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As thousands walk new 520, Arboretum begins Loop Trail construction


As thousands from around Seattle visited the new 520 bridge over the weekend — waiting in amazingly long lines so long, officials had to close down the celebration’s shuttle runs early to better handle the crowds already in the middle of Lake Washington — a much, much smaller part of the massive construction project is moving forward to create a new community asset to enjoy the swath of nature preserved at the eastern base of Capitol Hill.

The Washington Park Arboretum has seen plenty of alterations since it was sketched to an Olmstead plan in the 1900s. Now, with $7.8 million in 520 construction mitigation funds from WSDOT, the rambling park/botanic collection is getting an enhancement that has been on the wish list for years: a 12-foot-wide paved path for walkers, wheelchairs, slow bikes, and strollers. The “slow” in “slow bikes” is operable — the path is to improve access to the plant collection and was designed with curves undesirable for your fast bike commute.

Meanwhile, the new 520 — the “longest floating bridge in the world,” they say — is ready to open to traffic later this month. Watch for lots of planned closures of the crossing during the transition. Seattle’s western edge of the project including “a box girder style bridge including a bike and pedestrian path over Portage Bay, redesigned highway lids with a new land bridge, and multimodal connectivity improvements” remains under construction.Loop Trail map

In the Arboretum, starting at the southern end of the Arboretum at 31st and Madison, the 1.2 mile path will proceed along the east side of Lake Washington Blvd. to Arboretum Drive through what is often a swampy valley with puddles. It will connect to the existing paved path to make an accessible, all-weather 2.5-mile loop. Construction has already started, and is scheduled for completion in December 2017.

Electric trams will run tours along the loop to provide additional accessibility. How frequently those tours will happen is to be determined, and “tram” is a somewhat misleading term.The quiet electric vehicles owned and operated by UW Botanic Gardens seat 13—and they’re more like large golf carts.

3. Bridge BImproved accessibility will no doubt bring more people to the Arboretum, a prospect not all current users may welcome. But Seattle’s increasing density means an increased need for recreational opportunities as well as wildlife habitat and urban forests, says Sarah Reichard. She’s the director of the University of Washington Botanic Gardens, which owns and manages the Arboretum’s collection of trees and woody shrubs. Reichard says her department worked closely with Seattle Parks on the design of the trail to balance recreational purpose with environmental concerns. “Our highest priority has always been in maintaining the health of the collection here … The case for moving or removing every individual plant was carefully considered, and those that couldn’t be moved were propagated for reintroduction into the collection.” Reichard thinks that, by opening up areas that are currently inaccessible, the path may actually make the Arboretum feel bigger for some users.

The Loop Trail project involves daylighting parts of Arboretum Creek, which runs underground at some points. Those improvements will give the creek room to rise when there’s a lot of water draining into it, and bridges on the new path will allow park users a closer view. “You’re really going to know where Arboretum Creek is, once we’re done with this work,” says Garrett Farrell, senior capital projects manager for Seattle Parks.

It’s the first phase of what will be salmon-ready enhancements to the jigsaw of springs and hydrology flowing to Lake Washington through the Arboretum. “Right now, are we a salmon-bearing stream? No,” says Farrell. “But the protocols we’re using for this are the same as if we were trying to bring salmon back to Arboretum Creek … In addition, we’ve done work with the team to take the storm drainage off Lake Washington Boulevard—instead of putting it in a pipe and dumping it into the creek, you’ll see the curb opened up and bioswales build to kind of pre-treat that storm water runoff. Everything we’re doing here, and everything that we touch, is setting a stage for what could come in the future.”

Imagine that for an ecotopia. Azalea Walk and spawning salmon at the foot of Capitol Hill.

The park will remain open during construction, and the Japanese Garden will be unaffected. Seattle Parks’ press release says, “We may temporarily close or reroute some trails when work is taking place nearby.” It advises people to email for construction updates.


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13 thoughts on “As thousands walk new 520, Arboretum begins Loop Trail construction

  1. Fantastic! Long time coming. So happy that green spaces were being improved along with the addition of the new bridge.

    Next up: Eastside light rail!

  2. Soon all folk in the Madison Valley and lakeside neighborhoods can enjoy an additional 30 minute commute as a major arterial through the Arboretum and 520 access points are eliminated. The only good news is that we will get to see more of the North Capital Hill and Montlake neighborhoods as we snake our way through the newly created congestion. We cannot blame Amazon for poor planning on the part of SDOT and WSDOT. Does anyone remember when the city side lake Washington neighborhoods lost their on and off ramps while Mercer Island got parks and express lanes? It only added 20 minutes to my I-90 commute. Same stuff, different decade. Let the bashing begin.

    • Someone should block the arboretum on ramp to 520 to beta test how long it takes to get everyone around the neighborhood to 520.

      Wsdot likes to be vague on the plans for the montlake interchange – they still haven’t produced a plan for how the traffic gets across the cut, or what happened to the proposed lids. Come back in 2020 for how they screw up portage bay to i5..

    • Oh no, wealthy people are inconvenienced! How could anyone let this happen?

      Maybe you should try public transportation, biking, or walking, like the rest of us plebes have been forced to do thanks to congestion.

    • Those 520 ramps should never have been built in the first place. Lake Washington Boulevard wasn’t developed to be an arterial. It’s not 100% clear to me what impact this trail will have on the street, but anything that brings it closer to what it was intended sounds good to me. Maybe this will also provide impetus for Boyer and Interlaken to no longer connect to Lake Washington Boulevard… they were even less designed to be arterials.

      For people in Madison Valley, going up to 23rd isn’t that much of a detour. For people east of that, it is a bit of one… I know, having grown up a few blocks southeast of the south end of the Arb. But that is the price paid for living in those neighborhoods. Again, Lake Washington Boulevard was never meant to be a thoroughfare the way it is now.

      The real problem here is 100 years in the past… taking the western half of the Puget Mill tract (the eastern half of which is now Broadmoor) without making provisions for a true arterial was shortsighted. Nothing much can be done about that now. Thank God the R.H. Thomson was shot down in the ’70s… that would make it a straight shot to drive from where you are, although I’m not sure your commute time would actually be much better.

      I wish I could remember the history, but wasn’t it the neighborhood itself that didn’t want auto traffic exiting I-90 east of Rainier?

  3. You missed out the utterly disastrous shuttle bus service off the bridge – 2 hour wait for a 10min journey. Go wsdot !

    • There was no wait if you would have just walked to the eastside end of the bridge and caught the shuttle there.

    • Yes – I finally escape by getting on at the other end. I could walk that far.

      Pity the old or young trapped in a 2hr line… that bus then headed down the bridge again after you delayed it and jumped ahead of the other 2000 people..

    • Oh the humanity!

      BTW, you and I both hopped on at a designated pick-up point, no “jumping ahead” on our part.

  4. ““Our highest priority has always been in maintaining the health of the collection here”

    as 130 trees of diameter 6 inches or more come down for another path.

    • I agree, this is a major move away from the mission of the Arboretum. The beauty of this park was its former focus on trees and plants. Also, there is already a paved road that is closed to cars that covers most of the length of the park. It is perfect for walkers and cyclists as it is wide enough to safety accommodate both. This new project seems unnecessary, and the removal of several large trees is always a negative.