Upgrade to MODFLOW-GUI: Addition of 

MODPATH, ZONEBDGT, and additional 

MODFLOW packages to the U.S. Geological 

Survey MODFLOW-96 Graphical-User Interface

By Richard B. Winston

U.S. GEOLOGICAL SURVEY 

Open-File Report 99-184

Reston, Virginia 

1999
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary 

U.S. GEOLOGICAL SURVEY 

Charles G. Groat, Director

Although the computer program described in this report has been tested and used by the 

U.S. Geological Survey (USGS), no warranty, expressed or implied, is made by the USGS as to 

the accuracy of the functioning of the program and related material. The code may be updated 

and revised periodically.

Any use of trade, product, or firm names in this publication is for descriptive purposes 

only and does not imply endorsement by the U.S. Government.

For additional information Copies of this report can be

write to: purchased from:

Office of Ground Water U.S. Geological Survey

U.S. Geological Survey Branch of Information Services

411 National Center Box 25286

Reston, VA 20192 Denver, Colorado 80225-0286
Contents

Page 

Abstract............................................................................................................................!

Introduction.....................................................................................................................^

System Requirements......................................................................................................4

Installation.......................................................................................................................^

Starting the Preprocessor...............................................................................................^

Entering Non-spatial Data................................................................................................6

Changes to Existing Features....................................................................................................... 6

Overall Appearance..................................................................................................................6

Geology Tab............................................................................................................................. 6

Stresses 1 Tab...........................................................................................................................?

Output Files Tab....................................................................................................................... 7

Time Tab.................................................................................................................................. 7

Sovers/Other Packages Tab .....................................................................................................8

MOC3D Tab............................................................................................................................ 8

MOC3D Particles Tab..............................................................................................................9

MOC3D Output + Dipsersivities Tab.................................................................................... 10

New Features............................................................................................................................. 10

Context-sensitive help............................................................................................................ 10

Deactivating Packages without Deleting the Data for the Package....................................... 11

Specifying Transmissivity, Vertical Conductance, and Confined Storage Coefficient......... 11

Saving Default Values ........................................................................................................... 12

Specifying Initial Head Formula............................................................................................ 13

Use Binary Head File for Initial Heads.................................................................................. 13

Using Alternative Export Templates...................................................................................... 13

Explicitly specify recharge or evapotranspiration layer........................................................ 14

Stream Package...................................................................................................................... 14

Flow and Head Boundary Package........................................................................................ 15

Horizontal-Flow Barrier Package.......................................................................................... 15

MODPATH............................................................................................................................16

ZONEBDGT..........................................................................................................................20

Entering Spatial Data.....................................................................................................21

Renamed Layers and Parameters............................................................................................... 21

Locked Recharge Elevation parameter...................................................................................... 22

Importing Well Data.................................................................................................................. 22'

MOC3D Transport Subgrid....................................................................................................... 22

IFACE[i] ....................................................................................................................................23

MODPATH information layers................................................................................................. 23

ZONEBDGT..............................................................................................................................24

Stream Package.......................................................................................................................... 24

Flow and Head Boundary Package............................................................................................ 26

Horizontal Flow Barrier Package.............................................................................................. 28

Running MODFLOW, MOC3D, MODPATH, or ZONEBDGT.........................................30

Creating Input Files................................................................................................................... 30

Processing the Export Template................................................................................................ 31

in
Running MODFLOW, MOC3D, MODPATH, or ZONEBDGT-Continued 

Using the MODFLOW PIE with Calibration Programs............................................................ 32

Running independent templates with the MODFLOW PIE.............................................33

Converting contours on information layers to data points on data layers................................. 33

Preparing Calibration Statistics.................................................................................................33

Files Created for MODFLOW-96, MODPATH, and ZONEBDGT Simulations ...............34

Files Created by Executing MODFLOW-96, MODPATH, and ZONEBDGT...................36

Visualizing Results.........................................................................................................37

Visualizing results from MODFLOW or MOC3D.................................................................... 37

Visualizing Results from MODPATH ...................................................................................... 40

Visualizing Results from ZONEBDGT..................................................................................... 40

Example.........................................................................................................................41

Problem Description.................................................................................................................. 41

Create a New Model.................................................................................................................. 42

Define the Study Area............................................................................................................... 43

Defining Specified-Head Boundaries........................................................................................ 44

Choosing the Stream Package................................................................................................... 44

Changing the Number of Geologic Units.................................................................................. 44

Accessing Context-Sensitive Help............................................................................................44

Finish Changing the Number of Geologic Units.......................................................................45

Defining a Stream Boundary..................................................................................................... 45

Define No-Flow Boundaries...................................................................................................... 46

Other Packages and Options...................................................................................................... 47

Save the Project......................................................................................................................... 47

Setting the Top Elevation.......................................................................................................... 47

Set Aquifer Properties................................................................................................................47

Create Pumping Wells............................................................................................................... 48

Create Specified-Flow Boundary ..............................................................................................48

Run MODFLOW....................................................................................................................... 49

Plot Heads Generated by MODFLOW...................................................................................... 49

Define MODPATH Particle Starting Points.............................................................................. 50

Run MODPATH........................................................................................................................ 51

Plot MODPATH Results........................................................................................................... 51

Define Horizontal-Flow Barrier and Rerun MODFLOW......................................................... 52

Use ZONEBDGT....................................................................................................................... 53

View ZONEBDT Results..........................................................................................................55

Customizing the MODFLOW PIE...................................................................................56

Conclusions...................................................................................................................56

References ....................................................................................................................57

Appendix 1: Edit Contours PIE ......................................................................................59

Appendix 2: Budgeteer ..................................................................................................60

Appendix 3: RotateCells ................................................................................................60

Appendix 4: MODFLOW_ReadFileValue.......................................................................61

Appendix 5: GetMyDirectory, SelectChar.exe, and WaitForMe.exe ..............................62

Appendix6: HydrographExtractor.exe..........................................................................-63

Appendix 7: Web-Based Tutorial ...................................................................................64

IV
Figures

Page 

Figure 1. Revised Appearance of the Geology Tab....................................................................... 7

Figure 2. Revised Appearance of the Time Tab............................................................................. 8

Figure 3. Revised Appearance of the MOC3D Tab (formerly Transport Subgrid Tab)................ 9

Figure 4. Revised Appearance of the MOC3D Particles Tab (formerly Particles Tab)............... 10

Figure 5. Example of context-sensitive help................................................................................ 11

Figure 6. Geology tabs with columns used to choose whether to specify Transmissivity

(Specify T), Vertical Conductivity (Specify Vcont), and Confined Storage Coefficient

(Specify sfl)...............................................................................................................

Figure 7. Stresses 2 tab used for selecting the Stream Package and Flow and Head Boundary

Packages................................................................................................................................ 15

Figure 8. Solvers/Other Packages Tab......................................................................................... 16

Figure 9. MODPATH Tab........................................................................................................... 17

Figure 10. MODPATH Options Tab............................................................................................ 18

Figure 11. MODPATH Times Tab..............................................................................................20

Figure 12. ZONEBDGTTab........................................................................................................21

Figure 13. Interpretation of IFACE[i] = 1 to 6............................................................................. 23

Figure 14. Illustration of the linkage among stream segments.................................................... 25

Figure 15. Two models that differ only in the orientation of the area surrounded by a

horizontal-flow barrier..........................................................................................................28

Figure 16. Close up of a section of the horizontal-flow barrier in model 2................................. 29

Figure 17. Method to calculate the reduction of HYDCHR when horizontal-flow barriers are

at an angle to the grid............................................................................................................ 29

Figure 18. Revised Run MODFLOW/MOC3D Dialog box. In this example, MOC3D is not

installed at the location specified in the MOC3D Path edit-box so the background of the

status bar, would appear red.................................................................................................. 31

Figure 19. PIE-Generated Progress Bar with error messages...................................................... 32

Figure 20. Dialog box to select type of data set for post-processing........................................... 38

Figure 21. MODFLOW Post-Processing Dialog Box.................................................................. 39

Figure 22. The "Layer Already Exists" Dialog Box.................................................................... 39

Figure 23. Plot MODPATH Results Dialog box after reading a set of pathlines........................ 40

Figure 24. Base map for a two-dimensional sample problem...................................................... 42

Figure 25. Domain Outline........................................................................................................... 44

Figure 26. The label of the stream segment indicates the stream flows from right to left........... 45

Figure 27. Heads Generated by MODFLOW Simulation............................................................50

Figure 28. Contours on "MODPATH Particles Unitl" layer....................................................... 51

Figure 29. MODPATH Pathlines................................................................................................. 52

Figure 30. Slurry wall connecting the two, internal, bedrock outcrops....................................... 53

Figure 31. Pathlines and head contours in the vicinity of the horizontal-flow barrier................. 53

Figure 32. ZONEBDGT Primary zones....................................................................................... 55

Figure 33. Budgeteer: Bar Chart of an Individual Zone.............................................................. 56
Tables

Page 

Table 1. System Requirements.......................................................................................................4

Table 2. New Files Created for MODFLOW Simulations..........................................................35

Table 3. Files Created for MODPATH........................................................................................ 36

Table 4. Files Created for ZONEBDGT...................................................................................... 36

Table 5. Files Created by MODFLOW........................................................................................ 37

Table 6. Files Created by MODPATH and ZONEBDGT........................................................... 37

Table 7. Parameter values for two-dimensional sample problem................................................ 41

VI
Upgrade to MODFLOW-GUI: Addition of 

MODPATH, ZONEBDGT, and additional 

MODFLOW packages to the U.S. Geological 

Survey MODFLOW-96 Graphical-User Interface

Richard B. Winston

Abstract

This report describes enhancements to a Graphical-User Interface (GUI) for 

MODFLOW-96, the U.S. Geological Survey (USGS) modular, three-dimensional, finitedifference ground-water flow model, and MOC3D, the USGS three-dimensional, method-ofcharacteristics solute-transport model. The GUI is a plug-in extension (PIE) for the commercial 

program Argus ONE . The GUI has been modified to support MODPATH (a particle tracking 

post-processing package for MODFLOW), ZONEBDGT (a computer program for calculating 

subregional water budgets), and the Stream, Horizontal-Flow Barrier, and Flow and Head 

Boundary packages in MODFLOW. Context-sensitive help has been added to make the GUI 

easier to use and to understand. In large part, the help consists of quotations from the relevant 

sections of this report and its predecessors. The revised interface includes automatic creation of 

geospatial information layers required for the added programs and packages, and menus and 

dialog boxes for input of parameters for simulation control. The GUI creates formatted ASCII 

files that can be read by MODFLOW-96, MOC3D, MODPATH, and ZONEBDGT. All four 

programs can be executed within the Argus ONE application (Argus Interware, Inc., 1997). 

Spatial results of MODFLOW-96, MOC3D, and MODPATH can be visualized within Argus 

ONE . Results from ZONEBDGT can be visualized in an independent program that can also be 

used to view budget data from MODFLOW, MOC3D, and SUTRA. Another independent 

program extracts hydrographs of head or drawdown at individual cells from formatted 

MODFLOW head and drawdown files. A web-based tutorial on the use of MODFLOW with 

Argus ONE has also been updated. The internal structure of the GUI has been modified to make 

it possible for advanced users to easily customize the GUI. Two additional, independent PIE's 

were developed to allow users to edit the positions of nodes and to facilitate exporting the grid 

geometry to external programs.
Introduction

The purpose of this report is to describe enhancements to the USGS MODFLOW 

Graphical-User Interface (GUI) Version 2 (Hornberger and Konikow, 1998; Shapiro and others, 

1997). Major changes introduced in this revision of the GUI include addition of contextsensitive help and incorporation of interfaces for the following programs or packages:

 MODP ATH (Pollock, 1994),

 ZONEBDGT (Harbaugh, 1990),

 Stream Package (Prudic, 1989),

 Horizontal-Flow Barrier Package (Hsieh and Freckleton, 1993), and

 Flow and Head Boundary Package (Leake and Lilly, 1997).

In addition, a variety of less significant changes have been made to the GUI. These 

include the following.

 It is now possible to specify transmissivity, vertical conductance, and the confined storage 

parameter directly rather than having them calculated from other parameters.

 It is now possible to specify that a unit be convertible between confined and unconfined 

conditions but with a constant transmissivity (LAYCON = 2).

 It is now possible to deactivate a package without deleting the layers and parameters for that 

package.

 The Modify buttons previously used to make changes to text in tables have been eliminated. 

Changes are now made directly in the table.

 An option has been added to allow users to choose among several expressions for defining 

the initial head and IBOUND parameters on the MODFLOW FD Grid layer.

 An option has been added to allow the user to use alternative export templates for the River, 

Drain, or General-Head Boundary packages. The alternative templates allow for more 

flexible specification of the river parameters but do not permit more than a single boundary 

of a given type in a cell.

 An About tab has been added to the Edit Project Info dialog box. The About tab includes 

the USGS identifier, bibliographic citations of the documentation of the GUI, the version of 

the GUI, a hypertext link to the URL where the GUI may be downloaded, and a link to email 

address for technical support.

 The edit-box for the WSEED parameter on the SIP tab is disabled unless the WSEED 

parameter is used by MODFLOW.

 The title of the PCG tab has been changed to PCG2 to reflect the version of PCG currently 

used by the USGS.

 On the PCG2 tab, the parameter IPCGCD has been replaced by DAMP because IPCGCD 

has been replaced by DAMP in the PCG2 package.

 The GUI no longer imposes any restriction on the number of geologic units or stress periods. 

However, if the number of MODFLOW layers exceeds 200, the limit in the standard release 

of MODFLOW-96, a warning message will be displayed.

 The dialog boxes provided by the GUI can now be resized.

 A variety of non-spatial data are now entered in different locations than previously to make 

data entry more intuitive.

 If any layers or parameters that should be present are missing, they will be added when 

clicking on the OK button in the Edit Project Info dialog box. A layer or parameter may be
absent because it was not used in a previous version of the GUI or because a user has 

mistakenly deleted it manually. By restoring missing layers or parameters, a model is 

returned to a useable state despite user-errors.

 The method for specifying the extent of the transport subgrid for MOC3D has been changed. 

Previously, users would enter the first and last row and column numbers of the transport 

subgrid. Now users define the subgrid boundary on an information layer. The change makes 

it possible to modify the grid without need to re-enter values of ISROW1, ISROW2, 

ISCOL1, and ISCOL2. To update old models, the user may need to open and then close the 

Edit Project Info dialog-box so that the MOC3D Transport Subgrid layer can be created. 

The user will be prompted to open it, if required, when reading a data set prepared with an 

older version of the GUI.

 A method of importing well information has been added that makes it simpler to import well 

data from spreadsheets than previously.

 It is now possible to specify the location of an executable file without needing to modify the 

export template.

 During the export process, a dialog-box appears. It displays the progress of the export 

process and the estimated time remaining for the export process to finish. It also displays 

error and warning messages.

 The speed of the export process has been increased especially for models with multiple stress 

periods.

 More extensive error checking is done during the export process.

 In post-processing charts, inactive cells are skipped. Because the inactive cells may vary 

among MODFLOW layers, it is no longer possible to make post-processing charts of 

different MODFLOW layers using the same data layer. Thus, the Post-processing PIE must 

be called separately for each MODFLOW layer for which a post-processing plot will be 

made.

 The language in which the GUI is written has been changed from C++ to Object Pascal.

 The internal structure of the GUI has been altered to make it possible for advanced users to 

customize the GUI. If the customization is done properly, it will be possible to incorporate 

future changes to the USGS version of the GUI into a customized version of the GUI with 

relatively little effort.

In addition to changes in the GUI a number of independent programs were created to 

facilitate various tasks that do not require integration with Argus ONE (Argus Interware, Inc., 

1997). One program, Budgeteer (Appendix 2), extracts, water budget data from files created by 

MODFLOW (McDonald and Harbaugh, 1988; Harbaugh and McDonald, 1996), MOC3D 

(Konikow and others, 1996), ZONEBDGT (Harbaugh, 1990), or SUTRA (Voss, 1984) and plots 

it. The data can be saved in a form suitable for import into commercial spreadsheet programs. 

