Port Mansfield, TX Coastal Erosion Rate
Is the coast eroding 26.5 miles north of Port Mansfield, TX?
Good news, and an honest one: USGS's data can't distinguish this stretch, 26.5 miles north of Port Mansfield, TX, from a flat trend. Whatever small movement it measured here is statistical noise, not a reliable direction, so none is claimed.
What this reading actually covers
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 Port Mansfield, TX, rather than showing one arbitrary line. Segment center: 26.95, -97.40. 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.
Where this fits nationally
This reading comes from 109 individual transects averaged together, 41% of which measured erosion rather than growth. The published margin on this reading runs ±1.02 ft/yr. The unadjusted figure here, 0.19 ft/yr, would place it 918 of 1211 if ranked directly - but an unreliable rank isn't a useful one, which is exactly why "no significant trend" is the headline instead. Source: USGS Open-File Report 2004-1089. Kennebunkport, ME sits at national rank 933 for growth (0.22 ft/yr), one reference point among the 1211 scored segments, 1883 miles from here. Sarita, TX, 3.5 miles off, is the adjacent measured stretch, itself no significant trend.
One address near Port Mansfield: the Coastal Change Hazards Portal zooms past this stretch to the underlying map.