Edgartown, MA Coastal Erosion Rate
Is the coast eroding 3 miles southwest of Edgartown, MA?
USGS's shoreline-change data puts this stretch, 3 miles southwest of Edgartown, MA, at 2.21 feet of erosion a year on average, a long-term rate for this specific ~3.5-mile section, not one storm's damage. At that rate, the shoreline has lost roughly 22.1 feet over the last decade.
What this reading actually covers
USGS surveys the coast in transects spaced a few hundred feet apart; this page groups the nearest ones into a single ~3.5-mile reading for the stretch closest to Edgartown, MA, rather than showing one arbitrary line. Segment center: 41.35, -70.55. USGS's New England / Mid-Atlantic assessment last surveyed this stretch through 2007-2009, computing the rate with its LRR method. Other US regions were surveyed in different years, sometimes decades apart, so this page states its own rather than implying one national vintage.
What 2.21 ft/yr means over time
Run 3 miles southwest of Edgartown, MA's 2.21 ft/yr rate forward 25 years and it implies about 55 feet of further retreat, assuming nothing changes, which is exactly the assumption a seawall or nourishment project exists to break.
Where this fits nationally
Averaging 81 separate transects produced this segment's rate, with 100% individually reading as erosion, rather than relying on any single survey line. Uncertainty on this specific number: 0.51 ft/yr either side. Sorted from fastest erosion to fastest growth across all 1211 measured segments nationally, this one lands at 122. Source: USGS Open-File Report 2010-1119. Davenport, CA sits at national rank 434 for erosion (0.26 ft/yr), one reference point among the 1211 scored segments, 2743 miles from here. 2.6 miles up the coast, Edgartown, MA shows 2.13 ft/yr of eroding.
Not this whole stretch, just Edgartown itself: the Coastal Change Hazards Portal is USGS's own live version of this data.