Tuesday, June 9, 2015

Back out to the Spit

The view from the end of Dungeness Spit

For the third year I was able to arrange with the US Fish and Wildlife Service to collect beach morphology data on Dungeness Spit for my shoreline monitoring program. This is such a special survey to me - its the most difficult logistically, but provides a chance to collect some data on what is really a spectacular coastal feature:

A view of the lighthouse from the end of the Spit, with the Olympics in the background.

Spits are really such important coastal features. In the case of Dungeness Spit it creates a very unique and productive shallow water habitat in its lee. And its "sister", Ediz Hook, creates what many argue is the best harbor in the region. In my view, we simply need to do a better job at understanding what makes these sorts of coastal features work. One surprise, at least based off looking at the preliminary data, is that the end of the Spit appears to have retreated a bit, at least over the last few years:

Again, these data are very preliminary, and just one profile doesn't tell the whole story...but given the average rates of growth reported by Maury Schwartz this is an interesting finding. Part of the story could be related to the migration of the top of the Spit, but it clearly is a complicated story. These profiles cutting through the bulge at the end of the spit for example, suggest the possibility (again, using the caveat that just one set of profiles per year doesn't a convincing story make) that erosion on the seaward side of the spit was associated with accretion on the landward side between 2012-2014:

But that pattern didn't hold up in 2015.

More to come - I will head out to finish the long skinny part of the Spit later this month or next, and then hopefully continue annual surveys for at least another two years.

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