Updated: March 2, 2015
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)
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 4 a.m. to 10 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*
- 4 a.m. to 10 a.m., Friday, March 6
- 4 a.m. to 10 a.m., Friday, March 13
- 4 a.m. to 10 a.m., Wednesday, March 18
*Please note, dates may change due to the dynamic, weather-dependent nature of construction. This page will be updated as new information becomes available.
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)
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.