Another program, Hydrograph Extractor (Appendix 6), reads head or drawdown for individual 

cells from the formatted head or drawdown files produced by MODFLOW. It also plots the data 

and allows it to be saved in a form suitable for import into commercial spreadsheet programs.

A web-based tutorial on the use of MODFLOW with Argus ONE is available for 

downloading together with version 3 of the MODFLOW GUI (Appendix 7). The tutorial was 

originally prepared by Argus Interware for use with version 1 of the MODFLOW GUI.

I appreciate the suggestions for improvements made by USGS colleagues A.M. Shapiro, 

L.F. Konikow, G.Z. Hornberger, Earl Greene, and numerous users of previous versions of the 

MODFLOW-GUI. I wish to thank S. Dolev and J. Margolin of Argus Interware for their
technical assistance. I would also like to thank all those who provided "bug-reports" or other 

advice while the revised GUI was under development.

I would like to thank Argus Interware for granting permission to update their 

MODFLOW tutorial.

System Requirements

The revised MODFLOW-GUI has been tested on personal computers with Windows 95 

and Windows NT 4.0. It has not been tested extensively on Windows 98. The user must have 

the Windows version of Argus Open Numerical Environments (Argus ONE ). Argus ONE 

largely determines hardware requirements. At the time this was written, the requirements for 

Argus ONE were the following:

CPU Pentium, Pentium Pro recommended

Mouse Required

RAM 32 MB or more recommended

DISK 7 MB

Display VGA/SVGA Display, 65,000 colors

In addition, the MODFLOW-GUI requires a display with a resolution of at least 632x590.

Installation

Table 1. System Requirements.

Files required for installation Location to install

MFGUI_30.dll <Argus directory>\ArgusPffi\MODFLOW

MODFLOW.cnt <Argus directory>\ArgusPffi\MODFLOW

MODFLOW.hlp <Argus directory>\ArgusPffi\MODFLOW

*.met (see readme.txt file for <Argus directory>\ArgusPIE\MODFLOW

details)

MODFLOW_JoinFiles.dll <Argus directory>\ArgusPIE\JoinFiles

MODFLOW_BlockList.dll <Argus directory>\ArgusPffi\BlockList

MODFLOW_ReadFileValue.dll <Argusdirectory>\ArgusPffi\ReadFileValue

MODFLOWJListdll <Argus directory>\ArgusPIE\List ,

GetMyDirectory.dll <Argus directory>\ArgusPIE\GetMyDirectory

SelectChar.exe <Argus directory>\ArgusPIE\GetMyDirectory

WaitForMe.exe <Argus directory>\ArgusPIE\GetMyDirectory

MODFLOW_ProgressBarPIE.dll <Argus directory>\ArgusPIE\ ProgressBarPIE

Ctl3d32.dll (Windows NT 3.51) <Windows directory>\System32__________

Except for ctl3d32.dll, all the files used by the PIE should be placed in the ArgusPIE 

directory or in subdirectories under the ArgusPIE directory. Unless otherwise noted, it is 

generally a good idea to place each PIE in its own subdirectories under the ArgusPIE directory. 

The export templates used by the PIE (*.met), and the help system files (modflow.hlp and 

modflow.cnt) should be placed in the same directory as the MODFLOW PIE (MFGUI_30.dll). 

Ctl3d32.dll is only required for Windows NT 3.51. If required, it should be placed in the 

System32 directory under the main directory for the operating system (normally WinNT).
Many, but not all, users will already have Ctl3d32.dll on their computer and in such cases they 

generally should not replace the existing version with the one distributed with the PIE. Export 

templates that are meant to be modified and executed manually by the user may be placed in any 

convenient location. These include contour2data.met and statistics.met. All the files comprising 

the PIE are available from the U.S. Geological Survey, but they require an executable version of 

Argus ONE (version 4.20i or higher) to operate. Although not required to operate the 

MODFLOW PIE, the EditContours, RotateCells, MODFLOW_ReadFileValue, and 

GetMyDirectory PIE's and the Budgeteer, SelectChar, WaitForMe, Extract Hydrograph 

programs and MODFLOW tutorial (see Appendices 1-7) were designed for use with models in 

the MODFLOW PIE and are thus distributed with the MODFLOW PIE. The may also be useful 

for other purposes.

Previous versions of the GUI (Shapiro and others, 1997; Hornberger and Konikow, 1998) 

used a number of array PIE's that are not used by the current version of the PIE 

(Chk_BlockArray.dll, Chk_LayArray.dll). If those files are present, they may be deleted without 

affecting the new version of the MODFLOW-GUI. Previous versions of the MODFLOW-GUI 

and post-processing PIE's (mfgui_20.dll, mfpost20.dll, mcpostl0.dll) should be deleted from the 

Argus PIE directory because they will interfere with the new version of the PIE. The functions 

performed by all three of these older PIE's have been incorporated into the new GUI.

Executable versions of MOC3D (Version 1.2 or later), MODFLOW-96, MODPATH, and 

ZONEBDGT must be installed to run these models from the Argus ONE environment. The 

MODFLOW-96 code and the MOC3D code are integrated into one code (MOC3D). 

MODFLOW-96 (without MOC3D) is executed when using the GUI to simulate ground-water 

flow only, without transport; MOC3D is executed when simulating ground-water flow with 

transport. Although it does not matter what compiler was used to create the executable versions 

of the models, it is important that they all be compiled with compatible compilers. This is 

because ZONEBDGT and MODPATH read binary files created by MOC3D and MODFLOW96. The format of the binary files is compiler-dependent. The versions of these programs on the 

USGS software web site are all compatible with one another.

The MODFLOW-GUI consists of a dynamic-link library (MFGUI_30.DLL) that 

provides the core functionality. It provides the Edit Project Info, Run MODFLOW, and a 

variety of other dialog boxes. It is responsible for creating and destroying MODFLOW-related 

layers and parameters in the Argus ONE project and for accessing its context-sensitive help. It 

processes the model-related export templates and prepares them for execution by Argus ONE . 

It also provides a number of hidden PIE functions that are called when the export templates are 

executed. The model-related export templates are the files MODFLOW.met, ZoneBud.met, and 

MODPATH.met. These files contain the instructions for creating the input files for 

MODFLOW, MOC3D, ZONEBDGT, and MODPATH. When they are executed, the export 

templates use PIE functions provided by the following dll's: List.dll, BlockList.dll, 

ProgressBar.dll, and JoinFiles.dll. Of these, only ProgressBar.dll will be visible to the user. It 

displays a progress bar during the execution of export templates and provides an estimate of the 

time required until execution of the export template is complete. It also displays error and 

warning messages. Modflow.hlp and Modflow.cnt provide the online help for the PIE. Finally, 

ctl3d32.dll, a dynamic-link library from Microsoft Corporation , provides the three-dimensional 

appearance of the certain portions of the dialog boxes when the PIE is operated on computers 

using the Windows NT 3.51 operating system.
Starting the Preprocessor

The user can start a new model or open an existing model in the same way as in previous 

versions of the MODFLOW-GUI. To start a new model, start Argus ONE and select 

PIEs|New MODFLOW Project. To open an existing model, start Argus ONE and select 

File|Open... and then select the file to open. In some cases, if the user opens a model created by 

the previous version of the MODFLOW/MOC3D PIE, the PIE will need to update the data for 

specifying the transport subgrid. If this is the case, a message will notify the user that he will 

need to open the Edit Project Info dialog box and close it again. The data will be automatically 

updated when the user clicks OK after opening the Edit Project Info dialog box. Other layers, 

such as group layers for each geological unit may also be created at the same time. (The group 

layers provide a convenient mechanism for organizing Argus ONE layers but are not required 

for the model to operate.)

Entering Non-spatial Data

Non-spatial data are entered in the Edit Project Info dialog box. The user can display it 

by selecting PIEsjEdit Project Info... Most of the non-spatial data are the same as in previous 

versions of the MODFLOW-GUI (Shapiro and others, 1997; Hornberger and Konikow, 1998). 

Only those portions of the Edit Project Info dialog box that have changed or are new will be 

described here. Complete explanations of all items in the Edit Project Info dialog box are 

included in the online help.

Changes to Existing Features

Overall Appearance

The tabs in the Edit Project Info dialog box now appear on multiple rows and all tabs 

currently in use are always visible. In the previous versions, the tabs were on a single row and 

the user would sometimes need to scroll to the right or left to select another tab.

The Misc. Controls tab has been removed. The data that were formerly entered in this 

tab are now entered on the Wetting, Geology, or Output Files tabs.

The SIP, SOR, PCG, and PCG tabs have been removed. The data formerly displayed 

on those tabs is now displayed in the new Solvers/Other Packages tab.

Geology Tab

On the Geology tab (figure 1), the edit-boxes and modify button from version 2 have 

been removed. The user should now enter data directly in the table. For Simulated, Interblock 

Transmissivity, Aquifer Type, Specify T, Specify Vcont and Specify spl select a cell and then 

click in it or press the Enter key on the keyboard to display a list of choices. For the other 

columns, just select the cell and type the data. A new button, Add can be used to add a new 

geologic unit to the end of the list of geologic units. The GUI now supports LAYCON = 2 in the 

Block-Centered-Flow package (convertible layers with constant transmissivity). You can resize 

the columns on this or other tables. To ensure that the title of a column is always legible 

regardless of the size of a column, the title of the column over which the mouse is positioned will 

be displayed in the status bar at the bottom of the dialog box.

On the Geology Tab, IAPART is now automatically set to the correct value and disabled 

if the Interblock Transmissivity is set to Arithmetic & Logarithmic in any geological unit. 

IAPART was formerly on the Misc. Controls tab.
h MODFLOW DalaSels

RHS occupy same space (0) Jj^^l^il

Figure 1. Revised Appearance of the Geology Tab.

Stresses 1 Tab

The Stresses/Solvers tab has been replaced by three new tabs Stresses 1, Stresses 2, and 

Solvers/Other Packages. The choice of solvers has been moved to the Solvers/Other 

Packages tab. The check box for selecting MOC3D and the radio buttons for selecting the 

MOC3D solver have been moved to the MOC3D tab.

Output Files Tab

On the Output Files Tab, CHTOCH is automatically set to the proper value if the 

MOC3D checkbox on the MOC3D tab is checked. The control is also disabled if the MOC3D 

checkbox is checked so that it can not be changed to an incorrect value. CHTOCH was 

formerly set with a combo-box. It is now set with a check-box. The root name is now limited to 

eight characters and will be converted to lower case. The latter facilitates using the MODFLOW 

input files on computers with UNIX operating systems. The eight-character limitation is 

imposed because the current version of MODFLOW-96 for the DOS operating system 

distributed by the USGS does not support long file names. Combo boxes have been added to 

allow the user to specify the format in which to print heads and drawdowns.

Time Tab

On the Time tab (figure 2), the edit-boxes and Modify button have been removed. The 

user now enters data directly into the table. A new Add button can be used to add a new stress
period to the end of the list of stress periods. The user now can change the number of stress 

periods by entering a number in the Number of stress periods edit-box. The change takes effect 

as soon as the user clicks outside the edit-box. A new field has been added to the table. It 

displays the length of the first time step in the stress period. This number can not be edited 

directly. Instead it is calculated based on the length of the stress period, the number of time steps 

and the time step multiplier. It is displayed as a convenience to the user but is not exported to 

the MODFLOW input files.

H MODFLOW Data Sets

Figure 2. Revised Appearance of the Time Tab.

Severs/Other Packages Tab

On the new Sovers/Other Packages tab, the IPCGCD parameter of the PCG2 package 

has been replaced by DAMP. DAMP replaces IPCGCD in the most recent version of the PCG2 

solver. In setting data for the SIP solver, it is now only possible to specify WSEED if IPCALC 

is set to 0. This is because MODFLOW will only use WSEED if IPCALC is set to 0.

MOC3D Tab

The Transport Subgrid tab has been renamed the MOC3D tab (figure 3). On the 

MOC3D tab, the user no longer specifies the rows and columns in the transport subgrid. This is 

now done on the information layer named MOC3D Transport Subgrid. In addition the Help 

button next to INCRCH has been eliminated. The help for INCRCH has been incorporated into 

the new context-sensitive help for the PIE. The check box for selecting MOC3D and the radio
buttons for selecting the MOC3D solver have been moved from the Stresses/Solvers tab to the 

MOC3D tab.

Eg MODFLOW Data Sets

I^^^I^^Jffiifpa^^il^'l^t^A^iH | lElliBD^ff

Figure 3. Revised Appearance of the MOC3D Tab (formerly Transport Subgrid

Tab).

MOC3D Particles Tab

The Particles tab has been renamed the MOC3D Particles tab (figure 4). On it, the 

three help buttons have been eliminated. The help that they formerly provided has been 

incorporated into the new context-sensitive help for the PIE. The edit fields and Modify button 

have also been eliminated. Instead, enter values directly into the table.
B MODFLOW Data Sets

^^a^^Optlgtts^ ]; MOC3D: 

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$5J:ftlntf ":| :;iJi%uJ#aesi

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Maximum Sact»m efceB tosSskns p«r movjO.5

|0.05

1

(FZHd)

(HFTPNC)

Position in Raw

L_

Position in Cohatm

Figure 4. Revised Appearance of the MOC3D Particles Tab (formerly Particles

Tab).

MOC3D Output + Dipsersivities Tab

A pair of radio buttons has been added to the MOC3D Output + Dipsersivities tab to 

allow the user to choose to the format in which in which concentration will be printed in if the 

concentrations are printed in a separate output file (file type CNCA).

New Features

Context-sensitive help

Context-sensitive help (figure 5) is available for the major dialog boxes created by the 

MODFLOW-GUI. These include the Edit Project Info, Run MODFLOW, MODFLOW Post 

Processing, and Display Horizontal Flow Barriers dialog boxes. To access the help on any of 

these dialog boxes, click on the Help button on the dialog box or click on a control (combo-box, 

check-box, etc.). Then press the Fl key. Another way to access the help is to click on the 

question-mark icon in the upper right corner of the dialog box and then click on a control such as 

a check box.

10
Adding Geologic Units

Geology Tab

To add a geologic unit, move the cursor to the table listing 

the geologic units and select a row by clicking on it.

Clicking the Insert button adds a geologic unit above the 

highlighted geologic unit. Attributes associated with the 

selected geologic unit are copied to the new geologic unit. 

The geologic units are then renumbered to reflect the 

addition of the new geologic unit.

Clicking the Add button adds a geologic unit at the end of 

the list of geologic units. Attributes associated with the last 

geologic unit are copied to the new geologic unit.

Figure 5. Example of context-sensitive help.

Help is also available for all the layers and parameters created by the PIE although this 

help is not context-sensitive. To access the help file, select PIEs|MODFLOW Help. It is 

possible to access the MODFLOW help without starting a MODFLOW project.

Deactivating Packages without Deleting the Data for the Package.

If the Use checkbox next to the check box for a package is not checked, the layers and 

parameters for that package will be retained in the Argus ONE project but the package will not 

be used in the model. You can check on uncheck these checkboxes to enable or disable a 

package without deleting the information you have entered for those packages.

Specifying Transmissivity, Vertical Conductance, and Confined Storage Coefficient. 

The geology data table on the Geology tab has three new columns labeled Specify T, 

Specify Vcont, and Specify sfl (figure 6). It may be necessary to resize the Edit Project Info 

Dialog box or to use the scroll bar under the Geology data table to see these new columns. These 

are used to decide whether to specify transmissivity, vertical conductance, and the confined 

storage coefficient respectively. If the user selects a cell in any of these three columns, a dropdown menu will appear. Select Yes to specify any of the three parameters directly. Select No to 

calculate these parameters from other parameters. If the user selects Yes, the appropriate 

information layers and parameters will be created.

11
H MQDFLQW Data Sets

I'letesal-fUpgrStoeages ;] BUFF, RHS occupy same space (0)

r

Figure 6. Geology tabs with columns used to choose whether to specify 

Transmissivity (Specify T), Vertical Conductivity (Specify Vcont), and Confined 

Storage Coefficient (Specify sf1).

