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SR 520 - Floating Bridge and Landings Project: Boater Information

Key resources for drivers and boaters

SR 520 Bridge Information page

More info on WSDOT movable bridges

Updated: September 7, 2016


Construction activities continue near SR 520

Due to the volume of construction activities taking place near the floating bridge and near the new West Approach Bridge North, boaters should be vigilant and boat with care. Using appropriate boater etiquette and following speed limits near construction activities will keep both boaters and construction crews safe. 

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 (see below for navigational height restrictions). 

To receive updates about upcoming blockages of the navigation channels, email us.

Decommissioning update

The pontoons from the old floating bridge will continue to float out through the Hiram M. Chittenden Locks for the remainder of the year. There are also a variety of other decommissioning activities happening in and around the SR 520 navigation channels. Please view our factsheet to learn more about some of the upcoming decommissioning activities and what you can expect to see in the water (pdf 1 mb).

East Navigation Channel

There are no east navigation channel closures at this time.

It is important to note that there may be interim closures of the east navigation channel as crews continue to decommission the remainder of the old SR 520 floating bridge.

East navigation channel clearance under the new SR 520 floating bridge

Below you will find graphics that show the east navigation channel clearance under the new SR 520 floating bridge. As you travel through the east navigation channel in the coming weeks, you will see two signs indicating clearance. Both signs are gauges posted at the water level to show the clearance for boaters at the current water level.

The only sign currently posted on the bridge is on the pontoon located at the west side of the channel. While this sign is a gauge, as shown below, this sign will always show a clearance of 70 feet at water level since the pontoon rises and falls with changes in water levels on Lake Washington.

In the next few weeks, a sign will be posted on the fixed, east approach column at the east side of the channel. The clearance is currently 65 feet at the east end of the channel so boaters will see that portion of the sign at water level. As water levels lower, the clearance on the east side of the channel may rise up to approximately 67 feet. 

East navigation channel gauges

East navigation channel height of the new SR 520 floating bridge. Click on the image above for a larger, printable version (pdf 6.3 mb).

West Navigation Channel

At this time, the west navigation channel is closed and will remain closed through Friday, September 30. Please note that one navigation channel will always be open and accessible to boaters. While the west navigation channel is closed to boaters, the east navigation channel is open.

Closure information
Navigation changes on Lake Washington at SR 520. Click image for printable version (pdf 3.2 mb).  



SR 520 navigation channel restrictions

An exclusion zone is 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.

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 2016. 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.