Visual MODFLOW Flex Readme

/Visual MODFLOW Flex Readme
Visual MODFLOW Flex Readme2018-07-06T10:50:54+00:00

Version 5.1 | Build 5.0.6759.0 (Jul 2018)

Defects Addressed:

  • SSM schedule not correctly translated for models when the flow model was steady state.

Version 5.1 | Build 5.0.6750.0 (Jun 2018)


Data Import/Export:

  • Surfaces created in Visual MODFLOW Flex can be exported as Surfer ASCII grid files (.GRD) for use in other Visual MODFLOW Flex projects and other software packages (e.g. Surfer, ArcMap, QGIS).
  • Pumping Wells in Visual MODFLOW Flex numerical models can be imported as text files (.CSV) using the same format that they are exported from Flex projects allowing you to transfer Wells between projects.

Visualization and Settings:

  • Vertical exaggeration in 3D views can be manipulated by keyboard commands.

Packages, Properties, and Boundary Conditions:

  • Field values for Properties and Boundary Conditions are available as variables in the Expression Builder.

Grid Editing:

  • You can now specify which numerical model run(s) are carried over when performing grid edits.

Defects Addressed:

  • In some scenarios (for instance if CHD cells are specified at the very bottom of the model [such as in the Henry model]), the parallel version of SEAWAT may have convergence problems that cannot be resolved by changing solver parameters.
  • SEAWAT engine run output was truncated and formatted incorrectly.
  • Concentration values of -1 in the specified concentration boundary condition (indicating the species should be skipped) were incorrectly translated to the SSM file as 0.
  • Error in translating diffusion arrays to the DSP package when specifying the Multidiffusion option in MT3D-MS or SEAWAT runs.
  • In rare occasions, property zones were set to -1 and uneditable.
  • In some cases, successive model translation times increased due to a memory leak.
  • In ZoneBudget runs, Flex does not read in values for zones that are not directly adjacent to Zone 1.
  • Errors thrown if user skips straight to Translate without selecting an engine.
  • In some cases, changes to stress periods do not update instantly to the translation settings resulting in incorrect translated time discretization and/or output control (.OC) files, following changes.
  • In some cases, PEST results will not update correctly into a new run.
  • An error is shown when user clicks […] button to change the path to Previous MODFLOW Run HDS file if the HDS file is not present.
  • Hitting Apply in the Settings dialog for a concentration doesn’t update the BC view properly.

Version 5.0 | Build 5.0.6597.0 (Jan 2018)



  • Visual MODFLOW Flex now supports SEAWAT (v4.00.05), a three-dimensional variable density flow and multi-species solute transport model developed by the USGS, based on a combination of MODFLOW and MT3D-MS.  Version 4 of SEAWAT also supports viscosity effects and heat transport.
  • The following SEAWAT flow packages are supported in Visual MODFLOW Flex:
    • BAS6 – Basic Package
    • DIS – Discretization Package
    • BCF6 – Block-Centered Flow Package
    • LPF – Layer Property Flow Package
    • OC – Output Control Package
    • RCH – Recharge Package
    • EVT – Evapotranspiration Package
    • WEL – Well Package
    • DRN – Drain Package RIV – River Package
    • GHB – General-Head Boundary Package
    • FHB – Flow and Head Boundary Package
    • CHD – Time-Variant Constant Head Package
    • LAK – Lake Package (LAK3)
    • HFB6 – Horizontal Flow Barrier package (HFB6)
    • OBS – Observation
    • HOB – Hydraulic-Head Observation
    • GMG – Geometric Multi-Grid Solver
    • PCG – Pre-conditioned Conjugate Gradient Solver (PCG2)
    • WHS – BiCGSTAB-P Matrix Solver
    • LMG – Link Multi-Grid package for using the SAMG (Systems Algebraic Multi-Grid) Solver
  • The following SEAWAT transport packages are supported in Visual MODFLOW Flex:
    • VDF – Variable Density Package
    • VSC – Viscosity Package
    • BTN – Basic Transport
    • ADV – Advection
    • DSP – Dispersion
    • SSM – Source/Sink Mixing
    • RCT – Reaction Package
    • GCG – Generalized Conjugate Gradient Solver

NOTE: Advanced Translate/Run Settings (see below) enable partial support for simulating additional processes/packages (e.g. subsidence, drain return) developed outside of Flex.


  • Visual MODFLOW Flex now supports RT3D (v2.50), an advanced reactive transport engine based on the popular MT3DMS transport engine.
  • The following RT3D reaction modules are supported in Visual MODFLOW Flex:
    • Instantaneous aerobic degradation of BTEX.
    • Six Species, First-Order, Rate-Limited, BTEX Degradation using Sequential Electron Acceptors
    • Rate-Limited Sorption
    • Double Monod Model
    • Sequential First-Order Decay (up to 4 species, e.g., PCE/TCE/DCE/VC)
    • Aerobic/Anaerobic PCE/TCE Dechlorination

Visualization and Settings:

  • Cell Inspector: View and inspect structured and unstructured models at the cell-level using the new cell inspector, available in the workflow viewers. The cell inspector displays cell values for user-specified input and output data fields.
  • Status Bar: Cell dimensions have been added to the status bar.
  • Time-Picker: A time-picker is now available for unstructured grid workflow viewers.
  • Layer-Picker: A layer-picker is now available for unstructured grid workflow viewers.


  • Additional Translation/Run Settings: Added advanced settings for all supported engines (excluding MODFLOW-USG) so that you can specify whether individual packages are translated and/or run with the model, which provides the flexibility to integrate your own package input files within the Flex environment.

Property and Boundary Condition Tools:

  • Field Calculator: Populate boundary condition fields using a calculator that includes an expression builder dialog to facilitate the inclusion of variables based on your model’s properties (e.g. grid dimensions, elevations).
  • Dispersion Parameters: Values can be edited in the Dispersion Parameter Dialog using copy, paste, and fill commands.

Usability and Other Enhancements:

  • Easy Classic Importing: Import your Classic project into Visual MODFLOW Flex directly from the file menu.
  • Import Classic Concentrations: Boundary condition concentrations are now imported from Classic Projects.
  • Animate Relative times in 3D views: in 3D View animations, the time stamp label for heads can be specified in relative or absolute time.
  • Descriptive Title Bars for Settings Windows: settings windows now display descriptive window titles including the data layer and viewer settings to which they apply.
  • Rename Objects: objects in the Data Explorer and most objects in the Model Explorer can be renamed.
  • Feedback Button: added anonymous feedback buttons so that you can easily report what features you like or don’t like.
  • SAMG Solver: added a single-processor version of the SAMG solver for Visual MODFLOW PRO users.

