Monte Carlo Simulation
Select this option to perform multi-realization Monte Carlo simulations for stochastic flow and transport modeling and probabilistic analysis.NOTE: For the free version of IGW-NET, the maximum number of realizations allowed for Monte Carlo Simulation is NumbRLZ = 100.
IGW-NET Flow
Selecting this option will tell IGW-NET to utilize the finite-difference code from Interactive Groundwater (IGW) to solve the partial differential equations of flow and transport. The algorithms available with IGW-NET flow include:- Hybrid Successive Over Relaxation
- Successive Over Relaxation
- Conjugate Gradient
- Bi-Conjugate Gradient
- Bi-Conjugate Gradient with Partial Pivoting
ModFlow
Select this option to utilize MODFLOW solvers/packages. Click the 'Edit MF Solver' link to explore a full set of options for the MODFLOW engine.Cell Face Averaging Scheme
To calculate specific discharge between two model cells (from cell-center-to-cell-center), an effective (or average) hydraulic conductivity at the cell-interface is needed. Choose to calculate the cell-face conductivity as the harmonic average or arithmetic average of the conductivities of the two adjoining model cells.Apply Recharge to 1st Active Cell
This default option will apply recharge input to the top-most active computational layer. In other words, recharge is not applied to dry cells, but instead to the first wet cell encountered beneath the dry cell(s) under this default settings.Unchecking this box will make it so that recharge can only be applied to the top-most computational layer.
Sy only in unconfined layers
This option is related to the storage approximation term used when solving a transient groundwater flow model. The default setting (unchecked box) is to calculate storage for an unconfined layer as Sy (specific yield) plus Ss*b, where Ss is the specific storage and b is the aquifer thickness. When the 'Sy only in unconfined layers', storage is simply equal to Sy for an unconfined aquifer.Convergence Criterion
The user may specify the convergence criterion for the numerical flow solutions, namely: the maximum number of iterations; the threshold of acceptable relative percent error (between successive iterations); the damping/relaxation factor; and the number of preconditions (or condition number). The user may also customize the ‘outer loop’ matrix solve scheme by specifying the number of maximum iterations, the threshold of acceptable relative percent error, the Relaxation Factor, and the frequency with which the dry/wet cells are scanned in the solution matrix.Transport Options
The same algorithms available with IGW-NET flow are available for solving the transport equations:- Hybrid Successive Over Relaxation
- Successive Over Relaxation
- Conjugate Gradient
- Bi-Conjugate Gradient
- Bi-Conjugate Gradient with Partial Pivoting
The users may also specify the convergence criterion for the numerical transport solutions: he maximum number of iterations; the threshold of acceptable relative percent error (between successive iterations); the damping/relaxation factor; and the number of preconditions (or condition number).