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SR 520 - Floating Bridge and Landings: Boater Information

Key resources for drivers and boaters

SR 520 Bridge Information page

More info on WSDOT movable bridges

Updated: April 23, 2015


May 2015: Important restrictions to note for boaters, pedestrians and neighbors participating in opening day activities

This year, both the West Approach Bridge North Project (WABN) and Floating Bridge and Landings Project (FB&L) have construction equipment and large structures on Lake Washington. While construction will not be taking place on Lake Washington on Saturday, May 2, there are certain construction activities and structures that cannot be moved. While you are enjoying Opening Day activities, please stay at least 500 feet away from all construction areas for your own safety.

See below for a map that shows the construction areas to avoid near Opening Day activities on Lake Washington. Please note the restricted parking access that you may have used previously when attending Opening Day. These parking areas are now construction staging areas and are not publicly accessible. If you have any questions on opening day about navigating around construction, please call our 24-hour hotline – (206) 708-4657. 

Click image for printable version (pdf 551 kb).

Construction activities continue near east navigation channel

From mid-February until the weekend of Opening Day of Boating Season festivities, Thursday, April 30, the east navigation channel will be periodically blocked one to two times per week for critical construction activities. Blockages will typically last from 2:30 a.m. to 11 a.m. During this time, marine vessels shorter than 45 feet tall can continue to navigate through the west navigation channel.

Planned, temporary channel blockages*
- 2:30 a.m. to 11 a.m., Friday, April 24
- 6:00 a.m. to 6:00 p.m., Tuesday, April 28
- 5:00 a.m. to 6:00 p.m., Wednesday, April 29

*Please note, dates may change due to the dynamic, weather-dependent nature of construction. This page will be updated as new information becomes available.

SR 520 drawspan closed, east navigation channel open

On the morning of Tuesday, Feb. 17 , construction activities for the new floating bridge permanently blocked the drawspan on the existing SR 520 floating bridge.  

At the same time, the east navigation channel was reopened, allowing boats up to 58 feet tall to navigate around both the existing floating bridge and construction for the new floating bridge. The west navigation channel remains open to vessels up to 45 feet tall. (pdf 954 kb)
The graphic below illustrates the changes to navigation around SR 520 that will be in place beginning on February 17, 2015 through late 2016. (pdf 200 kb)

Boaters, email us to stay informed.

Have questions? Please read through our drawspan obstruction common questions and answers document to learn more.

Important restrictions to note (boats over 58 feet tall)

Vessels more than 58 feet tall will not be able to navigate beyond SR 520 until the existing bridge is removed from Lake Washington, currently planned for late 2016. The new floating bridge will not have a drawspan, but the east navigation channel will be 70 feet tall, the same as the I-90 East Channel Bridge.

Mid-2015: New pontoons installed at west end

The west navigation channel will shift slightly west, to its permanent location. See Section A in the graphic. (pdf 200 kb)

Click image for  printable version.
 (pdf 200 kb)
Representation of nav channel configuration after the drawspan is obstructed.

SR 520 Navigation Channel Restrictions

In April 2014, the new bridge's western-most pontoon was moored in its permanent location, 50 feet north of the existing bridge near Madison Park. The pontoon is located on the west side of the existing 206-foot-wide  channel, reducing the channel width to 120 feet. The narrower channel is marked by traditional red and green buoy channel markers.  This new configuration (pdf 596 kb) will be in place until additional pontoons are joined with Pontoon A.

A new exclusion zone is also active immediately north and south of the pontoon. This off-limits zone is marked by six white buoys and a sign on each end of the pontoon. Please note, the white buoys represent the locations of the anchor lines and it is dangerous to pass between the sign and the buoys.

The east navigation channel under the SR 520 bridge is currently operating with reduced clearance. Navigational clearances are higher on the east side of the channel, but obstructions north of the channel reduce the navigational height to 58 feet. Boats taller than 58 feet should not attempt to navigate through the channel.

If your vessel, mast or other aerial equipment is over 58 feet tall and cannot be lowered please do not attempt to navigate around the floating bridge.

What do drivers need to know ?

On Tuesday, Feb. 17, newly placed pontoons obstructed the drawspan of the existing bridge, permanently blocking marine passage through the bridge opening. While openings will no longer occur for marine traffic, crews will still need to open the drawspan for monthly, late-night maintenance work. High winds may also require an opening to relieve stress on the existing bridge.