Saving Default Values

Files with the extension ".val" are text files that are used to set defaults for all options in 

the Edit Project Info dialog box. If the user clicks the Save Val File button on the Advanced 

Options tab and accept the default file name and location, a ".val" file will be created that will 

be used for all new MODFLOW projects. The default file name is "modflow.val". The default 

location is the directory in which the MODFLOW-GUI is installed. The ".val" file will save all 

the information in the Edit Project Info dialog box. If the user saves it with a different file 

name or location, a ".val" file will be created that can be opened later by clicking the Open Val 

File button. Opening a ".val" file will cause the options specified in the ".val" file to override all 

the data in the Edit Project Info dialog box.

Files with the extension ".val" files created for versions 1 and 2 of the MODFLOW-GUI 

are not used by the current version of the MODFLOW-GUI. Users who have not edited the 

"modflow.val" file to specify default values, should delete the modflow.val file. Users who have 

edited the modflow.val file, should replace it with a new version created in the method described 

above. If an old version of a ".val" file is read by the MODFLOW-GUI, a warning message will 

be displayed.

12
Specifying Initial Head Formula

The combo-box labeled Method for assigning the EBOUND parameter and prescribed 

heads in the initial head MODFLOW FD Grid parameter on the Advanced Options tab gives 

three choices for how initial head will be determined: 

Method from MF-GUI versions 1 and 2 

Average Points and Open Contours 

Use Point Contours First

These options affect how prescribed head boundaries will be treated especially when open 

contours or point contours are used. For Method from MF-GUI versions 1 and 2, the initial 

head in a cell containing a contour on the Prescribed Head Unit[i] layer will be interpolated from 

all the contours on the layer. This was the method used in versions 1 and 2 of the MODFLOWGUI. For Average Points and Open Contours, any cells that have both point and open 

contours on the Prescribed Head Unit[i] layer will be assigned the average of the point and 

open contours on that layer. Locations inside closed contours will have the value of that contour 

unless the cell also contains a point or open contour. For Use Point Contours First, any cells 

that have both point and open contours on the Prescribed Head Unit[i] layer will be assigned 

the average of the point contours on that layer. If the cell contains no point contours but does 

contain an open contour, it will be assigned the average of the open contours on that layer. 

Locations inside closed contours will have the value of that contour.

These options also affect which cells are inactive. If Method from MF-GUI versions 1 

and 2 is selected, all cells whose centers are outside the domain outline will be inactive. For the 

other choices, any cell on the domain outline will be either an active cell or a prescribed head 

cell even if its center is outside the domain outline.

Use Binary Head File for Initial Heads

If the Use MODFLOW binary head file as source of initial heads checkbox is 

checked, MODFLOW will read the initial heads directly from the file specified in the File Name 

edit box rather than from values entered in the GUI. This affects the heads at all cells including 

the prescribed head cells. Any changes in the grid will make this method invalid.

Using Alternative Export Templates

If the Use alternate River package export template, Use alternate Drain package export 

template, or Use Alternate GHB package export template check box is checked an alternative 

export template is used for the River Drain, or General-Head Boundary package. This 

alternative template allows you to set the value of all parameters in the river layers using 

expressions.

On the Line River Unit[i], Line Drain Unit[i], or Line GHB Unit[i], layers, there will 

be one boundary created in each cell in which there is an open contour. The bottom and stage 

stress will be evaluated at the block center. The conductance exported to MODFLOW will be 

the conductance parameter evaluated at the cell center multiplied by the lengths of all the 

contours in the block.

On the Area River Unit[i], Area Drain Unit[i], or Area GHB Unit[i] layers, there will 

be one boundary created in each cell in which the conductance parameter is a number (rather 

than $N/A) at the block center. The bottom and stage stress will be evaluated at the block center. 

The conductance exported to MODFLOW will be the conductance parameter evaluated at the 

cell center multiplied by the area of the block.

13
Explicitly specify recharge or evapotranspiration layer

If the Explicitly specify recharge layer or Explicitly specify evapotranspiration layer

check box is checked, parameters will be added to the Recharge or Evapotranspiration layer 

that can be used to specify the MODFLOW layer to which recharge or evapotranspiration will 

apply instead of calculating the layer from the Elevation parameter.

Stream Package

Three additional MODFLOW Packages have been added to the interface; the Stream 

Package (Prudic, 1989), the Horizontal-Flow Barrier Package (Hsieh and Freckleton, 1993), and 

the Flow and Head Boundary Package (Leake and Lilly, 1997). To activate the stream package, 

go to the Stresses 2 tab (figure 7) in the Edit Project Info dialog box and check the STR checkbox. This will activate the other stream-related controls on the Stresses 2 tab. If the user 

attempts to activate both the stream package and MOC3D, a warning message will be displayed. 

If the user selects Steady Stress for the stream package, all the variables that are specified for 

the first stress period will apply to the remaining stress periods. However, there will still be 

parameters created for the other stress periods. This allows the user to switch between timevariable stress and steady stress without loss of information. If the user chooses to calculate 

flow, specify both the length and time units for the model. The length units are specified on the 

Stresses 2 tab. The time units are specified on the Time tab. If the user does not specify the 

time units, a warning message will appear when the Edit Project Info dialog box is closed or the 

input files for MODFLOW are exported. The user can choose whether or not to simulate stream 

tributaries and diversions. Depending on the choices made, parameters related to tributaries, 

diversions, and calculating flow will be created on the Stream Unit[i] information layers when 

the Edit Project Info dialog box is closed. See Prudic (1989) for more information about the 

Stream package.

14
Figure 7. Stresses 2 tab used for selecting the Stream Package and Flow and

Head Boundary Packages.

Flow and Head Boundary Package

To activate the Flow and Head Boundary package, change to the Stresses 2 tab (figure 7) 

of the Edit Project Info dialog box and select the Flow and Head Boundary check-box. This 

will activate some or all of the other controls related to the Flow and Head Boundary package. 

The controls that are activated depend on the current set-up of the model. In all cases, the user 

can set the number of Flow and Head Boundary times. This will change the number of Flow 

and Head Boundary times that can be edited. The first such time must always be zero. It can not 

be edited. All subsequent times must be larger than or equal to their predecessors. If invalid 

times are specified, a warning message will appear when the Edit Project Info dialog box is 

closed. The steady-state option for Flow and Head boundaries is only available for steady-state 

models with multiple stress periods. Weighting factor for concentration at specified flux cell 

and Weighting factor for concentration at specified head cell will only be available for 

models in which MOC3D is selected. More information about the Flow and Head Boundary 

Package is in Leake and Lilly (1997).

Horizontal-Flow Barrier Package

To activate the Horizontal-Flow Barrier package, change to the Solvers/Other Packages 

tab (figure 8) of the Edit Project Info dialog box and select the Horizontal-Flow Barrier 

check-box. There are no time-dependent parameters for the Horizontal-Flow Barrier package so

15
there is no steady state option. See Hsieh and Freckleton (1993) for more information about the 

Horizontal-Flow Barrier package.

20NEBDOT.

'%( "liojeel ;j| Geotegy j 

17 Use

Figure 8. Solvers/Other Packages Tab.

MODPATH

To activate MODPATH, change to the MODPATH tab (figure 9) and select the 

MODPATH check-box. A new tab will appear labeled MODPATH Options (figure 10). In 

addition, if the user selects Compute locations at specific points in time and specify times 

individually on the MODPATH Options tab, another new tab will appear labeled MODPATH 

Times (figure 11). The descriptions for the MODPATH options below are largely quoted or 

paraphrased from those in the MODPATH 3.0 manual (Pollock, 1994).

16
H MDDFLOW Data Sets

evapotranspirations is assigned to top face (1)

Figures. MODPATH Tab.

If the Use COMPACT Option check-box box is checked, MODPATH will generate 

endpoint, pathline, or time series files as text files using the global node number to indicate cell 

location. If it isnY checked, the cell locations will be designated using the row-column-layer grid 

indices (as in previous versions of MODPATH).

If the Use BINARY Option check-box is checked, endpoint, pathline, and time series 

files will be generated by MODPATH in binary form. If the BINARY option is used, it will also 

need to be used with MODPATH-PLOT to correctly read binary versions of these files. The 

MODFLOW-GUI does not read binary MODPATH output files so this option should not be used 

if the user intends to use the MODFLOW-GUI to display MODPATH results.

The Maximum Number of Release Times edit-box controls the maximum number of 

release times that can be specified for any object on MODPATH Particles Unit[i] layers. 

MAXSIZ is the maximum allowed size (in bytes) of the Composite Budget File. If MAXSIZ = 

0, the program uses a default value that is set in the MODPATH main program.

NPART is the maximum number of particles allowed for a MODPATH run. If NPART 

is set equal to 0, MODPATH automatically resets NPART to a default value that is defined in 

the MODPATH main program.

TBEGIN is the time value assigned to the beginning of the MODFLOW simulation. 

Any convenient value may be specified, including values less than zero.

BeginPeriod, BeginStep, EndPeriod, and EndStep specify the beginning and ending 

stress period and time-step numbers that will be processed by MODPATH. The interface will 

not allow the user to specify values that are beyond the range specified in the model.

17
The Recharge ITOP parameter indicates whether the recharge is assigned to the top face 

of the cell. If ITOP = 0, recharge is treated as an internal source. If ITOP = 1, recharge is 

assigned as a vertical component of flow to the top face.

The Evapotranspiration ITOP parameter indicates whether the evapotranspiration is 

assigned to the top face of the cell. If ITOP = 0, evapotranspiration is treated as an internal sink. 

If ITOP = 1, evapotranspiration is assigned as a vertical component of flow to the top face.

a MODFLOW Data Sets

Stresses! | 5 S 

) MQBPATH

Fioject j Geolbgjr 

Output Files | Advanced Options * 4 * 

strcssjenodandtnne step jrj

Compute bostons at 

in tine ' (Constant time interval (1)

Time.iatervBl

JFonvard in the direction of flow (1) jj sjPass thrcragh weak sink cells (1)

UHS! of ftactbnpfItew

Figure 10. MODPATH Options Tab.

In steady-state models, the user can stop computing paths after a specified time, by 

checking the Stop computing paths after a specified time check-box. The user will then be 

able to enter the stopping time in the Time to stop computing paths check-box. In transient 

models, the user can stop computing paths after a specified time is reached by checking the Stop 

computing paths after a specified value of tracking time check-box. The user will then be 

able to enter a time in the Maximum tracking time edit-box.

The reference time for releasing particles is the time from which all other times are 

measured. It need not be the starting time of the model (although that is the default). The user 

may enter the reference time using either stress period, time step and relative time within a 

time step or the user can specify the reference time directly as measured from the beginning of 

the model. This option is only available for transient models.

Use the Output mode combo-box to select the type of data generated by MODPATH. 

The type of data can be one of the following: End points (1): (initial and final locations of

18
particles.), Pathlines (2): (locations are recorded where a particle crosses a cell boundary, at the 

end of each time step and at user-specified times.), or Time Series (3): (locations are recorded at 

user-specified times.)

If the user wishes to specify times at which MODPATH will generate output, check the 

Compute locations at specific points in time check-box and the Method of specifying times 

for output combo-box will become enabled. The user can choose this option only if the Output 

mode is Pathlines.

If the user checks the Stop particles if they enter a specific zone check-box, the Zone 

in which particles will stop edit-box will become enabled allowing the user to specify which 

zone particles will stop in. If the user chooses to have only endpoints in the output and chooses 

to have particles stop in a specific zone, the user can also decide whether to have Record 

endpoints for all particles or Record endpoints only for particles in a specific zone.

A weak sink is a cell that contains a boundary condition that removes water from the 

model but which also allows some water to flow to one or more adjacent active cells. Because 

MODFLOW does not define the precise location of sinks within cells, it is impossible for 

MODPATH to unambiguously determine whether a particle that enters a weak sink should be 

removed from the model or should enter an adjacent active cell. The user must decide what is 

the best option. MODPATH gives three choices; particles pass through weak sink cells, 

particles stop at weak sink cells, or particles can stop at weak sink cells that exceed a 

specified strength. If the treatment of particles that enter weak sinks is to Stop at weak sink 

cells that exceed a specified strength, specify the fraction of the flow discharged that will 

cause particles to stop. For example, if 70 per cent of the water that enters a cell is discharged 

through a well and the user specifies a fraction of 0.5 (50 per cent) then any particles entering the 

cell will be stopped. However, if only 30 per cent of the water entering the cell was discharged 

through the well, particles entering the cell would not stop at the cell but instead would be free to 

flow into adjacent cells.

The Compute volumetric budgets for all cells, Check data cell by cell, and 

Summarize final status of particles in summary.pth file check-boxes cause MODPATH to 

perform those functions. In the case of the volumetric budget, you must also specify a 

percentage Error tolerance in the Error tolerance (%) edit-box.

19
MODFLOW Data Sets

Figure 11. MODPATH Times Tab.

Depending on the Output mode, the user may have a choice about whether to compute 

locations at specific points in time. To specify output at specific points in time, the user must 

either specify a time interval for output or specify the times individually. In the latter case, the 

MODPATH Times tab (figure 11) will become visible and the user will be able to specify the 

number of times at which output from MODPATH is desired (Nvalues) and the times at 

which data will be generated (Modpath Time (Tvalue)). For more information about 

MODPATH, see Pollock (1994).

ZONEBDGT

If the ZONEBDGT check-box is checked on the ZONEBDGT tab (figure 12), 

information layers for ZONEBDGT will be created and options relating to ZONEBDGT in the 

Edit Project Info dialog box will become enabled.

20
H MODFLOW Data Sets

Stresses Ls

'|ZONEBDGT Title

o

Figure 12. ZONEBDGTTab.

ZONEBDGT Title is the title that will be printed on the ZONEBDGT output.

To use composite zones in ZONEBDGT, set Number of ZONEBDGT composite zones 

to a number greater than 0 and then enter the zone numbers in the ZONEBDGT Composite 

Zones table. The zones must match the primary zones in the ZONEBDGT information layers. 

The user may generate budgets for all times for which cell-by-cell flows are saved or specify up 

to ten times at which budgets will be generated. To do the latter, the user must enter the stress 

periods and time steps in the ZONEBDGT Specified output times table.

Entering Spatial Data

To provide an interface for the additional MODFLOW packages as well as MODPATH 

and ZONEBDGT, several new parameters and information layers have been added. Other layers 

and parameters have been renamed to better reflect their function. Finally, a new method of 

importing well data has been added. These changes are described here.

Renamed Layers and Parameters

The MODFLOW Grid Density layer has been renamed the MODFLOW Grid

Refinement layer to better reflect what the layer controls. The Density parameters on that layer 

and the MODFLOW Domain Outline layer have both been renamed to MODFLOW Grid 

Refinement and MODFLOW Cell Size respectively. The Maps Unitl layer has been renamed 

the Maps layer because it is not associated with a specific geologic unit. On Line River Unit[i]

21
and Area River Unit[i] layers, the Bottom parameter has been renamed Bottom Elevation for 

greater clarity. When opening files created by previous versions of the MODFLOW GUI, these 

layers and parameters are automatically changed to their new names. If any layers or parameters 

are renamed while opening a file, a dialog box will appear that informs the user about the 

renamed layers or parameters. In some cases, users may need to update expressions that they 

have created to reflect the new names.

Locked Recharge Elevation parameter

The Elevation parameter on the Recharge layer now has the Dont Override, Dont Eval 

Color, and Lock Def Val parameter locks set when that parameter is not used. The parameter is 

used only if recharge option (NRCHOP) on the Stress 1 tab of the Edit Project Info dialog box 

is set to Vert distribution in IRCH (2). This prevents users from entering data for this 

parameter unless the data will be used.

Importing Well Data

The MODFLOW GUI has a special mechanism for importing Well data. To import the 

well data do the following.

1. Select PIEs|Import Wells.

2. Enter the correct geologic unit in the edit box labeled "Geologic Unit" or click the 

"Use Multiple Units" checkbox. (If the "Use Multiple Units" checkbox is checked, the user 

must specify the geologic unit for each well individually.)

3. A dialog box will appear with a table with spaces for all the data defining the well. 

You may type the required information into the table. However, it is usually easier to import the 

data from a spreadsheet or from a tab-delimited text file.

