MODFLOW Resources

Last modified on Friday, February 02, 1996 - 12:12:42 PM

This is the Internet Resource page of The Modflow Help File. If you have installed the Modflow Help File are accessing this page locally you can update it by loading the most recent version of this page and saving it locally as mfh_rec.htm. On the most recent version of the Modflow Resource page you can also check the version number (1.01) of the Modflow Help file to see whether you want to download an updated version. The MODFLOW help file has been completed and will be released as soon as I get the approval of Louisiana State University.

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Note: The Contents link will not work unless you have installed the Modflow Help file and are accessing this page locally.

Although you can get a free copy of MODFLOW, you may prefer to get a commercial one instead. The advantages that you may get from commercial versions include: Not all commercial versions of MODFLOW are alike. As far as I know no version of MODFLOW incorporates all the packages that have been written. Before purchasing MODFLOW, you should find out what packages you think you might want and what are available. You should also find out about customer support. MODFLOW is not an easy program to use and at some point you will probably want someone you can turn to for assistance. Some versions of MODFLOW include preprocessors and postprocessors. Others do not. Preprocessors and postprocessors may also be purchased independently of MODFLOW. Preprocessors simplify the preparation of MODFLOW input files tremendously. Several versions of MODFLOW are available as demos either free or for a small fee. It would be worth-while investigating which of those is fastest. (You should also inquire whether the demo is significantly slower than the full version.) You will probably spend more time preparing input file and interpreting output file than actually running the model (though it may not seem like that sometimes) so ease of use is a major consideration.

The commercial sources I have listed here are all those of which I am aware. I do not endorse these or any vendors nor have I received any fee or any other material benefit from any of them. The order in which vendors appear is generally the reverse of the order in which I became aware of them. (i.e. the ones I most recently became aware of are closest to the top.) All quotations are used with permission.

Free Resources

Free versions of MODFLOW can be obtained at a variety of places. I compiled one version which you can download from Louisiana, USA; or Germany (401 kb). The following packages are included. BAS1, BCF3, RIV1, DRN1, WEL1, GHB1, RCH1, EVT1, SIP1, SOR1, UTL1, PCG2, STR1, IBS1, CHD1, GFD1, HFB1, and TLK1. The German site is at the Register of ecological models which has a number of other groundwater models as well.

The groundwater model library at Kilburn has source code for MODFLOW, hst3d, sutra, wateq, and several other models. It also has source code for mmsp, a preprocessor for MODFLOW.

Another site with MODFLOW source code. Only the original McDonald and Harbaugh packages are included.

Another place to get MODFLOW (Did they really mean this to be available to everyone?). Both source code and an executable are present but the source code is only for the original McDonald and Harbaugh packages

Preprocessors:

MODFLOW -related programs
  • MODFLOWP, 1.2 Mb, MODFLOW with Parameter Estimation. Source code for a newer version is available at ftp://brrcrftp.cr.usgs.gov/pub/mchill. You must use an ftp program such as WS_FTP to link it.
  • ZONEBUDGET, 253 kb, Calculates Water Budgets of Zones in Modflow
  • MODPATH, 384 kb, Particle Tracking with MODFLOW
  • STREAMLINK, 636 kb, MODFLOW Linked with a 1D Stream Model
  • MODFLOWARC Modifications of the U.S. Geological Survey Modular, Finite-Difference, Ground-Water Flow Model to Read and Write Geographic Information System Files (Arc/Info) Version 5.0 as of 1/6/96,

  • PEST: Parameter Estimation with any model PEST Lite is free. It can calibrate models with up to four unknown parameters. A proprietary version can calibrate an unlimited number of unknown parameters. There are utilities to link PEST with MODFLOW and MT3D
  • Ground-Water and Vadose Zone Models/Manuals at Center for Subsurface Modeling Support at Kerr Lab. 13 different programs are available from this site including MT3D. MT3D can use MODFLOW output files to model contaminant transport.
  • Environmental HydroSystems, Inc. maintains the Enviromod Software Repository. They also have a Searchable Data Warehouse Broker. It doesn't get all the URL's that some of the other search engines do but it does seem to find things related to groundwater modeling that the others don't. As of Jan. 15, 1996 both of these were closed for maintenance.
  • Intera distributes COSIM, a FORTRAN program for co-conditional and co-unconditional geostatistical simulation using the approach of Carr and Myers. Their version is set up to interface with MODFLOW (150 Kb). They also have a list of software distributors and an extensive list of commercial programs many of which are linked to MODFLOW including

    The following two sites have source code or executables but it may be impossible to link to these sites using Netscape or Mosaic. Instead you may have to use an ftp program such as WS_FTP to link to them. Some contain files that are compressed as TAR.Z or TAR.GZ files. They can be decompressed with WinZip.

