Topanga, CA Coastal Erosion Rate
Is the coast eroding 4 miles south of Topanga, CA?
4 miles south of Topanga, CA: 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 "Topanga" 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 Topanga, CA. Centered near 34.04°N, 118.60°W. Survey years: 1852-2016, method LRR, from USGS's California shoreline-change assessment. That's how current the data is here, real, but not a live feed, since a shoreline survey is a major undertaking, not an annual check-in.
What backs this reading up
86 transects feed this segment's number; 59% of them individually measured retreat. Uncertainty on this specific number: 0.1 ft/yr either side. Taken at face value, this segment's raw -0.05 ft/yr reading would land it 717 of 1211 nationally - a number worth ignoring, since it's statistical noise rather than a real trend. Source: USGS National Shoreline Change data release (ScienceBase, DOI 10.5066/P94J0K7Z), Kratzmann 2024 / Data Report 1187. Rank 1001 nationally for growth belongs to Bertsch-Oceanview, CA, 612 miles from this stretch, measured at 0.41 ft/yr. Santa Monica, CA, 2.8 miles off, is the adjacent measured stretch, reading slight accretion (beach growing) at 0.21 ft/yr.
Topanga, CA on the source map: try the Coastal Change Hazards Portal, zoomable well past this page's ~3.5-mile grain.