To import the data from a spreadsheet, arrange the spreadsheet so that it has all the same 

data shown in the table headers and in the same order. Then select the block of data that you 

wish to import and copy it to the clipboard. Make Argus ONE active and click on the Paste 

from clipboard button. The data will be pasted from the clipboard.

To import the data from a tab-delimited text file, make a file containing the data. Any 

line that begins with a # will be treated as a comment and ignored. Every other line must contain 

data for a single well. The data for each well must be in the same order as shown in the Well 

Data table. Each item in the line must be separated from the next item by a single tab character. 

Then click on the Read from file button and select the file from which you wish to read data.

You don\ need to set the number of wells before pasting data into the table or reading it 

from a file; the number of wells will be set automatically when the data is read.

The data to be imported may be delimited by tab-characters or by commas, spaces, and 

tab-characters. If the latter option is used, the well name either must not include any spaces, tabs 

or commas or it must be enclosed in single or double quotation marks. For example, "A Well 

Name" and 'A Well Name'would both be acceptable. If you copied data to the clipboard from a 

spreadsheet and wish to paste it into the Well Data table, use the tab-delimited format.

4. Click on the OK button and the data will be imported into the correct Wells Unit[i] 

layer or layers.

MOC3D Transport Subgrid

The MOC3D subgrid boundary is now specified using an information layer named 

MOC3D Transport Subgrid. If there are no contours on the MOC3D Transport Subgrid

22
layer, the MOC3D Subgrid will encompass the entire grid. If there are contours on the MOC3D 

Transport Subgrid layer, the location of each vertex of each contour on the layer will be 

compared to the row and column locations. The subgrid will extend from the lowest row and 

column adjacent to any vertex to the highest row and column adjacent to any vertex. The value 

assigned to the parameter on the MOC3D Transport Subgrid layer has no effect. The transport 

subgrid can be visualized with a new parameter on the MODFLOW FD Grid layer named 

Subgrid Boundary. (Previously there were separate parameters for each geologic unit named 

Subgrid Boundary[i].)

IFACEfi]

On a number of layers, there will now be an IFACE[i] parameter added if MODPATH 

is selected. The layers on which this parameter is present include Wells Unit[i], Line River 

Unit[iJ, Area River UnitfiJ, Line Drain Unit[i], Area Drain UnitfiJ, Point Gen Head 

Boundary Unit[i], Line Gen Head UnitfiJ, Area Gen Head UnitfiJ, and Stream UnitfiJ.

IF ACE [i] is used to specify how MODPATH will treat the flow to or from a cell for stress 

period i. However, if steady stress has been chosen for the relevant package in the Edit Project 

Info dialog box, only IF ACE 1 will be used for the entire duration of the model. The other 

IFACE[i] parameters will be ignored. If IF ACE [i] is from 1 to 6, the flow is assigned to a cell 

face according to the diagram below. If IFACE[i] < 0, the source/sink flow term is distributed 

uniformly across any of the faces 1 through 4 that form boundaries with inactive cells. If 

IFACE[i] = 0 or IFACE[i] > 6, the flow is treated as an internal source. If IFACE[i] is from 1 

to 6, the flow is assigned to a cell face according to the figure 13.

Figure 13. Interpretation of IFACE[i] = 1 to 6.

MODPATH information layers

In addition to the IF ACE parameter, two new information layers will be added for each 

geologic unit when MODPATH is selected: MODPATH Zone Unit[i], and MODPATH

23
Particles Unit[i]. The Porosity Unit[i] layers will also be created if MODPATH is selected. 

This layer is also used with MOC3D.

MODPATH Zone Unit[i] represents the zone code used by MODPATH-PLOT to 

determine the color of pathlines and particle points. MODPATH requires that the zone code lie 

between 1 and 999 inclusive. Under rare circumstances the user may wish to override the default 

value of MODPATH Zone Unit[i]. If so the user must first unlock the default value. See the 

Argus ONE documentation for version 4.10m for how to unlock parameter values. 

MODPATH Zone Unit[i] is multiplied by MODFLOW FD Grid.IBOUND Unit[i] to 

determine the value exported to MODPATH.

MODPATH Particles Unit[i] contains several parameters that determine where within a 

cell particles are created. If IF ACE < 0, the particles are distributed uniformly across all of the 

faces 1 through 4. If IF ACE = 0, the particles are placed within the cell. If IFACE is from 1 to 

6, the particles are assigned to a cell face according to figure 13. X Particle Count, Y Particle 

Count, and Z Particle Count set the number of particles within or on the face of a cell in the X, 

Y, and Z directions respectively. For example, if X Particle Count = 2, Y Particle Count = 3, 

and IFACE = 6 there would be 2 x 3 = 6 particles on the top face of the cell. Release Time[i] is 

a release time for the particles specified by the contour. The release time is measured relative to 

the reference time specified for MODPATH.

ZONEBDGT

One layer for each geologic unit is created for ZONEBDGT: ZONDBDGT Unit[i]. Its 

single parameter is Primary Zone. ZONDBDGT Unit[i] layers are used to enter zones for 

which water budgets will be determined. Zone numbers may range from 1 to 25.

Stream Package

One layer for each geologic unit is used to enter data for the stream package: Stream 

Unit[i]. Streams are drawn on this layer using open contours. Stream direction is determined by 

the order in which the user draws the contour representing the stream. The place where the user 

begins drawing the contour is the upstream end. The last vertex in the contour is at the 

downstream end. For contours with 3 or more vertices, the upstream end can be determined by 

the position of the label on the contour. The label is between the first and second vertices and is 

thus at the upstream end of the contour. If there are only two vertices, copy the contour to the 

clipboard and paste it in a text editor. Look at the coordinates of each vertex to determine which 

end is which. The upstream end will be the first vertex. The EditContours PIE (see Appendix 1) 

can be used to reverse the order of the vertices in a contour.

Each open contour on a Stream Unit[i] layer represents a stream segment. Segment 

Number must be a unique, positive integer to identify each open contour. Any segment which 

receives flow from another segment must have a higher segment number than the segment from 

which it receives flow.

The GUI renumbers segments in consecutive order as required by the Stream package 

during the export process. A segment can not branch nor can two contours have the same 

segment number. Where a stream branches, a new segment must begin. The branches can either 

be tributaries or diversions. Two or more tributaries can join to form a new segment or a 

segment can split into one or more diversionary segments and a mainstem. The mainstem is 

designated using Downstream Segment Number. Listing the upstream segment as its source in 

Upstream Diversion Segment Number designates the diversion.

24
Downstream Segment Number is the segment number of a stream segment that receives 

flow from the current segment. This is illustrated in figure 14 where three segments (shown in 

green) all have a Downstream Segment Number of 201. The Segment Number of the 

remaining segment (shown in black) is 201 so it receives flow from the other three segments. Up 

to ten segments can join together to contribute flow to a single downstream segment. The flow 

from the current segment will be routed to the downstream segment. The Flow[i] in the 

downstream segment should be set to -1. The number of a downstream segment must always be 

larger than the number of the segment from which it receives flow. If no segment is downstream 

of the current segment, leave Downstream Segment Number equal to 0.

Figure 14. Illustration of the linkage among stream segments.

Upstream Diversion Segment Number is the segment number of a stream segment 

from which flow is diverted into the current segment. The segment number of the segment from 

which flow is diverted must always be less than the segment number of the segment that receives 

the diverted flow. If the current segment does not divert flow from another segment, leave 

Upstream Diversion Segment Number set to 0.

Flow[i] is the streamflow into the upstream end of the current segment in stress 

periodji]. However, if steady stress has been chosen for the stream package in the Edit Project 

Info dialog box, only Flowl will be used for the entire duration of the model. Other Flow[i] 

parameters will be ignored. In general, whenever there is a time-related parameter, only the first 

parameter will be used if steady stress has been chosen. If the flow in the segment will be the 

sum of the flows from its tributaries, set Flow[i] to -1. If the segment is a diversion, the value of 

Flow[i] is the amount that will be diverted.

Upstream Stage fi] is the stream stage at the upstream end of the current segment in 

stress period[i]. If Downstream Stage[i] is $N/A, Upstream Stage fi] will be the stage for the 

entire length of the segment. If Downstream Stage [i] is not $N/A, the stage at each cell will be

25
determined by linear interpolation along the open contour from the upstream end to the 

downstream end. In general, whenever there is both an "upstream" and "downstream" 

parameter, setting the "downstream" parameter to $N/A will cause the "downstream" parameter 

to be ignored. When Argus ONE uses an expression to set the value of a parameter for a 

contour, it always evaluates that expression at the same spot: the location of the first vertex. 

Thus an expression for a "downstream" parameter is evaluated at the upstream end. The current 

version of Argus ONE doesn't have any way of recognizing that a particular parameter should be 

evaluated anywhere other than the default location.

Streambed hydraulic conductivity is the hydraulic conductivity of the streambed 

material. Streambed hydraulic conductivity has units of (length/time). In the Stream package, 

"Cond" is the streambed hydraulic conductance. It is equal to KLW/M where 

K = the hydraulic conductivity of the streambed material, (units = Length/time) 

L = the length of the reach, (units = Length) 

W = the width of the stream (units = Length), and 

M = the thickness of the streambed material (units = Length).

The MODFLOW-GUI measures the length of each open contour in a cell and multiplies 

the length by Streambed hydraulic conductivity, and Width [i], and divides by the streambed 

thickness to determine "Cond". The streambed thickness is determined from the parameters 

Upstream bottom elevationfi], Upstream top elevationfi], Downstream bottom elevationfi], 

Downstream top elevation [i].

Upstream bottom elevation[i] is the elevation of the bottom of the streambed at the 

upstream end of the current segment in stress period[i].

Upstream top elevation [i] is the elevation of the top of the streambed at the upstream 

end of the current segment in stress period[i].

Upstream Width [i] is the channel width at the upstream end of the current segment in 

Stress Period[i]. Upstream Width [i] has units of length.

Slope[i] is the channel slope in stress period[i]. Slope[i] has units of length/length 

(dimensionless). Slope is used in calculating the stage of the river from the discharge.

Mannings roughness [i] is the Manning's roughness coefficient in stress period[i]. 

Manning's roughness is used in calculating the stage of the river from the discharge. Tables of 

Manning's roughness coefficient are present in most introductory surface-water-hydrology 

textbooks.

Flow and Head Boundary Package

The Point FHB Unit[i] layers are used to define Flow and Head boundaries with point 

contours. Only point contours should be used on Point FHB Unit[i] layers. The Line FHB 

Unit[i] layers are used to define Flow and Head boundaries with open contours. Only open 

contours should be used on Line FHB Unit[i] layers. The Area FHB Unit[i] layers are used to 

define Flow and Head boundaries with closed contours. Only closed contours should be used on 

Area FHB Unit[i] layers.

The Top Elev and Bottom Elev parameters on the Point FHB Unit[i] and Line FHB 

Unit[i] layers are compared with Elev Top Unit[i], Elev Bot Unit[i] and the vertical 

discretization of a unit to determine in which layer or layers a flow or head boundary should 

occur within the geologic unit. If the top and bottom elevation of the Flow and head boundary 

are outside the unit as specified in Elev Top Unit[i] and Elev Bot Unit[i] the boundary will be

26
placed in either the uppermost or lowermost layer in the unit. For flow boundaries that will be 

split among several layers the flow will also be divided among those layers.

Head Time[i] on the Point FHB Unit[i] and Area FHB Unit[i] layers is the specified 

head at Time i. The "Time i" values are specified on the Stresses 2 Tab. Values at all times 

other than the specified times will be determined by linear interpolation among the specified 

times. (See Leake and Lilly, 1997.) If Head Time[i] is left at the default value of $N/A, the 

contour represents a flux boundary rather than a head boundary. In the Area FHB Unit[i] layer, 

the head boundaries will be assigned to every layer within the geologic unit. MODFLOW does 

not allow both a specified flux and a specified head boundary at a single cell. If both are 

specified for a single cell, the specified flux boundary will be ignored.

Flux Time[i] on the Point FHB Unit[i] layers is the specified flux rate at Time i. The 

"Time i" values are specified on the Stresses 2 tab of the Edit Project Info dialog box. The 

total flux for a time step will be determined by taking the integral of the flux rate versus time 

function for the time step. (See Leake and Lilly, 1997.) If Flux Time[i] is left at the default 

value of $N/A, the contour represents a specified head boundary rather than a specified flux 

boundary.

Head Concentration Time[i] on the Point FHB Unit[i], Line FHB Unit[i], and Area FHB 

Unit[i] layers is the solute concentration at the specified head cell at Time i. Flux Concentration 

Time[i] on the Point FHB Unit[i], Line FHB Unit[i], and Area FHB Unit[i] layers is the solute 

concentration at the specified flux cell at Time i. For both types of boundaries, values at all 

times other than the specified times will be determined by linear interpolation among the 

specified times.

Start_Line Head Time[i] on the Line FHB Unit[i] layers is the specified head at the 

start of an open contour at Time i. Values at all times other than the specified times will be 

determined by linear interpolation among the specified times. If Start_Line Head Time[i] is 

left at the default value of $N/A, the contour represents a flux boundary rather than a head 

boundary. If Start_Line Head Time[i] is a number but End_Line Head Time[i] is $N/A, The 

value of StartJLine Head Time[i] will be used all along the contour. If both Start_Line Head 

Time[i] and End_Line Head Time[i] are numbers, the starting head at intermediate cells will be 

determined by linear interpolation between Start_Line Head Time[i] and End_Line Head 

Time[i]. The direction of a contour can be determined by the methods described under the 

section entitled Stream Package.

Flux per Length Time[i] on the Line FHB Unit[i] layers and the Flux per Area 

Time[i] on the Area FHB Unit[i] layers are the specified flux rate per unit length at Time i. 

The Flux per Length Time[i] will be multiplied by the length of the contour within a cell to 

determine the total flux rate for that cell. The Flux per Area Time[i] will be multiplied by the 

area of the contour within a cell to determine the total flux rate for that cell. The total flux for a 

particular time step will be determined by taking the integral of the flux rate versus time function 

for the time step. If Flux per Length Time[i] or Flux per Area Time[i] are left at the default 

value of $N/A, the contour represents a specified head boundary rather than a specified flux 

boundary. In the Area FHB Unit[i] layer, the flux boundaries will be assigned to every layer 

within the geologic unit. The flux will be divided among the layers.

27
Horizontal Flow Barrier Package

To define horizontal flow barriers use open or closed contours on the Horizontal Flow 

Barrier Unit[i] layers. These layers have two parameters: Barrier Hydraulic Conductivity 

and Barrier Thickness.

Barrier Hydraulic Conductivity represents the hydraulic conductivity of the horizontal 

flow barrier. Barrier Thickness represents the thickness of the horizontal flow barrier. Barrier 

Hydraulic Conductivity is divided by the Barrier Thickness to obtain the hydraulic 

characteristic of the conceptual model. The hydraulic characteristic of the conceptual model is 

then adjusted by the angle of the barrier to obtain the hydraulic characteristic of the numerical 

model.

To visualize the location of the horizontal flow barriers in the numerical model, select 

PIEsjDisplay Horizontal Flow Barriers. This will display a dialog box in which the horizontal 

flow barriers can be displayed. Enter the unit number in the Unit Number edit-box and click on 

the Display button to display the horizontal flow barriers for that unit. If there are barriers on the 

selected unit, they will be displayed. If not, a warning message will appear. The grid is shown 

in this dialog box without any rotation. Use the check-boxes in the dialog box to indicate the 

correct coordinate direction. At present there is no zooming capability on this dialog box but it 

can be resized to make the grid larger. Click on the Close button to close this dialog box.

The GUI must adjust the hydraulic characteristic exported to MODFLOW based on the 

grid angle because the length of the flow barriers differs between the conceptual and numerical 

models. For example, the only difference between the two models in figure 15 is that in one the 

area surrounded by the horizontal-flow barrier is rotated 36 degrees. However, when the models 

were run, the leakage through the flow barrier in model 2 was much higher than it was in model 

1.

Horizontal Flow Barriers

\

Model 1 Model 2

Figure 15. Two models that differ only in the orientation of the area surrounded 

by a horizontal-flow barrier.