Defects Addressed:

  • Defining BCs along irregular polylines that are close to the active model limits produced unexpected results
  • Reorder Tool was missing in some views
  • The Show/Hide Gridlines button and associated toolbar disappeared intermittently from the viewer
  • Well Data import failed without warning the user that the pumping schedule had inconsistencies, including pumping start date before model start date or pumping start date after pumping end date
  • User could not assign polygon attribute data to conceptual recharge/evapotranspiration elements
  • Problem(s) with Time Series Viewer
  • Multiple PEST Workflows could be created for the same model run which corrupted the PEST workflow.
  • Multiple issues in the advanced run/translation settings
  • PCG Solver translation settings of the PCG2, PCG4, and PCG5 solver packages for MODFLOW-SURFACT models

Version 4.1 | Build 4.0.6408.0 (July 2017)


Visualization and Settings:

  • 2D/3D View Keyboard Navigation: Navigate in the active 2D or 3D view using the keyboard. Arrow keys pan the view, +/- keys (on the number pad) and page up/page down keys zoom in and out. In an active 3D view, the +arrow up/down keys changes the inclination of the model relative to the horizon and +arrow right/left rotates the model about the vertical axis
  • Custom Contours: Customize contours in 2D, 3D, and Flex Viewers by setting start and finish contour values for contour lines and isolines. You can also specify a contour interval. Changes in one part of the Flex Viewer are reflected in the other parts.
  • 3D View Setting Defaults: Create and Save Project-Specific Default View Settings for each each data type in the 3D Viewer.
  • Time-Series Viewer: View time series data such as heads, saturation, and concentration at points within transient models without specified observation points


  • Modeling Objectives: Modeling Objectives for Transport Simulations can be changed at any time, not just during initial setup or conversion.
  • Model Settings for Translate/Run: You can now specify whether individual packages are translated and/or run with the model, which provides the flexibility to use your own packages similar to the advance settings in Classic for model translate/run

Grid Editing Enhancements:

  • Cell Size Control for Conceptual Models: Similar to numerical grids, you now have full control over the grid cell size specification during initial grid creation; you can set grid cells to whole numbers for ease of calculation and reporting.

Property and Boundary Conditions:

  • Boundary Conditions in LGR Models: Boundary conditions that span the parent/child grid interface(s) in an LGR model can be specified in both the Conceptual and Numerical workflows.
  • Dual Domain mass transfer: Flex now supports dual domain mass transport modeling through the MT3DMS and MODFLOW SURFACT (see below) transport engines.
  • Unsaturated Zone Flow (UZF) Package: Flex now supports 1-D unsaturated flow associated with the UZF package.
  • Time-varying Material Properties (TMP) Package: Flex now supports the TMP package associated with MODFLOW-SURFACT

Updated Engines:

  • Upgraded MODFLOW 2005: Flex is now packaged with MODFLOW-2005 v1.12.00, the latest official USGS version as of the release date of Flex 4.1.
  • Upgraded MODFLOW NWT: Flex is now packaged with MODFLOW-NWT v1.1.2, the latest official USGS version as of the release date of Flex 4.1


  • Added Support for MODFLOW SURFACT: Visual MODFLOW Flex now supports MODFLOW SURFACT Version 4.0, a fully-coupled flow and transport engine developed by Hydrogeologic, Inc. which features many robust methods and enhanced simulation capabilities for handling complex saturated/unsaturated subsurface flow and transport processes. Based on the USGS modular groundwater flow model, MODFLOW, it supports the following packages:
    • BAS4 – Basic Package
    • BCF4 – Block-Centered Flow Package
    • BTN1 – Basic Transport Package
    • TMP1 – Time-Varying Material Properties Package
    • CHD – Time-Variant Specified Head
    • DRN – Drain Package
    • EVT – Evapotranspiration Package
    • FHB – Flow and Head (Time-Varying) Boundary
    • FWL5 – Multi-Node Fracture Well
    • GHB – General-Head Boundary
    • HCN1 – Prescribed-Head-Concentration Boundary
    • HFB – Horizontal Flow Barrier (Wall)
    • LK3 – Lake Package V3
    • PCN1 – Prescribed-Head-Concentration Boundary
    • RSF4 – Recharge-Seepage Face Package
    • RIV – River Package
    • WEL – Well Package
    • HOB – Head Observation Package
    • OBS – Observation Nodes
    • OC – Output Control
    • PCG5 – Preconditioned Conjugate Gradient Solver
    • SIP – Strongly Implicit Procedure
    • SAMG – Algebraic Multi-Grid Solver
    • GMG – Geometric Multi-Grid Solver
    • WHS – BiCGSTAB-P Matrix Solver
  • NOTE: MODFLOW SURFACT was developed by Hydrogeologic, Inc. and is sold as a separate add-on for Visual MODFLOW Flex. A demo-version that supports model grids of up to 10,000 cells is included for evaluation purposes. Additional packages (e.g. subsidence [SUB], streamflow routing [SFR], etc.) are supported by SURFACT and may be developed outside Flex.


  • Undock/redock Tabs: Tabs can be undocked as separate windows. Simply drag and drop or right-click on the Tab name and select the “Undock Tab” option and you can place the new window anywhere on your monitor screen(s). Redock a window back to the main program window using drag and drop or right-click and select “Dock Tab” option.
  • Explorer Support: Open a Visual MODFLOW Flex .AMD file directly from Windows Explorer.
  • .Net Framework 4.6.1: now bundled with Flex installation
  • About/Splash Screen: Version and Build number are displayed on the Splash Screen and on the About Screen.
  • Improved Performance: Improved memory handling and performance enhancements

Defects Addressed:

  • Could not edit or define a Boundary Condition when multiple grids were present as part of the same LGR grid
  • Inconsistency between calculating and displaying leakance in the lake boundary condition when using certain time units
  • Some PEST runs were not successful due to incorrect observation files.
  • Issue when importing time schedules for recharge package
  • Translation issue when importing some Visual MODFLOW 2010.1 Classic projects into Flex.
  • Progress bar does not provide adequate feedback when opening large projects
  • Issue with extracting multiple species from sub-grids for MT3DMS runs
  • Toolbox was blank after translating/running the model and clicking Define Properties step
  • Translation issue in MT3DMS RC3 file for bulk density values when using inconsistent units
  • Improved feedback/reporting for certain engine runs that do not converge

Version 4.0 | Build 4.0.1039.3 (December 2016)


Grid Editing Enhancements:

  • Numerical grid editing – you can now edit your numerical grids after they have been created.
  • Fractional grid refinement – Allows you to change grid spacing by a fraction, rather than just whole number. For example; you can choose over a specified model area to convert every 3 rows or columns to 2 rows or columns (or whatever fraction you wish). This is particularly useful for grid smoothing to ensure that grid step sizes aren’t too large.
  • Cell size control – Full control over the grid cell size specification during initial grid creation; you can set grid cells to whole numbers for ease of calculation and reporting.
  • Grid quality indicators – Visual indication during grid editing of cells that violate the maximum cell step size, and flexibility to define the cell step size tolerance for each grid, so you can ensure a high quality grid and reduce potential for grid-based dispersion and/or larger computational times.

