Costa Mesa, CA Coastal Erosion Rate
What USGS measures 3.7 miles southwest of Costa Mesa, CA
3.7 miles southwest of Costa Mesa, CA, the coast is advancing, not retreating, at a measured 1.48 feet a year, sediment accumulating faster than any erosion USGS recorded here. At that rate, the shoreline has gained roughly 14.8 feet over the last decade.
What "Costa Mesa" means on this page
Nothing here is parcel-level. USGS's raw transects run every few hundred feet along the shore; this page averages the ones nearest Costa Mesa, CA into one ~3.5-mile reading rather than picking a single arbitrary line to represent the area. Centered near 33.63°N, 117.96°W. The survey behind it runs to 1852-2016, in USGS's California assessment, using the LRR 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.
25 years at this rate
Holding the 1.48 ft/yr accretion rate 3.7 miles southwest of Costa Mesa, CA for 25 years would add roughly 37 feet of shoreline, again assuming nothing about the local sediment supply changes.
What backs this reading up
This reading comes from 55 individual transects averaged together, 0% of which measured erosion rather than growth. USGS's confidence interval here is ±0.46 ft/yr. Sorted from fastest erosion to fastest growth across all 1211 measured segments nationally, this one lands at 1140. Source: USGS National Shoreline Change data release (ScienceBase, DOI 10.5066/P94J0K7Z), Kratzmann 2024 / Data Report 1187. For scale: Longport, NJ, 2420 miles away, ranks 1168 of 1211 nationally for growth, 2.33 ft/yr, 1.6x this stretch's rate. 1.9 miles away, Costa Mesa, CA is the nearest other measured stretch: slight accretion (beach growing) at 0.48 ft/yr.
One address near Costa Mesa: the Coastal Change Hazards Portal zooms past this stretch to the underlying map.