A close-up of Model 2 reveals the problem (figure 16). In MODFLOW it is impossible 

to specify a flow barrier that is at an angle to the grid. Instead a zigzag line of flow barriers 

along the cell boundaries must approximate the actual flow barrier. The total length of the flow 

barriers in the numerical model is longer than the angled flow barrier they represent in the

28
conceptual model. Thus, there is more area through which flow could occur in the numerical 

model than in the conceptual model.

..........

Figure 16. Close up of a section of the horizontal-flow barrier in model 2.

To compensate for the excessive flow barrier length in the numerical model, the 

hydraulic characteristic of the barriers (HYDCHR) must be reduced. The method used to reduce 

the hydraulic conductivity in the MODFLOW-GUI is shown in figure 17.

Flow barrier in conceptual 

model

Flow barriers in 

numerical model

II < 

00

II X

UU 

QQ

HYDCHRnummod = 

HYDCHRcon;mod xCOSa

Figure 17. Method to calculate the reduction of HYDCHR when horizontal-flow barriers are at an 

angle to the grid.

HYDCHRnum mod = Hydraulic characteristic of numerical model. 

HYDCHRconc_mod = Hydraulic characteristic of conceptual model.

29
Running MODFLOW, MOC3D, MODPATH, or ZONEBDGT

Creating Input Files

Selecting Run MODFLOW/MOC3D, Run MODPATH, or Run ZONEBDGT from the 

PIEs menu accesses the Run MODFLOW/MOC3D dialog box (figure 18). These menu items 

are only present if the MODFLOW FD Grid layer is the active layer. Use the radio buttons to 

select which model to run and whether or not to run the model or just create the input files for the 

model. For MOC3D models, users can choose to either run MODFLOW (without solute 

transport) or MOC3D (with solute transport) by checking or unchecking the Run MOC3D to 

simulate solute transport check-box. If the input files for a model have already been created 

and the data for one or more packages have not changed since the last time the model was run, 

there is no need to create a new copy of that input file. Instead, the user can save time during the 

process of exporting the MODFLOW input files by not exporting a new copy of the input file for 

the package. All those packages whose check-boxes are both checked and enabled will be 

exported to the MODFLOW input files.

In some special cases, the user may elect to develop their own export template for one or 

more MODFLOW Packages. In such cases, there is no need for the usual export template to 

create the input files for those packages so the user may elect not to create them with the usual 

export template.

The full paths to the executables should be displayed in edit-boxes on the Model Paths 

tab of the Run MODFLOW/MOC3D dialog box. If the executable for the chosen model is not 

at the location specified in the edit-box, the background of the edit-box and the status bar will 

change to red and a warning message will be displayed in the status bar to indicate that the path 

is incorrect (figure 18). Normally, the user should correct the path before attempting to create 

the input files. Although it is possible to export the input files using an incorrect path, Argus 

ONE will not be able to start the model if the path is incorrect. Type the correct path or click 

on the Browse button to set the correct path. When a model is saved, the paths for all of the 

models will be saved in a file named modflow.ini in the directory containing the MODFLOW 

PIE. Modflow.ini will be read whenever a new MODFLOW project is created or an old one is 

read so that the model paths do not need to be reset frequently.

30
Run MODFLOW/MOC3D

i{>&|H^^ ' , ...

w8nuqgiW9Hips9,- 

Warru«g: If thfMODFLOWFD Grid layer

r

& t-i^gii.

Figure 18. Revised Run MODFLOW/MOC3D Dialog box. In this example, MOC3D 

is not installed at the location specified in the MOC3D Path edit-box so the 

background of the status bar, would appear red.

If any of the non-spatial data for the model need to be edited, click the Edit Project Info 

button to show the Edit Project Info dialog box. Click on the OK button in the Run 

MODFLOW/MOC3D dialog box to begin exporting the input files for the selected program. 

Click on the Cancel button to close the Run MODFLOW/MOC3D dialog box without 

exporting input files for any program.

Because MODPATH and ZONEBDGT use the output from MODFLOW (or MOC3D) as 

part of their input, the user must ensure that the required output files are in the directory in which 

MODPATH or ZONEBDGT will be run. Normally, this is most easily accomplished by running 

MODPATH or ZONEBDGT in the same directory in which the model was run.

Processing the Export Template

When the user clicks on the OK button, the PIE modifies the export template 

(modflow.met) before passing it on to Argus ONE . When the export template has been 

processed and passed to Argus ONE , a dialog box is displayed for selecting the directory in 

which the input files for the model should be generated. (The model will generate its output files 

in this same directory.) The file name (MODFLOW_FD_Grid.exp) in the dialog box may be 

ignored. If a file by that name already exists, Argus ONE will generate a warning message 

stating that MODFLOW_FD_Grid.exp will be overwritten. This warning message may be 

ignored. Click OK to ignore the warning message.

Two progress bars will then appear. Argus ONE generates one and a PIE generates the 

other (figure 19). The progress bar generated by Argus ONE contains a "barbershop" progress 

bar. One way to abort the export process by selecting the window containing the "barbershop" 

progress bar and pressing Ctrl-C. A PIE generates the other progress bar. It shows how much of 

the export template has been processed by Argus ONE . It also displays warning and error 

about inconsistencies or errors in the input specified by the user. These warnings can be

31
suppressed by unchecking the Show Error and Warning Messages check box in the Run 

MODFLOW/MOC3D dialog box. prior to starting the export process. An Abort Simulation 

on this second progress bar and may also be used to stop the export process.

Export Progress

Negative or zero unit thickness at Unit 1; Column: 109; Row: 74 

Negative or zero unit thickness at Unit 1; Column: 110; Row: 74 

Negative or zero unit thickness at Unit 1; Column: 111; Row: 74 

Negative or zero unit thickness at Unit 1; Column: 112; Row: 74 

Negative or zero unit thickness at Unit 1; Column: 113; Row: 74 

Negative or zero unit thickness at Unit 1; Column: 114; Row: 74 

Negative or zero unit thickness at Unit 1; Column: 115; Row: 74 

Negative or zero unit thickness at Unit 1; Column: 116; Row: 74

Estimated Jkne Remanbig: 00:01:18

Figure 19. PIE-Generated Progress Bar with error messages.

Using the MODFLOW PIE with Calibration Programs

The MODFLOW PIE has been designed to allow calibration programs such as UCODE 

(Poeter and Hill, 1998) to use it to create MODFLOW input files and run MODFLOW. If the 

checkbox labeled External Calibration Program running Argus ONE is checked, the DOS 

window in which MODFLOW runs will close as soon as MODFLOW finishes running. In 

addition, the batch file used to run MODFLOW will have a command to try to start a copy of 

WaitForMe.exe (see Appendix 5). If the calibration program starts another copy of 

WaitForMe.exe before exporting the MODFLOW input files, that copy will continue running 

until the batch file attempts to start the new copy. Attempting to start a new copy will cause both 

copies to close. The calibration program can detect the closure of the first copy of WaitForME 

before attempting to process the MODFLOW output files. The SelectChar program (see 

Appendix 5) may be useful in writing a batch file that will start Argus ONE exporting the 

MODFLOW input files. The following is an example of such a batch file.

UcodeTest.mmb

d:\PROGRA~l\ARGUSI-l\ArgusPIE\GETMYD~l\SelectChar.exealt-P 

d:\PROGRA~l\ARGUSI~l\ArgusPffi\GETMYD~l\SelectChar.exe M O chr-13 

d:\PROGRA~l\ARGUSI~l\ArgusPIE\GETMYD~l\WaitForMe.exe

This batch files makes UcodeTest the active program. If the MODFLOW FD Grid layer 

is the active layer, it will then activate the PIE's menu and start running MODFLOW. Finally it 

starts a copy of WaitForMe which will be closed when a second copy starts after MODFLOW 

has finished executing.

32
Another PIE, MODFLOW_ReadFileValue, is useful in defining parameters to be 

calibrated by the calibration program (See Appendix 4). It can be used to read the current value 

of a calibration parameter from a text file and use that value to define the value of an Argus ONE 

parameter or contour.

These PIE's are useful in allowing calibration programs to run MODFLOW through 

Argus ONE. However, in simple cases, it may be faster to have the calibration program 

construct the MODFLOW input files directly rather than constructing them through Argus ONE.

Running independent templates with the MODFLOW PIE

The MODFLOW PIE comes with two separate templates that may be useful in some 

circumstances but which must be run manually. These include contour2data.met and 

statistics.met. Both these templates will need to be modified slightly by the user to fit their 

individual needs.

Converting contours on information layers to data points on data layers

In some cases, the user may wish to convert contours on an information layer to data 

points on a data layer. The primary advantage of this is that interpolation among data points on a 

data layer can be significantly faster than interpolation among contours on a contour layer 

especially if there are a large number of contours or the contours contain many vertices. To 

make the conversion, make the MODFLOW FD Grid layer the active layer and select 

File|£xport|£dit Template. The export editor will appear. Click on the Load button and select 

the file contour2data.met distributed with the MODFLOW GUI. Read the comment at the 

beginning of the export template. Follow the instructions for how to modify the template for 

your purposes. The modification consists of changing one line to refer to the layer for which you 

wish to convert the contours. When you are done making the change, click the Done button to 

return to the Argus ONE main window. Then select File|Export|By Template. You must have 

created a grid on the MODFLOW FD Grid layer for this option to be available. When the 

export process is done, save your file. Then delete the contours on the layer you wish to convert 

to a data layer. Next select View|Layers. Select the layer you wish to convert on the upper half 

of the Layers dialog box. Under Type, select the down-arrow next to Information and select 

Data. This option is locked on certain layers such as Wells Unitl where converting a layer to a 

data layer would interfere with the functioning of the MODFLOW GUI. Click on the Done 

button. Make the layer you just converted the active layer. Select File|Import <layer 

name>|Text File. Select Scattered data. Click OK and then select the file exported by the 

export template (Points.exp) and click on the Open button. The data will be imported into the 

data layer.

Preparing Calibration Statistics

A common task in groundwater modeling is preparing calibration statistics for comparing 

modeled and observed heads or drawdowns with measured values. The following describes one 

method of preparing such statistics.

1. Import your model results into Argus ONE using the Post Processing PIE 

(PIEs|MODFLOW/MOC3D Post Processing).

2. Create a global variable named Number of Observation Times. (EditjEdit Global 

Variables). Set the value of this variable to the number of times at which you have 

observations.

33
3. Create another global variable named Number of Model Layers. Set the value of this 

variable to the number layers in the MODFLOW model. If you have non-simulated units or one 

geologic unit represents multiple model layers be sure to set the variable to the number of model 

layers not the number of geologic units.

4. Create a new information layer named Observations Layerl. (See the Argus ONE 

documentation on how to create information layers.)

5. Create two new parameters on the Observations Layerl layer named Observations 1, 

and Model Resultsl.

6. Set the expression for Observations! to $N/A.

7. Set the expression for Model Resultsl so as to link it to the data layer and parameter 

containing your model results for the first observation time. The data layer for MODFLOW is 

normally named MODFLOW Data. The parameter names for the model results depend on the 

stress periods and times that you have imported.

8. Select the Observations! parameter and click on the Duplicate button in the lower half 

of the Layers dialog box to duplicate that parameter. The duplicates will be named 

Observations2, Observations3. ... Make as many duplicates as you have observation times.

9. Select the Model Resultsl parameter and duplicate it just as you did the 

Observationsi parameter.

10. Set the expressions for the Model Results!, Model Results3, ... parameters so that 

they are linked to the correct layers and parameters for your model results.

11. Select the Observations Layerl layer in the upper half of the Layers dialog and click 

on the Duplicate button in the upper half of the dialog box to make copies of the layer. Make as 

many copies as you have MODFLOW model layers.

12. In each copy of the Observations Layer[i] set the expressions for the Model 

Results [i] parameters to the correct values.

13. Create point contours on the Observations Layer [i] layers at each of your 

observation points and assign the Observations [i] parameters your observation values. Do not 

override the Model Results[i| parameters.

14. Create an export template that will calculate and print the statistics you desire. To 

start creating an export template, make the MODFLOW FD Grid layer the active layer and select 

File|Export|Edit Template. Consult the Argus ONE documentation for more information on 

export templates. The export template Statistics.met distributed with the MODFLOW GUI will 

calculate a variety of commonly used calibration statistics and or may be used as a starting point 

for your own template.

15. Run the export template by selecting File|Export|By Template. You can only do 

this if the MODFLOW FD Grid layer is the active layer and there is a grid on that layer.

Files Created for MODFLOW-96, MODPATH, and ZONEBDGT 

Simulations

When creating MODFLOW-96 input files from within Argus ONE, a variety of files are 

created as documented previously in Shapiro and others (1997) and Hornberger and Konikow 

(1998). In addition to those files, the revised GUI may also additional files for MODFLOW 

simulations as documented in Table 2.

34
Table 2. New Files Created for MODFLOW Simulations.

Filename Purpose

Rootname. i[Number] 

Rootname. h [Number] 

Rootname.s [Number] 

Rootname. s [Number] 

Rootname. k[Number] 

Rootname.z[Number]

Rootname.str

Rootname.hfb

Rootname.fhb

File containing the IBOUND array for Geologic

Unit[Number+l].

File containing the initial head array for Geologic

Unit[Number+l].

File containing the storage coefficient array for Geologic

Unit[Number+l].

File containing the specific yield array for Geologic

Unit[Number+l].

File containing the hydraulic conductivity or transmissivity array

for Geologic Unit[Number+l].

File containing the vertical conductance array for Geologic

Unit[Number+l].

File containing information for the stream package. This file is

created only if the stream is chosen in the Stresses 2 tab.

File containing information for the horizontal-flow barrier

package. This file is created only if the horizontal-flow barrier is

chosen in the Other Packages/Solvers tab.

File containing information for the Flow and Head Boundary

package. This file is created only if the Flow and Head

Boundary package is chosen in the Stresses 2 tab.

Dummy, TempGHBPer, TempGHBPer[Number], TempGHBl, 

TempRivPer, TempRivPer'[Number], TempRiverl, TempDrainPer, 

TempDrainPer[Number], TempDrainl, TempWellPer, 

TempWellPer[Number], TempWelll, TempStreaml, TempStream2, 

TempStreamB, temphfbl, temphft>2, TempHFBB, 

TempFHB5Line[Number], TempFHB6Line[Number], 

TempFHB 7Line [Number], TempFHBSLine[Number], 

TempFHB5Point[Number], TempFHB6Point[Number], 

TempFHB7Point[Number], TempFHBSPoint[Number], 

TempFHB 5Area [Number], TempFHB6Area[Number], 

TempFHB?AreafNumber], TempFHBSArea [Number], FHBTemp

Temporary files 

used during the 

export process. 

These files are 

normally deleted 

before the end of 

the export 

process.

When creating input files for MODPATH, the files shown in Table 3 may be created. 

MODPATH.BAT is used to run the model from the directory in which the files were created (for 

example, if the model was not executed from within Argus ONE). Files must be exported with 

the Create input files and run MODPATH or Create MODPATH input files only options in 

the Run MODFLOW/MOC3D Dialog Box selected for MODPATH.BAT to be created and used.

35
Table 3. Files Created for MODPATH.

Filename Purpose

MODPATH.BAT 

Rootname.pnm

Rootname.mpa 

Rootname. ip[Number]

Rootname.prt 

Rootname. tim 

Rootname.rsp 

Dummy

A DOS-executable batch-file created by the export template that

contains the path of the executable for MODPATH.

The name file used by MODPATH to specify the names of files

that will be used by MODPATH.

The main MODPATH data file.

File containing a MODPATH zone array for geologic unit

[Number+1].

File containing MODPATH particle starting locations.

The MODPATH time file.

File containing responses to interactive queries in MODPATH.

A temporary file used during the export process. This file is

normally deleted before the end of the export process.

When creating input files for ZONEBDGT, the files documented in Table 4 may be 

created. Zonebdgt.bat is used to run the model from the directory in which the files were created 

(for example, if the model was not executed from within Argus ONE). Files must be exported 

with the Create input files and run ZONEBDGT or Create ZONEBDGT input files only 

options in the Run MODFLOW/MOC3D Dialog Box selected for Zonebdgt.bat to be created and 

used.

