North Mercer Island/Enatai sewer upgrade

General project updates

October 20, 2026

Project-wide updates

Mercer Slough Connector Trail reopened

The Mercer Slough Connector Trail reopened on October 20. Construction is ongoing 24 hours a day, 7 days a week, and flaggers are stationed at three locations to guide people walking and biking through the active work area.

Trail users should expect delays of up to 10 minutes while crews move construction vehicles, equipment, and materials.

Please travel slowly and follow all posted signs, traffic control signals, and crew instructions. 

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Construction activity in Mercer Island*

Area 1. North Mercer Pump Station: Crews are continuing restoration work at the North Mercer Pump Station. Expect noise, vibrations, and occasional traffic delays as equipment enters and leaves the site. For more information, please review our May Area 1 notification.

Area 2. North-central Mercer residential streets: Final paving on SE 22nd St, 78th Ave SE, SE 24th Street, and 81st Ave is complete. For more information, check past Area 2 updates.

Area 3. North Mercer Way: no updates.

Area 4. I-90 Trail: The I-90 Trail between 84th Avenue Southeast and Shorewood Drive is open.

Crews have started restoration work on the last closed section of the I-90 trail between Southeast 35th Street/North Mercer Way and Southeast 35th Place/East Mercer Way. Once the remaining pipe work on SE 36th St is complete and the trail is fully paved and restored, this final section of the I-90 trail will reopen. For more information, please review our June Area 6 notification. Trail users should follow the posted detour route during construction:

• Trail detour map between S.E. 35th St and S.E. 35th Pl. This takes trail users on East Mercer Way, Southeast 36th Street, and North Mercer Way, before connecting back to the I-90 Trail. Drivers, please drive slowly and watch for cyclists on the roadway.

For more information, check past Area 4 updates.

Area 5. 90th Pl S.E.: Crews are continuing restoration and testing of the odor control unit in the cul-de-sac at the top of 90th Place Southeast. Crews will return to pave a small area behind the odor control unit during the next permitted paving window, which begins in Mid-March. For more information, check past Area 5 updates.

Area 6. NE Mercer Island:

Fruitland Landing: Crews completed substantial work at the north access point for the 96th Avenue Siphon and are now beginning demobilization. Expect noise while the vacuum truck is in use and short delays when traveling through the area. Demobilization is expected to continue through August. For more information, please review our June Area 6 notification.

S.E. 36th St near City Hall: Crews are now completing the final phase of work for the I‑90 Crossing sewer pipe upgrade at the south access point near Mercer Island City Hall and along the section of the I-90 trail between Southeast 35th Street and Southeast 35th Place. This work includes sidewalk and curb restoration, removal of the temporary pedestrian detour, roadway paving, trail paving, and final landscaping. For more information, please review our September Area 6 notification.

S.E. 35th Pl: Restoration continues on Southeast 35th Place.

For more information, check past Area 6 updates.

Luther Burbank Park: King County’s contractor has moved construction equipment out of the back half of the South Parking Lot at Luther Burbank Park. The full parking lot is open for community use.

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Construction activity in Bellevue*

Area 7. Enatai Beach Park: Beginning as early as October 5, King County’s contractor will begin preparation work to reline the existing pipe along the Bellevue shoreline between Enatai Beach Park and Sweyolocken Boat Launch. The swim beach, boathouse, playground, and dock at Enatai Beach Park will be closed to the public during construction. For more information, check out our October Area 7 notice.

Area 8. Sweyolocken/Mercer Slough: The Mercer Slough Connector Trail has reopened. Construction is active 24 hours a day, 7 days a week, as crews continue sewer pipe relining between Sweyolocken Boat Launch and Enatai Beach Park. Flaggers are stationed at three locations along the trail to direct people walking and biking through the work zone.

Trail users should expect delays of up to 10 minutes when construction vehicles and equipment are moving through the area. Please travel slowly and follow all signs, traffic control devices, and instructions from crews. For more information, check out our October Area 8 notice.

* Construction schedules can change based on factors such as site conditions, weather, and material availability. Please check this website for updates.

Construction status

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This map is updated as construction progresses across north Mercer Island and southwest Bellevue. It shows areas of planned construction, active construction, and post-construction restoration.

If you need this map in another format, please leave a voicemail on the project hotline at 425-305-3578 or call TTY Relay 7-1-1. Reasonable accommodations are available to you for free.

Map current as of February 1, 2025