U.S. Geological Survey national shoreline change— Summary statistics for updated vector shorelines (1800s–2010s) and associated shoreline change data for the Georgia and Florida coasts

Abstract

Rates of shoreline change have been updated for the open-ocean sandy coastlines of Georgia and Florida as part of the U.S. Geological Survey’s Coastal Change Hazards programmatic focus. This work was formerly within the National Assessment of Shoreline Change project. Shorelines were compiled from the original report published in 2005, recent update reports, and additional light detection and ranging (lidar) shorelines which were extracted from lidar data collected prior to and following Hurricane Irma, which made landfall in September 2017. These shorelines were used to compute long- and short-term rates that incorporate the proxy-datum bias on a transect-by-transect basis. The proxy-datum bias accounts for the unidirectional onshore bias of proxy-based high water line shorelines relative to datum-based mean high water shorelines. In this study, the coast of Georgia exhibited the highest average rates of erosion and accretion in both the long term (approximately 150 years) and the short term (approximately 30 years). Shoreline positions from the mid-1800s through 2018 were used to update the shoreline change rates for Florida and Georgia using the Digital Shoreline Analysis System (DSAS) software.