Water Mill, NY Coastal Erosion Rate
Is the coast eroding 2.5 miles south of Water Mill, NY?
Nothing alarming measured 2.5 miles south of Water Mill, NY: whatever shift USGS's transects picked up here is too small to call reliably one way or the other, which this site reports as "no significant trend" rather than forcing a direction.
What "Water Mill" means on this page
Water Mill, NY is the nearest named place, 2.5 miles away, to a ~3.5-mile stretch of coast USGS has surveyed - the reading below covers that whole stretch, not a single property in it. Segment center: 40.89, -72.35. 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.
How solid is this number
94 transects feed this segment's number; 100% of them individually measured retreat. The published margin on this reading runs ±0.3 ft/yr. The unadjusted figure here, -0.27 ft/yr, would place it 422 of 1211 if ranked directly - but an unreliable rank isn't a useful one, which is exactly why "no significant trend" is the headline instead. Source: USGS Open-File Report 2010-1119. Rank 1195 nationally for growth belongs to Warrenton, OR, 2565 miles from this stretch, measured at 4.41 ft/yr. 1.7 miles up the coast, Southampton, NY shows the same lack of a significant trend.
Water Mill, NY on the source map: try the Coastal Change Hazards Portal, zoomable well past this page's ~3.5-mile grain.