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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.

Map of 8 project areas, starting from the North Mercer Island Pump Station extending eastward to Enatai in Bellevue.

General project updates

September 27, 2024

Project-wide updates

Check out our 2024 newsletter for an overview of this year’s progress and upcoming work. This newsletter is available in English, Español (Spanish), 中文 (Chinese, Simplified), and 正體字 (Chinese, Traditional).

Read the newsletter here to learn more

Crews are working extended Saturday work hours from 7 am to 7 pm in parts of the project area. Check out our June notification for more information.

Construction activity in Mercer Island*

Area 1. North Mercer Pump Station: Crews continue to upgrade the existing pump station. There may be intermittent single-lane traffic near the pump station for deliveries. For more information, check out the June Area 1 notification.

Area 2. North-central Mercer residential streets: Pipe repair work continues on 78th Avenue Southeast, Southeast 24th Street, and 81st Avenue Southeast. Expect periodic, single-lane traffic with flaggers until the work is complete.

Please use caution when traveling through the work area and follow all signage and directions from the crew. For more information, check out the August Area 2 notification.

Area 3. North Mercer Way: Crews installed pipe and paved North Mercer Way in 2023 and installed accessible curb ramps in spring 2024. For more information, check out past Area 3 updates.

Area 4. I-90 Trail: The I-90 trail is closed between Southeast 26th Street and Shorewood Drive for paving and restoration. This section of the trail is expected to reopen in October once paving and restoration are complete. For more information, check out the September Area 4 notification.

The I-90 trail remains closed between Southeast 35th Street and Southeast 35th Place for pipe installation. Trail users should follow posted detour routes:

For more information, check past Area 4 updates.

Area 5. 90th Pl S.E.: Paving on Shorewood Drive and the lower section of 90th Pl S.E. is complete. Crews continue work on the structures in the cul-de-sac at the top of 90th Pl S.E. For more information, check past Area 5 updates.

Area 6. NE Mercer Island:

S.E. 36th St near City Hall:  Utility potholing work on Southeast 36th Street near City Hall as early as September 26. Expect noise and traffic lane shifts in the area. Check out the September Area 6 notice for more details.

Fruitland Landing: Fruitland Landing park is closed while crews upgrade Lift Station 11. Crews are preparing to reline the existing pipe on 97th Ave S.E. north of S.E. 34th St. As early as September 30, crews will finish work on the new pipe installed on 97th Ave S.E. south of S.E. 34th St. Please follow instructions from flaggers and traffic signs when driving through the area.

S.E. 35th Pl: Crews continue to install pipe and structures on S.E. 35th Pl. Most residents will continue to access their homes from the temporary access road off Frontage Road. Paving on S.E. 35th Pl is planned to occur as early as early October. For more information, check out the August Area 6 notification.

I-90 trail: As construction continues on northeast Mercer Island, I-90 trail users should follow posted detour routes off the I-90 bridge trail. This takes trail users on East Mercer Way, Southeast 36th Street, and North Mercer Way. Trail users will then be able to connect back onto the I-90 trail. Drivers, please drive slowly and watch for cyclists on the roadway.

Mercer Island Boat Launch: Crews restored the Mercer Island shoreline in spring 2024. Construction equipment moved out of the parking lot in June 2024, and the parking lot is fully reopen for public use.

For more information, check past Area 6 updates.

Luther Burbank Park: Construction equipment moved out of the South Parking Lot on May 15. This parking lot is now fully reopen for public use.


Construction activity in Bellevue*

Area 7. Enatai Beach Park/Lake Washington’s East Channel: Crews began restoring the shoreline along Enatai Beach Park under the I-90 bridge in late July. Crews continue to work on pipes and structures near the swim beach and under the I-90 bridge. For more information, check out the July Area 7 notification.

The intersection at 108th Ave S.E. and S.E. 34th St is closed for final paving. Expect flaggers, single-lane traffic, and detours in this area through September. Please drive carefully and follow all signage and instructions from crews when traveling through the area. For more information, check out the September Area 7 notification.

Area 8. Sweyolocken/Mercer Slough: The Sweyolocken boat launch and Mercer Slough connector trail is open for community use. Crews will begin restoration activities starting as early as September 23. This includes paving the parking lot and road near the boat launch. During this time, vehicles accessing the boat launch will need to park further up the road. The trail is expected to remain open during paving and restoration activities. For more information, check out the September Area 8 notification.

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

Construction status

Click for larger view.

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 September 1, 2024

Previous general project updates

Project location

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