The Roles of Storminess and Sea Level Rise in Decadal Barrier Island Evolution

Barrier islands protect mainland coastal communities during storms. In the future, the effects of storms and sea level rise (SLR) threaten barrier islands with increased inundation and loss of land. Barrier islands can keep pace with SLR by moving sand across the island during storm events to maintain height and width. However, if storms are too intense or sea levels are too high, the island may drown. This study uses computational models to assess the future response of a barrier island to higher sea levels and changes in frequency and intensity of storms (storminess). We found that the barrier island exhibits five behaviors in response to storms and SLR: keeping pace by maintaining height and width, losing width but maintaining height, losing height but maintaining width, losing height and width, and gaining height and width. These behaviors shifted based on the amount of SLR and storminess. Both increased SLR and increased storminess resulted in less of the island keeping pace and more of the island losing height and width; in some cases, this caused channels to be cut through the island. Under the most frequent and intense storm scenarios, the island lost significant amounts of land and was unable to recover.