Napili-Honokowai, HI Coastal Erosion Rate
Is the coast eroding 0.8 miles west of Napili-Honokowai, HI?
0.8 miles west of Napili-Honokowai, 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.
The grain of this number
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 Napili-Honokowai, HI. Centered near 20.98°N, 156.68°W. 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.
Where this fits nationally
25 transects feed this segment's number; 76% of them individually measured retreat. Uncertainty on this specific number: 0.24 ft/yr either side. Taken at face value, this segment's raw -0.19 ft/yr reading would land it 513 of 1211 nationally - a number worth ignoring, since it's statistical noise rather than a real trend. Source: USGS Open-File Report 2011-1009. Rank 1043 nationally for growth belongs to Inwood, NY, 4924 miles from this stretch, measured at 0.59 ft/yr. 1.7 miles up the coast, Kapalua, HI shows the same lack of a significant trend.
Napili-Honokowai, HI on the source map: try the Coastal Change Hazards Portal, zoomable well past this page's ~3.5-mile grain.