Table 4. Files Created for ZONEBDGT.

Filename Purpose

Zonebdgt.bat

Rootname.zbi 

Rootname.zon 

Dummy

A DOS-executable batch-file created by the export template that

contains the path of the executable for ZONEBDGT.

The input file for ZONEBDGT.

The zone file for ZONEBDGT.

A temporary file used during the export process. This file is normally

deleted before the end of the export process.

Files Created by Executing MODFLOW-96, MODPATH, and 

ZONEBDGT

When MODFLOW-96 is executed from within Argus ONE, a variety of files are created 

as documented previously in Shapiro and others (1997) and Hornberger and Konikow (1998). In 

addition to those files MODFLOW-96 may also produce the files documented in Table 5 for 

MODFLOW simulations.

36
Table 5. Files Created by MODFLOW.

Filename Purpose

Rootname.bs

Rootname.bs2

Rootname.bfh

The file of cell-by-cell flows between the stream and aquifer from the 

stream package if it is specified in the Output Files dialog that cell-bycell flows from the stream package are to be exported, and the export of 

this information is to be placed in a separate file. This file is created in a 

binary format.

The file of cell-by-cell stream flows among stream cells from the stream 

package if it is specified in the Output Files dialog that cell-by-cell 

flows from the stream package are to be exported. This file is created in 

a binary format. This information is always placed in a separate file. 

The file of cell-by-cell flows from the Flow and Head Boundary 

package if it is specified in the Output Files dialog that cell-by-cell 

flows from the Flow and Head boundary package are to be exported, 

and the export of this information is to be placed in a separate file. This 

file is created in a binary format.

Files created when running MODPATH and ZONEBDGT from within Argus ONE 

include the files documented in table 6.

Filename

Table 6. Files Created by MODPATH and ZONEBDGT.

Purpose

Rootname. mpo 

Rootname.mli 

Rootname.end 

Rootname. lin 

Rootname.zbl.

The MODPATH composite budget file. 

The MODPATH summary output file. 

The MODPATH endpoint file. 

The MODPATH pathline file. 

The output file from ZONEBDGT.

Visualizing Results

Visualizing results from MODFLOW or MOC3D

To visualize the results of a MODFLOW or MOC3D model, select

PIEs|MODFLOW/MOC3D Post Processing. A dialog box will appear in which the user can 

choose to read output from MODFLOW head or drawdown files, MOC3D concentration files or 

MOC3D velocity files (figure 20). Choose the type of data to visualize and click on the Select 

Data Set button. Depending on the choice, the user will be able to select formatted head files 

(with the extension "fhd"), formatted drawdown files (with the extension "fdn"), concentration 

files (with the extension "cna"), or velocity files (with the extension "via"). Choose only files 

that were created with the finite-difference grid in the MODFLOW FD Grid layer of the current 

project file.

37
Select Data Set

| X Canc$l| Sefect Date Set

Figure 20. Dialog box to select type of data set for post-processing.

The data sets in the file will be read and their captions displayed in the MODFLOW 

Post-Processing dialog box(figure 21). Choose the data set or sets to plot, the type of chart to 

create, the model layer for the chart, and whether data values for inactive or dry cells should be 

imported in this dialog box. Click OK to create a data layer containing the data and a map layer 

containing the postprocessing charts. If the default names for either or both of these layers 

already exists, the Layer Already Exists dialog box (figure 22) will appear. Radio buttons on 

this dialog box allow the user to choose between overwriting the existing layer and creating a 

layer with a new name. If latter option is selected, the user can choose either to accept a default 

name or to type a new name.

38
W MODFLOW Post-Processing

D IHEAD Per i

D 'HEAD'PerT 

D HEAD Per 1 

D HEAD Per 1 

D HEAD Per 1 

D HEAD Per 1 

D HEAD Per 1 

D HEAD Per 1 

D HEAD Per 1 

0 HEAD Per 1

TS 10 Time 99.9296

TS 30 Time 1031. 398 

TS 40 Time 2775.1 11 

TS 50 Time 7297.854 

TS 60 Time 19028.69 

TS 70 Time 49455.45 

TS 80 Time 128374.7 

TS 90 Time 333070.8 

TS 100 Time 863999.9

Figure 21. MODFLOW Post-Processing Dialog Box.

Layer Already Exists

3y exists. Whit do yonii^attfcfo do?

Overwrite tlie existing data.

Figure 22. The "Layer Already Exists" Dialog Box.

If the user chooses to read a velocity file, the radio buttons for chart type will be disabled 

and a vector plot will be created. See the Argus ONE documentation for more information

39
about vector plots. To create a vector plot the user must choose pairs of X and Y velocities. The 

Z velocities will also be read and displayed on the list of available data sets but the PIE does not 

have a method for creating velocity plots along vertical profiles.

Visualizing Results from MODPATH

To plot the results from MODPATH, the user may either use MODPATH-PLOT (a 

separate program) or use Argus ONE to display the results. To use Argus ONE to display 

the results, select PIEs|Plot MODPATH Results. The Plot MODPATH Results dialog box 

(figure 23) will appear. Choose the type of data you wish to import by selecting the data type in 

the group of radio buttons labeled Data type. Click on the Read Data button and select the file. 

The data will be displayed in the dialog box. For endpoint files, there will also be a statistical 

summary of the data. After clicking OK, the data will be plotted as contours in an Argus ONE , 

information layer named MODPATH Pathlines or MODPATH Endpoints. Pathline contours 

will have four parameters Starting Layer, Starting Time, Ending Layer, and Ending Time. 

Endpoints will have two additional parameters: Starting Zone and Ending Zone.

The statistical summary of MODPATH endpoints includes information about travel 

distance and travel velocity. This distance refers only to the distance traveled in a straight, 

horizontal line from the starting to the ending point. Vertical travel and deviations from a 

straight line along the travel path are ignored. The velocities are calculated from the horizontal, 

straight-line distances and thus have the same limitations as do the distances.

Eui Plot MODPATH Results

Figure 23. Plot MODPATH Results Dialog box after reading a set of pathlines.

Visualizing Results from ZONEBDGT.

To visualize results from ZONEBDGT, the user may use Budgeteer.exe as described in 

Appendix 2.

40
Example

Problem Description

The following example is modified from Hornberger and Konikow (1998). It is designed 

to illustrate the new features of the MODFLOW-GUI. That example was loosely based on the 

ground-water contamination problem documented at the Rocky Mountain Arsenal, Colorado 

(Konikow, 1977). Because the example is greatly simplified, it does not represent any actual 

field situation. The information needed to define the problem are in the base map (figure 24, 

rma_map.dxf) and Table 7.

Table 7. Parameter values for two-dimensional sample problem. 

Parameter Value

hydraulic conductivity 0.0001 m/s

storage coefficient 0.0

effective porosity 0.20

saturated thickness 12m

longitudinal dispersivity 30 m

horizontal transverse dispersivity 3 m

initial concentration 0.0 mg/L

total simulation time 20 years

Pumping rate: Well 1 -0.001 m3/s

Pumping rate: Well 2 -0.002 m3/s

Infiltration rate: disposal pond 0.025 m3/s

Head in lake 75 m

Stream Stage: east 26 m

Stream Stage: west 3 m

Streambed top elevation: east 24 m

Streambed top elevation: west 1 m 

Streambed bottom elevation: east 23 m 

Streambed bottom elevation: west 0 m

Stream width 10m

Streamflow 30 m3/s

41
Q = 0.025 m/s

Q =-0.001 m/s eQ =-0-002 m/s

h = 23.5 m 

h = 5m

0 0.5 1.0km

 ^ Freshwater Lake Disposal Pond

/ Impermeable Bedrock @ Pumping Well

^ Stream

Figure 24. Base map for a two-dimensional sample problem.

The model area is bounded on the east, west, and south by impermeable bedrock outcrops 

that act as no-flow barriers. Two additional bedrock outcrops occur within the model domain 

and are also treated as no-flow areas. To the north, a lake acts as a constant-head boundary. A 

stream to the south acts as a head-dependent flux boundary. The stream slopes from east to west. 

The area also has a disposal pond, and two pumping wells.

Create a New Model

1. First start Argus ONE . Then start a new MODFLOW model by selecting PIEs|New 

MODFLOW Project. The Edit Project Info dialog box will appear. Click on the OK button 

to close it without making any changes. This starts a new MODFLOW project. Next activate 

the Maps layer by clicking to the left of the "eye" icon in the Layers floater. A check mark 

should appear to the left of the eye icon to indicate that Maps is the active layer. A file 

containing a digitized map (rma_map.dxf) of the problem is included with the standard release 

of the MODFLOW GUI. Import rma_map.dxf into the project by selecting Filejlmport 

Maps|DXF File.... Then select rma_map.dxf. A dialog box will appear with a message that the 

objects are too large to fit in the current project. Accept the default choice to fit only the

42
imported objects. Then select Scale and Units from the Special menu. Change the label for 

units to "m". Check the scale at the bottom of the map to make sure that the scale in the map 

matches the scale used in Argus ONE . In this case it should match. (If it didn't match, it 

would be necessary to adjust the size of the map objects to match the scale in Argus ONE .)

Define the Study Area

2. Next define the boundary of the model. Click outside the objects on the map to 

deselect all of them and then select the rectangle at the edge of the figure and copy it to the 

clipboard using either EditjCopy or Ctrl-C. Make MODFLOW Domain Outline the active 

layer and paste it into that layer using either EditjPaste or Ctrl-V. Double click on the contour 

just pasted into the MODFLOW Domain Outline. A dialog box will appear. In the dialog box 

assign MODFLOW Grid Cell Size a value of 100. This number sets the size of the grid blocks 

in the model. To learn more about controlling the grid cell size, see the Argus ONE help and 

the online help for the MODFLOW Domain Outline and MODFLOW Grid Refinement 

layers. (To access the online help, for the MODFLOW PIE select PIEs|MODFLOW Help.)

The northern boundary will go through the center of the lake, so we need to move that 

edge of the boundary to the south. If the boundary is not already selected, select it. Click on the 

"Lasso" button on the left margin of the Argus One main window and use to circle the vertices 

in the upper half of the rectangle. They should turn from black to white to indicate that they are 

selected. Click on the "Navigate" button (it has an arrow on it) next to the Lasso button. Click 

on the line on the top half of the rectangle. While holding the mouse button down, move it down 

to the middle of the lake. This will drag the top boundary south to the middle of the lake. We 

won't be modeling the area in the upper left and right hand corners of the mapped area, so we 

will need to adjust the boundary a little more. Locate the "Add Vertex" button below the Lasso 

button. Click on it and then click on the domain outline where it meets the edge of the lake. 

Now switch back to the "Navigate" button and click on the nodes in the upper left and right hand 

corners and drag each of them south so that the boundary is perpendicular to the direction of the 

area between the impermeable bedrock and the lake. It should look similar to the model shown 

in figure 25.

43
Uyer; JDDFLOW Domain Outline

Figure 25. Domain Outline.

Defining Specified-Head Boundaries

3. Now we will create a specified-head boundary to represent the lake. Change to the 

Maps layer and click on the line that represents the lake. Copy it to the clipboard and paste in 

Prescribed Head Unitl layer. Double click on the lake contour and assign it a specified head of

75.

Choosing the Stream Package

4. The river at the south end of the model could also be defined as a specified-head 

boundary, but in this case we will treat it as a stream boundary instead. Thus, we will need to 

use the stream package. To select the stream package, select PI£s|£dit Project Info and then 

select the Stresses 2 tab. Click the stream (STR) check-box to activate the stream package.

Changing the Number of Geologic Units

5. We will only use one geologic unit in this model. At present there are three units 

present. To get rid of the extra units, first click on the Geology tab. Next click on one of the 

cells in the bottom row to select it and then click on the Delete button. That unit will be deleted. 

Click the delete button again to delete another unit. Because at least one geologic unit must be 

present, the delete button will be disabled at this point so it is impossible to delete the last 

geologic unit.

Accessing Context-Sensitive Help

6. The Edit Project Info dialog box has extensive context-sensitive help. To see an 

example, click on the question mark icon in the upper right-hand corner of the dialog box. A

44
question mark will appear next to the cursor. Now click on the Internal Array Storage combobox near the bottom of the Geology tab. The online help will be displayed. In some cases, the 

online help is too extensive to be displayed in this manner. For example, try clicking on the 

question mark icon and then click on the table displaying the data about each geologic unit. The 

context-sensitive help will appear but, except on screens with very high resolution, much of it 

probably will not be visible. In such cases, click on the Help button and then follow the links for 

the item of interest. In this case, click on Attributes of Geologic Units to see the help for all the 

items in the table.

Finish Changing the Number of Geologic Units

7. We are now done with the Edit Project Info dialog box so click on the OK button to 

accept all the changes in the dialog box. A layer named Stream Unitl should have been added 

and all layers related to geologic units 2 and 3 should have been deleted.

Defining a Stream Boundary

8. Next we will place a stream on the south end of the model. Make Maps the active 

layer and copy the contour representing the stream and paste it into Stream Unitl. The stream 

slopes from an elevation of 26 m in the east to 3 m in the west. The contour direction and thus 

the direction of the stream is defined by the order of the vertices in the contour. Because Argus 

ONE can not place arrows on contours to indicate their direction, other characteristics must be 

used to indicate the direction of the contour. One characteristic that can be used is the position 

of the label on a contour. The label is always placed between the first and second nodes on a 

contour. In this case the label is on the right so the direction of the contour is correct (figure 26).

Figure 26. The label of the stream segment indicates the stream flows from right

to left.

45
If the contour direction is wrong, it is possible to reverse the direction of the contour 

using the following procedure. First cut the contour to the clipboard by selecting it and then 

selecting £dit|Cut or Ctrl-X. Then select File|Import|Reverse Contours on Clipboard. A 

dialog box will appear. Select the Stream Unitl Layer. The contour will be pasted back onto 

the selected layer but its direction will be reversed. This option is only available if the 

EditContours PIE is installed (see Appendix 1).

Now double-click on the contour to bring up a dialog box with the parameters for the 

layer. There are 11 parameters for this layer. To see what these parameters represent, close the 

dialog box by clicking on the Cancel burton and select PIEs|MODFLOW Help. Double click 

on Spatial Data and then on Layers related to specific geologic units and then on Stream 

Package. The information about each parameter that can appear on the Stream Unitfi] layers 

will be under Stream Unit[i] parameters. There is also general information about the Stream 

package.

Double-click on the stream contour again. Each stream contour must have a unique 

Segment Number. Each Segment Number must be a positive integer. We can assign this 

segment a Segment Number of 1. The stream bed sediments have the same hydraulic 

conductivity as the aquifer, so we will link the two. Click on the OK burton. Select 

View|Layers... to bring up the layers dialog box. Select Stream Unitl in the list of layers if it 

is not already selected. Select Streambed hydraulic conductivity in the list of parameters. In 

the Value column a burton labeled "fx" will appear. Click it to bring up the Expression editor. 

Locate Hydraulic Cond Unitl in the list of layers and select it. The Kx and Kz parameters will 

appear in the list of parameters. Double-click on Kx. The expression shown in the upper part of 

the expression editor should now be Hydraulic Cond UnitLKx. Click the OK button to close 

the expression editor and then click the Done burton to close the Layers dialog box. Now double 

click on the stream contour again. Select the Streambed hydraulic conductivity parameter and 

delete its value. Click on another parameter and the linked value of hydraulic conductivity 

should appear. The measured flow at the upstream end of the stream is 30 m3/s, so assign Flowl 

a value of 30. This represents the flow into the upstream end of the stream segment during stress 

period 1. The stage at the upstream end is 26 m and at the downstream end it is 3 m, as 

mentioned previously. Assign those parameters. In between the upstream and downstream end, 

the stream stage will be determined by linear interpolation along the length of the stream. The 

Streambed top and bottom elevations vary from 24 and 23 m respectively at the upstream end to 

1 and 0 m respectively at the downstream end. Set Upstream Bottom Elevationl to 23 and 

Upstream Top Elevationl to 24. Set Downstream Bottom Elevationl to 0 and Downstream 

Top Elevationl to 1. Finally set the Upstream widthl to 10. The Downstream vvidthl can 

remain at $N/A. This means that Downstream widthl will be ignored and the width will be 

equal to 10 all along the length of the segment.

