Environmental Hydrodynamics
The movement and mixing of wastes introduced into marine and freshwater environments are controlled by the circulation characteristics of the water body. To predict the circulation characteristics, the hydrodynamic transport processes must be defined by various hydrographical (runoff), meteorological (surface wind, heating/cooling), adjacent open ocean (large-ocean circulation offshore), astronomical (tides) and internal (gradients) forcing mechanisms. HydroQual has developed and applied steady-state, two- and three-dimensional time dependent models to compute hydrodynamic circulation. In recent years, scientists and engineers have come to rely on hydrodynamic circulation to provide the necessary ingredients (i.e., currents and dispersion) for use in water quality modeling and sediment transport studies. ECOM3D is HydroQual's most renowned and widely used circulation model. This model is three-dimensional and time-dependent. Evolving water masses, plumes, fronts and eddies are accounted for by the prognostic equations for the thermodynamic quantities, temperature and salinity. Free surface elevation is also calculated prognostically so that tides and storm surges events can be simulated. The vertical turbulent mixing processes are parameterized using the turbulent closure sub-model of Mellor and Yamada. ECOM3D incorporates a σ-coordinate system such that the number of grid points in the vertical is independent of depth so that the dynamically important surface and bottom boundary layers across a sloping region can be adequately resolved. The model also uses a curvilinear coordinate system that enhances model efficiency in treating irregularly shaped coastlines and meeting high-resolution requirements in specific local regions.

ECOMSED is available to the public and can be downloaded from our website by registering here.

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