Cortez, FL Coastal Erosion Rate
Is the coast eroding 2.5 miles south of Cortez, FL?
2.5 miles south of Cortez, FL, the coast is advancing, not retreating, at a measured 1.02 feet a year, sediment accumulating faster than any erosion USGS recorded here. At that rate, the shoreline has gained roughly 10.2 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 Cortez, FL, rather than showing one arbitrary line. Segment center: 27.43, -82.67. 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 1.02 ft/yr means over time
Holding the 1.02 ft/yr accretion rate 2.5 miles south of Cortez, FL for 25 years would add roughly 26 feet of shoreline, again assuming nothing about the local sediment supply changes.
What backs this reading up
38 transects feed this segment's number; 0% of them individually measured retreat. Uncertainty on this specific number: 0.96 ft/yr either side. This segment ranks 1109 of 1211 measured US coastal segments, ordered from fastest erosion to fastest growth. Source: USGS Open-File Report 2004-1089. Gearhart, OR sits at national rank 1188 for growth (3.67 ft/yr), one reference point among the 1211 scored segments, 2582 miles from here. 2 miles up the coast, Bradenton Beach, FL shows the same lack of a significant trend.
Cortez, FL on the source map: try the Coastal Change Hazards Portal, zoomable well past this page's ~3.5-mile grain.