Mastic Beach, NY Coastal Erosion Rate
What USGS measures 2.1 miles east of Mastic Beach, NY
The coast 2.1 miles east of Mastic Beach, NY has been retreating at a measured 1.06 feet a year, USGS's own long-term rate for this stretch, built from historical shoreline positions rather than a single survey. At that rate, the shoreline has lost roughly 10.6 feet over the last decade.
The grain of this number
This is a roughly 3.5-mile stretch of coast, not one address or parcel - USGS's own transects run every few hundred feet, but that's finer than any one property needs, so this page reports the stretch nearest Mastic Beach, NY. Centered near 40.75°N, 72.80°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 1.06 ft/yr holds for the next 25 years, the coast 2.1 miles east of Mastic Beach, NY would retreat roughly 27 more feet, a projection, not a certainty: erosion rates shift with storms, sediment supply and any armoring built in the meantime.
How solid is this number
This reading comes from 92 individual transects averaged together, 100% of which measured erosion rather than growth. The published margin on this reading runs ±0.31 ft/yr. Sorted from fastest erosion to fastest growth across all 1211 measured segments nationally, this one lands at 191. Source: USGS Open-File Report 2010-1119. Lompoc, CA sits at national rank 404 for erosion (0.3 ft/yr), one reference point among the 1211 scored segments, 2614 miles from here. West Hampton Dunes, NY, 2.7 miles off, is the adjacent measured stretch, reading slight erosion at 0.6 ft/yr.
Not this whole stretch, just Mastic Beach itself: the Coastal Change Hazards Portal is USGS's own live version of this data.