User:Jcreer/MODFLOW 6 Changes for GMS 10.6

Simulations Options

New Simulation

Simulation Run Queue

IMS Package

The Iterative Model Solution (IMS) dialog

The Iterative Model Solution (IMS) dialog is accessed by double-clicking on the IMS package under a MODFLOW 6 simulation in the Project Explorer. It contains the following sections and options:

• Sections list – A list of sections that can be turned on or off:
  • Comments – Turn on to make the Comments section visible.
  • Options – Turn on to make the Options section visible.
  • Nonlinear – Turn on to make the Nonlinear section visible. This section is on by default.
  • Linear – Turn on to make the Linear section visible. This section is on by default.
• Comments section – Enter general alphanumeric comments. Comments entered here get written at the top of the file, preceded by a '#' symbol.
• Options section
  • PRINT_OPTION – A flag that controls printing of convergence information from the solver. Turn on to make the following print options available from the drop-down:
    • "None" – Print nothing. This is the default when PRINT_OPTION is not turned on.
    • "Summary" – Print only the total number of iterations and nonlinear residual reduction summaries
    • "All" – Print linear matrix solver convergence information to the solution listing file and model specific linear matrix solver convergence information to each model listing file in addition to "Summary" information.
  • COMPLEXITY – Optional. Defines default non-linear and linear solver parameters. Turn on to make the following options available from the drop-down:
    • "Simple" – Default solver input values will be defined that work well for nearly linear models.
    • "Moderate" – Default solver input values will be defined that work well for moderately nonlinear models.
    • "Complex" – Default solver input values will be defined that work well for highly nonlinear models.
    • Set NONLINEAR and LINEAR Parameters to Complexity Defaults – This will set all nonlinear and linear parameters to their default values corresponding to the current complexity setting. A confirmation dialog will appear.
  • CSV_OUTER_OUTPUT FILEOUT – Turn on to specify that the record corresponds to the comma separated values solver convergence output. Enter the desired filename for the output ASCII CSV file in the empty field to the right of the option.
  • CSV_INNER_OUTPUT FILEOUT – Turn on to specify that the record corresponds to the comma separated values solver convergence output. Enter the desired filename for the output ASCII CSV file in the empty field to the right of the option.
  • NO_PTC – Turn on to disable pseudo-transient continuation (PTC). Only applies to steady-state stress periods for models using the Newton-Raphson formulation.
    • "ALL"
    • "FIRST"

• Nonlinear section – A table with three columns: "Use" to turn on or off options, "Option" (giving the name of the option), and "Value", where a value can be entered for the option. The options include the following:
  • OUTER_DVCLOSE – Real value defining the head change criterion for convergence of the outer (nonlinear) iterations, in units of length. Default value is "0.001".
  • OUTER_MAXIMUM – Integer value defining the maximum number of outer (nonlinear) iterations. Default value is "25".
  • UNDER_RELAXATION – Optional drop-down value. Defines the nonlinear under-relaxation schemes used.
    • "None" – Under-relaxation is not used.
    • "Simple" – Simple under-relaxation scheme with a fixed relaxation factor is used.
    • "Cooley" – Cooley under-relaxation scheme is used.
    • "DBD" – Delta-bar-delta under-relaxation is used.
  • UNDER_RELAXATION_THETA – Real value defining the reduction factor for the learning rate (under-relaxation term) of the delta-bar-delta algorithm. Default value is "0.0".
  • UNDER_RELAXATION_KAPPA – Real value defining the increment for the learning rate (under-relaxationterm) of the delta-bar-delta algorithm. Default value is "0.0".
  • UNDER_RELAXATION_GAMMA – Real value defining the history or memory term factor of the delta-bar-delta algorithm. Default value is "0.0".
  • UNDER_RELAXATION_MOMENTUM – Real value defining the fraction of past history changes that is added as a momentum term to the step change for a nonlinear iteration. Default value is "0.0".
  • BACKTRACKING_NUMBER – Integer value defining the maximum number of backtracking iterations allowed for residual reduction computations. Default value is "0".
  • BACKTRACKING_TOLERANCE – Only available if BACKTRACKING_NUMBER" has a value of "1" or higher. Real value defining the tolerance for residual change that is allowed for residual reduction computations
  • BACKTRACKING_REDUCTION_FACTOR – Only available if BACKTRACKING_NUMBER" has a value of "1" or higher. Real value defining the reduction in step size used for residual reduction computations
  • BACKTRACKING_RESIDUAL_LIMIT – Only available if BACKTRACKING_NUMBER" has a value of "1" or higher. Real value defining the limit to which the residual is reduced with backtracking.
  • LINEAR_SOLVER – Enter the linear solver being used.

