Saturday, August 8, 2009
Dating the Elwha Bulge
Hugh Shipman of the Washington Department of Ecology posted to his blog a few days ago a few thoughts on an area of sediment accretion on the east side of Angeles Point. I had first noted the feature last summer during a walk along the beach, but without Hugh's historic perspective I thought little of it. I realized, however, that I might have the photos that would allow us to constrain, at least somewhat, the dates over which this feature started to build.
In 2003, when I started working for the Surfrider Foundation, I started a project designed to monitor the Elwha shoreline with simple digital photography. With the help of a few volunteer pilots, I was able to include oblique aerial photography in the project. I went back through those photos and believe that they constrain the date of initiation of accretion. Its all qualitative, but the beach widens noticeably between June 2005 and June 2006, and photos from January 2006 and March 2006 seem to show some slight widening. I've posted here the photo I collected during the June low tide in 2005 (bottom photo in this case) and the photo from the low tide flight in June 2006. The photos below were collected in March 2006. Compare them to Hugh's photos from July 2009.