Shoreline Change in Response to Sea-Level Rise on Florida's West Coast

Shoreline position measurements about 300 m apart have been made along the Florida shoreline from the 1800s. There has been net shoreline advance during this time on the Florida E and SW coasts, but the Florida W coast has had net recession. Information is available on factors causing shoreline change on the Florida W coast, including sea-level rise, beach nourishment, loss of sediment to inlets, offshore dredged-sediment disposal, longshore sediment transport, and long-term, onshore sediment transport. Estimates are presented on the contributions these factors have made to shoreline change since the 1800s along 334 km of shoreline in seven west Florida counties. Summing the contributions results in net shoreline recession that agrees with measured recession within standard deviation confidence intervals in each of the counties and for the total shoreline. Sea-level rise is shown to have accounted for less than 20% of the magnitude of all shoreline change (including shoreline advance produced by beach nourishment). Projections of future shoreline change are made using sea-level rise projections of the Intergovernmental Panel for Climate Change (IPCC), along with projections of shoreline change that would be produced by each of the factors. It is shown that beach nourishment quantities at past rates can offset the recessional effects of sea-level rise for most IPCC sea-level rise projections from 2016 to 2065 and 2016 to 2100. A modest increase in nourishment can offset shoreline recession from sea-level rise based on the worst-case IPCC sea-level rise scenario.