modflow-related freeware and shareware resources on the internet
TRANSCRIPT
MODFLOW-related freeware and shareware resources onthe internet
Richard B. Winston *
2145 Colts Neck Cl., Reston, VA 20191, USA
Received 16 April 1998; received in revised form 10 June 1998; accepted 10 June 1998
Abstract
MODFLOW (modular ®nite-di�erence groundwater ¯ow model), probably the most frequently used groundwater
modeling program, is in the public domain and may be downloaded from the US Geological Survey (USGS) andother sites. In addition, freeware and shareware pre- and postprocessors are also available. Some of the originaldocumentation can also be downloaded for free. A variety of other free or low-cost materials related toMODFLOW are also available. # 1999 Elsevier Science Ltd. All rights reserved.
Keywords: Groundwater; Finite di�erences
1. Introduction
The modular ®nite-di�erence groundwater ¯ow
model, frequently referred to as MODFLOW;
(McDonald and Harbaugh, 1988; Harbaugh and
McDonald, 1996a,b) is a program for simulating con-®ned or uncon®ned, saturated ¯ow in one, two, or
three dimensions. It allows both steady-state and tran-
sient simulations. At least with the public domain
packages, it does not simulate unsaturated ¯ow or
solute and heat transport. However, MT3D (Zheng,
1990) and MOC3D (Konikow et al., 1996), both of
which rely on MODFLOW, can simulate solute trans-
port.
MODFLOW is one of the most popular ground-
water modeling programs in existence. In a compara-
tively recent survey (Geragthty and Miller Software
Newsletter, 1992), it was, by far, the most popular
groundwater modeling program. Some reasons for this
popularity may be: (1) the program is applicable to
most types of groundwater modeling problems, (2) the
original packages in the program are well structured
and documented, (3) the source code is in the publicdomain and thus can be checked for errors and modi-
®ed by anyone with the necessary mathematical and
programming skills, (4) the program is accepted by
regulatory agencies and in litigation and (5) ongoingmodi®cations of the program continue to increase its
capabilities. Public domain and proprietary packages
have been written for MODFLOW both within the US
Geological Survey (USGS) where it was originally cre-
ated and outside the USGS (Tables 1 and 2). SinceMODFLOW was written, a variety of public-domain
and proprietary programs have built upon it either by
using the output of MODFLOW as the input for ad-
ditional modeling or by extending the capabilities of
MODFLOW. The public-domain programs that buildupon MODFLOW include MT3D (Zheng, 1990),
MODFLOWP (Hill, 1992, 1994) and MOC3D
(Konikow et al., 1996).
Before using any of the packages not currently sup-
ported by the USGS, users should carefully read the
documentation to ensure that the code has been
thoroughly tested. If it has not been thoroughly tested,you should test it yourself before relying on it.
Both MODFLOW itself and a variety of relatedprograms are freely available on the Internet. The
most prominent source is the USGS itself (http://
Computers & Geosciences 25 (1999) 377±382
0098-3004/99/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved.
PII: S0098-3004(98 )00141-1
PERGAMON
* E-mail: [email protected]; http://www.mind-
spring.com/0rbwinston/
Table
1
Publicdomain
packages
forMODFLOW
notin
originalversionofMODFLOW
Abbreviation
Packagename
Purpose
Reference
Sources
(see
Table
2)
PCG1
Preconditioned
Conjugate-GradientPackage1
usedto
solve®nite-di�erence
equations
Kuiper
(1987)
2,3
BCF2
Block-C
enteredFlow
2allowsdry
cellsto
becomewet
McD
onald
andHarbaugh(1992)
1,2,3
RIV
2River
Package2
usedforroutingriver
¯ow
downstream
from
one
river
reach
toanother
Miller(1988)
2
STR1
Stream¯ow-RoutingPackage
usedto
simulate
stream¯ow
routing
Prudic
(1989)
1,2,3
RIN
T1
River
InteractionsPackage
simulate
stream¯ow
routingandriver
interaction
withalluvialdeposits
SchenkandPoeter
(1990)
5
PCG2
Preconditioned
Conjugate-GradientPackage2
usedto
solve®nitedi�erence
equations
Hill(1990)
1,2,3
IBS1
Interbed
StoragePackage1
allowssimulationofwaterrelease
byinterbeds
LeakeandPrudic
(1991)
1,2
CHD1
Tim
e-VariantSpeci®ed-H
eadPackage1
usedforspeci®ed
headsthatvary
withtime
LeakeandPrudic
(1991)
1,2
BCF3
Block-C
enteredFlow
3allowsmore
accurate
simulations
GoodeandAppel
(1992)
1,2,3
GFD1
GeneralizedFinite-Di�erence
1allowsdirectspeci®cationofallintercell
conductances
Harbaugh(1992)
1,2
LAK1
LakePackage1
usedto
simulate
lakes
ChengandAnderson(1993)
6
none
Modi®ed
Stream
Package
usedto
simulate
stream¯ow
routingincluding
streamsthat¯ow
into
oroutoflakes
ChengandAnderson(1993)
6
HFB1
Horizontal-Flow
BarrierPackage1
simulatesthee�
ects
ofthin
verticalbarriers
to
horizontal¯ow
such
asintrusionsorfaults
Hsieh
andFreckleton(1993)
1,2,3
SHY1
HydrographPackage
saves
hydrographdata
forspeci®ed
cells
Plato
(1993)
7
BAR
andCUT
Flow-Barrier1andCanyon-C
utter
Packages
1together,thesepackages
simulate
pinchouts
andthe
e�ects
ofthin
verticalbarriers
tohorizontal¯ow
such
asintrusions,faultsorcanyons
Hansen(1993)
2
Hansen(1993)
TLK1
TransientLeakagePackage1
simulatesleakagefrom
