Port St. Joe, FL Coastal Erosion Rate
Shoreline change 8.6 miles southeast of Port St. Joe, FL
Unusual good news for this stretch: the shoreline 8.6 miles southeast of Port St. Joe, FL has grown by a measured 0.73 feet a year on average, per USGS's long-term transect data for this section. At that rate, the shoreline has gained roughly 7.3 feet over the last decade.
The grain of this number
USGS surveys the coast in transects spaced a few hundred feet apart; this page groups the nearest ones into a single ~3.5-mile reading for the stretch closest to Port St. Joe, FL, rather than showing one arbitrary line. Segment center: 29.70, -85.25. 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.
What 0.73 ft/yr means over time
Holding the 0.73 ft/yr accretion rate 8.6 miles southeast of Port St. Joe, FL for 25 years would add roughly 18 feet of shoreline, again assuming nothing about the local sediment supply changes.
What backs this reading up
This reading comes from 95 individual transects averaged together, 0% of which measured erosion rather than growth. Uncertainty on this specific number: 0.66 ft/yr either side. This segment ranks 1067 of 1211 measured US coastal segments, ordered from fastest erosion to fastest growth. Source: USGS Open-File Report 2004-1089. Rank 1125 nationally for growth belongs to Coronado, CA, 1890 miles from this stretch, measured at 1.22 ft/yr, 1.7x this stretch's rate. 3.1 miles up the coast, Port St. Joe, FL shows the same lack of a significant trend.
Not this whole stretch, just Port St. Joe itself: the Coastal Change Hazards Portal is USGS's own live version of this data.