Apalachicola, FL Coastal Erosion Rate
Is the coast eroding 8.3 miles south of Apalachicola, FL?
The coast 8.3 miles south of Apalachicola, FL shows no statistically significant trend either way. USGS's transects measured a rate here, but it's smaller than the survey's own margin of error for this stretch, so calling it "eroding" or "growing" would overstate what the data actually shows.
What this reading actually covers
Nothing here is parcel-level. USGS's raw transects run every few hundred feet along the shore; this page averages the ones nearest Apalachicola, FL into one ~3.5-mile reading rather than picking a single arbitrary line to represent the area. Centered near 29.61°N, 85.04°W. 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.
How solid is this number
129 transects feed this segment's number; 53% of them individually measured retreat. USGS's confidence interval here is ±0.77 ft/yr. Taken at face value, this segment's raw -0.77 ft/yr reading would land it 231 of 1211 nationally - a number worth ignoring, since it's statistical noise rather than a real trend. Source: USGS Open-File Report 2004-1089. El Segundo, CA sits at national rank 1114 for growth (1.04 ft/yr), one reference point among the 1211 scored segments, 1975 miles from here. 1.7 miles up the coast, Apalachicola, FL shows 0.98 ft/yr of eroding.
Apalachicola, FL on the source map: try the Coastal Change Hazards Portal, zoomable well past this page's ~3.5-mile grain.