Wednesday, January 27, 2010

Warm Beach

The Warm Beach Conference Center is perched on the bluff overlooking the north end of Port Susan and has great views out over the Stilliguamish Delta.

I walked down the hill at lunch to find the beach largely underwater. I'll come back someday when the tide is lower. This is where the beach - which has rolled along for many miles (including Kayak Point (2007, 2009) and the southern part of Warm Beach) - runs out. Or more accurately, the beach runs into the delta. Littoral drift is to the north, driven by southerly storms and fetch, but the delta is growing southwards as the river continues to pump out ground-up chunks of the western Cascades. The beach likely continued farther northward in the past, but the delta has gradually subsumed it, burying the gravelly beach face in finer sediment and eventually, covering it with marsh.

It looks like the beach here was once a spit with a back-barrier wetland between it and the base of the bluff, but now the backshore is heavily forested and the beach is on its last legs.

The old 1800s maps show the Stilli flowing through its northern distributary past Stanwood, but at some point it was directed (yes, it was pushed) into the more southern Hat Slough and has been building a big fan at its mouth ever since. Since the river is constrained by dikes, all the sediment is dumped in one big pile, instead of being distributed more evenly across the landscape, as it probably was naturally.
The Mississippi has the same problem. Meaningful restoration may eventually require letting the lower river move around.

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