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Project description 

King County is replacing sewer pipes that serve areas in North Mercer Island, the southwest portion of Bellevue near Enatai Beach Park, and the Town of Beaux Arts Village. This pipeline carries wastewater from the North Mercer Island Pump Station to the Sweyolocken Pump Station in Bellevue. Once installed, the new pipes will provide sewer service for 50 years or more. To learn more about the project overall, including what we are building, construction information, and what to expect, view our StoryMap.

To meet community needs, we broke the project up into 8 project areas, shown on the map. We provide updates about specific areas depending on where work is taking place.


General project updates

February 21, 2024

Project-wide Updates: Crews with unique expertise in underwater construction are placing pipe under the East Channel of Lake Washington. Read the news release and watch the video about this construction activity.

Construction activity in Mercer Island* 

Area 1. North Mercer Pump Station: Work continues at the North Mercer Pump Station. For more details on what to expect over the next few months, check out our recent notification

Area 2. North-central Mercer residential streets: Maintenace hole work was completed at the Pump Station. Check out past updates here.

Area 3. North Mercer Way: Striping and repaving was completed along N. Mercer Way. Click here for past updates. 

Area 4. I-90 Trail: The I-90 trail is closed for pipe installation between Southeast 26th Street and Shorewood Drive and between Southeast 35th Street and Southeast 35th Place. For more information please review our Area 4 recent updates

Click here for the trail detour map between S.E. 26th St and Shorewood Dr.

Click here for trail detour map between S.E. 35th St and S.E. 35th Pl.

Area 5. 90th Pl S.E.: Work continues on structures in the cul-de-sac following paving and restoration. Click here for past updates.

Area 6. NE Mercer Island: I-90 Trail closed between S.E. 35th St and S.E. 35th Pl. Drivers, please be aware of cyclists on E. Mercer Way, S.E. 36th St, and N. Mercer Way during trail detour. In addition, S.E. 35th Pl will be closed to through-traffic for pipe installation starting mid-December. Expect phased detours on S.E. 35th Pl and traffic control measures along Frontage Road. Mercer Island Boat Launch remains open. For more details, check out our recent notification

Frontage Road and the Mercer Island Boat Launch will be closed on Friday 2/9, Saturday 2/10, Saturday 2/17, and Saturday 2/24 from 7 a.m. to 7 p.m. for pipe installation. For more details, check out our recent notification.

As early as February 12, expect trenchless pipe installation along 97th Avenue Southeast for approximately two months. For more details, check out our recent notification.

Pipe installation and structural upgrades are coming to Lift Station 11 at Fruitland Landing and to 97th Avenue Southeast. One day of work with single-lane alternating traffic is planned to take place on February 23 with major activities planned to begin mid-March. For more details, check out our recent notification.

Luther Burbank Park: Construction equipment and material storage coming to South Parking Lot as early as October 2. For more details, see the latest update.


Construction activity in Bellevue*

Area 7. Enatai Beach Park/Lake Washington’s East Channel: In-water work continues on the Mercer Island side of the East Channel. Click here for past updates

Area 8. Sweyolocken/Mercer Slough: Work continues near the Sweyolocken Pump Station and the Mercer Slough Boat Launch. The Mercer Slough connector trail is expected to reopen Spring 2024 with a temporary closure as early as June for repaving. Here is the current Mercer Slough trail detour mapClick here for past updates

Construction status

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Revised December 4, 2023

Previous general project updates

Project location