    Commercial Resources

    I have requested permission to quote selective passages from the web pages of all the following suppliers of MODFLOW and MODFLOW related programs. Some have not yet responded. The amount of material I have listed here bears no relationship to the quality of that companies products. I urge you to find out for yourself what each of these companies has.

    Companies listed (in no particular order).

    Software Solutions Directory

    Software Solutions Directory sells ModelGIS which links MODFLOW to ARC/INFO®

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    Environmental Systems and Technologies

    EST has an extensive list of commercial programs for sale including MODFLOW, MODFLOW preprocessors, and MODFLOW postprocessors. You can purchase demo versions of some of the commercial programs for modest fees. The following are quotes from their web pages and an email message.
    PM is a tool to simplify creating of data files for MODFLOW, MODPATH and MT3D and for post-processing model output. The program utilizes pull down menus and graphical editing to facilitate the otherwise tedious job of running 3-D flow and transport models.
    The newest version of PMWIN (available soon) is a tool to simplify the creation of data files for MODFLOW, MODPATH and MT3D and for post-processing model output. The program utilizes graphical editing in Windows to facilitate the otherwise tedious job of running 3-D flow and transport models.
    ES&T distributes the IGWMC version of MODFLOW which includes two executable codes: 1) a small site version that will run on PCs with only 640 KB of memory, and 2) an extended memory version for more powerful computers. The program includes a pre-processor, PREMOD, for data entry and editing and a post-processor, POSTMOD, which reformats MODFLOW binary files into a form that can be read by GRAPHER, SURFER and other packages.
    MODFLOWP is an extension of MODFLOW that includes a Parameter Estimation Package to estimate parameters by nonlinear regression. MODFLOWP functions identically to MODFLOW when the Parameter Estimation Package is not used. Parameters may be estimated by minimizing a weighted least squares objective function by the modified Gauss Newton method or by a conjugate gradient method.

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    S.S. PAPADOPULOS & ASSOCIATES, INC.

    S.S. PAPADOPULOS & ASSOCIATES, INC. has an extensive list of commercial programs for sale including MODFLOW, MODFLOW preprocessors, and MODFLOW postprocessors. You can download a demo version of MODFLOW and some MODFLOW related programs including MT3D. They are also selling a text on applied groundwater transport modeling. The following quotes are from one of their web pages and email messages

    MODFLOW/mt is an enhanced version of the U.S. Geological Survey finite difference ground water flow simulator. In addition to full compatibility with the standard USGS version, MODFLOW/mt includes the additional packages BCF2, PCG2, and STR2, and SSP&A's LKMT package which links MODFLOW to MT3D. MODFLOW/mt also includes enhanced array readers which simplify data input.
    PATH3D
    ======
    PATH3D is a three-dimensional particle tracking code for MODFLOW. PATH3D can be used to visualize 3-D flow patterns, to delineate capture zones and wellhead protection areas, and to evaluate the effectiveness of ground-water remedial designs under complex hydrogeologic conditions. PATH3D is capable of performing forward and reverse particle tracking for steady flow fields, and forward tracking for transient flow fields. The particle tracking algorithms in PATH3D incorporate automatic stepsize control to achieve a user-specified error criterion with a minimum of computational effort. PATH3D also includes techniques that increase the accuracy of tracking in the vicinity of weak sinks and deformed model layers.
    MT3D
    ====
    MT3D is a comprehensive simulation code for analyzing the three-dimensional migration of solutes in ground-water systems. MT3D is capable of simulating the advective and dispersive transport of a single dissolved species, and can consider equilibrium sorption with linear and nonlinear isotherms and first-order decay and production reactions. MT3D interfaces directly with the USGS ground-water flow code MODFLOW, and accommodates steady and transient flow solutions. MT3D incorporates four solution options for treating the advection term, including an accurate and efficient 3-D implementation of the method-of-characteristics. The multiple solution options permit the calculation of accurate and efficient solutions for a wide range of transport conditions.
    ModIME
    ======
    ModIME is an integrated modeling environment for MODFLOW, PATH3D and MT3D. ModIME allows users to prepare input data rapidly and accurately, run simulation codes, and display and analyze model results in an interactive and intuitive graphical environment. ModIME users can either import existing data files from different sources, or enter and edit data directly with the mouse on a screen display of the model grid and basemap. ModIME includes an advanced zoom capability that allows users to generate automatically small-scale local models over any subregion of a larger scale model.