con®ninglayersin
transient
quasi-three-dim
ensionalmodels
Leakeet
al.(1994)
1,2
DE45
Direct-SolutionPackage5
usedto
solve®nitedi�erence
equations
Harbaugh(1995)
1,2
RES1
ReservoirPackage1
usedto
simulate
¯ow
into
andoutofreservoirs
Fenskeet
al.(1996)
1,2
none
Spatialvariable
anisotropypackage
allowsspatiallyvariable
anisotropy
KladiasandRuskau�(1997)
4
FHB1
Flow
andHeadBoundary
Package1
usedfortransientspeci®ed
headandspeci®ed
¯ux
boundaries
LeakeandLilly
(1997)
1,2
R.B. Winston / Computers & Geosciences 25 (1999) 377±382378
water.usgs.gov/software/mod¯ow.htm1 or http://www.geogr.unijena.de/software/mod¯ow.html). How-
ever, a variety of other sites exist that have either thesource code or executable versions of MODFLOW(Table 3). In some instances the non-USGS versions
have extra capabilities that the USGS version lacks.
2. Preprocessors
Although MODFLOW is a powerful program, itcan hardly be described as user-friendly. All input for
the program is in the form of large text ®les thatdescribe the grid structure, hydraulic properties,boundary conditions and transient data. These ®les
must follow a strict format. If the format requirementsare violated MODFLOW will either not be able to runor will produce incorrect results. To alleviate this pro-
blem, a large number of preprocessors have beendeveloped that provide a graphical user interface forMODFLOW. In some cases, the programs are either
freeware or shareware.One shareware preprocessor is MODUSER which can
be obtained from the Computer Oriented GeologicalSociety ftp site among other places. (ftp://ftp.csn.org/
COGS/Hydrology/moduser.zip or http://sunsitc.un-c.edu/pub/academic/geology/COGS/Hydrology/). It is a
DOS program and has a US$10.00 registration fee. Itsupports the original MODFLOW-88 packages. It can
be used to set up a grid and assign values to cells byclicking on the cells. In a brief test of MODUSER, it was
not clear how to reenter data in order to correct mistakes.There is little documentation of the program making it
di�cult to use.UNCERT (http://uncert.mines.edu/, Wingle et al.,
1995; Wingle, 1997) is a free MODFLOW preproces-sor for Unix. It is reputed to do more than just act as
a MODFLOW preprocessor.MFI (http://water.usgs.gov/software/m®.html;
Harbaugh, 1994) is free. It supports MODFLOW-96,the stream package and MOC-3D. To use the DOS
version a spreadsheet program that can read and writeLotus 123.WK1 ®les is required, such as Microsoft
Excel. MFI requires a bit more work to install prop-erly than do most modern programs. After download-
ing and extracting the program, the Con®g.sys ®lemust be modi®ed and a batch ®le run. Every timeMFI is run, a batch ®le must be copied into the direc-
tory where MFI is installed. This batch ®le controlsthe interaction between MFI and the speadsheet pro-
Table 2
Sources for MODFLOW Packages
Reference
number Web page or email address or mailing address of MODFLOW package
1 http://water.usgs.gov/software/ground_water.html
2 http://water.usgs.gov/software/to_order.html
3 FTP://kilburn.keene.edu/Kilburn/ftp/GWM-L/
4 ftp://ftp.mindspring.com/users/rbwinston/incoming/varan3.zip
5 [email protected] (Judith A. Schenk) or [email protected] (Eileen Poeter)
6 [email protected] or [email protected] (Mary Anderson)
7 Arizona Department of Water Resources, Hydrology Division, Modeling Section, 15 S 15th Ave., Phoenix, AZ
85007, or Paul R. Plato, Harding Lawson Associates, 2800 N. 44th St. Ste. 500, Phoenix, AZ 85008
Table 3
Non USGS sources for free versions of MODFLOW
URL Added features
http://www.argusint.com/Mod¯ow.html or http://www.mindspring.com/
0rbwinston/ModDyn.htm
dynamic arrays, additional packages, link to MT3D
http://hydro.geo.ua.edu/mt3d/mt3d150d.htm link to MT3D, additional options for reading data
http://www.¯owpath.com/ additional packages
http://dino.wiz.uni-kassel.de/model_db/server.html no extra features
http://ourworld.compuserve.com/homepages/W_H_Chiang/ link to MT3D
FTP://kilburn.keene.edu/Kilburn/ftp/GWM-L/ no extra features
http://www.epa.gov/ada/models.html link to MT3D, additional options for reading data
(compiled version may not work on modern PCs)
R.B. Winston / Computers & Geosciences 25 (1999) 377±382 379
gram. MFI deletes this ®le when it exits, so it cannotbe left in the directory with MFI. MFI appears to be
an e�ective program for creating MODFLOW input®les. It is much less user-friendly than commercial pre-processors. The manual is available online at: http://
h2o.usgs.gov/software/m®_manual/ofr-94_468_1.html.The USGS also provides another free user interface
for MODFLOW. The `MODFLOW-GUI' (http://
water.usgs.gov/software/mod¯ow-gui.html, Shapiro etal., 1997) is a plug-in for Argus open numerical en-vironments (Argus ONE). Thus to use it, you must
have Argus ONE. I have written an updated version ofthe plug-in that supports MT3D in addition toMODFLOW. It is available for free from the ArgusWeb site (http://www.argusint.co). In theory some
other program besides Argus ONE might be adaptedto use either USGS or my version of the MODFLOWplug-in. However, this would probably be impractical.
