Lake Union Park Subsidence Repair

Updated: April 4, 2017


Seattle Parks and Recreation closed the Lake Union Park Bridge in late October 2014. Visitors to the park will need to access the opposite side of the park by following the pathway to the south and around the small inlet.

The closure is necessary because the east concrete abutment for the bridge has moved laterally, resulting in a loss of camber for the bridge. Hart Crowser, Geotechnical Consultant, has completed a geotechnical assessment of the area to determine the reasons behind the lateral movement and has developed corrective measures. The following recommendations are going to be developed further by an engineer with subsequent design documents illustrating these fixes for bidding and construction.

A design remedy has been achieved that will alleviate settlement that has occurred on the Park Site.  The project will remove and repair specific site elements and lighten soil loads by using geofoam to minimize future settlements.  Work includes:  

  • Removal of existing soil and installation of lightweight geofoam under hardscapes (walkways) along the western portion of the park 'peninsula' (west of MOHAI) to reduce load.
  • Bridge abutment will be modified to allow for continued use of the existing abutment while allowing for possible lateral deformation of the abutment in the future. 
  • A portion of the Boardwalk between the bridge and the bulkhead will be repaired. 
  • Once the lightweight geofoam is placed and abutment is modified all hardscapes will be reinstalled. 

Thank you for your cooperation and patience.


Lake Union Park, 860 Terry Ave N, 98109

Budget & Schedule

See the budget and schedule for this project on our Open Budget website

Project Description

This project, funded with 2008 Parks Levy funds redirected from the Seattle Asian Art Museum renovation project, investigates and repairs subsidence issues in walkway areas at Lake Union Park, along the north side of the park adjacent to the water, and east and north of the pedestrian bridge on the west side of the park. Temporary repairs have been made to eliminate tripping hazards, but this project constructs a long term solution to ensure safe and accessible walkways.