Morphodynamic analysis and numerical modeling of Sebastian Inlet, Florida, USA

In order to renourish the downdrift beaches at Sebastian Inlet, FL, USA, multiple fill projects have been undertaken over the past 2 decades, with the most recent one in 2007. Sebastian Inlet has undergone intense monitoring by the Sebastian Inlet District (SID) which includes hydrodynamic data (waves, water level, current), hydrographic surveys and aerial images. The data are used to calculate bathymetric and shoreline changes over various time scales, and to apply and calibrate a morphologic model of the Coastal Modeling System (CMS), developed by the US Army Corps of Engineers. Results indicate sand deposition and shoreline advancement south of the project location, and around the ebb shoal system. The model successfully reproduced sedimentation patterns over a year-long run, including a complex cross-shore sand transport along the reef lines. Simulations also demonstrated reversals in the longshore transport direction due to wave refraction around the ebb shoal, providing an explanation which could explain sand back-passing toward the inlet.