Monday, September 20, 2010

Cape Shoalwater or Washaway Beach

Cape Shoalwater is located at the north entrance of Willapa Bay on the southwest coast of Washington. This is a site of very rapid coastal erosion. I found by comparing satellite images from 1990 to 2009 the rate of erosion is impressive. Since the late 1800s the erosion has moved inland over 2 miles. Prior to 1990, thirty homes have been destroyed or moved, a light house, school, cannery and grange halls have been lost and the state highway and a cemetery were moved. In 1995 the State Department of Transportation spent 27 million dollars building a heavy groin and jetty to protect the new highway. 
Red line marks the 1990 coastline

2009 coastline with 1990 coast marked in red

I got a bit confused when I was at the site as I was looking for a sand dune with buried trees. It turns out that nearly the entire dune is now gone. I took a few pictures of the old state highway and erosion features. It is thought that the erosion is caused by a natural channel realignment at the entrance to Willapa Bay from the south to the north and it appears that the erosion may have slowed in the past few years. The erosion is the opposite of the general accretion that is taking place on other areas of the southwest Washington coast.   

The old highway comes to an abrupt end

Fragments of road on beach

View of heavily rocked home site from top of the last part of an eroding dune.

Looking north from eroding dune

Erosion towards homes

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