Maili, HI Coastal Erosion Rate
Shoreline change right at Maili, HI
USGS's shoreline-change data puts this stretch, right at Maili, HI, at 0.41 feet of erosion a year on average, a long-term rate for this specific ~3.5-mile section, not one storm's damage. At that rate, the shoreline has lost roughly 4.1 feet over the last decade.
What "Maili" means on this page
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 Maili, HI, rather than showing one arbitrary line. Segment center: 21.41, -158.18. Survey years: 2007-2010, method WLR, from USGS's Hawaii shoreline-change assessment. That's how current the data is here, real, but not a live feed, since a shoreline survey is a major undertaking, not an annual check-in.
What 0.41 ft/yr means over time
Run right at Maili, HI's 0.41 ft/yr rate forward 25 years and it implies about 10 feet of further retreat, assuming nothing changes, which is exactly the assumption a seawall or nourishment project exists to break.
What backs this reading up
112 transects feed this segment's number; 88% of them individually measured retreat. The published margin on this reading runs ±0.33 ft/yr. This segment ranks 345 of 1211 measured US coastal segments, ordered from fastest erosion to fastest growth. Source: USGS Open-File Report 2011-1009. Metompkin, VA sits at national rank 47 for erosion (5.6 ft/yr), one reference point among the 1211 scored segments, 4937 miles from here. Nanakuli, HI, 2.4 miles off, is the adjacent measured stretch, itself no significant trend.
Maili, HI on the source map: try the Coastal Change Hazards Portal, zoomable well past this page's ~3.5-mile grain.