FEFLOW can simulate unsaturated and variably saturated conditions in 2D and 3D by using Richards' equation in combination with a parametric model for the saturation vs. pressure head and saturation vs. relative conductivity relationships. FEFLOW offers:

• Flexible parameter models (also combinations):
  van Genuchten, Brooks-Corey,  van Genuchten modified (variable m), Haverkamp, Exponential, Linear, Spline interpolation of tabular data
• Different formulations of Richards' equation (head based, mixed, and variable substitution form)
• Different numerical schemes
• Consideration of capillary hysteresis if required
• Parameter fitting for different parameter models in FE-LM² (inclusive)