Dauphin Island, AL Coastal Erosion Rate
Shoreline change 4 miles west of Dauphin Island, AL
The coast 4 miles west of Dauphin Island, AL has been retreating at a measured 2.07 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 20.7 feet over the last decade.
What "Dauphin Island" means on this page
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 Dauphin Island, AL. Centered near 30.25°N, 88.24°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 2.07 ft/yr holds for the next 25 years, the coast 4 miles west of Dauphin Island, AL 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.
How solid is this number
50 transects feed this segment's number; 100% of them individually measured retreat. The published margin on this reading runs ±0.43 ft/yr. Among the 1211 US coastal segments with a measurable trend, this one ranks 131 for erosion, 1 being the fastest-retreating coast in the dataset. Source: USGS Open-File Report 2004-1089. For scale: Port St. Joe, FL, 177 miles away, ranks 147 of 1211 nationally for erosion, 1.72 ft/yr, 0.8x this stretch's rate. 2.3 miles up the coast, Dauphin Island, AL shows 2.67 ft/yr of eroding.
Not this whole stretch, just Dauphin Island itself: the Coastal Change Hazards Portal is USGS's own live version of this data.