Apalachicola, FL Coastal Erosion Rate
What USGS measures 9.6 miles southwest of Apalachicola, FL
9.6 miles southwest of Apalachicola, FL: USGS's transects didn't pick up a trend here that beats the survey's own uncertainty. That's the majority case nationally, and for this stretch specifically it means the coast is holding, not that the data failed to find anything.
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 Apalachicola, FL. Centered near 29.66°N, 85.14°W. USGS's Gulf of Mexico assessment last surveyed this stretch through 2001, 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.
Where this fits nationally
This reading comes from 78 individual transects averaged together, 42% of which measured erosion rather than growth. The published margin on this reading runs ±2.44 ft/yr. Taken at face value, this segment's raw 0.24 ft/yr reading would land it 943 of 1211 nationally - a number worth ignoring, since it's statistical noise rather than a real trend. Source: USGS Open-File Report 2004-1089. For scale: Dillon Beach, CA, 2230 miles away, ranks 1029 of 1211 nationally for growth, 0.53 ft/yr. Apalachicola, FL, 1.8 miles off, is the adjacent measured stretch, itself no significant trend.
One address near Apalachicola: the Coastal Change Hazards Portal zooms past this stretch to the underlying map.