Ewa Beach, HI Coastal Erosion Rate
Shoreline change 0.8 miles east of Ewa Beach, HI
0.8 miles east of Ewa Beach, 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 "Ewa Beach" 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 Ewa Beach, HI. Centered near 21.31°N, 157.99°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
206 transects feed this segment's number; 50% of them individually measured retreat. Uncertainty on this specific number: 0.1 ft/yr either side. Taken at face value, this segment's raw -0.01 ft/yr reading would land it 763 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 993 nationally for growth belongs to Huntington Beach, CA, 2574 miles from this stretch, measured at 0.39 ft/yr. 1.3 miles up the coast, Iroquois Point, HI shows the same lack of a significant trend.
One address near Ewa Beach: the Coastal Change Hazards Portal zooms past this stretch to the underlying map.