to collect some information. You may have already noticed some crews marking utilities and areas to be surveyed. Over the coming months, we will continue to conduct preliminary survey work in the Tosh Creek Watershed. You may see crews near project sites taking measurements and photos, placing small markers to identify survey and testing points and collecting various data. Crews will not enter private property without prior authorization.

You may have noticed markings left by our survey crew on some of the trees around Onyx Pond and some other locations. The surveyors leave ribbons to indicate that they have identified the location of the tree in their maps. Some of the trees may be marked with paint, indicating that the tree may be removed at some point in the next few years. Some trees conflict with locations where we will make improvements to or perform maintenance activities on the pond. These actions, which may result in tree removal, are important for the Onyx Pond flood control structure to help reduce flooding on private properties during large storms.

Future fieldwork efforts may be more visible and require larger equipment. For example, in August, we plan to conduct geotechnical investigations. This requires the use of a large drill rig. In some areas, part of the street may be closed to accommodate the drill rig.

We will continue to keep you informed as our work progresses, both during this initial fieldwork phase and as we develop the design.

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