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    International Groundwater Modeling Center

    You should be able to get almost any ground water modeling program at IGMC. You can download a free demo of Visual MODFLOW from "FREE!! Demos of IGWMC software/".

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    Argus Numerical Environments

    The Argus Numerical Environments and its MeshMaker modules are pre- and post processors for a variety of groundwater models including MODFLOW. You can download a demo version, an interactive tutorial and on-line documentation in Adobe Acrobat format. If you already have Argus Numerical Environments, you can download several free templates that work with it from their Export page.
    Whether you develop your own numerical models, use public domain models or work with commercial models, ANE enables you to do all your pre- and post-processing in one friendly environment and export the data you linked to your grid and mesh to all your models. Using the Export Template dialog you create an Export Template for each of the models you use and save it to disk. Whenever you need to export your data to a model, just load the appropriate Export Template form disk and choose the Export menu. Using export templates, Argus Numerical Environments users export their data to different models such as: All USGS Public Domain models such as MODFLOW, MOC, SUTRA, etc.; Commercial numerical models such as: COSMOS/M, MATLAB, ECLIPSE, etc.; Self Developed models.
    Using the new post-processing tools you can present and investigate your model results in the same window you've created your model input. The six new scientific visualization methods are: 3D Surface, Color Map, Contour Map, Vector Diagram, Particle Path-lines and Cross-Section.

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    Groundwater Modeling System

    The Groundwater Modeling System is a pre- and postprocessor for a variety of groundwater models including MODFLOW. You can download a demo version. They also have a mailing list which has interesting discussions from time to time. One of the software managers involved in the project has an online description which is separate from the main web page. The following is quoted from one of the web pages at the main site.
    The Department of Defense Groundwater Modeling System (GMS) is a comprehensive graphical user environment for numerical modeling. GMS provides tools for site characterization, model conceptualization, mesh and grid generation, geostatistics, and sophisticated tools for graphical visualization. Several types of models are supported by GMS. The current version of GMS provides a complete interface for the codes FEMWATER, MODPATH, MODFLOW and MT3D. Many other models will be supported in the future. The interface to GMS has been designed in a modular fashion. Nine separate modules representing different data types are provided.

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    Environmental Simulations, Inc.

    They sell MODFLOW and a few other programs. They claim their version of MODFLOW is 10-20% faster than other versions. They have reformatted all the MODFLOW manuals as Windows help files which you can buy separately. You can download a free demo of their version of MODFLOW. In an email message they said they are working on a Windows® pre- and post-processor. The following is quoted from one of their web pages.
    MODFLOWwin32 is ESI's version of this popular groundwater flow model, originally developed by the USGS. MODFLOW is a 3D finite-difference groundwater flow model and there are many versions available. Unlike MODFLOW versions from other vendors, however, ESI's MODFLOWwin32 was developed specifically for Microsoft Windows (Win32s) and Windows NT. Using a unique technology, MODFLOWwin32 runs as a DLL which is controlled by a shell program or by ESI's ContourWin32 which is provided with MODFLOWwin32.
    MODFLOWwin32 contains all of the popular add-on packages (BCF2, PCG2, etc.) and is a 32-bit program utilizing all available memory. ContourWin32 is a postprocessor for contouring MODFLOWwin32 results and displaying particle trace pathlines computed by MODPATH.

