The code has been developed by groundwater professionals in response to a need for a better transport model than is currently commercially available. Both central differencing and upstream weighting approximation options are available for solution of the advective terms.
Various solvers are available for matrix solution.
For transport, the available solvers are Slice Successive Overrelaxation and Orthomin. The new Orthomin solver has advantages over traditional solvers. When used for flow simulations, the Orthomin solver functions as an enhanced version of the preconditioned conjugate gradient method. However, coding improvements make this solver faster and computationally more efficient than traditional PCG2. This is particularly true for simulations with complex geology comprised of variable layer elevation and thicknesses.