ABSTRACT
In estuarine modeling, water movements and mixing are required for water quality simulations. Accordingly, hydrodynamic computations are conducted to quantify the mass transport. This chapter presents a perspective of hydrodynamic calculations and their relationships with water quality modeling. Hydrodynamic models are formulated with momentum equations, the continuity equation, and a salt balance equation. The appropriate equations of motion for a one-dimensional vertically and laterally averaged estuary are well known and have been applied to the calculation of the stage and discharge variation over a tidal cycle. The principal application to problems of water quality has been for the computation of salinity intrusion in estuaries. The seaward portions of most estuaries have sufficiently large width so that a two-dimensional segmentation is more appropriate. The processes affecting estuarine circulation and mixing may be described using equations based on conservation of mass and momentum.
