Jamaica Beach, TX Coastal Erosion Rate
Is the coast eroding 12.1 miles southwest of Jamaica Beach, TX?
USGS's shoreline-change data puts this stretch, 12.1 miles southwest of Jamaica Beach, TX, at 2.72 feet of erosion a year on average, a long-term rate for this specific ~3.5-mile section, not one storm's damage. At that rate, the shoreline has lost roughly 27.2 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 Jamaica Beach, TX, rather than showing one arbitrary line. Segment center: 29.09, -95.14. 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 2.72 ft/yr means over time
Run 12.1 miles southwest of Jamaica Beach, TX's 2.72 ft/yr rate forward 25 years and it implies about 68 feet of further retreat, assuming nothing changes, which is exactly the assumption a seawall or nourishment project exists to break.
What backs this reading up
This reading comes from 46 individual transects averaged together, 70% of which measured erosion rather than growth. The published margin on this reading runs ±2.34 ft/yr. Among the 1211 US coastal segments with a measurable trend, this one ranks 100 for erosion, 1 being the fastest-retreating coast in the dataset. Source: USGS Open-File Report 2004-1089. Rank 88 nationally for erosion belongs to Port O'Connor, TX, 87 miles from this stretch, measured at 3.29 ft/yr, 1.2x this stretch's rate. 1.9 miles up the coast, Surfside Beach, TX shows the same lack of a significant trend.
Not this whole stretch, just Jamaica Beach itself: the Coastal Change Hazards Portal is USGS's own live version of this data.