NUMERICAL INTERMEDIATE AND FAR-FIELD DILUTION MODELING

Studies of wastewater outfalls to coastal waters are now being perform ed using numerical hydrodynamic and transport models. Modelling of coa stal waters requires specifying tidal boundary conditions along open w ater boundaries. It is not possible to obtain open water tidal boundar y conditions from tide height observations alone because the datum bet ween different tide gages cannot be determined to the accuracy require d for numerical modelling. Presented in this paper is a method for est imating open water tidal boundary conditions from coincident current m eter and pressure sensor measurements. The methodology is applied to a numerical hydrodynamic and transport model to analyze the dilution fi eld and rate of sedimentation around a proposed wastewater outfall int o outer Saint John Harbour on the Bay of Fundy. The intermediate and f ar field numerical model used in this study includes the momentum of t he discharge to account for near field mixing.