EFDC+ is the most up-to-date, enhanced version of EFDC, one of the most popular 3D hydrodynamic and water quality models available. The U.S. Environmental Protection Agency (EPA) has described the original EFDC as “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.”  DSI has taken the EPA version of EFDC and greatly improved on it, creating EFDC+.  Since 1998, DSI has been continuously upgrading the model’s hydrodynamics and stability, while also decreasing run times.


Water temperature is one of the most important physical characteristics of surface waters, impacting both density effects and thermal effects on water quality kinetics and solubility. 

EFDC+ provides you a range of options to accurately simulate surface heat exchange and solar radiation attenuation in the water column.  Multiple computed evaporation options are available to better represent your system.


Variations in salinity often impact estuarine stratification more than variations in temperature. In hundreds of studies, EFDC+ has been shown to successfully predict the response of rivers and estuaries to ocean salinity changes related to seasonal variation in freshwater inflow and human activities such as harbor and ship channel deepening.

Hydraulic structures

To produce a realistic simulation of actual physical conditions, you may need to account for man-made structures such bridges, sluice gates, culverts, pipes, and/or weirs.  With EFDC+, you can simulate these structures using a standard lookup table approach or take advantage of the enhanced EFDC+ feature that uses standard hydraulic equations of typical hydraulic structures to calculate the appropriate flow for each time step.

Dye flowing through a sluice gate.

Internal Wind-waves

One advantage of EFDC+ over the EPA version of EFDC is that EFDC+ incorporates a wind-wave sub-model. This allows for temporally and spatially varying wave conditions to be directly coupled to the EFDC+ hydrodynamics. In your EFDC+ model, you can choose to allow these conditions to impact just the bed shear stress or you can also model wave-generated currents by inclusion of the radiation shear stresses on the water column.


Wave Action

Waves action can have a significant impact on hydrodynamics and sediment transport. EFDC+ can be linked to external wave modeling results or you can compute wind-generated waves internally.

External Wave Linkage

EFDC+ has been enhanced to efficiently link to external wind models such as SWAN model output. As with the internal wind wave sub-model, you can choose to include or exclude wave-generated currents.