Dewey Beach, DE Coastal Erosion Rate
Shoreline change 0.7 miles northwest of Dewey Beach, DE
Averaged across every transect USGS ran 0.7 miles northwest of Dewey Beach, DE, the shoreline has been moving inland at 0.91 feet a year, a real measured rate, not a regional estimate applied to this stretch. At that rate, the shoreline has lost roughly 9.1 feet over the last decade.
What this reading actually covers
Dewey Beach, DE is the nearest named place, 0.7 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: 38.70, -75.09. Survey years: 2007-2009, method LRR, from USGS's New England / Mid-Atlantic shoreline-change assessment. That's how current the data is here, real, but not a live feed, since a shoreline survey is a major undertaking, not an annual check-in.
What 0.91 ft/yr means over time
Run 0.7 miles northwest of Dewey Beach, DE's 0.91 ft/yr rate forward 25 years and it implies about 23 feet of further retreat, assuming nothing changes, which is exactly the assumption a seawall or nourishment project exists to break.
What backs this reading up
Averaging 112 separate transects produced this segment's rate, with 100% individually reading as erosion, rather than relying on any single survey line. The published margin on this reading runs ±0.58 ft/yr. Sorted from fastest erosion to fastest growth across all 1211 measured segments nationally, this one lands at 210. Source: USGS Open-File Report 2010-1119. Watch Hill, RI sits at national rank 390 for erosion (0.33 ft/yr), one reference point among the 1211 scored segments, 249 miles from here. 3.4 miles away, Henlopen Acres, DE is the nearest other measured stretch: moderate erosion at 2.23 ft/yr.
Dewey Beach, DE on the source map: try the Coastal Change Hazards Portal, zoomable well past this page's ~3.5-mile grain.