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    Water Information Center, Inc. (Geraghty & Miller)

    Geraghty & Miller sell MODFLOW, MODFLOW preprocessors, and MODFLOW postprocessors among other things. They have some Downloadable software . They also have a BBS at (703)758-1203 with a N-8-1 prot configuration. (no parity, 8 data bits, 1 stop bit). The following quotes from their web pages.
    MODFLOW386
    MODFLOW386 is the current version of MODFLOW as distributed by the USGS (McDonald & Harbaugh, 1988). Geraghty & Miller has added unique items to the MODFLOW code, however, that are not readily available anywhere else: MODFLOW386 has the ability to use all available extended memory on a 80386 or 80486-based microcomputer. The new STREAM ROUTING (STR) Package, developed by the USGS, has been added to MODFLOW. The STREAM ROUTING Package is an enhanced version of the RIVER Package that allows the modeler to perform simple flood routing and more detailed surface water/groundwater interaction. A new solver, the PRECONDITIONED CONJUGATE GRADIENT (PCG2), has been added. The PCG2 Solver provides a more stable solution to complex flow problems. The new Block-Centered Flow Package, BCF3 (Goode & Appel, 1992), has been added to allow dry cells to resaturate (this was in BCF2) and to provide additional interblock averaging methods. The Horizontal Flow Barrier (HFB) Package is included to simulate slurry walls and low-permeability fault zones. The TLK1 package has been included to simulate transient leakage resulting from storage changes in containing units. A utility program is provided that produces SURFERTM grid and XYZ files from MODFLOW output. This utility, used in place of the SURFER GRID program, is very fast and allows the user to contour all or any portion of the model grid.

    MODFLOW Utilities
    Geraghty & Miller, Inc. has created a set of utilities for MODFLOW386 (and other MODFLOW versions). These utilities perform a variety of postprocessing functions intended to make your modeling life easier. MODGRID is a utility that will create SURFER-compatible grid files, XYZ files (ASCII), or Geosoft Format files from MODFLOW head-save or drawdown files. MODGRID will also process MT3D concentration (UCN) files. ZONEBUD is the USGS utility (Report # OFR 90-392) that allows you to compute mass balances on subgrid areas. MOD_B2A is a utility that will convert MODFLOW head-save and cell-by-cell binary data files into ASCII summary or XYZ format. MOD_B2B is a utility that will convert MODFLOW binary head-save file from UNFORMATTED to true BINARY or vice versa. This is useful, for example, if you have purchased your version of MODFLOW from another company and wish to run MODGRID or ZONEBUD. VELPLOT is a utility that creates velocity vector maps from your MODFLOW or MOC output. VELPLOT will create SURFER XYLINE files or DXF files. CALSTATS computes calibration statistics from a MODFLOW run. TIMESER is a utility that will extract hydrograph data from a MODFLOW head-save file. HDSINFO displays the contents of a MODFLOW head-save or drawdown file (time step, stress period, layer number, etc.).

    MODPATH
    MODPATH is an advective transport model (particle-tracking) that uses MODFLOW output to compute particle paths and travel times within a 3D flow system. MODPATH386 is the latest version of MODPATH (Version 1.3, Pollock, 1994) released by the USGS. Geraghty & Miller has added the following enhancements: A utility is provided to convert the particle traces computed by MODPATH386 into a SURFER-compatible file (XYLINE File) that may be posted on a contour map. The program dimensions have been increased with the ability to address all available memory. A utility is provided to convert version 2.0 files to equivalent version 3.0 files.

    ModelCad386
    ModelCad386 is a software package designed to bridge the gap between the scientific aspects of modeling and the creative design of a model. ModelCad386 allows the modeler to be creative by providing a fast, flexible, and interactive graphical method of designing a finite-difference groundwater flow or solute transport model. The model is created by visualizing the model design in relation to the system being modeled, not by fitting numbers into a matrix or by answering a series of questions.

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    SSESCO

    makes The Environmental WorkBench which is an interactive post-processor for MODFLOW SSESCO makes among other things. The following are quoted from an old version of one of their web pages.
    The Environmental WorkBench product (EWB) from SSESCO is an extremely easy to use visualization and analysis application targeted at environmental data. It is aimed at putting sophisticated interactive visualization capabilities directly in the hands of the scientist or engineer working with the data, without the need for a computer support person. It is distinguished from data flow products like AVS in that it provides a ready to use interface without any network programming required. The EWB currently has numerous users in the fields of meteorological research, air quality work, and groundwater remediation.
    SSESCO does not develop models. We work with research groups and other businesses that have developed models to make a whole package. At this point we have models from various environmental fields connected to the system including groundwater, atmospheric, photochemical, and pollution dispersion models. The models we have worked with include: MODFLOW, PORFLOW, STMVOC, RAMS, ARPS, MM5, Minerve, Hermes, ADOM, RADM, ISCST, LPDM.

