Updated: Nov. 5, 2015
The east and west navigation channels will be periodically blocked for critical construction activities. During these blockages, marine vessels should plan to navigate through the unaffected channel.
Planned, temporary channel blockages*
- The east navigation channel will be partially obstructed 7 a.m. to 5 p.m., Nov. 1 - Dec. 30, with the exception of Nov. 9 - 20 (see below). Marine vessels shorter than 43 feet can navigate through the west navigation channel during this time. Vessels greater than 43 feet should contact tugboat Big Eagle on Channel 16 to have the obstruction temporarily cleared to allow for safe passage.
- The east navigation channel will be partially obstructed for 24 hours a day, Nov. 9 - 20. Marine vessels shorter than 43 feet can navigate through the west navigation channel during this time. Vessels greater than 43 feet should contact tugboat Big Eagle on Channel 16 to have the obstruction temporarily cleared to allow for safe passage.
*Please note, dates may change due to the dynamic, weather-dependent nature of construction. This page will be updated as new information becomes available.
West navigation channel moves to temporary location
Boaters should note new width on north side of west side navigation channel
On Friday, October 23, crews moved channel markers at the northern portion of the west navigation channel to accommodate construction activities for the West Approach Bridge North (WABN) project. The movement of these buoys narrowed the channel by approximately 40 feet. See Section A in the below graphic. (pdf 2.5 mb)
In consultation with the U.S. Coast Guard, the new temporary west navigation channel will include a maximum navigable height of 43 feet and minimum channel width of 96 feet.
Marine vessels over 43 feet tall will still be able to use the east navigation channel, which currently has a reduced navigational height clearance of 58 feet.
Click image for printable version. (pdf 2.5 mb)
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.
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 above illustrates the changes to navigation around SR 520 that will be in place beginning 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.
SR 520 Navigation Channel Restrictions
An exclusion zone is also active immediately north and south of the western-most 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.
Also, please note that the U.S. Coast Guard has established a temporary safety zone around the east span of the SR 520 floating bridge through the end of December 2015. During this time, boaters are prohibited from entering all waters within 100 yards of the east span, unless within the navigation channel. This zone is in place to protect boaters and bridge crews while construction barges are located in the navigation channel under the east span of the bridge.
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.