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Run Numerical Engines


At this step, you can run the set of engines selected at the Single Run step.

The button will run the selected numeric engines using the required data files already present in the project folder the were generated at the Translation Step. If the required files are not present in the project folder, the numeric engines will not run. A warning message will appear indicating that the Visual MODFLOW files will not be translated prior to running the model.


Starting a Model Run

At the Run Numerical Engines Step, separate tabs will be generated for each engine or post-processing utility selected at the single run step.  The particle tracking utilities may generate multiple tabs depending on the number and type of particle groups to be simulated:


Press the button to start the simulation.  The models will run in succession:

Engines waiting to be run will be denoted by a static horse icon

The currently active engine or utility will be denoted by a running horse icon

Engines that have successfully completed will be denoted by a green checkmark

Engines that failed to run or ran with errors will be denoted by a red "x"


Model Run Progress

During a flow and/or transport engine run, Visual MODFLOW Flex will provide feedback on the progression of the model run in a text console. By default, Visual MODFLOW Flex will also display an optional chart with the solution progress by iteration reported by the engine's solver, including:

the global residual error and/or

the maximum change in the heads or concentrations relative to the previous iteration



Note that MODFLOW-6 models will show one chart for each model included in the solution (e.g. a groundwater flow model (GWF) solution and one groundwater transport model (GWT) solution for each species)


Chart Controls

The chart can be toggled on and off by clicking the plot button ().  You can also change the display settings the chart by clicking the Run View Settings button ():


Iterations to Display - allows you to select how many iterations to show.  If a specified number is selected, then only that many of the most recent iterations will be displayed


Dynamic Rescaling - allows you to select whether the vertical axes of the chart will be rescaled after a given number of iterations


Model Run Completion

When the run completes additional information including the run time and other diagnostics will be to the text console of each engine. Model output will also be added to Run > Output folder in the Model Explorer:


Flow Engine Outputs

The following nodes will be added to the Output folder on the Model Explorer:



Flooded Cells,


Velocity, and

Water Table


A saturation node will also be added if an unsaturated flow model is run (using MODFLOW-SURFACT or the UZF package). One or more residuals nodes may be added if head or flow observations were added to the run.


Transport Engine Outputs

One node will be added per simulated species for simulations including groundwater transport (e.g. using MT3D-MS, RT3D, SEAWAT, or MODFLOW-SURFACT with transport). A separate node for each species will also be added for the immobile domain if sorption is included in the Modeling Objectives. One or more residuals nodes may be added if concentration observations were added to the run.


Particle Tracking Outputs

One node will be added per particle group with pathline information if particle tracking was included as part of the simulation.


When you have finished reviewing the model run results, click (Next Step) button to proceed to the View Results step.



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