Sunday, October 27, 2013

Building beaches in Puget Sound

Boulevard Park's new beach

The notion of putting beaches back together in circumstances where they have been lost (either due to erosion, armoring, or filling of intertidal habitat) is not a new one. There are countless case studies on-line describing some truly giant beach nourishment projects, and the Program for the Study of the Developed Shoreline at Western Caroline University maintains a nice interactive database of projects in the U.S. One thing that is notable from this database, though, is that beach nourishment on the west coast, and in Washington in particular, is still a relatively rare and small-scale thing...not absent, but not utilized here at the scale that it has been applied elsewhere - particularly on the east and Gulf coasts. As Hugh Shipman notes, though, we are seeing more and more of these sorts of "beach building" projects in our area...and with the increasing emphasis on coastal restoration, combined with the pressure that communities are going to face in the coming decades due to sea level rise, it is likely that we will see many more.

This weekend I had the chance to check out the newly engineered beach in Boulevard Park in Bellingham Bay. This is a popular and heavily used park in Bellingham, with a shoreline that had been composed primarily of various sorts of rock, concrete, tires and piling to protect the shoreline. Designed by Coastal Geologic Services, the new beach is clearly designed to stay in place while providing new aesthetic, recreational and, possibly, ecological value to a highly altered shoreline. Anyhow, here is the site as it looks now:

I was definitely struck by how popular this little section of new beach was, despite being composed of a fairly coarse substrate. It has a small groin to the north to, I presume, trap sediment in transport due to the powerful south winds that sweep into Bellingham Bay in the winter. One process that was definitely in play when I visited - strong offshore transport of sediment due to numerous rock throwers...the grain size utilized is the perfect throwing size!

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