Property and Boundary Condition Editing Enhancements:

  • Cross-Section assignment – Assign or edit boundaries and properties in cross-sectional views.
  • Calculated value support – Use calculated values to determine boundary condition attributes, such as conductance and cell in-flow rates.
  • Boundary condition validation – Internal system checks on assigned boundary conditions to ensure that they meet MODFLOW engine requirements – For example; start and ending heads are above cell top. Flex automatically suggests corrective actions for any violations.
  • Multi-segment linear interpolation for boundary condition values – Now you have full control to define linearly interpolated values over a section of a boundary, or multiple segments with different linear interpolations as needed, to simplify assigning the boundary values you want.
  • Copy/paste and bulk property or boundary value assignment – If you have your values already defined outside of Flex, you can now quickly copy and paste them right into the boundary or property zone dialogues.
  • Need a way to insert the same value in multiple cells? Now you can do that too with one click or keystroke.
  • Visually interactive editor – Would you like to edit boundary or cell values cell-by-cell to improve your model calibration? The new visually interactive editor lets you select a value and see where the cell is located in the grid viewer, or, select a cell in the grid viewer and directly edit the cell values.

Other Enhancements:

  • Sub-grid creation – quickly create a new model based on a sub-grid from a larger model (including creation of all appropriate boundary conditions) with two mouse clicks.  This is particularly useful for creation of local transport models from larger scale flow models.
  • DXF support – display 2D or 3D DXFs in any of the Flex viewer windows to use as base-maps and help understand and place simulation results in real-world context.
  • Heads from a previous run – use heads files from previous model runs as the starting point for new model runs.
  • FlexScript DSL scripting – Hate the mouse and love your keyboard?  Now you can use FlexScript to make quick adjustments or exact replicas of grid designs, property, and boundary specifications without having to click-through the user interface.

Defects Addressed:

  • Numbering of Conceptual Model horizons is now consistent with zones.
  • Updated the import project file dialog to allow all supported file types.
  • Fixed a cosmetic issue with the Workflow Diagram legend message.
  • User cannot enter invalid characters when creating a numeric grid.
  • An issue with project naming which prevented the model from running has been resolved.
  • Inactive legend labels are no longer shown in the chart view.
  • The Next and Previous workflow arrows are now disabled during engine run and translation.
  • Inconsistencies with how the Model Explorer handles click events have been fixed.
  • Rotated surfaces in the 3D viewer now always align and correctly cover the grid.
  • The “User Virtual Grid” style setting is now correctly saved during project save/load.
  • An intermittent issue displaying wells in the 2D viewer has been corrected.
  • Enabled Wells in View Charts is now saved after successive translate and run operations.
  • Transport settings are now correctly synced between the conceptual model and numerical model.
  • An intermittent error when drawing a polygon property zone has been resolved.
  • You are no longer able to launch multiple identical property dialog boxes.
  • VMOD Flex now saves your current workflow step when saving a project.
  • All style settings are now saved when a project is saved.
  • Some minor color issues with the 2D/3D view have been corrected.
  • An occasional error when unchecking the “User Virtual Grid” checkbox in the standalone 3D viewer has been resolved.
  • When cloning a model run the wall boundary condition is now always included.
  • Occasionally duplicate run nodes were displayed in the Model Explorer.  This scenario has been resolved.
  • Minor label fixes were applied to the calibration charts.
  • Issues adding initial head and storage properties in the conceptual workflow have been addressed.
  • MODFLOW run project files are now always cleaned up when a model run is deleted.
  • An incorrect warning message presented during the conceptual model boundary condition creation step has been removed.
  • All boundary condition attributes are now being correctly saved when edited.
  • Some project properties which are not editable are now correctly displayed.
  • The 3D view wireframe selector’s state is now correctly saved during project save/load.
  • All chart settings are now correctly retained on project save/load.
  • An incorrect warning message no longer displays when changing the Damping Factor (DAMP).
  • Installation issues with the MS Visual C++ package have been addressed.
  • Duplicate entries in the Windows Programs & Features list have been removed
  • An error adding data to the composite view for certain projects has been corrected.
  • When exporting the Water Table the elevations column has now been included.
  • A validation message displayed during River boundary condition validation now lists the problems detected.
  • A warning message is no longer incorrectly displayed when a well pump start date is the same as the model start date.
  • Icons in the view charts legend have been resized.
  • The “Open Workflow” window has been made resizable.
  • Improper translation of a constant head boundary condition between conceptual and numerical models has been fixed.
  • Settings for Flux boundary conditions are now available.
  • Shapefiles that contain attributes are now able to be imported.
  • Error log location has been added to error messages.
  • The (S)AMG solver feature is now available to premium users.
  • A scenario where mass balance results were not available has been resolved.
  • Creating a USG boundary condition of the same name no longer causes an error.
  • Inactive cells are no longer rendered with flux values.
  • A rare condition where the boundary condition dialog opens and is blank has been resolved.

Build 3.0.786.16 (March 2016)

Defects Addressed

  • Recharge boundary, assign to polygons with “Apply to All” was not working
  • River boundary condition with linear interpolation conceptual to numerical conversion was not working
  • Updated website links for web help and release notes
  • Added support for Windows 10

Build 3.0.653.1 (December 2015)

Defects Addressed

  • Error when exporting heads to shapefile, and selecting all output times
  • Opening project gives error “Error loading finite difference mesh” numerous times
  • Trying to export Calc vs Obs chart data to .CSV causes “Cannot export Calibration data. the given key was not present in the dictionary” error (project specific)
  • Translating and running the project and viewing the output node, shows concentrations for elements undefined in the model
  • Conceptual Model is frozen, non-responsive (on Windows 10)
  • Error during saving project (on Windows 10)
  • USG model cannot load water-table after model run
  • Sink/Source Boundary condition Package translator. Translation failed error
  • Assigning Isosurfaces for conductivity causes error
  • Transient model flux output does not change with time in 3D Viewer
  • Using polyline object to assign constant head boundary condition creates various numbered zones in define boundary condition step
  • Well Translation Failed (project specific)
  • Heads results are different/incorrect for imported Classic models (when using distributed property zones)
  • Create Pumping Wells window, the OK button is cut off on low resolution or large font sizes
  • When importing 3D Gridded data, Tecplot .DAT format, rotated grids are now supported

