Port Mansfield, TX Coastal Erosion Rate
Shoreline change 9.3 miles east of Port Mansfield, TX
9.3 miles east of Port Mansfield, TX: USGS's transects didn't pick up a trend here that beats the survey's own uncertainty. That's the majority case nationally, and for this stretch specifically it means the coast is holding, not that the data failed to find anything.
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 Port Mansfield, TX. Centered near 26.55°N, 97.29°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.
What backs this reading up
This reading comes from 104 individual transects averaged together, 85% of which measured erosion rather than growth. USGS's confidence interval here is ±1.44 ft/yr. Taken at face value, this segment's raw -1.15 ft/yr reading would land it 187 of 1211 nationally - a number worth ignoring, since it's statistical noise rather than a real trend. Source: USGS Open-File Report 2004-1089. Camp Pendleton South, CA sits at national rank 1005 for growth (0.44 ft/yr), one reference point among the 1211 scored segments, 1293 miles from here. 2.8 miles up the coast, Port Mansfield, TX shows 1.53 ft/yr of eroding.
Port Mansfield, TX on the source map: try the Coastal Change Hazards Portal, zoomable well past this page's ~3.5-mile grain.