Kaaawa, HI Coastal Erosion Rate
Is the coast eroding 2.2 miles south of Kaaawa, HI?
2.2 miles south of Kaaawa, 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 "Kaaawa" means on this page
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 Kaaawa, HI. Centered near 21.51°N, 157.84°W. The survey behind it runs to 2007-2010, in USGS's Hawaii assessment, using the WLR 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
154 transects feed this segment's number; 57% of them individually measured retreat. Uncertainty on this specific number: 0.22 ft/yr either side. Taken at face value, this segment's raw -0.11 ft/yr reading would land it 637 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 1187 nationally for growth belongs to Gearhart, OR, 2550 miles from this stretch, measured at 3.64 ft/yr. 2.3 miles up the coast, Kaaawa, HI shows the same lack of a significant trend.
Kaaawa, HI on the source map: try the Coastal Change Hazards Portal, zoomable well past this page's ~3.5-mile grain.