SR 520 Bridge Replacement and HOV Program - Boater information

Updated: July 2018

To receive updates about boating activities and navigation restrictions on Lake Washington, email us at .


Navigation restrictions

All Lake Washington construction restrictions lifted for boaters, canoers and kayakers in 2018 season

Construction of the new West Approach Bridge North (WABN) is complete and construction-zone boater restrictions have been lifted for the 2018 boating season. See the map below for updated parking/water access information.

REMINDER: All boaters should still be vigilant and navigate with care around SR 520 bridges. Safety is our top priority; use appropriate boater etiquette and follow speed and navigation signs near the bridges.

Boat/canoe/kayak restrictions on Lake Washington to resume in next phase of construction

In the next phase of SR 520 construction, scheduled to begin in late 2018, crews will conduct on-lake construction activities near the Montlake shoreline, the Arboretum and Madison Park. Cranes and other waterborne construction equipment will limit water access under SR 520 bridges. The exact boundaries of the construction-zone and in-water boater restrictions will be determined closer to the start of construction. We will provide updates once restriction details are confirmed.

Until then, enjoy the spring and summer months out on Lake Washington!

Canoe/kayak landings in the area are open. We recommend using the launches in the Arboretum or at the University of Washington's Waterfront Activities Center . If you are unsure which boat launch to use, take a look at the map below and/or contact our information line at 206-770-3554.

The map also shows parking access areas.

An aerial view of union bay with the state route 520 highway running through it. Various locations are labeled for parking or water access.
View larger image (pdf, 287 kb)


Floating bridge navigation channels

The east and west navigation channels under the new floating bridge are open.
In future phases of construction, one navigation channel may be blocked periodically for critical construction work. During these blockages, marine vessels should plan to navigate through the unaffected channel (see below for navigational height restrictions). At least one navigation channel will always be open and accessible to boaters. 

A number of graphic that show the state route 520 floating bridge and the eastern and western navigation channels and their heights.
View larger image (pdf, 384 kb)


East navigation channel's clearance under the new SR 520 floating bridge

At the east navigation channel, boaters will see two signs indicating clearance heights. Both signs are gauges posted at the water level to show the clearance for boaters at the current water level. The graphic below shows the east navigation channel's clearance under the new SR 520 floating bridge.

A sign currently is posted on the pontoon located at the west side of the east channel. While this sign is a gauge, as shown below, the 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.

Another sign is posted on the fixed, east approach column along the east side of the channel. The clearance typically is 65 feet at the east end of the channel, so boaters will see that portion of the sign at water level. When water levels lower, the clearance on the east side of the channel may rise to approximately 67 feet. 

A graphic of a bridge over water with two pillars on either side of a navigation channel. Signs on the left pillar show a clearance of 70 feet with signs on the right pillar show a clearance of 65 feet.
East navigation channel height under the new SR 520 floating bridge.
View larger image (pdf, 3.3 mb)


Nautical mile markers

The new SR 520 floating bridge has nautical mile markers to indicate distance for boaters on Lake Washington. The markers are placed on both the north and south sides of the bridge. The graphic linked below shows the layout for the nautical mile markers.

A diagram of the state route 520 floating bridge. On either side of the bridge are markers that signify the location of a nautical mile marker.
View larger image (pdf, 157 kb)


Buoys near SR 520 navigation channels

In fall 2017, in response to concerns from boaters, we changed the buoys near the navigation channels at the ends of the new floating bridge. We replaced the smaller, white buoys with large, bright orange buoys that include reflective elements. (See photo below.)

These buoys indicate the location of shallow, submerged anchor cables that secure the new floating bridge.

Image of new buoys at southwest corner of new SR 520 floating bridge.
New buoys at the southwest corner of the new SR 520 floating bridge. See a high-resolution image on Flickr.


How to stay informed

Want to receive updates regarding SR 520 construction and Lake Washington boater restrictions?

Email us at and asked to be added to the boater-notification list. Notification emails will be on an as-needed basis.