Processing Modflow 8.047

Processing ModflowTM (PMWIN) is a comprehensive integrated groundwater modeling system that is used by many organizations, such as research institutions, consulting firms, agencies, and entities of the United Nations. Processing Modflow 8 succeeds Processing Modflow Pro (7.x) and includes the following components. 

  • Intuitive graphical user interface to greatly simplify and clarify data input and result visualization processes that work with result files of practically unlimited file size (way greater than 2 GB).
  • 3D finite-difference groundwater model MODFLOW. Supports multiple versions, including MODFLOW-96, MODFLOW-2000, MODFLOW-2005, and MODFLOW-NWT.
  • Solute transport models MT3DMS (v5.3), MT3D, RT3D (v2.5), and MT3D99 (MT3D99 is sold separately by SSP&A.) 
  • Multicomponent reactive transport model PHT3D (v2.17) that incorporates MT3DMS (v5.3) for the simulation of three-dimensional advective-dispersive multi-component transport and the geochemical model PHREEQC-2 (v2.14) for the quantification of reactive processes.
  • Variable-density groundwater flow and multi-species solute and heat transport model SEAWAT (v4.0) .
  • Nonlinear parameter estimation package PEST (v12.0). Supports advanced features such as regularization, truncated singular value decomposition (SVD), and powerful SVD-Assisted Parameter Estimation.
  • Particle-tracking Model PMPATH which uses a semi-analytical particle-tracking scheme similar to MODPATH to calculate the groundwater paths and travel times. Through the interactive graphical modeling environment of PMPATH, the user can place particles and perform particle tracking with just a few mouse clicks.
  • Water Budget calculator for computing sub-regional water budget and inter-region water budget. It can optionally creates time-series of water budget for transient models.
  • Field Generator to generate heterogeneously-distributed parameter fields for stochastic simulation.
  • Field Interpolators to interpolates from point-wise data to model cells by using interpolation methods such as Kirging, Inverse distance, etc.

Data Input Features

  • Supports models with up to 1,000 stress periods, 200 layers and 1,000,000 cells in each model layer.
  • Graphical grid design tools.
  • Specify model parameters using Cell-by-Cell, Polygon, or Polyline tools.
  • Rotate and align the model grid related to the overlay maps in AutoCAD (.dxf), SURFER BLN, or bitmap image (bmp, jpg) formats.
  • Imports and refines (telescopes) existing MODFLOW models stored in the MODFLOW-88, MODFLOW-96, MODFLOW-2000, or MODFLOW-2005 formats.
  • Exports model results to SURFER and ASCII files.
  • Import/export model parameters from/to SURFER and ASCII files.
  • Visualize model input parameters.
  • Interpolates discrete data by means of Inverse Distance Weighting, Kriging, or Triangulation.
  • Telescopic Mesh Refinement for creating local-scale refined model from a large scale model.
  • Visualize boundary conditions (rivers, drain, wells, fix-head cells, etc).
  • Compatible with the upcoming Seer3D application for 3D visualization and animation of model output.

MODFLOW Flow Simulation Files/Packages

  • Discretization File
  • Basic package
  • Block-Centered-Flow Package
  • Layer-Property-Flow Package
  • Upstream-Weighting Package (MODFLOW-NWT)
  • Horizontal-Flow-Barrier 
  • General-Head-Boundary Package 
  • Drain Package
  • Interbed-Storage Package
  • Recharge Package
  • Evaporation Package
  • River Package
  • Reservoir Package
  • Streamflow-Routing Package (STR)
  • Time-Variant-Specified Head Package 
  • Well Package 
  • Solvers: Strongly Implicit Procedure (SIP) Package, Slice-Successive Overrelaxation (SSOR) Package, Preconditioned Conjugate-Gradient (PCG2) Package, Direct Solver (DE45) Package, Geometric Multigrid Solver (GMG) Package, Preconditioned Conjudate Gradient Solver with Improved Nonlinear Control (PCGN) Package, and Newton Solver (NWT) Package. 
  • Output Control Option

MT3DMS Solution Transport Packages

  • Basic Transport Package: defines the initial concentration and active/inactive cells for simulation.
  • Advection Package: supports various solutions schemes including Upstream Finite Difference Method, Method of Characteristics (MOC), Modified Method of Characteristics (MMOC), Hybrid MOC/MMOC, and Third-order Total-Variation-Diminishing (TVD) Scheme.
  • Dispersion Package: supports cell-by-cell dispersivity and species-dependent diffusion coefficient.
  • Chemical Reaction Package: up to 60 species are support by Processing Modflow.
  • Sink and Source Mixing Package: specified concentration values of individual species can be assigned to source water, such as injection wells, river, stream, etc.
  • Generalized Conjugate Gradient Solver is used for fast solution.

