Sunday, February 08, 2009

Libbey Beach

Libbey Road ends with a quick drop down the bluff to a small park, perhaps built into a small glacial kettle.
And then there is another short drop (a steep 15-20' bluff) down to the beach itself. Many decades ago, a notch was cut into this lower bluff so that a boat ramp could be constructed.
The steep ramp was exposed to big storms coming down the Strait and the northern side was gradually undermined. By the time I first visited this site in the early 1990s, just walking down the ramp was a challenge (even when new, launching a boat would have been difficult)

The old boat ramp trapped the gravel working its way northward along this beach from Partridge Point (0.5 miles south) towards Deception Pass (almost 15 miles north). We often brought field trips here to talk about the effects of groins on shorelines (and bluff erosion rates and the origins of glacial marine drift). The higher beach to the south helped protect the bluff immediately updrift, whereas the beach to the north (down-drift) has eroded, taking the bluff with it.

In the early 2000s, the county replaced the ramp with a new beach access structure. The problem is, once a groin has influenced the topography of the beach and a significant offset has developed in the shoreline, it becomes almost impossible to restore the beach without serious complications. Maintaining the structure would have resulted in the situation continuing to deteriorate. Removing it entirely would have resulted in rapid "catch-up" erosion on the south side.

The compromise was to replace the old structure with a new structure that didn't project quite as far. Which meant that the down-drift erosion continued and the up-drift side began to erode faster. The new structure had a few design and construction shortcomings, so now they've taken another shot at it. Plus, they have extended the huge timber seawall along the south side to meet up with a private bulkhead built in the mid 90s.

One of the frustrating things about trying to fix old mistakes is that sometimes there's no good solution. Better to not make the mistake in the first place. I can think of some other things where that's true, too.

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