Define No-Flow Boundaries

9. Now we will define the no-flow boundaries. Change to the Maps layer and select all 

five contours representing the impermeable bedrock. Copy them to the clipboard and paste them 

in the Added Inactive Area Unitl layer. Assign all of them a value of 0 if they do not already 

have that value. To assign them all at once, select them all, double clicking on one of them, set 

the parameter value to 0 and then clicking the "Set All" burton.

46
Other Packages and Options

10. Now we will go to the Edit Project Info dialog box to set a number of other 

parameters in the model. Select PIEs|Edit Project Info. On the Project tab set the project 

name and title to "MFGUI 3.0 example problem". On the Stresses 1 tab check the Wells checkbox (WEL). On the Stresses 2, check the Flow and Head Boundary check-box (FHB). 

Change Number of Times to 1. On the Solvers/Other Packages tab, check the Horizontal 

Flow Barrier check-box (HFB). The solver can remain set to PCG2. On the PCG2 tab, change 

HCLOSE and RCLOSE to 0.0001. On the Time tab, change the time units to seconds. In the 

table, change the value for Length (PERLEN) of the first item from 1 to 6.31152E+8. (This is 

approximately the number of seconds in 20 years.) On the Output Files tab, change the 

Rootname for MODFLOW Simulation files to "rma2". On the MODPATH tab, check the 

MODPATH check-box. All the default values for MODPATH are acceptable so there is no 

need to make no other changes for MODPATH. On the ZONEBDGT tab, select the 

ZONEBDGT check-box. Change the ZONEBDGT title to "MFGUI 3.0 example problem". 

The other ZONEBDGT default values are acceptable. Now click on the OK button. Several 

new information layers will be added to the project.

Save the Project

11. Now might be a good time to save the project. Select File|Save to save it. If no file 

name has already been assigned, the user will be prompted to choose one. A suitable file name 

might be rma2.mmb.

Setting the Top Elevation

12. We will assume that the top of the unit is a plane surface tilted to the southeast. The 

slope towards the south is 0.01 and the slope toward the east is 0.005. At (4000, 8600) the top 

elevation is 75 m. From this it is easy to derive an expression for the top elevation: E = 75 + 

0.005(x-4000) + 0.01(y-8600) where E equals the elevation and x and y are the x coordinates. 

To enter the expression, bring up the Layers dialog and then bring up the Expression editor for 

Elevation Top Unitl. Be careful to choose the Elevation Top Unitl layer and not the Elev 

Top Unitl parameter that appears in the MODFLOW FD Grid layer. The expression should 

appear as follows.

75 + 0.005 * (X() - 4000) + 0.01 * (Y() - 8600)

In the expression "XQ" and "YQ" are functions found under the category "Mathematical".

Sef Aquifer Properties

13. The saturated thickness of the aquifer is 12 m, so the expression for Elevation 

Bottom Unitl should be "Elevation Top Unitl -12".

14. Set the Hydraulic Conductivity.Kx parameter to l.OE-4 m/s. Because this is a twodimensional problem, Kz can be ignored. After changing the hydraulic conductivity, go back to 

Stream Unitl and check the value of the streambed hydraulic conductivity. It should give the 

same value as the Hydraulic Conductivity.Kx because the two were linked previously.

15. Leave Porosity Unitl set to 0.2, the correct value. Set the Initial head equal to the 

top elevation of the layer. The best way to do this is to use the Expression editor as described 

previously in step 12.

47
Create Pumping Wells

16. There are two pumping wells in the model. Their pumping rates and locations are 

shown in figure 24. We will assume that the wells fully penetrate the aquifer, so we will set the 

top and bottom elevations of the well screen equal to the top and bottom elevations of the 

aquifer. Link them using the expression editor. The expression for Top Elevation on the Well 

Unitl layer should be Elevation Top Unitl. The expression for Bottom Elevation on the Well 

Unitl layer should be Elevation Bottom Unitl. Click on the Done button and activate the Well 

. Unitl layer. Now select the Point contour tool. To do this, locate the contour button on the left 

side of the Argus ONE main window. It is underneath the navigate button. Click on the 

contour button and hold down the mouse button until a pop-up menu appears. Select the third 

item in the menu to select the point contour tool. Its symbol should look like a cross. Now click 

once at the location of one of the pumping wells to check the values assigned to the top and 

bottom elevations. They should now be set correctly by the expressions. Set the pumping rates 

to the values shown in figure 24. The negative values of the pumping rates indicate that these 

wells pump water out of the aquifer rather than into it. Stressl is the parameter used to set the 

pumping rate for the first (and, in this case, only) stress period. The default values of IFACE1, a 

MODPATH parameter, can be left. By default, the contours will be labeled with the value of 

their first parameter. If you wish them to be labeled with their pumping rate, color the contours 

by their pumping rate. You can do this by selecting the down arrow next to Color on the left 

side of the Argus ONE main window and then selecting Stressl.

Create Specified-Flow Boundary

17. The disposal pond will be modeled with the Flow and Head Boundary package. 

Change to the Maps layer and select the oval that represents the disposal pond. Copy it to the 

clipboard and paste it in the Area FHB Unitl layer. Now double click on the contour in the 

Area FHB Unitl layer. This contour will represent a specified-flux boundary, so delete the 

value of "0" for Head Timel that was copied from the Maps layer and click on the OK button.

We wish to have a specified flux for the contour but the value we must enter is the 

specified flux per unit area. To make it easier to enter the correct value, we will add a new 

parameter to the Area FHB Unitl layer named Flux and create an expression that will calculate 

the flux per unit area and assign that value to the Flux per Area Timel parameter. Bring up the 

Layers dialog box (View|Layers...). Select Area FHB Unitl if it is not already selected. In the 

lower half of the Layers dialog box, click on the "New" button to create a new parameter. Type 

in the name Flux as the name of the parameter. Set the default value for the Flux parameter to 

"$N/A" (= not available). (An easy way to do this is to click on the "N" in the expression 

editor.) Now set the default value of the Flux per Area Timel parameter to 

"If(ContourArea()>0, Flux / ContourAreaQ, $N/A)". (The If() function is listed under the 

category "Mathematical" in the Expression editor. The "ContourAreaQ" function is listed under 

the category "Contour".) This function checks if the contour area is greater than 0. If it is, the 

value of the parameter is set to the total flux divided by the contour area. Otherwise the value of 

the parameter is $N/A. If a value is assigned to the Flux parameter, the value of the Flux per 

Area Timel parameter will be set automatically. Now double click on the contour that 

represents the disposal pond in the Area FHB Unitl layer and assign the Flux parameter a value 

of 0.025. Click OK to close the dialog box. Now double click on the contour again. The Flux 

per Area Timel should be calculated as 1.15257e-06.

48
Run MODFLOW

18. We will now create the grid, run the model and plot the results. Change to the 

MODFLOW FD Grid layer. Locate the Magic Wand tool on the left-hand side of the main 

Argus ONE window. Click anywhere within the Domain Outline and a grid will be created. 

You can create or modify your grid at any time without needing to reenter any data provided that 

you enter all you data on information layers rather than overriding the values of individual grid 

cells.

If you wish, you may wish to examine the values of individual grid cells or to color the 

grid by the value of one of the grid parameters. To examine the value of an individual grid cell, 

double click on the cell. To color the grid by one of the grid parameters, click on the down 

arrow next to Color on the left side of the main Argus window and then select one of the 

parameters from the list of grid parameters.

Next, run MODFLOW. Select PIEs|Run MODFLOW/MOC3D. Check that the dialog 

box has the correct path for the MODFLOW executable by clicking on the Model Paths tab. If 

the path is wrong, the edit-box and the status bar will have a red background. If the path is 

wrong, either type in the correct path or click on the appropriate Browse button and locate it. 

When the path is correct, click on the OK button. As the PIE processes the export template, a 

progress bar will appear on screen. After the PIE has passed the export template to Argus 

ONE , a prompt-message will appear to select a directory. Ignore the file name, 

MODFLOW_FD_Grid.exp, in the Enter export file name: dialog box. Only the directory, not 

the file name, is used. When directory is selected, Argus ONE will begin to process the export 

template. Two progress bars will appear. Argus ONE generates "barbershop-pole" progress 

bar that can be used to halt the export process. A PIE generates the other progress bar. This 

second progress bar displays warning and error messages as well as the progress through the 

export template. When the export process is complete, MODFLOW will begin to run.

Plot Heads Generated by MODFLOW

19. To plot the results of the model, select PIEs|MODFLOW/MOC3D Post 

Processing. Click the Select Data Set button and select the file rma2.fhd. Click the Open 

button and then the OK button to make a contour plot the head in layer 1 (figure 27).

49
; INFLOW Post Processing Charts jjj

HEAD Per 1 TS 1 Time 631152000 Layer

Figure 27. Heads Generated by MODFLOW Simulation.

Define MODPATH Particle Starting Points

20. Now try using MODPATH to determine the locations that receive water that 

infiltrated at the disposal pond. First, define the starting locations of the particles for 

MODPATH. Make MODPATH Particles Unitl the active layer and zoom in on the area with 

the disposal pond. Draw four contours on that layer as shown in figure 28.

50
Figure 28. Contours on "MODPATH Particles Unitl" layer.

Select all 4 contours and double click on 1 of them. Assign X Particle Count, Y 

Particle Count, and Z Particle Count values of "5". Assign Release Timel a value of 0. 

Click the Set All button and then the OK button. Now just select one contour at a time. Set 

IFACE for the contour on the left to 1. Set IFACE for the contour on the right to 2. Set IFACE 

for the contour on the bottom to 3. Set IFACE for the contour on the top to 4.

Run MODPATH

21. To run MODPATH, change to the MODFLOW FD Grid layer and select PIEs|Run 

MODPATH. Make sure the path for MODPATH is correct. Click the OK button to start 

exporting the MODPATH input files and run MODPATH. Be sure to run MODPATH in the 

same directory in which you ran MODFLOW because MODPATH needs some of the 

MODFLOW input and output files as input.

Plot MODPATH Results

22. To plot the results from MODPATH, select PIEs|MODPATH Post Processing. 

Click on the Read Data button and select a pathline file created by MODPATH. It will have the 

extension "lin". The data will be read and plotted in the dialog box. If the file is large, this may 

take a while and a progress bar will be displayed. To import this data into Argus ONE , click 

the OK button. Another progress bar will be displayed as the data are imported into Argus 

ONE . The progress bar may appear somewhat "jerky" in the way it progresses and Argus 

ONE may redraw several times during the process of drawing the contours. This is normal. It 

is possible to speed up the process of exporting contours by making sure that the redraw process 

is fast. The redraw process is faster if only a small portion of the model is displayed, no cells are 

colored, and layers with lots of contours are hidden. The pathlines will be plotted on a layer 

named MODPATH Pathlines as illustrated in figure 29. Each contour will have four 

parameters: Starting Layer, Starting Time, Ending Layer, and Ending Time.

51
Figure 29. MODPATH Pathlines.

Define Horizontal-Flow Barrier and Rerun MODFLOW

23. We will now modify the model to include a slurry wall extending between the two, 

internal, bedrock outcrops and see how the slurry wall affects the head distribution and particle 

tracks. Change to the Horizontal Flow Barrier Unitl layer and select the open contour tool. 

Draw an open contour between the two, internal, bedrock outcrops (figure 30). Accept the 

default values for the contours. To see exactly how the PIE translates the contours to flow 

barriers, select PIEs|Display Horizontal Flow Barriers and click on the Display button. Rerun 

MODFLOW and MODPATH as before and plot the results. The only difference in the 

procedure is that when plotting the results, prompt-message will appear to overwrite the existing 

data or to create new layers. For the heads, it will be necessary to create two new layers, one for 

the data and one for the post-processing charts. For MODPATH, it will only be necessary will to 

create one new layer. Examine the results in the vicinity of the flow barrier. There should be an 

abrupt change in head at the location of the barrier and more of the particles should go around 

the internal bedrock outcrops rather than between them (figure 31).

52
Figure 30. Slurry wall connecting the two, internal, bedrock outcrops.

£dft SSew JSj^M

layer; f LOW Post Processing Chartsl

Figure 31. Pathlines and head contours in the vicinity of the horizontal-flow

barrier.

UseZONEBDGT

24. Finally, we will use ZONEBDGT to check that the fluxes for the FHB package were 

calculated correctly and to add up the fluxes between the stream and the aquifer. (We might

53
want to know the total flux so that we could compare it with measured values of baseflow.) We 

will also create a ZONEBDGT zone for each of the two pumping wells and define a composite 

zone comprising the two primary zones around the wells. Change to the ZONEBDGT Unitl 

layer and draw closed contours around the stream, each pumping well, and the disposal pond 

(figure 32). Assign each contour a different value. In figure 32, the primary zone for the stream 

is 1, the primary zones for the wells are 2 and 3, and the primary zone for the disposal pond is 4. 

To create the composite zone, select PIEs|Edit Project Info and go to the ZONEBDGT tab. 

Change the number of ZONEBDGT composite zones to 1 and enter "2" and "3" in the first two 

cells in the ZONEBDGT Composite Zones table. Click on the OK button. Change to the 

MODFLOW FD Grid layer and select PIEsjRun ZONEBDGT. The process of running 

ZONEBDGT is much the same as that used to run MODFLOW or MODPATH. When 

ZONEBDGT is done, open the output file from ZONEBDGT in a text editor. The extension of 

the output file will be "zbl". For the zone containing the disposal pond, specified flows into the 

model should be 0.25000E-01 which is the same as the flow we actually specified (0.025). The 

composite zone comprises the two zones containing the two pumping wells. It should have a 

combined pumping rate out of the aquifer of 0.30000E-02. Our specified rates were-0.001 and 

-0.002 so this matches the values we specified. The stream has fluxes both into and out of the 

aquifer although the flux out of the aquifer is far larger than the flux into the aquifer. In some 

cases it might be important to determine which cells had flow from the aquifer. To do this, you 

could open the Edit Project Info dialog box. On the Stress 2 tab you could select the Print 

Flows check-box. If the input files for the Stream package were then regenerated and 

MODFLOW was re-run, the flows would be printed in the MODFLOW listing file. However, 

the stream cell-by-cell flows would no longer be in the cell-by-cell flow file. If ZONEBDGT 

was run again, it would not calculate the correct fluxes for the stream. This is because the 

. current version of the stream package does not provide a mechanism for simultaneously printing 

these flows and saving them in the cell-by-cell flow file.

54
2000 4000 , 60pO

Figure 32. ZONEBDGT Primary zones.

View ZONEBDT Results

25. Another way of examining the results of ZONEBDGT would be to use the 

Budgeteer program (Appendix 2). Start Budgeteer by locating Budgeteer.exe on and double 

clicking on it. Select FilejOpen and then find the ZONEBDGT output file and select it. The 

data for the first zone will be plotted for each time step of the model (figure 33). Use the 

checkboxes to decide which budget items to plot. Use the Plot Type radio buttons to choose 

whether to make a bar graph of data for an individual time step or a time series plot. Use the 

combo-boxes to choose which zone or time step to plot.

55
0.04

0;OI4o.i 1

10 In: CONSTANT HEAD

10 In: WELLS

10.004 In: STREAM LEAKAGE

10 In- SPECIFIED FLOWS

10.051 In: Zone 0 to 1

10.055 In: Total IN

10 Oat: CONSTANT HEAD

10 Oat: WELLS

10.047 Out: STREAM LEAKAGE

10 Oat: SPECIFIED FLOWS

10.008 Out: Zone 1 to 0

10.055 Out: Total OUT

10 IN - OUT

I -0.02 Percent Discrepancy

CONSTANT HEAD 

WELLS

STREAM LEAKAGE 

SPECIFIED FLOWS 

Zone Oto 1

03 CONSTANT HEAD

WELLS

STREAM LEAKAGE 

0 SPECIFIED FLOWS

Zone 1 to 0

(Stress Period: 1; Tune Step: 1

Figure 33. Budgeteer: Bar Chart of an Individual Zone.