SEAWAT Features

SEAWAT is based on MODFLOW and MT3DMS and therefore supports all their packages and features.

  • Up to 60 species can be simulated simultaneously, including temperature for heat transport. 
  • Each individual species may or may not affect the fluid density. 
  • Species-dependent diffusion coefficient can be assigned to individual model cells. 
  • Fluid density can be assigned to Time-Variant Specified-Head cells.
  • For uncoupled mode (when density effect of all species are turned off), fluid density can be specified to water sources (e.g., injection wells, rivers).

RT3D Features

RT3D is based on MT3DMS and includes the following features.

  • Two Species Instantaneous Reaction (BIOPLUME-II type reactions; e.g., Hydrocarbon & Oxygen)
  • Six Species, First-Order, Rate-Limited, BTEX Degradation using Sequential Electron Acceptors (e.g., O2, NO3-, Fe2+, SO42-, CO2)
  • Rate-Limited Sorption
  • Double Monod Model
  • Sequential First-Order Decay (up to 4 species, e.g., PCE/TCE/DCE/VC)
  • Aerobic/Anaerobic Chlorinated Ethene Dechlorination.

PHT3D Features

PHT3D (v2.17) incorporates MT3DMS (v5.2) for the simulation of three-dimensional advective-dispersive multi-component transport and the geochemical model PHREEQC-2 (v2.14) for the quantification of reactive processes. PHT3D uses PHREEQC-2 database files to define equilibrium and kinetic (e.g., biodegradation) reactions. For the reaction step, PHT3D simulations might include the following.

  • Equilibrium complexation reaction/speciation within the aqueous phase
  • Kinetically controlled reactions within the aqueous phase such as biodegradation
  • Equilibrium dissolution and precipitation of minerals
  • Sorption and dual domain option for extremely heterogeneous porous media or media composed of fractures and pores.
  • Kinetic dissolution and precipitation of minerals
  • Single or multi-site cation exchange (equilibrium)
  • Single or multi-site surface complexation reactions

PEST Features

PEST is the industry standard software package for parameter estimation and uncertainty analysis of complex environmental and other computer models. Processing Modflow seamlessly links PEST with MODFLOW and enables users to run model calibration with PEST with the following features. 

  • Processing Modflow can run PEST in either Parameter estimation or Regularization modes.
  • Prior information can be assigned to facilitate parameter estimation process.
  • Truncated Singular Value Decomposition (SVD) and a PEST-specific SVD-Assist methods can be activated with Regularization mode.
  • Head and drawdown observations are supported.
  • Parameters that can be estimated are
    • Aquifer properties, including hydraulic conductivity, anisotropy, storage coefficient, specific yield, etc.
    • Drain Package: Conductance of drain cells.
    • Evapotranspiration package: Maximum evapotranspiration rate.
    • General-Head Boundary (GHB) package: Conductance of GHB cells.
    • Horizontal-Flow Barrier (HFB) package: Combination of horizontal conductivity/barrier-thickness in HFB cells. 
    • Interbed Storage package: Inelastic storage factor.
    • Recharge package: Recharge flux.
    • Reservoir RES Conductance of RES cells
    • River RIV Conductance of RIV cells
    • Stream-Flow Routine STR Conductance of STR cells
    • Well Pumping or injection rates of WEL cells.

MODFLOW-2000 Parameter Estimation Features

  • Observation Process:
    • Observation file contains information applicable to all observations.
    • Head-Observation input file to specify observations of head.
    • Specified-Head Flow Observation input file to specify observations of flow through constant-head boundaries.
    • Drain Observation input file to specify observations of flow through Drain boundaries.
    • River Observation input file to specify observations of flow through River boundaries.
    • General-Head-Boundary Observation input file to specify observations of flow through General-Head boundaries.
    • Stream Observation input file to specify observations of flow through Stream boundaries.
  • Sensitivity Process to calculate the sensitivity of model results to variations in parameter values.
  • Parameter Estimation Process is used for model calibration. In this process, parameters defined in the groundwater-flow process and selected in the Sensitivity process are varied to minimize an objective function defined in the Observation process.

System Requirements

  • PC running Windows 10, Windows 7 32-bit/64-bit, Windows 2000, Windows XP, Windows Vista 32-bit.
  • Monitor(s) to display windows, Mouse to drag windows around, and Keyboard to punch in data.


  • User's Guide and Evaluation Copy of PM8 can be downloaded here.

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