Kekaha, HI Coastal Erosion Rate
What USGS measures 0.9 miles east of Kekaha, HI
0.9 miles east of Kekaha, 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 Kekaha, HI. Centered near 21.96°N, 159.70°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
This reading comes from 261 individual transects averaged together, 69% of which measured erosion rather than growth. USGS's confidence interval here is ±0.51 ft/yr. Taken at face value, this segment's raw -0.45 ft/yr reading would land it 325 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 1192 nationally for growth belongs to Ocean City, WA, 2627 miles from this stretch, measured at 4.1 ft/yr. Kekaha, HI, 2.1 miles off, is the adjacent measured stretch, itself no significant trend.
One address near Kekaha: the Coastal Change Hazards Portal zooms past this stretch to the underlying map.