Presenter: Ap Van Dongeren (Deltares)

Description:
  U.S. coastal communities are threatened annually by large storms and hurricanes, which cause flooding, erosion, coastal breaching, and infrastructure damage. It is essential to accurately forecast flood-related hydrodynamics (e.g., tides, surges, and waves) and morphodynamic changes (erosion and accretion of sediment) in order to protect lives and property. While tides and surges are now routinely incorporated into forecasting products, the effects of waves, erosion, and damages are typically unaccounted for. In a collaborative project with the U.S. Geological Survey, U.S. Naval Research Laboratory, IHE Delft, and Deltares (Netherlands & USA), a modeling system is being developed that incorporates hydrodynamics, morphodynamics, and risk assessment in a computationally efficient way to make real-time forecasts of coastal hazards during hurricanes. Basin-scale hydrodynamic models (Delft3D and SWAN) of the Gulf of Mexico and Northwestern Atlantic Ocean are forced with high-resolution COAMPS winds and drive nearshore models which compute the total water level (using the Bayesian model BEWARE), shoreline change (CoSMoS-COAST), and dune erosion (PIG-F) at high-resolution intervals (500 m) along 100s of kilometers of the US coast. In areas of interest, detailed 2D flood models (SFINCS) and morphodynamic models (XBeach) are applied to compute local flood and erosional hazards. In addition to these deterministic forecasts, we also assess the uncertainties of the hurricane impacts due to variations in storm track and intensity. This presentation will focus on the methodology used to compute total water levels and flooding on meteorological forecast time-scales (i.e., hour to days). We will present the coastal impact results of two pilot cases: a mildly-sloping coast in the Florida Panhandle (2018 Hurricane Michael, Category 5 at landfall) and 2) a steep beach in Puerto Rico.