Port St. Joe, FL Coastal Erosion Rate
Shoreline change 7 miles southwest of Port St. Joe, FL
0.77 feet a year: that is the measured retreat rate USGS's transects show for the coast 7 miles southwest of Port St. Joe, FL, averaged across the full historical record surveyed here. At that rate, the shoreline has lost roughly 7.7 feet over the last decade.
The grain of this number
Nothing here is parcel-level. USGS's raw transects run every few hundred feet along the shore; this page averages the ones nearest Port St. Joe, FL into one ~3.5-mile reading rather than picking a single arbitrary line to represent the area. Centered near 29.73°N, 85.37°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.
25 years at this rate
If 0.77 ft/yr holds for the next 25 years, the coast 7 miles southwest of Port St. Joe, FL would retreat roughly 19 more feet, a projection, not a certainty: erosion rates shift with storms, sediment supply and any armoring built in the meantime.
How solid is this number
This reading comes from 33 individual transects averaged together, 100% of which measured erosion rather than growth. The published margin on this reading runs ±0.29 ft/yr. Sorted from fastest erosion to fastest growth across all 1211 measured segments nationally, this one lands at 230. Source: USGS Open-File Report 2004-1089. Rank 395 nationally for erosion belongs to East Quogue, NY, 1051 miles from this stretch, measured at 0.32 ft/yr, 0.4x this stretch's rate. 1.8 miles up the coast, Port St. Joe, FL shows 0.53 ft/yr of eroding.
Not this whole stretch, just Port St. Joe itself: the Coastal Change Hazards Portal is USGS's own live version of this data.