Arboretum Waterfront Trail
The largest remaining wetland in Seattle is located at the Arboretum Waterfront. This unique ½-mile long trail leads you across floating walkways and through a variety of little-seen marsh environments. Marsh and Foster Islands host a variety of both native and nonnative plants in the environment of an urban wildlife sanctuary.
The marsh nature trail allows for observation of plants and animals living together on a water-soaked mat in a completely urban setting. This buoyant mass of vegetation and its cargo of small fauna lie between a busy ship canal and an even busier state highway. The marshlands surrounding Lake Washington have been building since glacial times, some 15,000 years ago. This includes the build-up of the floating mat called Marsh Island. Humans have been altering this marsh for many years by channeling, dredging, filling, burning, and building a freeway through it. When this area was originally logged, a small canal was dug to float logs to Lake Union. Then, in 1916, the Hiram M. Chittenden Locks were constructed, further lowering the lake level by approximately 20 feet. The present configuration of the marsh area dates from that time.
Please stay on the developed trail. The quiet observation of nature in a wildlife sanctuary was the purpose of building the trail. Bicycling, jogging, and dogs are prohibited in order to preserve this fragile environment. Unfortunately, many people either do not see the posted signs at the western and eastern entry points of the trail, or choose to ignore these regulations.
Trail guide brochures that describe the natural features found along this self-guided trail are available at the Washington Park Arboretum Visitor Center or the Seattle Parks Department. Much of the information on this cache page is from this brochure.
The numbered posts along the trail are keyed to interesting informational stops in the trail guide. For this multi-cache, however, the numbered posts do not refer to the trail guide, but will be used to create the coordinates for the final cache location.
Starting coordinates: N 47 38.752 W 122° 17.982
The opening coordinates will lead you to an informational sign at the western entrance of the Arboretum Waterfront Trail, where you'll see post number 1.
Waypoint One: N 47° 38.759 W 122° 17.932
Let the numbered post at this location equal A.
From this vantage point, kayaks and canoes will travel underneath you on their way to and from the Washington Aquatic Center. You're also within view of Highway 520 on its approach to the Evergreen Point Floating Bridge. Early access across Lake Washington was by ferry; now there are two floating bridges. On an average day, over 100,000 vehicles pass along this stretch of Highway 520. The structure offers nesting sites for several species of birds.
Waypoint Two: N 47° 38.760 W 122° 17.851
Let the numbered post at this location equal B.
From this spot along the trail, you should be able to glimpse through the vegetation and see Husky Stadium. It's an interesting experience to see the crowd of human confetti from this angle during a game.
Waypoint Three: N 47° 38.784 W 122° 17.717
Let the numbered post (the one with the arrow) at this location equal CD.
There are several offshoots from the trail that end in viewing platforms. If you follow the arrow on post CD, you'll find a great location to sit and watch the ship canal traffic as it passes by.
Waypoint Four: N 47° 38.783 W 122° 17.544
Let the numbered post at this location equal EF.
It can be entertaining to stroll along the floating walkway, trying to avoid the water that splashes up between the panels. People are sometimes fishing from this location, looking toward Union Bay.
Waypoint Five: N 47° 38.784 W 122° 17.489
Let the numbered post at this location equal GH.
From this elevated platform, you can look back over the marsh trail. Looking north across the boat passage you can see Union Bay with University Village Shopping Center and the building and playing fields that make up the University of Washington's athletic complex. All of these structures are built on fill. If you were standing on this elevated platform in 1890, you would have been under water.
With two short subtraction problems, you'll soon have the coordinates for the final micro container.
H - G = I
F - E - A = J
The final cache location is at N 47° 38.BIJ W 122° 17.DJC
This has been one of my favorite Seattle walks for as long as I can remember. I hope you'll enjoy your exploration of this urban wildlife sanctuary.