Visual MODFLOW Flex 9.0 Product Release

March 21, 2023

Visual MODFLOW Flex – Integrated Conceptual & Numerical Groundwater Modeling Software

On March 29, 2023 we released Visual MODFLOW Flex 9.0, the latest version of the popular graphical user interface that brings together industry-standard codes for groundwater flow and contaminant transport, essential analysis and calibration tools, and stunning 3D visualization capabilities in a single environment. The conceptual model approach which is unique to Visual MODFLOW Flex in groundwater modeling user interfaces allows you to:

  • Build a conceptual model of the groundwater system, prior to the simulation – hydrostratigraphic structures, hydrogeologic properties, and boundary conditions are all designed outside the model grid or mesh; providing the flexibility to adjust your interpretation of the groundwater system before applying a discretization method and converting to a numerical model.
  • Build the model with minimal data pre-processing required – Working with grid-independent data allows you to maximize the use of your existing GIS data and incorporate physical geology and geographic conditions before designing a grid or mesh.
  • Generate and simulate regional and local-scaled models – With support for MODFLOW-LGR, you can design local grids around areas of interest, directly within the conceptual model environment. Calculated heads from a regional model can also be used as boundary conditions for local-scaled models.
  • Design the correct model faster – The grid-independent raw data is left intact and is not constricted by grid cells or mesh elements when modifying the data and project objective. This allows you to generate multiple numerical models from the same conceptual model.
  • Make changes to the model data and immediately see results – The conceptual model environment provides simultaneous 2D and 3D views which are updated whenever changes to the data are made.

Visual MODFLOW Flex Improvements

Version 9.0 of Visual MODFLOW Flex includes the following improvements:

MODFLOW-6 Groundwater Flow and Transport:

Visual MODFLOW Flex now supports MODFLOW-6, the newest core version of the groundwater modeling code developed by the USGS. MODFLOW-6 is based on a redesigned framework that supports 3D groundwater flow, solute transport, and various processes with an all new and more legible input file structure for both structured and unstructured grids. The following MODFLOW-6 flow packages are supported in Visual MODFLOW Flex:

Simulation Packages:

  • MFSIM.NAM – Simulation Name File
  • TDIS – Time Discretization
  • MS – Iterative Model Solution

Groundwater Flow Model (GWF): Simulate saturated groundwater flow using structured finite difference grids or unstructured control volume finite difference grids (Voronoi or Quadtree).

  • GWF.NAM – Groundwater Flow Model Name File
  • DIS – Discretization Package
  • DISV – Discretization by Vertices Package
  • IC – Initial Conditions (Heads)
  • OC – Output Control Package
  • NPF – Node Property Flow Package
  • STO – Storage Package
  • CHD* – Time Varying Constant Head Package
  • WEL* – Well Package
  • DRN* – Drain Package
  • RIV* – River Package
  • GHB* – General-Head Boundary Package
  • RCH – Recharge Package
  • EVT – Evapotranspiration Package

Solute Transport Model (GWT): Simulate groundwater solute transport using structured finite difference grids or unstructured control volume finite difference grids (Voronoi or Quadtree), including a variety of sorption, reaction, and immobile domain models.

  • GWT.NAM – Groundwater Transport Model Name File
  • DIS – Discretization Package
  • DISV – Discretization by Vertices Package
  • IC – Initial Conditions (Concentrations)
  • OC – Output Control Package
  • ADV – Advection Package
  • DSP – Dispersion Package
  • MST – Mobile Storage Transfer Package
  • IST – Immobile Storage Transfer Package (up to three immobile domains)
  • SSM – Source Sink Mixing Package
  • CNC* – Time Varying Constant Concentration Package
  • SRC* – Mass Source Loading Package
  • Multiple Instance Packages: MODFLOW-6 allows you to include multiple instances of certain packages (marked with * above) in a simulation and track budgets separately for each package.
  • Support for ZoneBudget-6: Evaluate sub-regional flows for your groundwater flow models using MODFLOW-6.

Engines and Packages

  • Assign Grid (In)active cell zones using data objects: You can use point, polyline, and polygon data objects to set the active/inactive flag for grid cells in the Finite Difference grid workflows
  • Import MNW1 Wells from Classic Projects: Well information using the MNW1 well model in Classic Projects can be imported into Visual MODFLOW Flex
  • Minimum thickness for Unstructured Grids: You can specify a minimum cell thickness below which unstructured grid cells will be removed from the grid so that you have more control on grid design around pinchout areas.
  • MODPATH with SEAWAT: You can run a MODPATH particle tracking simulation based on a SEAWAT flow (and transport) run.
  • Compare: Compare results for heads, drawdowns, or concentrations between two model runs using the same unstructured grid.

Performance, Usability, and Other Enhancements

  • The unstructured grid workflow now uses the more familiar and intuitive conceptual well controls that uses coordinates and well screen information instead of cell indices
  • You can specify default Total and Effective Porosity values at the Define Modeling Objectives step
  • You can add particles for a particle track simulation based on Well objects in the Model Explorer as well as in the Data Explorer
  • Improved speed and performance saving and loading projects
  • You can specify a custom default project save location to save time when creating new projects
  • New Keyboard Shortcuts:
    • Press CTRL+T at the Translate Step to translate a model
    • Press CTRL+R at the Run Step to run a model

For a full version history, see the Visual MODFLOW Flex readme file at: