Tidal Simulations for the Loxahatchee River Estuary (Southeastern Florida): On the Influence of the Atlantic Intracoastal Waterway versus the Surrounding Tidal Flats

Abstract

Two-dimensional tidal flows within the Loxahatchee River estuary (Southeastern Florida) are simulated in order to assess the effects of incorporating the Atlantic Intracoastal Waterway (AICWW) versus including the surrounding tidal flats in the computational domain. The region of interest is modeled with three variations of an unstructured, finite-element mesh, including a localized mesh with and without tidal flats, and an extended mesh that describes the AICWW. Phase and amplitude errors between model output and historical data are quantified in terms of water surface elevations at five locations within the Loxahatchee River estuary to assess the relative performance of the various computational meshes. While it is shown that the surrounding tidal flats provide some benefit to the numerical model, the hydrodynamics resulting from the inclusion of the AICWW results in a more significant improvement in the simulated water levels—an important modeling consideration that is commonly disregarded in practice. The application of additional boundary conditions enables for both hydrodynamic factors (AICWW; surrounding tidal flats) to be included in the numerical simulation. As a corollary, velocity residuals are computed on a domain-wide basis to reveal significantly different net circulation patterns within the Loxahatchee River estuary, depending on the level of description of the AICWW, and further demonstrate the importance of including the AICWW in the numerical model.