Wednesday, March 11, 2009

Marrowstone Point

In previous years, we've brought this class to Kala Point, but this year we shifted things around and headed to Marrowstone Island and Fort Flagler instead. Marrowstone Point is a cuspate foreland at the northeastern tip of the island, fed by sediment from the eastern shore of the island and a short stretch of bluffs on the north. The north side has been turned into a dike and armored with riprap, the better to protect the point from whatever it is that it didn't need protection from for the previous two thousand years (and pretty much eliminating the high tide beach and the backshore). Right at the base of the point, where the bluff starts to rise, there's a big glacial boulder eroding out of the till, along with an old military pillbox or something of that sort. Someting to measure future erosion against.

The bluffs northwest of the point have been impressively collapsing for the last three years, dumping sandy sediment onto the beach (the pictures of the bluffs this trip were really dark, but there's a nice slightly outdated one at Fort Flagler, May, 2006) . I don't know of another 1/4 mile stretch of shoreline in the Sound where this much erosion has happened so quickly.
Locals report a significant loss of kelp, which the heavy sediment loading might help explain, but the kelp started disappearing long before this recent episode of mass-wasting and has been disappearing in other places where erosion isn't a clear culprit. There's so much that we don't understand about this system!

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