Build 3.0.507.4, v.2015.1 Release (June 2015)


  • Added support for MODFLOW-NWT: translate NWT and UPW package, import MODFLOW-NWT model from VMOD Classic.
  • Added options to modify MODPATH results: adjust pathline travel time and time marker frequency
  • During import of wells (pumping or observation) in absolute times, show warnings of any well data that comes before the model start date
  • When define obs. wells, added check for observation dates to be equal to or greater than the modeling objectives start date, and show any offending records
  • Added option to Assign Single or Assign Line for define properties, in the numerical modeling workflow (regular MODFLOW)
  • Added option to “Assign/Single” for inactive cells in numerical workflow
  • Added option to copy boundary condition cell geometry and parameters to other layers in the numerical modeling workflow (regular MODFLOW and MODFLOW-LGR only)
  • Update Export option for Forward/Backward pathlines to use the adjusted pathline length and defined time markers
  • Added units to the Boundary Condition parameter windows
  • Added a new “Object list in view” section to the Flex viewer, to simplify access to settings and options for data objects displayed at a particular workflow step
  • When creating pumping well boundary conditions, added validation for start time for source data to ensure schedule comes on or after the model start date. In addition, for wells that start at different times, added option to automatically insert zero pumping rate until the schedule is defined
  • During Conceptual Model to Numerical Model conversion (regular grids), honour varying boundary condition end times in the resulting numerical model
  • Remove default start date (of today) in the modeling objectives section, for Numerical Model and Conceptual Model
  • Disabled option the change the model start date in the modeling objectives, since this had no impact on the numerical model start time, and only affected the start date for conceptual boundary condition objects; this created confusion for pumping wells/obs. well data that may have been imported with different absolute times
  • Added option to set time periods as active/inactive for numerical boundary conditions (CHD, RIV, GHD, DRN, Specified Flux, LAK), for regular MODFLOW
  • Translate boundary condition time periods “inactive” to appropriate packages (CHD, River, Drain, GHB), by inserting 0 cells for the specific stress periods
  • In the settings for wells data object spreadsheet, added an option to show pumping well schedule or observation times, as relative times.
  • Added option to show water table as a surface (contours/color shading) in 3D Viewer, for MODFLOW-USG runs
  • Added an option to export water table to CSV file, for MODFLOW-USG models
  • Add a legend option to the style settings for water table (surface) for 3D viewer, for MODFLOW-USG and regular MODFLOW
  • When defining active/inactive cells (regular MODFLOW), provide option to have the cell assigments span multiple layers in the model
  • Added an option to change an existing numerical boundary condition from steady state to transient
  • Added new operation for surfaces: Add, Subtract, Multiply, or Divide Z value for a surface, and save as a new surface data object
  • Added option to import observation wells object (heads and concentrations) in relative times from XLS file.
  • Adjusted the import from VMOD Classic option, for wells with point source concentrations, to account for the new pumping wells object with species concentrations
  • Added option to import raw pumping wells in relative times from XLS file.
  • Added option to view/edit observation data (in the regular MODFLOW numerical model) in CSV file, then reload edits back into the model
  • During translation, extend boundary condition stresses to the maximum end time from all boundary conditions, and add “zero” entry for the cell count to the translated package (regular MODFLOW-2000); behaviour similar to VMOD Classic.
  • Added an option to export new pumping wells object to CSV file.
  • Improved error handling and warning message in the event that a MODFLOW run does not converge.
  • Added a mechanism to notify user if they open a project that is created in a newer version of VMOD Flex, when running an older version (will only work for projects in v.2015.1 and future versions of the software)
  • Added a “Finish and Cancel” button to toolbox when doing assign and editing in the numerical model workflow, to improve usability
  • Added warning message when users attempt to edit “old” numerical pumping wells, with suggestion to convert these into “new” pumping wells.
  • Added translate active flag for new well, to basic WEL package
  • Added option to define species concentrations to entire well interval, for new wells object
  • When define boundary condition, using polyline or polygon, added option for attributes to apply defined values/methods for one polygon/polyline to all other polygons/polylines in the selected data object
  • Added option to add one or more new wells with a mouse click, in layer view, for regular MODFLOW models
  • Added option to recognize the active/inactive flag for pumping wells, when import a model from VMOD Classic
  • Added option to set pumping wells as active/inactive, in the new wells interface
  • Added option to see contours/color shading for Fluxes (in X, Y, or Z direction) in 3D viewer (for regular MODFLOW models)
  • Added option to edit conceptual pumping well boundary condition object, after it has been created (for new well model only)
  • Added option for color legends for USG models (properties, heads) to recognize user-defined values from the color settings
  • Added option to save the scene manipulation for USG models in 3D Viewer, after doing save and reload project
  • Added option to create new well boundary condition from within a numerical workflow (using existing well data object from data explorer)
  • Added option to create new well boundary condition in a conceptual workflow, using data object
  • Added a maximum horizon quality of 1000 rows * 1000 columns to improve performance based on “typical” model surfaces and scales; for more details on adjusting this, please contact technical support
  • Added options and toolbar to Data tab and Model explorer to collapse, move, and hide this panel
  • When import model from VMOD Classic, with recharge and EVT time periods set as inactive, set these time periods to have 0 recharge or EVT rate
  • Renamed Logger to Obs.Point in the wells import at the data mapping step
  • Renamed Logger to Obs.Point in the wells settings

