Friday, August 19, 2016


Pomeroy Park, in downtown Manchester (not to be confused with the grittier versions in England and New Hampshire), is a nice centerpiece to the small community's waterfront. Which contrasts nicely with the distant Seattle skyline.


I noted this site and the elevated boat ramp several years ago: Manchester: October 2010

Kitsap County recently completed an innovative stormwater project in town and the new outfall was integrated into the base of the pier. This is an interesting design and personally, I like the idea of allowing stormwater (relatively clean stormwater, at least) to run out across the beach much like a natural stream.

This does pose some coastal design issues, though, since the stream can erode sand and gravel on the upper beach and transport it to the lower beach. During heavy flows at low tide, this may result in a channel of sorts and this in turn can lead to localized erosion on adjacent banks. This has been addressed in part with a series of tiered logs backfilled with gravel. Fortunately, this type of erosion can be fairly ephemeral, and as long as there is adequate sediment on the beach, can recover quickly.

Traditionally, one approach to reducing erosion below an outfall would have been to construct an apron of angular rock across the beach. The irony is that this would have protected the beach from erosion by burying it under rock. I'm glad they didn't do that here - or at least if they did, it's below beach grade.

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