California Coastal Erosion & Shoreline Change

Choose what to map

ErosionAccretion

Historical context

Select a marker or region. Rates are linear-regression shoreline change in meters per year. Negative is retreat; positive is advance.

What the summary covers

USGS analyzed 19,063 transects across three open-ocean sandy-coast regions. Regional net rates are averages; the erosion and accretion rates separately average only transects in each direction.

A regional average can conceal local change. Marker positions are approximate orientation points—not source transects, parcels, or hazard boundaries.

Use limits

This dated historical summary is not a live shoreline, forecast, setback map, survey, engineering assessment, property estimate, or site-specific erosion rate. Confidence intervals are essential; an interval spanning zero is not statistically significant at the stated confidence level.

Sources

USGS Data Report 1187
Associated USGS data release
DSAS method
Source and use notes