N Northlake Way Retaining Wall

Retaining wall construction, paving, sidewalk construction

Updated: September 29, 2020

What’s happening now?

We completed alternatives analysis and conceptual design in late 2019 and met with adjacent property owners via an in-person socially distanced session in August 2020, where we shared information about the conceptual project design, funding, the schedule, and the potential impacts of construction.

We are currently working on completing an application for potential funding through a new FEMA program called BRIC (Building Resilient Infrastructure and Communities).  This project may qualify for BRIC funding due to SDOT's plan to address the seismic hazard associated with historic fill and liquifiable soils located adjacent to and beneath the existing wall.

This winter we will solicit qualifications from consultants to perform preliminary design for the wall replacement.

Overview

The 432-ft long Northlake Retaining Wall supports the adjacent N Northlake Way including public utilities and arterial serving northeast Seattle. We estimate that approximately 3,000 vehicles travel this segment of N Northlake Way on an average day and know that wall provides access to multiple private lakeside businesses along Lake Union. 

In 2018, SDOT installed fencing and restricting parking adjacent to the retaining wall restricted parking at the top of the wall to reduce load on the wall.  The existing structure needs repairs to strengthen it and to address significant seismic hazards associated with the historic fill and liquifiable soils located adjacent to and beneath the existing wall.  

Projects of this type and scale provides opportunities to cost-effectively update street designs to promote safety, update and replace aging infrastructure (primarily utilities), and coordinate with other projects. They also provide an opportunity for community engagement to ensure feedback is gathered and incorporated into the final design.

Community Engagement

We will be reaching out to the community to solicit ideas and input for improvements that will serve the traveling public that uses this segment of N Northlake Way corridor.

While public safety remains the primary purpose of the planned wall replacement, this project will also include other measures and features including:

  • Sidewalks
  • Pedestrian safety improvements
  • Drainage improvements
  • Street Parking
  • Paving
  • Utility relocation and replacement

Planning project map

Project Area Map

Planning design concepts

We are currently in the planning phase of this project where we gather information, create concepts, and gather input from stakeholders, business owners and members of the community. As we gather input we will continue to adapt plans and concepts to represent community-informed designs moving forward. 

Based on our 2019 study, our leading concept for wall replacement relies upon significant stabilization and strengthening of soils behind the existing retaining wall using grout columns founded on hard glacial till.  Installation of the ground improvements would require excavation within most of the right of way behind the wall.  Upon completion, these ground improvements, coupled with a replacement cut-off wall along Lake Union would provide a resilient base for replacement of utilities in the right of way and complete streets elements like new sidewalks, parking, travel lanes and other desirable features.

Elevation concept plan

Plan view of potential subsurface work

The elevation and plans above are conceptual and not to scale. 

Schedule

This is our anticipated project timeline for the N Northlake Way retaining wall

Fall 2020 - spring 2021 
Planning

Spring, 2021
Begin design

Summer, 2023
Begin construction (subject to funding)

timeline

The three stages of an SDOT project

  1. Planning
    What we do: Collect data, review plans and gather community experiences to define options.

  2. Design
    What we do: Share updates as more details are known.

  3. Construction
    What we do: Provide construction schedules, expected impacts, and a contact for questions.

Funding

This project originated through SDOT's Retaining Walls program and is now funded for design through a project-specific CIP.  Construction funding has not been secured.

Project Materials

To view a PDF of project-related materials, please click on the links provided below.

Planning Phase

We're committed to building a productive, inclusive, and collaborative relationship with all who live, work, or travel in the project area. Please contact us with any questions.

Phone: 206-375-5636
Email: NorthlakeWall@Seattle.gov

Community Outreach Lead

Darrell Bulmer

Project Manager
Mike Ward

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