Defects Addressed

  • After edit the end time of an existing transient numerical boundary condition, returning and editing the value, it was not saved
  • After importing a model from VMOD Classic, some rewetting options at the Translate/Settings step were not correctly set
  • In certain cases, data objects on Data panel were disabled for 3D viewer inside the MODFLOW-USG workflow
  • Anisotropy calculation for LPF package (regular MODFLOW) used Kx/Ky instead of Ky/Kx (when using the anisotropy as specified option)
  • BCF package translation (for regular MODFLOW) was incorrect for layer type 0 and 2 (transmissivity values not correctly calculated)
  • In the Edit Boundary Condition window, the defined data values were not being saved in the scenario where you add a time schedule to a transient boundary condition
  • BTN translation (for MT3DMS) did not take into account spatially-varying porosity values; it always translated one constant value per layer
  • BTN translation (for MT3DMS) was incorrect for dY calculation (column array (DELC)
  • Could not delete boundary condition items from Model Explorer in a MODFLOW-USG numerical model
  • Incorrect cells rendering of Concentration output in a stand-alone 3D viewer
  • Colors of conceptual property zone objects were not saved in 3D viewer, after save/reload
  • Species concentration numerical attributes did not appear when editing specified flux boundary condition object, with concentration values defined
  • In some cases, species concentration values assigned to specified flux oundary Condition were not translated to SS3 (MT3DMS) package
  • Conceptual to Numerical conversion failed when river boundary condition was selected when the option “Define values at vertices (Linear Interpolation)” was used
  • Conductance value for river object after Conceptual to Numerical Model conversion was incorrect (due to river in inactive cells)
  • Contour lines of surface object were not properly turned off in 3D view
  • Delete menu option for head or concentration obs wells object on Model Explorer did not work
  • Deleting files from conceptual model explorer did not delete all files from the “Arrays” folder on data repository.
  • Deleting grids from the Model Explorer tree, after save and close, and reload, the numerical grids sometimes re-appeared on the model explorer
  • Deleting model run from the Model Explorer in a USG workflow did not delete all related files from the project folder on the hard drive
  • Deleting grid from Model Explorer did not delete GriddedPlugin objects from the .data folder.
  • Deleting numerical models with recharge did not delete .CDF files from data repository.
  • Deleting objects from model explorer did not clean up corresponding files in data repository, and leads to large data repository folders with obsolete files.
  • Deleting runs from model tree did not delete associated files in the data folder
  • Fixed the description of parameter names in the .MPT package
  • Could not close 2D viewer when in pick/edit mode, after doing edit wells, then close project.
  • Addressed errors when opening a complex polygon in 3D viewer
  • Improved error handling when MODFLOW-LGR run fails to converge
  • Addressed errors when using the operation Z=Surface for a map image.
  • Addressed errors when assigning particles, if circle of particles are outside model domain
  • Fixed buttons that were cut off on the Grid at the Translate step in numerical workflow
  • Fixed color legend in 3D viewer when you change background color to anything but black
  • Fixed order of columns for head and concentration obs. data in raw wells spreadsheet
  • Addressed error during Conceptual to Numerical Model conversion (regular grid) for constant head with linear gradient, which used intermediation layer option
  • Addressed errors “Cannot find finite difference grid” after loading old project where a grid was deleted
  • Addressed cleanup of the Grid folder (from project data repository) when an UnStructured grid was deleted from the Model Explorer
  • Addressed problem of MODPATH, ZoneBUDGET and MT3DMS starting in the event that the MODFLOW model failed to converge
  • Fixed issues with .WEL package not matching the .WEL package from a VMOD Classic model (project specific)
  • Added units to the property zone database window in numerical model workflow
  • Addressed problem of incorrect assignment of active cells when creating a new numerical grid with rotation angle exactly 45 degrees
  • Addressed problem of incorrect observation values after copy from excel, save, close and reopen View Spreadsheet
  • Addressed problem of LMG file being included with translation even though this solver was not selected
  • Addressed problem of MODPATH .MPT.ep porosity translation (only when you have spatially-varying porosity values)
  • Multiple forward particle data objects were added to the model explorer, when working with multiple model runs (there should be only one per numerical model)
  • Improved the behavior of assigning new property zone in the numerical model using polygon, where the polygon extends outside of model domain or covers inactive cells
  • Improved the display of the validation screen at the end of data importing, on Windows 8.1
  • Addressed incorrect import of porosity values when importing a model from VMOD Classic
  • Property zones with polygons were not converted correctly to all layers in the model
  • Encounter out-of memory issue when doing concpetual to numercial conversion, with large grids, when consecutive executions (typically more than 10 times)
  • Improved the Project/Save As performance and processing time
  • Improved the Project Save and Project Open time, due to the large project directory size that contained obsolete grids and model runs files
  • SSM (MT3DMS) translation did not include values from constant concentration, after save and reload project
  • Storage values are translated incorrectly for LPF and BCF package (for regular MODFLOW), when values are spatially-varying per layer
  • Surface in 3D or 2D viewer did not allow to turn off color fill and show only contour lines.
  • The check box beside boundary condition group folders in the model explorer (Numerical Model) did not show up after save and reload project
  • The defined name for new Conceptual Models was not being used in the Model Explorer
  • Translation for FHB package was incorrect for Transient mode
  • Translation for WEL package was incorrect for MODFLOW-LGR model, when well is screened over multple layers.
  • Addressed error when viewing water table (project specific)
  • Addressed error when trying to assign Constant Concentration to “Sides” of model domain
  • Improved usability issues when defining Boundary Conditions to the sides (selecting faces/sides)
  • Improved the save/reload states for 3D viewer in a USG numerical model workflow, including selected data objects, property zone selection, and style settings
  • Addressed problem of incorrect constant head attributes converted to numerical model, when using linear interpolation and transient attributes
  • Addressed problem of incorrect constant head cell location after converting from a conceptual model (project specific)
  • Addressed problem of contour interval setting not working for Layer View, when viewing Heads/Concentrations
  • Addressed problem with program not responding during Conceptual to Numerical Model conversion for complex Drain Boundary Condition and multi-layer numerical grid (project specific)
  • Addressed problem of incorrect .WEL translation in certain cases where there are inactive cells
  • Addressed problem of incorrect .WEL translation in the case where a well lies in a child grid that had layer refinement different from parent grid
  • Addressed incorrect Conductance calculation (for River, Gen Head, and Lake) in the case where the units for Conductivity were in a different convention then the project length and time units
  • Improved clean up of project data repository folder, after deleting Grid and Run objects from the model explorer
  • Addressed problem of icon changing in 2D viewer when doing editing.
  • Addressed problem of last selected folder not being saved, when doing consecutive import of data objects using File/Import.
  • Addressed incorrect .LPF package translation (regular MODFLOW) in the scenario where cell re-wetting is active and the model contains inactive cells.
  • Addressed differences in the displayed output times for Heads & Drawdown when comparing the list of times in 3D viewer settings vs. those shown in the Flex viewer, for transient MODFLOW runs

Build 2.1.300.0 (November 2014)

