Boothville, LA Coastal Erosion Rate
What USGS measures 48.9 miles northeast of Boothville, LA
Averaged across every transect USGS ran 48.9 miles northeast of Boothville, LA, the shoreline has been moving inland at 6.36 feet a year, a real measured rate, not a regional estimate applied to this stretch. At that rate, the shoreline has lost roughly 63.6 feet over the last decade.
What this reading actually covers
Boothville, LA is the nearest named place, 48.9 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: 29.85, -88.85. The survey behind it runs to 2001, in USGS's Gulf of Mexico 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.
What 6.36 ft/yr means over time
Run 48.9 miles northeast of Boothville, LA's 6.36 ft/yr rate forward 25 years and it implies about 159 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
This reading comes from 110 individual transects averaged together, 100% of which measured erosion rather than growth. Uncertainty on this specific number: 1.6 ft/yr either side. Sorted from fastest erosion to fastest growth across all 1211 measured segments nationally, this one lands at 40. Source: USGS Open-File Report 2004-1089. For scale: Edgartown, MA, 1297 miles away, ranks 110 of 1211 nationally for erosion, 2.47 ft/yr, 0.4x this stretch's rate. 3.4 miles up the coast, Boothville, LA shows 4.47 ft/yr of eroding.
Not this whole stretch, just Boothville itself: the Coastal Change Hazards Portal is USGS's own live version of this data.