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141st Avenue SW Culvert Replacement Project

Construction is expected to begin on July 7, 2025

Existing culvert pipe at 141st Avenue SW, Vashon Island.

The existing pipe under the road at 141st Ave SW on Vashon Island is old and failing and needs to be replaced.

Status update

June 20, 2025

Construction for this project will require a full road closure and is scheduled to last seven weeks. Work is expected to begin on July 7, 2025.

Please check this website and sign up to receive email notifications about the project by emailing abresslour@kingcounty.gov.

Project overview

Under 141st Avenue SW between SW 216th St and SW 220th St, there is an old and rusted pipe that must be replaced in the ravine. The pipe is getting plugged and doesn't allow water to flow through the culvert as it should. Sections of the pipe have fallen off causing the west side of the road to sink and slope outward.

A new larger diameter longer pipe will replace the existing culvert, and the road will be reconstructed at the pipe crossing. This work requires crews to close a section of road for up to seven weeks.

Close-up view of the existing metal pipe.

A closer look at the existing metal pipe under the road at 141st Ave SW.

To replace the culvert, crews will:

  • Temporarily regrade the road to a lower elevation to allow safe equipment access to the ravine.
  • Excavate to remove the existing road and pipe.
  • Once the pipe is removed and the ground has been stabilized, crews will replace the pipe with a much wider and longer heavy-duty plastic culvert.
  • Crews will then rebuild the road with wider slopes made out of rocks.
  • Next, the road will be lifted and slopes built out of sturdy fabric, rocks, and gravel.
  • Finally, the road will be paved and the road slightly widened by adding a small rock shoulder to both sides.

24/7 Road Helpline contact information

24/7 Road Helpline

Report road maintenance and safety issues in unincorporated King County 24 hours a day at 206-477-8100 or 1-800-527-6237.

Project location map

141st Avenue SW culvert replacement project location map.

Larger view of map (262KB)

The 141st Ave SW Culvert Replacement project is located on a sole access road on the west side of Vashon Island, Washington.

What to expect during construction

  • Work hours: We expect the crew to be on site Monday through Saturday during daytime hours. Occasional Sunday work is possible. Work could begin as early as 7:30 a.m. and last as late as 4 p.m. Occasionally the work could continue later in the day. The road will reopen at night and for a lunch break mid-day.

  • Pedestrian access during work hours: 141st Ave SW between SW 216th St and SW 220th St, will be closed to all vehicles, including emergency responders during work hours. The work area will re-open to thru traffic at least once during the day. There is no detour route. The project team will communicate with residents and first responders about the opening schedule prior to construction. If there is an emergency, crews will be able to open to road to vehicles, but please limit these requests to true emergencies as it could extend the length of the project. It may be possible for neighbors to walk through the construction zone during portions of the project.

  • During construction, travelers can expect a temporarily steeper and unpaved driving surface when the road is open. 

  • Delivery services: US Mail, deliveries, and garbage/recycling may be restricted or unavailable during construction. Residents should arrange to have packages delivered outside of project work hours or to an alternative location.

Project budget and funding sources

The project is funded through the drainage preservation program.

Frequently asked questions

Yes. Eleven trees were removed in February 2025. Four of these trees were already dead. Seven additional trees including four large fir trees were removed to make space for construction.
We are aware of the Vashon Garden Tour and Friday night pre-tour dinner scheduled for June 20th to 22nd, 2025. This conflict is highly unlikely, however, if construction has commenced but is not complete prior to the tour dates, Road Services commits to suspend work to keep the road open. It is possible that the road will be a gravel surface for the weekend.
​
The current metal pipe is 18 inches diameter by 51 feet long. We are replacing it with a heavy-duty plastic pipe that is 24 inches diameter by 80 feet long.

The road will be slightly wider once complete. Crews will add a small rock shoulder to both sides of the new road. The new road will be the same elevation as the existing road. 

Photo of a rock slope on Cunliffe Road SW.

Pictured above, crews built a rock slope on Cunliffe Road SW in 2024 using a similar technique. The project on 141st Ave SW will look similar once complete.

No. The road is too narrow for equipment and crews to maintain an open lane. Crews will open the road to traffic at night and on weekends and at least once during the day for their lunch break.
Road Services investigated and reviewed several options to build a detour route or a bypass road. Ultimately, the ravine and topography of the area made this option too challenging. Crews met with neighbors to discuss and review these options, and additional ideas such as an overland bypass road, but the solution would have been very complicated and costly.
Crews will work quickly to open the road for emergency vehicles but there will be a delay. Residents may request urgent access through the construction area by contacting our on-site crew chiefs in advance. Community members should use their own judgement to manage their personal risk during the road closure. These requests should be used only in true emergencies because they will significantly extend the length of the closure.
When crews are at work, the road will be closed to traffic. However, residents will be able to walk through the work zone during the day. We ask that the community only walks through when necessary, as it will slow the crews work. The road will reopen to traffic and pedestrians at night, on some Sundays, and midday during the lunch break. 
​
Yes. Once new culvert is installed, crew will pave the section of road that was repaired.
King County Road Services is working to keep neighbors up to date. We will do the following before and during construction:

  • Update the project website regularly.

  • Have an online community meeting prior to the project.

  • Provide updates on X/Twitter (@KCroads) and on MyCommute (kingcounty.gov/MyCommute).

  • Send email notices (sign up for Road Alert email notifications).

  • Have a flyer available to people living near the work area with complete construction timeline and closure details.

  • Speak with community groups upon request; please contact abresslour@kingcounty.gov to schedule a meeting or to join the email outreach list.

Photos

Crews standing on asphalted road.

In early December 2024, Crews added new asphalt as a temporary repair until the permanent work is scheduled.

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Roads' plans and reports for unincorporated King County

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