Bon Secour, AL Coastal Erosion Rate
Is the coast eroding 11.7 miles southwest of Bon Secour, AL?
0.39 feet a year: that is the measured retreat rate USGS's transects show for the coast 11.7 miles southwest of Bon Secour, AL, averaged across the full historical record surveyed here. At that rate, the shoreline has lost roughly 3.9 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 Bon Secour, AL into one ~3.5-mile reading rather than picking a single arbitrary line to represent the area. Centered near 30.24°N, 87.90°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 0.39 ft/yr holds for the next 25 years, the coast 11.7 miles southwest of Bon Secour, AL would retreat roughly 10 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 95 individual transects averaged together, 92% of which measured erosion rather than growth. USGS's confidence interval here is ±0.37 ft/yr. Among the 1211 US coastal segments with a measurable trend, this one ranks 356 for erosion, 1 being the fastest-retreating coast in the dataset. Source: USGS Open-File Report 2004-1089. For scale: Half Moon Bay, CA, 2031 miles away, ranks 372 of 1211 nationally for erosion, 0.36 ft/yr, 0.9x this stretch's rate. Gulf Shores, AL, 3 miles off, is the adjacent measured stretch, itself no significant trend.
One address near Bon Secour: the Coastal Change Hazards Portal zooms past this stretch to the underlying map.