Customizing the MODFLOW PIE

The MODFLOW PEE has been designed to make it easy to customize it for special 

purposes. A customized GUI might support other MODFLOW packages that were written 

outside the USGS or entirely separate programs that rely on MODFLOW. In most cases 

customization will require additions to the source code of the GUI. If these additions are done 

properly, it will be possible to incorporate future revisions of the GUI into a customized version 

easily. All that will be needed is to add any new source code files in the updated USGS version 

of the GUI to a project, recompile the PIE, and update the export template. Details on the proper 

method to prepare a customized version of the MODFLOW-GUI will be in a read_me file 

distributed with the source code.

The PIE's were developed using Borland Delphi 4.0 Professional. With minor 

modifications, it should be possible to compile the PIE with Borland Delphi 4.0 Standard. To 

do so, the user must provide a replacement for the Powerlnt function in a unit named 

"Powers.pas" and the line "($DEFINE MathUnitPresent}" should be commented out or deleted 

in ModflowUnit.pas. Rubenking (1996, p. 435-436) presents a suitable Powerlnt function. This 

has not been tested and it is possible that other changes would also be required.

Conclusions

The MODFLOW GUI is an efficient and effective method of creating the input files for 

MODFLOW, MOC3D, MODPATH, and ZONEBDGT. Because data for the model is entered in 

a form that is independent of the grid, the grid can be changed without reentering data.

56
MODFLOW GUI V 3.0 adds a number of new capabilities to the model. The major changes are 

the addition of a help-system and added support for MODPATH, ZONEBDGT, and several 

additional MODFLOW packages.

References

Andersen, P. F., 1993, A Manual of instructional problems for the U.S.G.S. MODFLOW model: 

Robert S. Kerr Environmental Research Laboratory, Office of Research and 

Development, U. S. Environmental Protection Agency, EPA/600/R-93/010, 279 p.

Argus Interware, Inc., 1997, User's Guide Argus ONE , Argus Open Numerical Environments 

 A GIS Modeling System, Version 4.0, Jerico, NY, Argus Holdings, Limited, 506 p.

Harbaugh, A.W., 1990, A computer program for calculating subregional water budgets using 

results from the U.S. Geological Survey modular three-dimensional ground-water flow 

model: U.S. Geological Survey Open-File Report 90-392,46 p.

Harbaugh, A.W., and McDonald, M.G., 1996, User's documentation for MODFLOW-96, an

update to the U.S. Geological Survey modular finite-difference ground-water flow model: 

U.S. Geological Survey Open-File Report 96-485, 56 p.

Hornberger, G.Z., and Konikow, L.F., 1998, Addition of MOC3D solute- transport capability to 

the U.S. Geological Survey MODFLOW-96 graphical-user interface using Argus Open 

Numerical Environments: U.S. Geological Survey Open-File Report 98-188, 30 p.

Hsieh, P. A. and Freckleton, J.R., 1993, Documentation of a computer program to simulate

horizontal-flow barriers using the U.S. Geological Survey modular three-dimensional 

finite-difference ground-water flow model: U.S. Geological Survey Open-File Report 92- 

477, 32 p.

Konikow, L.F., 1977, Modeling chloride movement in the alluvial aquifer at the Rocky

Mountain Arsenal, Colorado: U.S. Geological Survey Water-Supply Paper 2044, 43 p.

Konikow, L.F., Goode, D.J., and Hornberger, G.Z., 1996, A three-dimensional method-ofcharacteristics solute-transport model (MOC3D): U.S. Geological Survey WaterResources Investigations Report 96-4267, 87 p.

Leake, S.A., and Lilly, M.R., 1997, Documentation of a computer program (FHB1) for

assignment of transient specified-flow and specified-head boundaries in applications of 

the modular finite-difference ground-water flow model (MODFLOW): U.S. Geological 

Survey Open-File Report 97-571, 50 p.

McDonald, M.G., and Harbaugh, A.W., 1988, A modular three-dimensional finite-difference 

ground-water flow model: U.S. Geological Survey Techniques of Water-Resources 

Investigations, book 6, chap. Al, 586 p.

57
Poeter, E. P. and Hill, M. C., 1998, Documentation of UCODE, a computer code for universal 

inverse modeling: U.S. Geological Survey Water-Resources Investigations Report 98- 

4080, 116 p.

Pollock, D.W., 1994, User's Guide for MODPATH/MODPATH-PLOT, Version 3: A particle 

tracking post-processing package for MODFLOW, the U.S. Geological Survey finitedifference ground-water flow model: U.S. Geological Survey Open-File Report 94-464, 6 

ch.

Prudic, D.E., 1989, Documentation of a computer program to simulate stream-aquifer relations 

using a modular, finite-difference, ground-water flow model: U.S. Geological Survey 

Open-File Report 88-729, 113 p.

Rubenking, Neil, 1996, Delphi Programming Problem Solver: Forest City, CA, IDG Books 

Worldwide, 604 p.

Shapiro, A.M., Margolin, J., Dolev, S., and Ben-Israel, Y., 1997, A graphical-user interface for 

the U.S. Geological Survey modular three-dimensional finite-difference ground-water 

flow model (MODFLOW-96) using Argus Numerical Environments: U.S. Geological 

Survey Open-File Report 97-121, 50 p.

Voss, C.I., 1984, A finite-element simulation model for saturated-unsaturated, fluid-densitydependent ground-water flow with energy transport or chemically-reactive single-species 

solute transport: U.S. Geological Survey Water-Resources Investigations Report 84- 

4369, 409 p.

58
Appendix 1: Edit Contours PIE

The Edit Contours PIE is used to edit the positions of individual vertices in contours. To 

use it, move to an Information, Maps, or Domain Outline layer and select File|Import <layer 

name> [Edit Contours. The user will be prompted for a layer name. Select a layer. The PIE 

will read all the contours from the layer and display them. Click on any vertex, and a dialog box 

will appear in which it is possible to edit the vertex position. When done, click OK. The PIE 

will then clear the layer and write a new set of contours with the new vertex positions. 

Warnings:

1. The parameter values assigned to contour may be lost if you have selected 

"SpecialjPreferences" and among the clipboard preferences, you have turned off "copy contour 

parameter values".

2. If #1 does not apply, the contour parameter values will be the same as they were 

originally; however, any parameters that were set as default values will now be specified in the 

contour itself. To go back to having the contour value being set by the default value for the 

layer, edit the contour and delete the parameter value.

3. The PIE does not check for contours that are illegal in Argus ONE. A contour is illegal 

if it crosses another contour and "Allow Intersection" is not turned on for that layer. A contour 

is also illegal if it crosses itself even if "Allow Intersection" is turned on. Argus ONE will not 

accept illegal contours so illegal contours will be lost if you specify contours that are illegal. For 

this reason, it is best to back-up your file before using the Edit Contours PIE.

4. The parameter name will be lost if you have selected "Special|Preferences" and 

among the clipboard preferences, you have turned off "copy contour name".

5. The parameter icon will be lost if you have selected "Special|Preferences" and among 

the clipboard preferences, you have turned off "copy contour icon index".

The PIE also contains another function: "Reverse Contours on Clipboard". It reverses 

the order of the vertices in a contour. To use it, cut one or more contours to the clipboard and 

then select File|Import <layer name> [Reverse Contours on Clipboard. Select the layer in 

which the contours should be placed and click the OK button. Both of the above warnings apply 

to the Reverse Contours on Clipboard function.

Installation instructions: Place EditContoursPie.dll and EditContours.hlp in <Argus 

directory>\ArgusPIE\EditContours.

59
Appendix 2: Budgeteer

Budgeteer.exe is a simple program to read the output file from ZONEBDGT (Harbaugh, 

1990), MODFLOW (McDonald and Harbaugh, 1988; Harbaugh and McDonald, 1996), MOC3D 

(Konikow, and others 1996), and SUTRA (Voss, 1984). It plots the results, and saves the data in 

a form that can be readily imported into spreadsheet programs. To run the program, double-click 

on its icon in Windows Explorer. Then select FilejOpen or click the Open button. A dialog box 

will appear. Select an output file from ZONEBDGT, MODFLOW, MOC3D, or SUTRA and 

click on the Open button. The results will be plotted. It is possible to control the format of the 

plot in a number of ways. There is a pair of radio buttons that allow the user to plot the results 

for either a single zone in a single time step or for all the time steps or a single zone. If the user 

chooses to plot a single time step, the data will be plotted as a bar graph. Otherwise, it will be 

plotted as a line graph. There are check-boxes that can be used to select which budget items will 

be plotted and combo-boxes in which it is possible to select the ZONEBDGT zone and time step 

to plot. The latter is enabled only if the user chooses to plot data for a single time step. If the 

user selects FilejSave or clicks on the Save Data button, the data will be saved as a tab-delimited 

text file. Such files can be readily imported into most commercial spreadsheets. The program is 

not designed to provide publication-quality plots, but rather to provide rapid analysis of budget 

data and a method of exporting the data in a form that programs capable of making provide 

publication-quality plots can readily utilize.

Installation instructions: Place Budgeteer.exe in any directory. Consult the online help 

for the operating system for instructions on how to add an icon for the program to the Start menu 

or Program Manager.

Appendix 3: RotateCells

RotateCells.dll is a PIE that can take row or column positions provided by Argus ONE 

and convert them to (X, Y) coordinates. This could be done entirely by an export template, but 

using a PIE can make the export template simpler and easier to understand and perhaps faster 

too.

RotateCells.met is an export template that will export the row and column numbers 

followed by the X and Y coordinates of the four corners of the cell. It uses the RotateCells PIE. 

RotateCells.met can be used to reproducing the grid in other programs. Users may modify 

RotateCells.met to meet their specific requirements.

The PIE provides two functions, Rotated X and Rotated Y. Rotated X has three 

arguments: X, Y, and GridAngle. X is a column position. Y is a row position. GridAngle is the 

angle of the Grid. Rotated X returns the X-coordinate of the point defined by the intersection of 

the row and column positions. Rotated Y is just like Rotated X except that it returns the YCoordinate.

Installation instructions: Place RotateCells.dll and RotateCells.met in <Argus 

directory>\ArgusPIE\RotateCells.

60
Appendix 4: MODFLOW_ReadFileValue

MODFLOW_ReadFileValue.dll is a function PIE for Argus ONE. It contains three 

functions.

1. MODFLOW_RF_Get_Value_From_File(Key, Default_Value, [FileName]) 

FileName is an optional parameter. If FileName is not specified, FileName will be given the 

value of "Default.txt". The function checks if it has already opened FileName. If it hasnTt, it 

reads FileName into memory. If FileName does not exist, it creates a new version of the 

FileName in memory. It then checks for Key in FileName. If any full line in FileName is 

equal to Key, the next line is converted to a double-precision real number and returned as the 

result of RF_Get_Value_From_File. If none of the lines in FileName is equal to Key, the result 

of RF_Get_Value_From_File is "DefaulLValue".

2. MODFLOW_RF_Clear_Files() clears all files that it currently has in memory. This 

function is called at the beginning of the export of MODFLOW input files.

3. MODFLOW_RF_Save_Files() saves all files that it currently has in memory. This 

function is called at the end of the export of MODFLOW input files.

Further Notes:

FileName can be either a fully qualified path name or just a file name. If it is just a file 

name, MODFLOW_ReadFileValue.dll will look for FileName in the current directory.

The format of files to be read by MODFLOW_RF_Get_Value_From_File is as follows. 

Any line that starts with the character "#" or which consists entirely of blanks is considered a 

comment. Lines that are not comments must come in pairs, the first of which consists of a string 

and the second of which consists of a real number. The first line is treated as a Key and the 

second as the value to be associated with that Key. When a file is read, any comments are 

associated with the Key that precedes them. If no Key precedes a comment, the comments are 

associated with the file rather than with a Key. When a file is saved, the comments associated 

with the file are saved first followed by the Key's, their associated values and comments. The 

order of the Key's in the new file may be different from what it was in the original file.

This PIE is useful for allowing external parameter estimation programs such as UCODE 

to interact with Argus ONE.

61
Appendix 5: GetMyDirectory, SelectChar.exe, and 

WaitForMe.exe

SelectChar.exe is a console program that simulates a keyboard event based on its 

command line arguments.

In the following [Char] is used to represent any character and [N] represents any number

If a command line argument contains "Alt-[Char]", SelectChar.exe will simulate 

depressing the Alt key and the [Char] key simultaneously.

If a command line argument contains "Ctrl-[Char]", SelectChar.exe will simulate 

depressing the Ctrl key and the [Char] key simultaneously.

If a command line argument contains "Chr-[[N] ]", SelectChar.exe will simulate 

depressing the key whose key code is [N].

For any other command line argument, SelectChar.exe will simulate depressing the first 

character in the command line argument.

If SelectChar.exe is called with no command line arguments, it will simulate a carriage 

return.

WaitForMe.exe is a program that can run until it is closed. It is only possible to run one 

copy ofWaitForMe.exe at a time. If you attempt to run a second copy, the first copy will be 

activated instead. It can be closed by activating it and typing a carriage return. The purpose of 

this is to start the program before doing something else and then activate it again when that 

"something else" is done. You can then close it by running SelectChar.exe. An external program, 

such as UCODE, can be waiting for WaitForMe.exe to finish executing before continuing.

These three files are primarily useful for allowing an external program such as UCODE 

to run MODFLOW through Argus ONE and wait until MODFLOW has finished executing 

before continuing. In the MODFLOW GUI 3 and Sutra PIE 1.0.2 or later, if you define a Global 

variable named "Calibrate" and set its value to True (= 1). Argus ONE will activate and then 

close WaitForMe.exe in the directory containing GetMyDirectory.dll after running MODFLOW. 

It will also allow the DOS window in which MODFLOW or SUTRA ran to close. For this to 

work, GetMyDirectory.dll, SelectChar.exe, and WaitForMe.exe must all be in the same directory 

and must be in the ArgusPIE directory or a subdirectory of the ArgusPIE directory.

62
Appendix 6: HydrographExtractor.exe

HydrographExtractor.exe is a program for reading MODFLOW formatted head or 

drawdown files and extracting hydrographs for selected cells.

To use it, first, assign the row, column, and layer of each cell for which you wish to 

create a hydrograph. Next, Click on the "Read" button to read a MODFLOW formatted head or 

drawdown file. The data will be graphed and also written to an on-screen text box in a tabdelimited format. The text may be saved to a file by clicking on the save button. Most 

commercial spreadsheets can readily import tab-delimited text files such as the one saved by this 

program. If you wish to quit in the middle of reading a head or drawdown file, click on the 

"Cancel" button.

HydrographExtractor.exe accepts two optional command line parameters. The first 

parameter is the name of a file containing the locations of the cells to be read. The first number 

in the file must be an integer specifying how many cell locations will be read from the file. After 

that there must be groups of three integers specifying the column, row, and layer of each cell. 

The data in this file are read in free format. Numbers must be separated by spaces, tabs, or endof-line characters. The second optional parameter is the name of the formatted head or 

drawdown file from which data are to be read. 

Examples:

Typing any of the following three lines will start Hydrograph Extractor. 

HydrographExtractor. exe 

HydrographExtractor. exe CellLocations.txt 

HydrographExtractor.exe CellLocations.txt Heads.fhd

63
Appendix 7: Web-Based Tutorial

A web-based tutorial (originally prepared for version 1 of the MODFLOW GUI by Argus 

Interware) has been updated to reflect changes made in versions 2 and 3 of the MODFLOW 

GUI. The purpose of the tutorial is to teach users how to use MODFLOW, the MODFLOW 

GUI, and Argus ONE. Five of the examples in the tutorial are drawn from Andersen (1993). 

The tutorial includes two other examples. In one, the user makes simple changes to an existing 

model to become familiar with the process of editing model information and to observe the 

effects of making simple changes in models. In the other, the user creates a simple model based 

on topographic and geologic information.

The tutorial comes in the form of a self-extracting executable named

MODFLOW_Tutorial.EXE. When MODFLOW_Tutorial.EXE is run, a series of web pages 

and example models are extracted. To begin the tutorial, the user should double-click on a file 

named DoubleClickMe.html. The file will be opened by the default web browser on their 

computer.

64