Defects Addressed

  • Long processing time for .CSV editing and re-loading for a General Head Boundary condition group (MODFLOW-2000/2005)
  • After converting conceptual model to numerical model for a General Head  boundary condition assigned to the sides of the model domain, conductance value was being incorrectly calculated as 0 (MODFLOW-2000/2005)
  • Empty attribute data contained in the .csv file of river boundary after converting to a numerical model (MODFLOW-2000/2005) (project-specific)
  • Transport charts not showing up for models that used rotated grid (MODFLOW-2000/2005)
  • Transport charts not showing up when a grid cell contained more than one observation point (XY) (MODFLOW-2000/2005)
  • After refining a MODFLOW-2000/2005 grid, layer elevations were not re-calculated correctly.
  • Error when running animation for conceptual model structure in 3D view.
  • Error in converting the Specified Flux conceptual boundary condition (assigned to the sides of model domain) to numerical model (MODFLOW-2000/2005)
  • Translation error “The given key was not present in the dictionary” for certain projects. (MODFLOW-2000/2005)
  • Data operations, unable to assign the Z values of a polygon from the selected surface
  • Fixed Airport-Transport tutorial solution project files (previously was showing error when loading and also at the Translation step)

Build, v.2014.2 Release (July 2014)


  • Define New Zone Budget zones using Point, Polyline, and Polygon. (Available for MODFLOW-2000 and 2005)
  • Define Wall (HFB) boundary condition. (Available for MODFLOW-2000 and 2005)
  • Improved Options for Defining/Removing Particles
  • Show water table for structured MODFLOW models (plan, XS, 3D view). (Available for MODFLOW-2000 and 2005)
  • Edit numerical property zones or boundary condition attributes in CSV format, and reload back into the numerical model.
  • User-defined color classifications for color rendering (Heads, Conductivity, etc.)
  • Improved coloring of property/recharge zones, when render by ZoneID
  • Export chart data to CSV file
  • Support for rotated numerical grids in numerical workflow (when create new grids, for MODFLOW-2000 and 2005)
  • Improved usability for workflows (better defaults when importing models or generating numerical models from conceptual models)
  • Fix the default zoom level for the 2D (layer view) in the Flex Viewer, when at the View/Grid step and View/BC step (in MODFLOW-2000,2005 workflows)
  • Create the Grid Specification File (GSF) during MODFLOW-USG translation (reserved for future development, including MODPATH-3DU and PEST)
  • Export pathlines to polyline shapefiles
  • Add option to assign new Specified Flux Boundary (assign / polyline, assign/polygon), in the numerical workflow (Available for MODFLOW-2000, 2005)
  • When show unstructured grids in 3D viewer, added option to view the cell geometry as smoothed continuous  surfaces (and not discrete flat top/bottoms)
  • At the Define Boundary Condition step in numerical workflow, added option to create numerical boundary condition from existing data objects (polygon, polyline), (excludes Well objects.) (Available for MODFLOW-2000 and 2005)
  • Improvement in the way time schedules are handled for boundary conditions, to catch boundary conditions that have start/end times that are inconsistent with other boundary conditions.

Defects Addressed

  • Could not create thin layers (less than 0.01 m or ft) at the Create Grid step in Numerical workflow (MODFLOW-2000 and 2005)
  • When export raw point, polyline, or polygon data to shapefiles, VMOD Flex did not create shapefiles correctly. In some cases, the shapefiles could not be loaded in Third-party software
  • In the Import Data window, wells shows up twice in the list of data object types, after you close and reopen a project
  • The attributes below the Layer view (on status bar) did not refresh when changing the mouse locations for rotated grids.
  • Inactive cells were not showing up correctly for models with rotated grids
  • At the end of the PEST workflow, after save results as new run, in the new model run the head observations were not included on the model tree.
  • Could not create numerical grid with certain layer number configurations
  • PEST – after doing update model inputs,  the PEST workflow was also being cloned
  • When edit a conceptual boundary condition, the attribute values for species concentrations did not show up
  • In settings for imported 3D Grid object (.HDS) the transient output times were not showing correctly
  • During import VMOD Classic model with a few thousand wells, there was a very long delay when calculating time schedules
  • For a USG Grid, 3D Viewer, displaying Cells, the Legend option was not working
  • After import 3d grid object (HDS), the time values were not using the correct units from the project settings
  • Transparency did not work for 3D Gridded objects (eg. MODFLOW conductivity) for cells view
  • Error saving project, with USG numerical models (only occurred in certain computer/regional setting configurations)
  • Stand-alone 3D viewer was showing results from previous MODFLOW run (and was not refreshing after a re-run of the model)
  • After importing a Surface data object, when View Spreadsheet, values were showing duplicate XYZ values.
  • Storage property zone values were flipped/mirrored after importing a model from VMOD Classic
  • Error during import of project with rotated particles, and particles did not show in the correct location
  • 3D view, Z axis labels were mirrored/flipped, when viewing simple surfaces.
  • Improved the loading time in Flex viewer when displaying Recharge and EVT Boundary Condition cell zones.
  • Define Properties step in numerical workflow was reverting back to displaying Conductivity every time you return to this step
  • The status bar was cutting off the last few digits for Kx, when the value is E-04 range, and was incorrectly rounding up
  • When importing a surface, if you chose a text file that contains XYZ points, and not gridded ESRI ASCII .GRD, you got an error.
  • Improved engine run times by disabling detailed logging.
  • In PEST workflow,  were encountering error when trying to generate .PST file at the Sensitivity Analysis step (with certain parameter configurations)
  • When edit attributes for Specified Flux numerical boundary condition, the wrong units were being displayed.
  • MT3D runs failed due to problem with MXSS value in the SSM package
  • Improved error message at Translate step, when using the Initial Heads option “ Use Heads from previous MODFLOW Run” and the .HDS file could not be found
  • Error “object reference” occurs if you add a structural zone to the grid without first creating a new property zone (in Conceptual Model workflow)
  • Fixed the zoom level for 2D view by Row or Column,  when you adjust the vertical exaggeration
  • In 2D viewer, when editing points, it was taking a long time to add new points when other viewers were opened.
  • Unable to import well data (Excel data file-specific), and unable to convert pumping rates from L/day to project units.
  • 3D viewer, Settings/Isosurface, the correct values were not appearing when returning back to Edit an Isosurface
  • Added option to Edit/Single and Edit/Group for Specified Flux boundary condition in the numerical modeling workflow (MODFLOW-2000 and 2005)
  • MODFLOW USG, 3D viewer, showing slice, when reload style settings, make change to slice, it restores the Cells view.
  • Increased precision for the label for time values in the Head style settings
  • Improved the conversion time for Recharge and Evapotransperation boundary conditions when going from Conceptual Model to Numerical Model (MODFLOW-2000, 2005 and LGR)
  • Error when trying to create a surface with a blank point data object
  • Get error when creating a Surface if using points object created from an operation. (eg. well tops or HGA XS)
  • Fixed the behavior of the Assign and Edit buttons at the Define Boundary Conditions step (Numerical Workflow) in the event when you do not complete one of the selected actions; added an option to “Cancel Editing” when right-clicking on the view, will take you back to the original state.
  • Define Particles, when add new particles this was always overwriting the previously defined set of particles
  • Import Surface data object, if you chose a .txt file that is not ESRI ASCII grid format (such as XYZ points), you would encounter a non-user friendly error
  • When creating Voronoi USG grid consecutive times with the same grid generator settings, the resulting grid cell count was not exactly the same
  • Error message and program freezes when importing certain polyline objects

