Development of a Hydrodynamic and Salinity Model in the Caloosahatchee Estuary and Estero Bay, Florida

The South Florida Water Management District (SFWMD), jointly with the U.S. Army Corps of Engineers, is in the process of developing a large water resource restoration plan, the Southwest Florida Feasibility Study (SWFFS) for Southwest Florida area. SWFFS provides an essential framework to address the health and sustainability of aquatic systems. This includes a focus on water quantity and quality, flood protection, and ecological integrity. A regional hydrological model, an estuarine hydrodynamic model and an ecological model will work together as a chain of models to evaluate various restoration alternatives and size the reservoirs. The hydrodynamic model is required to simulate the salinity response of the estuary on a 30-year basis with 3–5 days of CPU time (wall clock run time). This study developed a hydrodynamic and salinity model based on the CH3D model. Three approaches, a vertically-integrated 2D model with constant horizontal turbulent diffusivity (A_H), a 2D model with spatially varying A_H and a 3D model with varying A_H, were investigated. A statistical analysis including RMS error calculation and linear regression was conducted to compare the results. The comparison concluded that a 3D model with 5 layer version of CH3D is able to predict the salinity under various alternative conditions with acceptable accuracy.