Captiva, FL Coastal Erosion Rate
What USGS measures 3.6 miles north of Captiva, FL
The coast 3.6 miles north of Captiva, FL has been retreating at a measured 2.08 feet a year, USGS's own long-term rate for this stretch, built from historical shoreline positions rather than a single survey. At that rate, the shoreline has lost roughly 20.8 feet over the last decade.
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 Captiva, FL. Centered near 26.55°N, 82.19°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.
25 years at this rate
If 2.08 ft/yr holds for the next 25 years, the coast 3.6 miles north of Captiva, FL would retreat roughly 52 more feet, a projection, not a certainty: erosion rates shift with storms, sediment supply and any armoring built in the meantime.
What backs this reading up
Averaging 104 separate transects produced this segment's rate, with 100% individually reading as erosion, rather than relying on any single survey line. The published margin on this reading runs ±1.38 ft/yr. Among the 1211 US coastal segments with a measurable trend, this one ranks 129 for erosion, 1 being the fastest-retreating coast in the dataset. Source: USGS Open-File Report 2004-1089. For scale: Matagorda, TX, 846 miles away, ranks 144 of 1211 nationally for erosion, 1.74 ft/yr, 0.8x this stretch's rate. Captiva, FL, 3.1 miles off, is the adjacent measured stretch, itself no significant trend.
Captiva, FL on the source map: try the Coastal Change Hazards Portal, zoomable well past this page's ~3.5-mile grain.