Build 2.0.102 (January 2014)

Defects Addressed

  • Problems importing 3D Gridded Data Object, TecPlot .DAT file format
  • PEST utilities were being flagged as potential virus threat on certain virus scanners
  • Inactive cells were showing up incorrectly in all layers of the model, instead of the specified layers
  • When using initial heads from a previous MODFLOW run, if the model contained inactive cells, the heads were not rendered correctly in the results
  • In some cases there was a problem using a .HDS file from a previous MODFLOW run for initial heads, when cycling between multiple projects
  • An error would occur when defining a new property zone with a polygon, after doing conversion from the conceptual model
  • Unable to create horizons for surfaces that have undefined values around the edges
  • When import polygon as .DXF format, in some cases the file would not load as a closed polygon

Build 2.0.88, v.2014.1 Release (November 2013)


  • added support for MODFLOW-USG
  • added option to define inactive cells for MODFLOW-2000/2005 grids in the numerical workflows
  • import transport boundary conditions when importing a VMOD Classic .VMF file project
    import concentration observation well data when importing a VMOD Classic .VMF project

Defects Addressed

  • in some cases, the cell attribute value for linear conceptual boundary conditions calculated using the method “Use Surface” were incorrect. The value was an average based on the min and max value from the start and end point of the line, as opposed to the actual surface value at the cell’s XY location. The magnitude of the error increases when the selected surface object has a wider range of max-min, and the line segment is longer.
  • fixed incorrect BT3 translation for initial concentrations for models that have inactive cells
    PEST translation, in some cases observations were not converted to the correct layer

Build 1.0.437.1, v.2013.1 Release (June 2013)


  • added support for defining and running transport models using MT3DMS
  • enabled the Create Numerical Grid step, with options to define the grid extents and define layer elevations (constant value) or with surfaces
  • improved the selection of workflow windows and viewer windows, with a “tab” approach across the top of the main window.
  • added option to define the layer order in 2D Layer views (and move layers up, down, to top and to the bottom)
  • improved Export PEST results to Charts; now populates pre-defined chart templates.
  • added option to delete Pilot points in the PEST workflow
  • improved error handling in PEST workflow, if you change the selected parameters, or adjust the numerical model.
  • in PEST workflow, added option to export sensitivity results to Excel charts.
  • added option to delete a PEST workflow from the model tree.
  • PEST will not run using a numerical model generated from conceptual model boundary conditions that are all steady-state
  • moved log files from …SchlumbergerHGB” to “…SchlumbergerVMODFlex”.
  • PEST, default transformation set to log for Kx and Kz parameters
  • provided an option to view/edit pumping well attributes at the Define Boundary Conditions step in the numerical model workflow.
  • added option to import MT3DMS results, .UCN file
  • added GUI shortcut to Define New Pumping Wells, at the Define Boundary Conditions step in the numerical model workflow.

Defects Addressed

  • constant head BC cells were not being assigned to the correct layer, when using the “Use Surface” option, after converting conceptual model to numerical model
  • fixed project specific issue, converting to numerical model caused error with incorrect Kx calculation
  • could not add particles to a numerical model – project specific
  • pathlines were shifed in the results with rotated grids
  • received error when trying to edit boundary condition cells, if the numerical model originated from a conceptual model.
  • unable to run Sensitivity Analysis in the PEST workflow – project specific
  • error occurred when trying to show a structural zone or property zone in 3D viewer, if geometry was invalid.
  • MODFLOW-LGR was not giving correct results with the SAMG solver.
  • exception occurs during “Edit Grid” step (refine rows/cols), if you set End row to be the last row.
  • error during translation to Finite Element model (project specific)
  • error when closing the 2D viewer if it is in pick/edit mode.
  • error in 2d viewer when showing a corrupted polyline (with only 1 vertex)
  • in some cases, Heads and Drawdown were removed from the model tree, after reloading a previously saved project.
  • the “Project/Save As” option was not working correctly; the MODFLOW packages were not being copied to the new directory.

Known Issues with VMOD Flex

The following issues may occur in Flex under described/applicable conditions. Where available, a workaround is provided.

