Nanakuli, HI Coastal Erosion Rate
Shoreline change right at Nanakuli, HI
right at Nanakuli, HI: 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.
What this reading actually covers
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 Nanakuli, HI. Centered near 21.39°N, 158.15°W. USGS's Hawaii assessment last surveyed this stretch through 2007-2010, computing the rate with its WLR method. Other US regions were surveyed in different years, sometimes decades apart, so this page states its own rather than implying one national vintage.
How solid is this number
138 transects feed this segment's number; 88% of them individually measured retreat. USGS's confidence interval here is ±0.25 ft/yr. Taken at face value, this segment's raw -0.14 ft/yr reading would land it 585 of 1211 nationally - a number worth ignoring, since it's statistical noise rather than a real trend. Source: USGS Open-File Report 2011-1009. Avalon, NJ sits at national rank 1171 for growth (2.37 ft/yr), one reference point among the 1211 scored segments, 4960 miles from here. 2.3 miles up the coast, Ko Olina, HI shows 0.41 ft/yr of eroding.
Nanakuli, HI on the source map: try the Coastal Change Hazards Portal, zoomable well past this page's ~3.5-mile grain.