Process-Based Numerical Modeling of Total Water Levels, Flooding, and Morphology Changes During Hurricane Impact at Florida Panhandle Beaches

Abstract Low-lying barrier islands around the Florida panhandle in the United States are highly susceptible to storm-induced coastal flooding and erosion. Projected sea level rise (SLR) and storm intensity resulting from climate change will amplify these effects. Predicting these effects accurately will aid in improving decision-making capabilities for coastal communities and military installations near the coast. This study utilizes CSHORE, a very efficient 1D process-based cross-shore model, for assessing flooding and morphological change along barrier island beaches. The model was applied to 71 transects over 70 km centering around Tyndall Airforce Base (TAFB), Florida, assessing total water level (TWL) flooding and morphological change during Hurricane Micheal (2018), and the spatial variability of these effects due to hurricane landfall location. Model validation generally underpredicted peak water levels compared to measured high-water marks (HWM), however, most HWMs were within one standard deviation of the modeled statistical mean value. Preliminary results of this study showed significant variability of TWL at the shoreline along the 70 km stretch of coast, from 0.83 m Mean Sea Level (MSL) northwest of TAFB, where winds propagated offshore, to 3.38 m MSL southeast of TAFB where winds propagated onshore. Future work includes validating the morphological change outputted from CSHORE using Hurricane Michael forcing conditions, assessing the impact of profile spacing and offshore profile length on model accuracy, and investigating the impact of various SLR scenarios on TWL flooding for TAFB.