Santiago, WA Coastal Erosion Rate
What USGS measures 1.5 miles south of Santiago, WA
1.5 miles south of Santiago, WA, the coast is advancing, not retreating, at a measured 1.54 feet a year, sediment accumulating faster than any erosion USGS recorded here. At that rate, the shoreline has gained roughly 15.4 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 Santiago, WA, rather than showing one arbitrary line. Segment center: 47.28, -124.22. USGS's Pacific Northwest assessment last surveyed this stretch through 2002-2011, 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 1.54 ft/yr means over time
Holding the 1.54 ft/yr accretion rate 1.5 miles south of Santiago, WA for 25 years would add roughly 39 feet of shoreline, again assuming nothing about the local sediment supply changes.
What backs this reading up
This reading comes from 14 individual transects averaged together, 0% of which measured erosion rather than growth. Uncertainty on this specific number: 1.05 ft/yr either side. This segment ranks 1143 of 1211 measured US coastal segments, ordered from fastest erosion to fastest growth. Source: USGS Open-File Report 2012-1008. For scale: Siesta Key, FL, 2633 miles away, ranks 1178 of 1211 nationally for growth, 2.82 ft/yr, 1.8x this stretch's rate. 2.1 miles away, Qui-nai-elt Village, WA is the nearest other measured stretch: accretion (beach growing) at 1.04 ft/yr.
One address near Santiago: the Coastal Change Hazards Portal zooms past this stretch to the underlying map.