Bayport, NY Coastal Erosion Rate
Is the coast eroding 4.8 miles south of Bayport, NY?
Unusual good news for this stretch: the shoreline 4.8 miles south of Bayport, NY has grown by a measured 0.83 feet a year on average, per USGS's long-term transect data for this section. At that rate, the shoreline has gained roughly 8.3 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 Bayport, NY. Centered near 40.68°N, 73.03°W. 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.
25 years at this rate
Holding the 0.83 ft/yr accretion rate 4.8 miles south of Bayport, NY for 25 years would add roughly 21 feet of shoreline, again assuming nothing about the local sediment supply changes.
Where this fits nationally
Averaging 36 separate transects produced this segment's rate, with 0% individually reading as erosion, rather than relying on any single survey line. Uncertainty on this specific number: 0.5 ft/yr either side. Sorted from fastest erosion to fastest growth across all 1211 measured segments nationally, this one lands at 1083. Source: USGS Open-File Report 2010-1119. For scale: Rockaway Beach, OR, 2545 miles away, ranks 1120 of 1211 nationally for growth, 1.15 ft/yr, 1.4x this stretch's rate. 1.4 miles away, West Sayville, NY is the nearest other measured stretch: slight accretion (beach growing) at 0.66 ft/yr.
Bayport, NY on the source map: try the Coastal Change Hazards Portal, zoomable well past this page's ~3.5-mile grain.