NUMERICAL INTERMEDIATE AND FAR-FIELD DILUTION MODELING

Studies of wastewater outfalls to coastal waters are now being performed using numerical hydrodynamic and transport models. Modelling of coastal waters requires specifying tidal boundary conditions along open water boundaries. It is not possible to obtain open water tidal boundary conditions from tide height observations alone because the datum between different tide gages cannot be determined to the accuracy required for numerical modelling. Presented in this paper is a method for estimating open water tidal boundary conditions from coincident current meter and pressure sensor measurements. The methodology is applied to a numerical hydrodynamic and transport model to analyze the dilution field and rate of sedimentation around a proposed wastewater outfall into outer Saint John Harbour on the Bay of Fundy. The intermediate and far field numerical model used in this study includes the momentum of the discharge to account for near field mixing.