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    BOSS International

    Visual MODFLOW among other things. Visual MODFLOW includes pre- and postprocessors

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    GIS\Solutions, Inc.

    MODFLOW and FEMWATER pre and post processors (models included). The following is quoted from one of their web pages.
    GIS\Key is used by environmental professionals to manage chemistry, geology, and hydrology data and create the standard environmental work products and reports used by the environmental community everyday.
    GIS\Key utilizes two basic components to manage data, create work products and reports. There is a database side of the system and a graphic side of the system. Both components use industry standard software and formats to guarantee compatibility with existing and future, data and reporting needs. The database is Microsoft FoxPro and the graphic engine is AutoCAD. FoxPro uses the popular dBase III+ or .DBF file format which can be read from and written to, by almost any software on the market. The graphic AutoCAD format is the most widely used and transferred graphic format.

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    Integrated Decision Support Group (IDS)

    This web page describes a future MODFLOW graphical user interface.

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    Waterloo Hydrogeologic, Inc..

    Temporarily out of service as of 1/6/96. The following is a quote from an email message.
    Visual MODFLOW, by Waterloo Hydrogeologic, Inc., is a fully integrated modeling environment for the USGS's MODFLOW and MODPATH. It supports all of the most popular and established MODFLOW and MODPATH packages for analyzing three- dimensional, steady-state or transient groundwater flow in confined or unconfined, heterogeneous and anisotropic porous media with irregular layer thicknesses. The model calculates and displays hydraulic head contours, drawdown contours, flow velocity vectors, time-related flow pathlines and calibration results. This seamless package contains both a pre- and post-processor which allows the user to graphically design the model, run the analysis, and display the results without ever leaving the Visual MODFLOW environment. Visual MODFLOW's innovative graphical-user-interface makes three-dimensional modeling more accessible and practical than ever before.
    In addition, a visual interface for MT3D (the popular three-dimensional contaminant transport program) is currently being developed and will be ready for release by March, 1996.

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    RockWare Inc. Earth Science Software

    Rockware has MODFLOW, MODFLOW preprocessors, and MODFLOW postprocessors including a postprocessor for Macintosh. Macintosh users, however, may find it difficult to get a commercial version of MODFLOW. Rockware used to sell one made by Geraghty & Miller but it is no longer for sale.
    Groundwater Modelers Prod. Pak: Converts MODFLOW, SUTRA and MOC output to a variety of file formats for graphical display of model results (Mac)
    Graphic Groundwater integrates grid development, data input, model execution, and analysis of the results all in one package. It is based on the U.S.G.S. Three-Dimensional Modular Finite Difference Groundwater Flow Model (MODFLOW). You no longer need cumbersome pre- and post-processors. You create the finite difference grid with the mouse and simple dialog boxes, and can superimposed and georeference the grid on a scanned or digitized map, if you choose.
    MOD3DFD386/486 is an enhanced implementation of the U.S. Geological Survey's modular 3-D finite difference groundwater flow simulation model ("MODFLOW"). MOD3DFD386/486 additional features: has a new River Routing package for flexibility in modeling surface water flows; produces graphics input files enabling graphical display of model results on the screen, dot matrix printer, ink jet, and laser printers, and pen plotters; includes User Guide and USGS documentation.
    ModelCad386 graphically generates the finite-difference model grid and saves it in a model-independent format. The modeler visually adjusts the grid spacing, boundary conditions, and aquifer properties and instantly generates the model input data files. Translators are provided for four of the most commonly used models: � the USGS model MODFLOW � the USGS model MOC � MT3D solute transport model � MODPATH particle tracking model.
    MODFLOW386 features: Addresses all available RAM; New option for resaturation of dry cells; Utility to produce SUR-FER grid files; Source code is included. Geraghty & Miller has added unique items to the MODFLOW code (as distributed by the USGS (McDonald & Harbaugh, 1988)) that are not readily available anywhere else. This allows you to run very large simulations.
    MODPATH386: USGS particle-tracking analysis for MODFLOW and extended DOS. Addresses all available RAM. Utility converts MODPATH output to SURFER-compatible file (XYLINE format). Includes source code. MODPATH386 is the latest version of MODPATH (Version 1.2, Pollack, 1990) released by the USGS. MODPATH is a three-dimensional advective transport (particle-tracking) package that works in conjunction with MODFLOW.
    ModflowP: Performs nonlinear least-squares parameter estimation for ModelCAD, allowing ModelCAD 386 users to quickly master the complexities of model calibration
    Modflow Utilities: Utility software for ModFLOW386
    Visual Modflow: DOS-based groundwater modeling environment for analyzing 3-D, steady-state or transient groundwater flow