• Linear section – A table with three columns: "Use" to turn on or off options, "Option" (giving the name of the option) and "Value", where a value can be entered for the option. The options include the following:
  • INNER_MAXIMUM – Integer value defining the maximum number of inner (linear) iterations. Default value of "50".
  • INNER_DVCLOSE (length) – Real value defining the head change criterion for convergence of the inner (linear) iterations, in units of length. Default value of "0.001".
  • INNER_RCLOSE (length³/time) – Real value that defines the flow residual tolerance for convergence of the IMS linear solver and specific flow residual criteria used. Default value of "0.1".
  • RCLOSE_OPTION – Optional. Defines the specific flow residual criterion used. Default selection of "None". Has the following options:
    • "None" – If selected, an absolute residual (infinity-norm) criterion is used.
    • "Strict" – Specifies that INNERRCLOSE represents an infinity-Norm (absolute convergence criteria) and that the head and flow convergence criteria must be met on the first inner iteration.
    • "L2NORM_RCLOSE" – Specifies that INNERRCLOSE represents a L-2 Norm closure criteria instead of an infinity-Norm (absolute con-vergence criteria).
    • "RELATIVE_RCLOSE" – Spcifies that INNERRCLOSE represents a relative L-2 Norm reduction closure criteria instead of an infinity-Norm (absolute convergence criteria).
  • LINEAR_ACCELERATION – Defines the linear acceleration method used by the default IMS linear solvers. Default selection of "CG". Has the following options:
    • "CG" – Preconditioned conjugate gradient method.
    • "BICGSTAB" – Preconditionedbi-conjugate gradient stabilized method.
  • RELAXATION_FACTOR – Optional. Real value that defines the relaxation factor used by the incomplete LU factorization preconditioners (MILU(0) and MILUT). Default value of "0.0".
  • PRECONDITIONER_LEVELS – Optional. Integer value defining the level of fill for ILU decomposition used in the ILUT and MILUT preconditioners. Default value of "0".
  • PRECONDITIONER_DROP_TOLERANCE – Optional. Real value that defines the drop tolerance used to drop preconditioner terms based on the magnitude of matrix entries in the ILUT and MILUT preconditioners. Default value of "0.0".
  • NUMBER_ORTHOGONALIZATIONS – Optional. Integer value defining the interval used to explicitly recalculate the residual of the flow equation using the solver coefficient matrix, the latest head estimates, and the right hand side. Default value of "0".
  • SCALING_METHOD – Optional. Defines the matrix scaling approach used. Default selection of "None". Has the following options:
    • "None" – No matrix scaling applied.
    • "Diagonal" – Symmetric matrix scaling using the POLCG preconditioner scaling method.
    • "L2NORM" – Symmetric matrix scaling using the L2 norm.
  • REORDERING_METHOD – Optional. Defines the matrix reordering approach used. Default selection of "None". Has the following options:
    • "None" – Original ordering.
    • "RCM" – Reverse Cuthill McKee ordering.
    • "MD" – Minimum degree ordering.

MODFLOW 6 Right-Click Menu

In the Project Explorer, right-clicking on MODFLOW 6 simulation brings up a menu with several commands. Some of these commands are common to other Project Explorer right-click menus. Others are unique to the simulation right-click menus. Some of these unique commands are:

• " Simulation Data"
  • Simulation Run Queue – Opens the Simulation Run Queue dialog which shows all current simulation runs.
• " MODFLOW 6 Simulations"
  • New Simulation – Creates a new MODFLOW 6 simulation in the Project Explorer. This simulation will not contain any of the packages in any existing simulations and therefor the packages must be added. Also, creating a new simulation using this method requires linking a UGrid to the simulation.
  • Simulation Run Queue – Opens the Simulation Run Queue dialog which shows all current simulation runs.
  • Save All and Run – Saves all MODFLOW 6 simulations in the project and exports all files needed for the model run. It then will launch the Simulation Run Queu dialog and begin the model runs for all simulations in the project.
• Model
  • Simulation Run Queue – Opens the Simulation Run Queue dialog which shows all current simulation runs.
  • New Package – Opens a sub-menu listing all available packages that can be added to the simulation. Selecting a package will add it to the simulation. Some packages cannot be added until certain packages have already been added to the simulation and therefore will not be available until the prerequisite package has been added.
  • Check Simulation – Checks the simulation for model errors and brings up the Model Check dialog if any errors are found.
  • Save Simulation – Saves the simulation and exports all files needed for the model run.
  • Run Simulation – Starts the simulation model run and opens the Simulation Run Queue dialog.
  • Save Project, Simulation and Run – Saves the simulation and exports all files needed for the model run. It then will launch the Simulation Run Queu dialog and begin the model runs for the simulation.
  • Read Solution – Loads the solution file for the associated simulation. Requires that the simulation has had a successful run.

Unsupported Features

In GMS, some features of MODFLOW 6 are not yet supported or only have minimal support. These include:

• MODFLOW 6 features
  • Only support for one SOLUTIONGROUP in the mfsim.nam file
  • ‘NONE’ for cellid in SFR PACKAGEDATA block is not supported
  • IPRN variable for arrays
  • Advanced package output files
• GMS interface functionality
  • Conceptual model approach for some packages
  • Observations coverage
  • Cell properties for array-based RCH and EVT packages

The MODFLOW 6 export option does not function with projects that are incompatible with MODFLOW 6. Projects with unsupported features or parameters will not be successfully exported.

Not all MODFLOW packages are supported in MODFLOW 6. The following table shows the correlation between MODFLOW 6 packages and packages from previous versions of MODFLOW.

MODFLOW 6 supported packages	Equivalent Mf2k5/USG package
CHD, DRN, GHB, RIV, WEL	CHD, DRN, GHB, RIV, WEL
DIS, DISV, DISU, TDIS	DIS, DISU
EVT, RCH	EVT, ETS, RCH
GNC	GNC
IC	BAS
LAK	LAK
MAW	MNW2
NPF, STO	BCF, HUF, LPF, UPW
SFR	SFR
UZF	UZF
MVR, GWF, OBS	Not supported
Not Supported	DRT, GAGE, MNW1, MNWI, STR, SUB, SWI, OBS, HOB, CHOB, RVOB, STOB, DROB