  • [17290] When working with an extracted sub-grid model, whose parent model used a .HDS file as input for starting heads, the initial heads may not be correct. Workaround: extract the heads into surfaces and assign to the appropriate layer(s)
  • [17402] When adding more species, closing the project, and NOT saving the changes, newly added species are saved regardless. Workaround: delete unnecessary species from the project.
  • [19663] Unhelpful translation error “Vmac is running in the task bar, please close it and try again”. Workaround: open Windows Task Manager, by right-clicking on the Windows Task Bar and close Vmac instance there.
  • [20310] Property and boundary condition zones may appear to be incorrect for child grids in 2D- or composite Viewers, particularly for the recharge and evapotranspiration packages. This is caused by the parent grid values being drawn on top of the child grid values in the viewer and parent grid properties are generally null within child grids. Workaround: reorder the layers.
  • [20994] Imported storage values from a Classic Project may have NAN values. Workaround: This issue may caused by a partially corrupted Classic File. If this occurs, temporarily remove the file called [Project Name].$STRG from the Classic Folder. This file may be located inside a sub-folder of the affected Classic project. Save it in another location while importing your project into Flex. The import of storage zones should proceed normally after doing this. Restore the file to its original location once the import is complete.
  • [21053] When importing pumping schedule date based on absolute time, Visual MODFLOW Flex fails to identify some time/date errors. Specifically, it does not record an error when the Pumping start date falls AFTER the pumping end date. Workaround: inspect dates in the Excel well file to be imported to verify that pumping starts on or after the model start date or import the well schedule using relative times.
  • [21079] In certain cases where grids have previously been generated, the grid refinement buttons in the View Finite Difference Grid step may not work following a subsequent model grid creation. Workaround: ensure that the grid is the active/turned on in the view (sometimes the conductivity grid is activated on top of or instead of the grid itself)
  • [21128] Adding a transient boundary condition to a steady-state model where none previously existed and subsequently converting the model to transient may result in incorrectly translated time discretization (.DIS) and output control (.OC) input files. Workaround: The user may have to step out of and return to the Translate workflow step to force a refresh of the master schedule
  • In some cases, when extracting a subgrid – the resulting Constant Head boundary condition contains invalid head values. Use Validate option to see and correct issue.
  • At the View Maps step sometimes the 3D view does not display data and legend. Use new 3D window to display data instead.
  • When running a model from a subgrid unable to use initial heads from a previous MODFLOW run option.
  • User is unable to select RCH or EVT for edit if another boundary condition is assigned to the cell and is currently turned on for display – user needs to turn off other boundary conditions to be able to select RCH or EVT for edit.
  • Edits to RCH and EVT zones are saved immediately, however edits to time schedule are not – this can cause the time schedule to get out of sync.
  • When assigning RCH and EVT zones to a USG model – each zone is assigned as its own Boundary Condition
  • After importing wells when viewing the Layer View – the Layer combo box becomes disabled (unable to view other layers of model) – user needs to close and reopen the workflow tab and the combo box will become enabled again
  • If the parent node for a boundary condition is selected (to turn on all of the individual boundary conditions) in the model explorer – when user selects Edit – the boundary condition disappears from view. User needs to uncheck the parent node and select the individual boundary conditions in the model explorer.
  • Some boundary conditions (Recharge, Evapotranspiration, and Wells) are not removed from border cells when extracting/creating a subgrid as expected (since they should be replaced with a constant head boundary that takes all boundary condition affects into consideration). User must make wells not active or delete them and reassign recharge and evapotranspiration rates to the border cells to be zero so that these effects are not duplicated.
  • PEST: when plotting parameter sensitivity values, if a parameter is log-transformed, the sensitivity is expressed with respect to the log of that parameter. The relative composite sensitivity of a log-transformed parameter is determined by mutiplying the composite sensitivity of that parameter by the absolute log of the value of that parameter.
  • If you are importing a Visual MODFLOW project with distributed properties, please be sure the $CND file (and $STR, $IHD) files have been generated in Visual MODFLOW. To do this, open your project in Visual MODFLOW Classic Interface, go to Inputs/Properties. Select Tools/Cell Inspector. Turn on All Flow properties. Then, scroll through each layer in your model. When you are finished, save and close the project, and import into VMOD Flex.
  • Rotated grids appear rotated in the 2D views.
  • When show a cross-section through a child grid (for LGR) that has been rotated, the gridlines do not show up correctly. Workaround: Use 3D Viewer.
  • When displaying a grid that contains a child grid (for LGR), and viewing in the Flex Viewer, the selected row, column, or layer is applied only to the parent grid; it is not applied to the child grid.
  • When importing Points, Polygons, or Polylines from a .DXF file, only the entities within the .DXF $EXTMIN and $EXTMAX will be imported; any entities outside these extents will not be imported. Therefore, please be sure to prepare your .DXF file properly, prior to importing.
  • Some data object style settings are not saved to the project, e.g., points color, symbol size, etc.
  • For some objects 3D viewer does not fully support color rendering/labeling
  • Polygons with multiple parts are not rendered properly in the 2D Viewer; the holes on the polygons will appear the same color as the polygon for which it overlaps.
  • When draping polygon or polyline over a surface, this is an approximation, since it relies on the vertices of the polygon or polyline to position this in 3D; there may be gaps/locations where it is not completely draped. The same problem occurs when viewing areal or linear boundary conditions in 3D Viewer
  • Vertical datum shifts are currently not supported. VMOD Flex assumes that all data you import is in the same vertical datum.
  • When using Kriging interpolation component, you may need to adjust the min and max radii in order to get an ideal interpolation; these parameter values will depend on your data set. Default values are 100 and 100, you will likely need to increase or decrease these values.
  • A 3D Gridded data object will not be positioned correctly in a 3D Viewer, if the grid origin is modified during the import process.
  • Grid rotation is not supported for imported 3D Gridded TecPlot (.DAT) data objects.
  • In 3D Viewer, child grids may not display correctly if the parent grid only has one layer.
  • In the color by attribute style settings, the MIN, MAX and color interval values may not update when a new attribute is assigned.
  • In a minority of cases where the user has restricted rights on Windows, an error will occur when starting VMOD Flex due to the TEMP folder being set as read-only. Granting full access to the TEMP folder resolves the issue.
  • If recharge boundaries are defined with a time schedule with multiple time entries for the same date, translation will be treated as static instead of transient.
  • When working with a project in Local Cartesian coordinate system, coordinate conversion is currently not supported. Please ensure that any data you import is in the same coordinates, and length (XY) units, as your project local coordinates.
  • Creating 2D Cross-sectional models is currently not supported due to limitations in the assignment of properties and boundary conditions in the numerical model.
  • In some cases, when opening a project from Hydro GeoBuilder or VMOD 3D-Builder, you may not be able to display and use specific grids or meshes. Workaround: Re-create the desired grids or meshes in VMOD Flex.
  • MODFLOW-USG Issues:
    • When defining the grid, if your conceptual model includes pumping wells, the wells object must be included as an add-in for the grid definition.
    • In the conceptual model, Property zones defined with the method “Use 3D Gridded Data” is not supported when converting to a USG numerical model
    • Boundary condition attribute method “Use Shapefile Attribute” is not supported when converting to a USG numerical model.
    • Conversion of transient boundary condition objects, with attributes defined at vertices, will show an error.
    • For existing projects, if your conceptual boundary condition has multiple parts, and you edit the attributes, you may face a problem that the “Edit Boundary Condition” GUI does not display the selection correctly (the 2D preview may not show the correct selection) or the attributes grid may be empty. If this is the case, re-create the conceptual boundary condition object.
  • Wall Boundary (HFB) is supported only on MODFLOW-2000 and MODFLOW-2005 models. When doing conceptual to numerical model conversion, only Deformed Grid types are supported.
  • Unsaturated Zone Flow (UZF) package is supported only on MODFLOW-2005 models.
  • During conversion from conceptual model to numerical model for properties, VMOD Flex will use the order in which the conceptual property zones were created to determine the order when assigning to grid cells; if a grid cell is occupied by more than one property zone for the same parameter group, the one that was defined last (most recently) will take priority.
  • No settings for adjusting MODPATH particle color/size, in the Output
  • MODFLOW-LGR flux visualization, values may not be correct for those cells along the parent/child grid interface
  • MODFLOW-USG translation does not take into account boundary conditions that end at different times;
  • Flux visualization not available for MODFLOW USG models
  • Translate to FEFLOW Model option will not work with the new pumping wells object. Workaround: re-define the pumping wells in FEFLOW
  • PEST is not available for MODFLOW-NWT
  • Import model from VMOD Classic, with distributed property zonation, the values and multipliers may not import correctly