GFLOW - A stepwise groundwater flow modeling system based on the analytic element method (AEM). Iis particularly suitable for modeling regional horizontal flow.
GMS supports both finite-difference and finite-element groundwater models in 2D and 3D including MODFLOW 2000, MODPATH, MT3DMS/RT3D, SEAM3D, FEMWATER, PEST, UTEXAS, MODAEM and SEEP2D.