Friday, April 16, 2010
This year, we wrapped up the beaches class with a trip down to Spencer Spit. We really didn't have enough time to do it justice, given the late hour and the logistics of folks having to catch ferries back to other islands, but still a worthwhile excursion. This place provides eroding bluffs, an elegant barrier beach, and a large salt marsh and lagoon -- all in a county better known for its rocky shorelines!
Spencer Spit reaches for rocky Frost Island, but doesn't quite get there (map view). I guess the tidal currents make it hard to close the gap. On the other hand, tombolos have formed in similar settings where the sediment must have eventually been too much for the currents to keep clear. Maybe it's just a matter of time. I suppose it's a function of the strength of the currents, the volume of sediment being delivered, and the bathymetry of the nearby area (which controls the "accommodation space" - the less space, the easier it is to fill it).
The last time I was here was shortly after the February, 2006, storm:
Spencer Spit, March 2006