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SW Cemetery Road Drainage Improvement Project

Work expected to begin in fall 2024

King County will realign the ditch on SW Cemetery Road on Vashon Island to improve drainage and reduce flooding. Photo: Google Maps

Status update

October 25, 2024

Crews will reduce traffic to a single lane on SW Cemetery Road between Beall Rd SW and 87th Ave SW from Mon. Nov. 4th to Fri. Nov. 22nd, from 8 a.m. to 3 p.m. each day for drainage improvement work in the public right of way. No weekend work is scheduled. Flaggers will direct alternating two-way traffic. All vehicles will have access through the work zone and travelers should expect minor traffic delays.

Project overview

When it rains a lot, the south side of SW Cemetery Road between 87th Avenue SW and Beall Road SW/91st Avenue SW on Vashon Island often floods. The water from flooding often extends to private property. This makes it hard for people traveling to and from Maury Island or the Vashon Island North-End Ferry Terminal. To fix this, the county plans to improve the drainage by replacing the old driveway culverts and fixing the roadside ditch. We will move the ditch further from the road and remove some trees that have grown in it. These trees cause problems because their roots, leaves, and branches clog the culverts and block water flow. The project will also add a five-foot-wide gravel shoulder to make it safer for people walking along the road.

View and download a PDF of the project plans here (30 MB)    

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What to expect during construction

  • Some trees will be removed within the county right-of-way, next to the drainage ditch, in September/October 2024.   
  • There will be single-lane restrictions on SW Cemetery Road between 87th Ave. SW and Beall Road SW for eight (8) weeks, starting as soon as October. 
  • Flaggers will direct two-way traffic weekdays from 7:30 a.m. to 4 p.m. daily. 
  • Driveway access will be maintained throughout construction as much as possible. 
 

Project location

The project is located on SW Cemetery Road between Beall Street SW and 87th Avenue SW on Vashon Island. View larger image (900KB)

Existing conditions

Tree roots, overgrown vegetation, and fallen branches along the roadside and in ditches clog the drainage ditch, which can clog drainpipes and lead to flooding. Photo: Google Maps

 

Dense vegetation and tree roots restrict the amount of water that can flow along the ditch and through nearby culverts. Photo: Google Maps

 

The project will move the drainage ditch to remove trees and improve drainage. The ditch will be relocated to its original location at the end of the project. The County will also add a gravel shoulder to improve safety for pedestrians. Photo: Google Maps

Project timeline 

  • Removal of trees in the right-of-way, next to the drainage ditch: Fall 2024
  • Construction begins: As early as October 2024 and as late as early winter 2024. 
  • Construction ends: late fall or early winter 2024
 

Frequently asked questions

The trees should have been removed when they began to grow, but a decision was made at the time to keep them. Their size and proximity to the road prevent a ditch or piped stormwater system from functioning properly. 

Unfortunately, the way the ditch has filled in over time, including the growth of the trees, changed the elevation along the path for the water to flow. This means that in this stretch, the water must flow uphill to reach the drainage pipe. There is too much debris to remove simply by clearing out the drainage ditch or mowing. Our project engineers are confident that this will be a long-term solution to the drainage problem.  


The trees were marked as part of a study by an arborist to determine their size, type, condition, and to determine if it was feasible to preserve the trees while constructing this project. All the trees that were marked were in King County’s right-of-way, not on private property. Marking provides a way for the trees to be accurately identified and does not necessarily mean they will be removed. 
Yes, the plans for the project are available for PDF download in the project overview section of this website.  

King County Road Services is working to keep neighbors up to date. We will do the following before and during construction:

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