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Brent Champaco
Community Relations
This website will be updated as additional information is developed

What is the status of slides on Vashon/Maury Island?




Action Plan


Action Plan

SW Luana Beach Rd. Slide

SW Luana Beach Drive

and 50th Place West

Fall/Winter 2016 –Area will be stabilized and work may be done to establish one-lane access.

Once vehicle access is restored, the site will be monitored.

Sunset Road SW Slide Investigation

Sunset Road SW

at 18911 Sunset Road SW

Fall/winter 2016 – Perform preliminary geotechnical investigation/place instrumentation/monitor conditions.

To Be Determined*
Continuing to monitor.

Westside Highway Slide

Westside Highway

at SW Cove Road

Spring 2016 - Completed temporary repairs.


Fall/Winter 2016/17-Geotechnical drilling and analysis.

Summer/Fall 2017-Develop permanent repair.

Vashon Highway Slide & Structure Demolition

11940 Vashon Highway


Fall 2016 – Temporary erosion control. Evaluating timeline for final site grading and erosion control.

Remaining work- Site restoration.

Manzanita Sloughs

Manzanita Beach Road SW

Continuing to monitor.           

Slough 1:  Repairs complete.
Continuing to monitor.

Slough 2:  To Be Determined*
Continuing to monitor.

*TBD depends on what is observed during monitoring

What caused the slides along SW Luana Beach Drive and Sunset Road SW?

The wet northwest weather, steep slopes, and often soils conditions are the typical factors associated with landslides. The county will often investigate soils conditions through geotechnical soils sampling at specific sites, evaluate any available surface imaging, and look at any historical records to determine slope vulnerability.

What type of repairs can be done?

In some cases, only erosion control and slope monitoring will be necessary. There are a variety of construction techniques that are used to stabilize slopes that may include various types of crib, gabion, or other retaining walls, pilings, anchors or soil nails, slope leveling or excavation. Drainage structures to dewater or to channel water may be used. Each site needs to be evaluated to determine geotechnical factors including slope, soils, ground and surface water flow, available space, and adjacent property conditions to try to determine possible solutions. Average daily traffic, alternative access, and available funds are also considerations in determining project options.

What are some of the tools you use to monitor roadways?

Roads staff conduct geotechnical studies and monitoring, which entails an assessment of a critical site over a specified period of time. Engineers rely on photographs, visual inspections, maintenance records, construction documentation, and geotechnical instrumentation to evaluate whether a site is performing as intended or if adverse conditions are developing that require maintenance or engineering actions.

In some cases, LIDAR imaging or historical records exist that provide information about soils condition or slope stability. LIDAR (light detection and ranging) is an optical remote-sensing technique that uses laser light to densely sample the surface of the earth, producing highly accurate measurements that can reveal critical areas.

Sometimes temporary materials such as erosion control fabric, straw waddles, and/or plastic are used to minimize/control runoff and erosion from further impacting unprotected exposed soils. Vegetative staking and/or seeding are also used to stabilize soils.

How has Roads coordinated project work with emergency response services?

Roads notifies local jurisdictions and all area emergency response and public safety agencies of project activities that may impact responses. When necessary, Roads also notifies local businesses about the closure and coordinates with those most affected to develop signage to help mitigate the impact of any closure or detour.

Why does it take a long time to fix some roads?

Bridge and road projects often involve complex engineering, and may be impacted by geology, critical areas, and weather windows. Many public works projects need to be designed, go through a sometimes multi-agency permitting process, and may then need to be competitively bid for construction. Weather and fish windows may impact the times of year that some work is accomplished.

How are Roads projects prioritized?

The adopted strategic plan for county roads directs that critical safety work is the first priority for the limited funds available. Then, required regulatory work, like clean water work, is prioritized followed by some preservation work. Priorities are outlined in the Roads strategic plan and line of business plans. The county also has a transportation needs report that lists priority capital needs for the bridge and road system, which are, unfortunately, largely unfunded.

What does the county maintain and why isn’t there more funding to address road needs?

King County maintains about 1,500 miles of roads and 181 bridges outside of cities that are not private roads or state highways. More than one million trips are taken on the public roads that connect cities each day – people traveling to work, school, and recreation; businesses and farmers delivering goods and services; and police and fire officials responding to emergencies. People from all parts of the county – and beyond – use them. About half the trips on the high-volume roads originate not only in cities, but in other counties. In addition, the road right-of-way serves as a pathway for water, sewer, storm water, energy, and communication utilities.

Unfortunately, nearly three decades of annexations, declines in gas tax revenues, and the effects of voter initiatives have led to the chronic underfunding of the local bridge and road system, particularly county roads outside of cities. Current funding levels for county roads and bridges are sufficient only to address critical life safety issues and a minor amount of work to preserve some of the existing infrastructure. Improvements necessary to address capacity and mobility issues are currently unfunded.

Without additional resources, it is estimated that the aging of these assets could result in the closure of about 35 bridges as they become unsafe, and approximately 72 miles of failing roadways could be restricted or closed. About 65% of the stormwater system is at risk of failure and more slides and flooding from clogged and aging drainage are expected.

The county has been working for a number of years to try to address the shortfall of funding. Most recently, the county convened a Bridges and Roads Task Force to consider these challenges, and they have issued a final report with their findings. The next steps include working with elected officials, cities and other regional stakeholders to develop detailed solution proposals. More information is available at the Bridges and Roads Task Force webpage.

If I have concerns about a road or bridge on Vashon/Maury Island, who should I contact?

If you observe any road-related issues, you can call the 24/7 Roads Helpline at 206-477-8100, or toll-free at 800-527-6237. These phones are staffed 24 hours a day, 7 days a week.

SW Luana Beach Road now open - crews have restored one lane to travel

SW Luana Beach Road now open
Sept. 23, 2016 - SW Luana Beach Road now open, travel restricted to one lane.

Crews at work on SW Luana Beach Road
Sept. 22 - Crews at work on SW Luana Beach Road.

SW Luana Beach Road

Slide area on Southwest Luana Beach Road looking south along roadway
Slide on SW Luana Beach Road—looking south along the roadway.

Sunset Road SW

Slide on Sunset Road Southwest looking upward at the roadway
Slide on Sunset Road SW—looking upward at the roadway.

Site Condition Assessments

SW Luana Beach Road and Sunset Road SW Slide Areas


Project locations map

Call us:

206-477-8100 or 1-800-527-6237 (1-800-KC-ROADS)


Send us an email.