Barrier dynamics and landward migration with Holocene sea-level rise

Barrier beaches (islands and spits) have become the subject of mounting interest 1,2 due to human development on these land-forms. It is commonly thought that barrier beaches continuously migrate landward in response to sea-level rise, often by over-wash processes, maintain mass through time, and that these processes are occurring at a rate commensurate with human (100 yr) time frames. While some barriers are naturally migrating quite rapidly 3,4 , other barriers decidedly are not. Here I present data which illustrate that many US Atlantic Coast barriers are not evolving over the short term in accordance with generally accepted hypotheses and argue that the presumed norm may actually be the exception.