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    The Scientific Software Group

    The Scientific Software group has an excellent printed catalog. Relatively little information is available on-line when this was written. I understand that they are working on getting their catalog on-line. You can download a demo of Visual MODFLOW among other things. They have provided the following descriptions of their versions of MODFLOW and other MODFLOW-related programs.
    MODFLOW/EM - A new version of MODFLOW is available that includes the spreadsheet preprocessor, MFI. MFI uses a Lotus-compatible spreadsheet for entering arrays. This allows the power of spreadsheet editing and programming functions to be used for generating model data. Arrays generated by other programs can also be used as part of a dataset. MODFLOW/EM runs independently or within Microsoft Windows. It includes the following packages: Transient Leakage, IBS1, CHD1, STR1, PCG2, BCF3, GFD1, RAD-MOD, ZONE BUDGET, and the Horizontal Flow Barrier Package. MODFLOW/EM is technically supported by Michael G. McDonald, co-author of MODFLOW.
    MODPATH/EM - Particle Tracking for MODFLOW/EM including transient flow. MODPATH/EM is a brand new version that permits forward and backward tracking in transient flow fields as well as steady-state flow fields. It also permits the release of particles over a time interval. It runs independently or within Microsoft Windows. MODPATH/EM is technically supported by Michael G. McDonald, co-author of MODFLOW.
    Visual MODFLOW - Integrated Modeling Environment for MODFLOW and MODPATH. Visual MODFLOW allows the user to graphically input data, run MODFLOW and MODPATH, and visualize the results in plan or cross-section views--all within one package. Visual MODFLOW's intuitive mouse-driven user interface has reduced the time to complete a typical simulation job from several days to a few hours. The input structure is designed so that the user concentrates on physical locations and times rather than model grid coordinates or model time steps. Multiple DXF sitemaps can be overlaid on the grid. Visual MODFLOW can also import MODFLOW data files making it useable for previously created MODFLOW models.
    PROCESSING MODFLOW for Windows (PMWIN) - A powerful graphical preprocessor and postprocessor for MODFLOW, MODPATH and MODPATH-PLOT, MT3D, MODINV and PEST. PMWIN is now a fully integrated package which includes MODFLOW, PMPATH, and PMDIS (assigns cell values by using Kriging). The preprocessor has pull-down menus and a graphical model designer that consists of PMCAD which allows for constructing a general map of the model area, the GRID EDITOR which is used for specifying the physical data of each model call individually, and the ZONES editor for specifying the areally-distributed physical data in the form of zones.
    GMS (Groundwater Modeling System) - The Department of Defense' comprehensive graphical modeling environment designed for the simulation of ground-water flow and transport. Features include site characterization, two- and three-dimensional mesh generation, graphically-based model input for finite-element and finite-difference flow and transport codes, interpolation and geostatistics, DXF input and output, as well as complete 3-D visualization in both the UNIX-X Windows and Microsoft Windows environments. GMS also provides an interface to MT3D and FEMWATER.
    MT3D - A 3-D solute transport model for simulation of advection, dispersion, and chemical reactions of contaminants in ground-water systems using the MODFLOW model. It includes 3-D transient flow fields with the presence of wells, drains, rivers, recharge, evapotranspiration and a variety of boundary conditions.
    MODFLOWP (Parameter Estimation for MODFLOW) - The USGS' Computer Program for Estimating Parameters of a Transient or Steady-State, Three-Dimensional, Ground-Water Flow Model using Nonlinear Regression. Code has been added to the original program to facilitate the input of file names and the opening of appropriate files.
    MODINV (MODFLOW Parameter Estimation) - A powerful non-linear weighted least squares MODFLOW parameter value optimizer. Given a single or multiple set of borehole water levels, MODINV is able to adjust parameter values within the active part of the MODFLOW finite-difference grid until the fit between observed and calculated borehole heads is minimized in the least squares sense. It can optimize parameter values for any model type that MODFLOW can run-single or multilayered, confined or unconfined, steady state or transient.
