Christopher Daly

Hurricane Ian impacted the Southwest Florida barrier island coast with devastating storm surge flooding. In its wake, numerous ebb surge channels cut across extensive stretches of shoreline on Sanibel Island, while Lover’s Key was overwashed and breached. The process-based model, XBeach, was used to predict the formation of these ebb surge channels and breaching events, and model results were compared to post-storm LiDAR DEMs. Results show that XBeach accurately predicts the number and locations of ebb surge channels; however, the results were limited by the ability to represent highly varied land cover within the model. Results suggest that non-erodible surfaces such as roads and parking lots prevented the extension of ebb surge channels deep inland on Sanibel during the surge. XBeach predicted substantial deflation of Lover’s Key compared to measurements, highlighting the importance of high resolution land cover data and accurate hydrodynamic boundary conditions.