Biddeford, ME Coastal Erosion Rate
Is the coast eroding 2.6 miles southwest of Biddeford, ME?
Good news, and an honest one: USGS's data can't distinguish this stretch, 2.6 miles southwest of Biddeford, ME, from a flat trend. Whatever small movement it measured here is statistical noise, not a reliable direction, so none is claimed.
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 Biddeford, ME, rather than showing one arbitrary line. Segment center: 43.40, -70.41. The survey behind it runs to 2007-2009, in USGS's New England / Mid-Atlantic 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.
How solid is this number
This reading comes from 26 individual transects averaged together, 4% of which measured erosion rather than growth. Uncertainty on this specific number: 0.43 ft/yr either side. The unadjusted figure here, 0.22 ft/yr, would place it 934 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 2010-1119. Kennebunkport, ME sits at national rank 933 for growth (0.22 ft/yr), one reference point among the 1211 scored segments, 5 miles from here. 0.9 miles away, Kennebunkport, ME is the nearest other measured stretch: also no significant trend.
Biddeford, ME on the source map: try the Coastal Change Hazards Portal, zoomable well past this page's ~3.5-mile grain.