The Effect Of Tidal Inlets On Open Coast Storm Surge Hydrographs: A Case Study Of Hurricane Ivan (2004)

Florida\u27s Department of Transportation requires design storm tide hydrographs for coastal waters surrounding tidal inlets along the coast of Florida. These hydrographs are used as open ocean boundary conditions for local bridge scour models. At present, very little information is available on the effect that tidal inlets have on these open coast storm tide hydrographs. Furthermore, current modeling practice enforces a single design hydrograph along the open coast boundary for bridge scour models. This thesis expands on these concepts and provides a more fundamental understanding on both of these modeling areas. A numerical parameter study is undertaken to elucidate the influence of tidal inlets on open coast storm tide hydrographs. Four different inlet-bay configurations are developed based on a statistical analysis of existing tidal inlets along the Florida coast. The length and depth of the inlet are held constant in each configuration, but the widths are modified to include the following four inlet profiles: 1) average Florida inlet width; 2) 100 meter inlet width; 3) 500 meter inlet width; and 4) 1000 meter inlet width. In addition, two unique continental shelf profiles are used to design the ocean bathymetry in the model domains: a bathymetry profile consistent with the west/northeast coast of Florida (wide continental shelf width), and a bathymetry profile similar to the southeast coast of Florida (narrow continental shelf width). The four inlet-bay configurations are paired with each of the bathymetry profiles to arrive at eight model domains employed in this study. Results from these domains are compared to control cases that do not include any inlet-bay system in the computational domain. The ADCIRC-2DDI numerical code is used to obtain water surface elevations for all studies performed herein. The code is driven by astronomic tides at the open ocean boundary, and wind velocities and atmospheric pressure profiles over the surface of the computational domains. Model results clearly indicate that the four inlet-bay configurations do not have a significant impact on the open coast storm tide hydrographs. Furthermore, a spatial variance amongst the storm tide hydrographs is recognized for open coast boundary locations extending seaward from the mouth of the inlet. The results and conclusions presented herein have implications toward future bridge scour modeling efforts. In addition, a hindcast study of Hurricane Ivan in the vicinity of Escambia Bay along the Panhandle of Florida is performed to assess the findings of the numerical parameter study in a real-life scenario. Initially, emphasis is placed on domain scale by comparing model results with historical data for three computational domains: an ocean-based domain, a shelf-based domain, and an inlet-based domain. Results indicate that the ocean-based domain favorably simulates storm surge levels within the bay compared to the other model domains. Furthermore, the main conclusions from the numerical parameter study are verified in the hindcast study: 1) the Pensacola Pass-Escambia Bay system has a minimal effect on the open coast storm tide hydrographs; and 2) the open coast storm tide hydrographs exhibit spatial dependence along typical open coast boundary locations