Anchor Bay, CA Coastal Erosion Rate
Is the coast eroding 3.9 miles southeast of Anchor Bay, CA?
The coast 3.9 miles southeast of Anchor Bay, CA is actually gaining ground, not losing it: USGS's transects measure 0.58 feet of accretion a year here, sediment building up rather than washing away. At that rate, the shoreline has gained roughly 5.8 feet over the last decade.
What "Anchor Bay" 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 Anchor Bay, CA into one ~3.5-mile reading rather than picking a single arbitrary line to represent the area. Centered near 38.76°N, 123.53°W. USGS's California assessment last surveyed this stretch through 1852-2016, computing the rate with its LRR method. Other US regions were surveyed in different years, sometimes decades apart, so this page states its own rather than implying one national vintage.
25 years at this rate
Holding the 0.58 ft/yr accretion rate 3.9 miles southeast of Anchor Bay, CA for 25 years would add roughly 14 feet of shoreline, again assuming nothing about the local sediment supply changes.
How solid is this number
Averaging 21 separate transects produced this segment's rate, with 0% individually reading as erosion, rather than relying on any single survey line. Uncertainty on this specific number: 0.23 ft/yr either side. Sorted from fastest erosion to fastest growth across all 1211 measured segments nationally, this one lands at 1039. Source: USGS National Shoreline Change data release (ScienceBase, DOI 10.5066/P94J0K7Z), Kratzmann 2024 / Data Report 1187. Rank 1059 nationally for growth belongs to Surfside Beach, TX, 1747 miles from this stretch, measured at 0.69 ft/yr, 1.2x this stretch's rate. 4 miles up the coast, Anchor Bay, CA shows the same lack of a significant trend.
Not this whole stretch, just Anchor Bay itself: the Coastal Change Hazards Portal is USGS's own live version of this data.