Leschi South Marina Wave Attenuator and Facility Improvements

Location

Leschi South Moorage; 100 Lakeside Ave S. 

Map

Budget

$13.2 Million 

Schedule

Upland utility work September 2026 through Winter 2027

• Utilities to be installed will support the new vessel sewage pump station, being constructed during the marine stage of the project, that will enhance the water quality of Lake Washington.
• Harkness Construction, the contractor selected through a competitive bidding process for this stage of the project, will mobilize to site on September 14, 2026. Work is expected to take 3-4 months, depending on the weather.  Some work on Lakeside Ave will occur at night.
  • Seattle Parks and Recreation’s parking lot (approximately 39 public parks parking spaces) will be closed for much of the duration of this work to install electrical, sewer and water utilities. SPR is looking into measures to reduce closure time, considering potential weather-related impacts.  Those potential measures will be communicated once determined.
  • The bus stop on northbound Lakeside Ave, in front of the Bluwater Bistro, will be temporarily re-located north to the end of the block. Street parking will be allowed in this area when it is not part of the work zone. Additional parking spaces for accessible and regular public street parking are under review.  Parking will also be redirected to the Leschi North Marina lot via signage.  This webpage will be updated when parking areas are finalized.
  • Night work dates and times will be communicated once determined, depending on weather and the pace of the work. Night work is currently not expected to occur until the end of October at the earliest.  Work will start in the evening, and the noisiest work activities, such as saw cutting and jackhammering will be performed before 10 PM.  This work is being performed at night to allow for parking and deliveries to occur at the Leschi Market during business hours, and will mostly impact the southbound traffic lane at Lakeside Ave.  Work, as feasible, on the northbound traffic lane will occur during the day.
  • Required curb ramp construction will occur during the day.
  • Stakeholders will be updated periodically.

Marine Construction September 2026 through Spring 2027

• Manson Construction, the contractor selected for this stage of the project through a competitive bidding process, will mobilize to site in late September/Early October to remove large debris, that were too large for the dive team contracted for earlier cleanup work, from under Leschi South Marina. No community impacts anticipated.
• Off-Site Fabrication of floats, piles and gangways will start in September 2026.
• Manson will return to site in December 2026 to begin demolition of the existing pier and begin construction of the new floating breakwater/moorage and sewage pump station facility. Construction is expected to last until Spring 2027.  Minor community impacts are expected: the area adjacent to construction in the SPR parking lot will be closed for safety reasons.  Noise impacts will be limited to daylight hours.

Project Need

The existing timber dock, supported by creosote treated piles, is nearing the end of its useful life. Creosote is bad for the environment and should be removed whenever possible. In addition, the pipe pile breakwater does not protect the marina from wave action. There is also no public transient moorage or boat sewage pump out in this part of Lake Washington. The existing dock is not accessible to all ages and abilities.

Project Benefit

Removing creosote from the water will benefit the aquatic ecosystem. Providing a sewage pump out facility will help keep Lake Washington clean. The new breakwater will protect the marina from damage due to wind and wave action. The moorage facility will allow the boating community to dock at this location. Public access, including some seating, will also be provided.

Community Participation

Community input is ongoing. Please contact Stephen.Levengood@Seattle.Gov with any questions or concerns regarding this project.