    Argus Numerical Environments (General Purpose Finite-Element and Finite-Difference Numerical Preprocessors) - A preprocessing tool for not only MODFLOW, but for any modeling package, for Windows, Unix Workstations, Macintosh and Power Macintosh. Its features include an unlimited number of windows, unlimited number of layers, undo/redo all commands, file compatibility across all platforms, and on-screen digitizer. It enables you to do your preprocessing in one friendly environment and export the data you linked to your grid and mesh to all your models. You can create a template for each of the models and save to disk.
    MODCELL - Converts cell-by-cell flow term unformatted files to ASCII files so that these files can be examined. These files contain all terms from the unformatted files.
    MODVEL - Uses unformatted head files from MODFLOW to produce unformatted files of 2-D ground-water velocity vectors for each model layer. A set of ground-water velocity vectors is automatically produced for each set of data in the unformatted head file.
    MODLOCAL - Constructs localized MODFLOW models. It takes, as input, a complete set of MODFLOW package files for a regional model and creates a new, complete set for a model which includes an arbitrary, user-defined localized region.
    MODGRAF - Provides graphics for MODFLOW and includes ground-water velocity vector capability. It automatically contours heads and drawdowns from each layer, stress period, and time step of the simulation. Both variable and constant stepsize grids may be used. MODGRAF can process and create contour plots for up to 100 sets of head or drawdown data in a single execution and save the results in a single file.
    MODRET - Unsaturated and saturated infiltration from stormwater ponds using MODFLOW. MODRET calculates infiltration losses from stormwater retention/detention ponds in unconfined aquifers with a variety of utility modules that give versatility to the model. It also allows for generation of single watershed stormwater runoff hydrographs, routing of runoff hydrographs, specification of overflow devices, and ground-water elevation cross-sectional graphics.
    MODCROS - Generates cross sections from MODFLOW. It graphically displays a cross section for a specified aquifer layer, stress period, and time step of a MODFLOW output data set and generates a cross section along any row or column of the model grid. It uses the BASIC data file, the Block Centered data file and the MODFLOW output data file to read the grid size and dimensions and the model output results.
    MODPUMP - MODFLOW simulated pumping test model. It allows calculation of aquifer parameters for single or multiple layer aquifer systems by simulating field pumping test data. It allows calculation of hydraulic conductivity, storage coefficient, specific yield and vertical leakance for up to three-layer aquifer systems. The aquifer parameters are calculated by trial and error, using graphical data points matching techniques where the observed drawdown at various time periods from a field pumping test are graphically compared to MODFLOW simulated drawdown.
    PEST - Parameter Estimation for Any Model. PEST creates a sophisticated nonlinear parameter estimator for not only MODFLOW, but for any model. PEST communicates with a model through the model's own input and output files. A model does not need to be adjusted, re-cast as a subroutine or even recompiled to be used with PEST. It implements a robust form of the Gauss-Marquardt-Levenberg method of parameter estimation. Its optimization algorithm includes a sophisticated derivatives calculator which allows successful parameter estimation, even for large numerical models.

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    Note: The Contents link will not work unless you have installed the Modflow Help file and are accessing this page locally.



    This page may be freely copied but may not be sold without permission. Richard B. Winston,
    rwinsto@lsuvm.sncc.lsu.edu
    Dept. of Geology and Geophysics
    Louisiana State University
    Baton Rouge, La 70803
    U.S.A.
    504-388-2337
    Fax 504-388-2302
    http://scribe.geol.lsu.edu/rbwinston.html
    ftp://aapg.geol.lsu.edu/pub/winston