Sunday, October 17, 2010

Jetty Island

Saturday afternoon I took the kayak up to Everett and paddled across to Jetty Island. In the summer, the City runs a ferry over to the island and the main beach on the west side fills up with people enjoying the warm (relatively) water flooding in over the broad sand flats, but on this trip I had the whole place to myself.

The tide was high, so there wasn't much beach to walk on (and the upland portion of the island, at least the north end, is North America's densest thicket of Himalayan blackberry). I walked up to the northeastern tip of the island,
which was littered with remnants of old structures and lots of big wood, washed down the river and stranded on the beach. Then I wandered back to the main beach, the spit, and the lagoon.

Everett is located just south of the mouth of the Snohomish River (as was the historic Tulalip community of Hibulb, long before Everett Colby's father founded the city). The shallow subtidal foredelta of the river extends out into Port Gardner, making deep water access difficult, so a century ago, a jetty (training structure or breakwater?) was constructed to channel the main stem of the river southward along the waterfront (see the aerial photo linked to the title of this post). Dredged sand was placed on the western side of this structure and gradually a new island was built. In 1989, the Port of Everett used the dredged material to create an artificial berm - basically a spit, that in turn formed a large tidal lagoon.

Jetty Island is a Puget Sound anomaly. It is all sand, river sand, unlike most of our gravelly beaches, which get their sediment from eroding bluffs and small, steep streams. It is completely artificial - this entire area was shallow sand flats historically. And it is the largest beach nourishment project on the Sound and the only one built from dredged river sand. It is a frequently cited example (particularly by the Corps) of beneficial use (of dredged sediment).

Some folks note that the ecological picture painted at Jetty Island isn't really true restoration (they're right). Others seem more put off by the blackberries and invasive species than they are impressed by the salt marsh and the birds. And some people are just leery of pretty much everything the Corps of Engineers does (not an unwarranted skepticism). But ultimately, this is a pretty neat place. Maybe they ought to build something like this outboard of the Shilshole breakwater or along a section of the railroad grade!

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