To this end, we conduct numerous tests of different forcing variations: wind-stress only, wind and wave stresses, and wind and wave stresses with mass flux transport. These options were simulated on three hurricanes and two SLOSH basins. The storms range in intensity between a Category 1 (34 m/s) and Hurricane Andrew, a Category 5 storm (74 m/s). Our two basins were chosen for bathymetric contrast: Tampa Bay, a shallow and gentle shelf, and Miami, which has a steeper and deeper shelf. Wave stresses and mass transports were obtained using the Simulating Waves Nearshore (SWAN) third-generation wave model with time dependent water level and wind inputs from the SLOSH wind-stress-only test.

Hurricanes wreak havoc on the lives and infrastructure of coastal communities. Storm surge, a local rise in sea elevations, is perhaps the most devastating element of these tropical cyclones. Storm surge depends on the tidal stage, barometric pressure, Coriolis effect, wind stress, and wave forcing, as well as the local bathymetry. In the past, many storm surge numerical models, such as Sea, Lake, and Overland Surges from Hurricanes (SLOSH) (JELESNIANSKI et al, 1992), neglect wave forcing components to conserve computational efficiency. However, numerous situations necessitate the inclusion of waves' effects to more correctly model the surge both spatially and temporally.

Hurricanes wreak havoc on the lives and infrastructure ofcoastal communities. Storm surge, a local rise in sea level elevations, is perhaps the most devastating element of these tropical cyclones. Storm surge depends on the tidal stage, barometric pressure, Coriolis effects, wind stress, and wave forcing, as well as the local bathymetry. In the past,many storm surge numerical models, such as Sea, Lake, and Overland Surges from Hurricanes (SLOSH), neglect wave forcing components to conserve computational efficiency. This omission would surely be preferred when wave forcing is not significant. However, numerous situations couldnecessitate the inclusion of waves' effects to more correctly model the surge both spatially and temporally. In its effort to characterize the combined effects of hurricane hazards (hurricane wind, storm surge, and waves) for use in developing structural design criteria for coastal structures, NIST in collaboration with the NOAA's MeteorologicalDevelopment Laboratory (MDL) and the Oceanic and Atmospheric Research (OAR) has developed a methodology that incorporates hurricane science, hydrology, probabilistic methods, and structural engineering needs for use in developing site specific, risk-based design criteria for coastal structures subjected to the above hurricane hazards. This early effort utilizes program SLOSH for hydrodynamic simulations without consideration of wave effects. Recognizing that wave set-up and mass flux might have a significant influence on total storm surge levels, the NIST then collaborated with NOAA's National Hurricane Center (NHC) to provide funding and technical guidance to the University of Florida for the incorporation of a wave model into the SLOSH model to extend SLOSH capability. The result of this effort is described in this report.

The primary function of seawalls and embankments is to protect against damage and injury caused by flooding. Coastal flooding is caused by combinations of high tides, waves, wind set-up and storm surges driven by low-pressure systems. However with global warming causing sea levels to rise and with increased storminess causing more extreme waves and storm surges, the likelihood of overtopping of seawalls with zero or negative freeboard may well be expected to increase. Researchers using physical and numerical models to develop design formulae have widely investigated wave overtopping of seawalls with positive freeboard. However the design of seawalls with zero or negative freeboard has attracted much less attention, and some variation exists between overtopping discharge calculated with current design formulae. The focus of this thesis is the extreme situation when overtopping caused by storm waves is combined with surge levels above the embankment crest. The local highly accelerative flow over the embankment crest caused by the high surge level will significantly alter the flow at the crest. This is likely to have a highly non-linear effect upon the overtopping waves. In this thesis, the flow is investigated with a 2DV numerical model based on the Reynolds averaged Navier-Stokes (RANS) equations developed by Lin and Liu (1998a). The model describes the flow characteristics of a breaking wave such as the velocities within the wave as well as the turbulence at the seabed boundary layer. As an example of the model's ability to describe complex hydrodynamic flows, this study investigates its ability to represent the second order mass transport under progressive and standing waves. The model results are compared with available theory and experimental results. This shows that mass transport is successfully predicted, although there is some variation in the magnitude compared to the experimental and theoretical results. To consider the model's ability to simulate storm surge wave overtopping of embankments, the RANS model has been used to simulate an experimental study conducted by Hughes and Nadal (2009). To examine the success of the model at reproducing the wave generation, transformation and overtopping processes the model results have been compared with the experimental laboratory data. This makes possible a wave-by-wave comparison of overtopping parameters such as discharge, depth and velocity for a storm surge event. Additionally the overtopping discharge predicted by the model is compared with design formulae and the differences in the overtopping discharge calculated with current design formulae are investigated and explained. Finally, the RANS model is used to determine the effect of embankment crest width on the magnitude of the overtopping discharge. Results from RANS model tests are used to provide design guidance in the form of an equation that allows the effect of crest width to be included when evaluating combined discharge at embankments.