Simulating Spring Freshet Conditions of 2003 in the Delaware Bay

A three-dimensional numerical model for the tidal portion of the Delaware Bay has been developed and used to simulate wet season conditions of Spring 2003. The model domain extends from Trenton, NJ south past the inlet at Cape May, NJ and incorporates a large portion of the continental shelf. A variable, harmonically decomposed, water level boundary condition of three diurnal (K₁, Q₁, O₁) and four semi-diurnal (K₂, S₂, N₂, M₂) constituents is used. The major forcings such as inflow and wind are used to reproduce the observed characteristics. The k- ε formulation of Generic Length Scale (GLS) model is used for turbulence closure. Comparison of salinity profiles for the high inflow, wet season is used to measure the capability of the closure. The calibration of bottom friction resulted in better representation of water levels. Harmonic analyses are performed to judge the overall accuracy of the model results. Salinity simulations are compared to the observations at two stations as well as a vertical transaction survey performed along the main shipping channel in the Delaware Bay. The model simulated the wet season conditions agreeably well and the usage of k- ε model during wet season conditions is justified for Delaware Bay. The model is able to capture water levels, salinity and velocity profiles in the bay. The effect of the severe conditions of March 2003 is also reproduced and the model proves to be a good candidate for such conditions in Delaware Bay. Moreover, it is found that mixing characteristics and salinity distribution in the bay do not depend much on the water surface elevations; rather it is controlled by the geometry of the bay and amount of river inflows.