Edgartown, MA Coastal Erosion Rate
Is the coast eroding 2.8 miles south of Edgartown, MA?
2.47 feet a year: that is the measured retreat rate USGS's transects show for the coast 2.8 miles south of Edgartown, MA, averaged across the full historical record surveyed here. At that rate, the shoreline has lost roughly 24.7 feet over the last decade.
The grain of this number
Nothing here is parcel-level. USGS's raw transects run every few hundred feet along the shore; this page averages the ones nearest Edgartown, MA into one ~3.5-mile reading rather than picking a single arbitrary line to represent the area. Centered near 41.35°N, 70.50°W. The survey behind it runs to 2007-2009, in USGS's New England / Mid-Atlantic assessment, using the LRR method. Shoreline surveys aren't repeated every year, so this is the most recent long-term measurement USGS has published for this coast, not a live reading.
25 years at this rate
If 2.47 ft/yr holds for the next 25 years, the coast 2.8 miles south of Edgartown, MA would retreat roughly 62 more feet, a projection, not a certainty: erosion rates shift with storms, sediment supply and any armoring built in the meantime.
What backs this reading up
83 transects feed this segment's number; 100% of them individually measured retreat. USGS's confidence interval here is ±0.61 ft/yr. Sorted from fastest erosion to fastest growth across all 1211 measured segments nationally, this one lands at 110. Source: USGS Open-File Report 2010-1119. Eastpoint, FL sits at national rank 199 for erosion (0.97 ft/yr), one reference point among the 1211 scored segments, 1131 miles from here. 2.2 miles up the coast, Edgartown, MA shows the same lack of a significant trend.
Not this whole stretch, just Edgartown itself: the Coastal Change Hazards Portal is USGS's own live version of this data.