Port Mansfield, TX Coastal Erosion Rate
What USGS measures 17 miles southeast of Port Mansfield, TX
2.99 feet a year: that is the measured retreat rate USGS's transects show for the coast 17 miles southeast of Port Mansfield, TX, averaged across the full historical record surveyed here. At that rate, the shoreline has lost roughly 29.9 feet over the last decade.
What this reading actually covers
Nothing here is parcel-level. USGS's raw transects run every few hundred feet along the shore; this page averages the ones nearest Port Mansfield, TX into one ~3.5-mile reading rather than picking a single arbitrary line to represent the area. Centered near 26.40°N, 97.24°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 2.99 ft/yr holds for the next 25 years, the coast 17 miles southeast of Port Mansfield, TX would retreat roughly 75 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
Averaging 117 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 ±0.51 ft/yr. This segment ranks 96 of 1211 measured US coastal segments, ordered from fastest erosion to fastest growth. Source: USGS Open-File Report 2004-1089. Sargent, TX sits at national rank 67 for erosion (4.3 ft/yr), one reference point among the 1211 scored segments, 188 miles from here. South Padre Island, TX, 3.3 miles off, is the adjacent measured stretch, reading severe erosion at 3.17 ft/yr.
Port Mansfield, TX on the source map: try the Coastal Change Hazards Portal, zoomable well past this page's ~3.5-mile grain.