Environmental Fluid Dynamics Code (EFDC)

The Environmental Fluid Dynamics Code (EFDC) is a state-of-the-art hydrodynamic model that can be used to simulate aquatic systems in one, two, and three dimensions. It has evolved over the past two decades to become one of the most widely used and technically defensible hydrodynamic models in the world. EFDC uses stretched or sigma vertical coordinates and Cartesian or curvilinear, orthogonal horizontal coordinates to represent the physical characteristics of a waterbody. It solves three-dimensional, vertically hydrostatic, free surface, turbulent averaged equations of motion for a variable-density fluid. Dynamically-coupled transport equations for turbulent kinetic energy, turbulent length scale, salinity and temperature are also solved. The EFDC model allows for drying and wetting in shallow areas by a mass conservation scheme. The physics of the EFDC model and many aspects of the computational scheme are equivalent to the widely used Blumberg-Mellor model and U. S. Army Corps of Engineers’ Chesapeake Bay model.

The EFDC model has been used to study: high freshwater inflow events in the northern portion of the Indian River Lagoon, Florida, and a flow through high vegetation density-controlled wetland systems in the Florida Everglades; discharge dilution in the Potomac, James and York Rivers; salinity intrusion studies include the York River, Indian River Lagoon and Lake Worth; sediment transport in the Blackstone River, James River, Lake Okeechobee, Mobile Bay, Morro Bay, San Francisco Bay, Elliott Bay – Lower Duwamish Waterway, and Stephens Passage; power plant cooling discharge impacts in the Conowingo Reservoir, the James River and Nan Wan Bay; contaminant transport and fate in the Blackstone and Housatonic Rivers, James River, San Francisco Bay, and Elliott Bay – Lower Duwamish Waterway; and water quality/eutrophication impacts in Norwalk Harbor, Peconic Bay, the Christina River Basin, the Neuse River, Mobile Bay, the Yazoo River Basin, Arroyo Colorado, Armand Bayou, Tenkiller Reservoir, and South Puget Sound.

The source code of the model can be downloaded here.