The MODFLOW-GUI is more sophisticated thanMODUSER or MFI because the data de®ning themodel are independent of the grid. Thus, the grid can
be altered without requiring the user to reenter data.The MODFLOW-GUI also provides postprocessing ofMOFLOW data.
For users of Arc-Info, there is a public domain pro-gram (MODFLOWARC, Orzol and McGrath, 1992)that can be used to link Arc-Info to MODFLOW. It isa Unix program. The source code and documentation
are available from http://wwworegon.wr.usgs.gov/projs_dir/mod¯owarc/mod¯owarc.html.The USGS provides one additional preprocessor:
RADMOD (http://water.usgs.gov/software/rad-mod.html, Reilly and Harbaugh, 1993a,b). It is aspecial purpose tool that can be used to prepare
radially symmetrical models using the General-FiniteDi�erence Package. It only prepares the input ®le forthe General-Finite Di�erence Package and not theremaining MODFLOW packages.
3. Postprocessors
The USGS provides several programs for processingand display of the data from MODFLOW and relatedprograms
CONTOUR (http://water.usgs.gov/software/con-tour.html, Harbaugh, 1990a) is a Unix program forcreating contour maps from gridded data. I have
not tested it.MODPATH (Pollock, 1994) is a particle tracking
program for MODFLOW models. The USGS has
compiled versions for Unix at http://water.usgs.gov/software/modpath.html. I compiled a free versionfor DOS. At present, I do not have the disk space
on my server to keep it on line so you must contactme to get it.
ZONEBUDGET (http://water.usgs.gov/software/zonebdgt.html, Harbaugh, 1990b) is used to createwater budgets for particular zones in a
MODFLOW model. Versions for DOS and Unixare available from the USGS. It is easy to use ande�ective.
I have written a freeware program MF2Hydrograph(http://www.mindspring.com/0rbwinston/mf2hy-drogrgph.htm) that will extract hydrograph data for
individual cells from the formatted head and draw-down ®les created by MODFLOW-96.
4. Documentation
MODFLOW and related programs are exhaustivelydocumented in USGS publications which may be pur-
chased at nominal fees. Documentation for some ofthe newer packages can be downloaded from theUSGS MODFLOW page (http://water.usgs.gov/soft-ware/mod¯ow96.html) as Postscript or pdf ®les. These
documents provide the theoretical basis for the pro-grams, detailed explanations of the source code, inputformats and example applications. This documentation
is a critical reason for the success of MODFLOW,because is detailed enough to allow users to add ad-ditional packages to the program: something which
can be said of no other USGS groundwater modelingprogram. The documentation may, however, seemoverwhelming for beginners. The original documen-
tation (McDonald and Harbaugh, 1988) is 586 pageslong and represents about one third of the total docu-mentation now available. To provide a more succinctguide to MODFLOW, I have written a `Help File' for
it, comprising a series of linked Web pages that explainhow to use each of the packages. There is also a shorttutorial on MODFLOW and a Web page with links to
all the free and commercial versions of MODFLOWor MODFLOW-related programs (of which I amaware) on the Internet. The guide may be used on a
trial basis for up to 30 days after which users arerequired to pay a small registration fee. The guide maybe obtained from http://www.mindspring.com/0rbwinston/modhelp.htm.
Another useful resource for beginners is the manualof MODFLOW instructional problems from theEnvironmental Protection Agency (Andersen, 1993,
http://www.epa.gov/ada/mod¯mn.html). It gives 20examples of simple MODFLOW models each designedto illustrate how to use speci®c aspects of
MODFLOW. It is an excellent source of informationon how best to use MODFLOW and to avoid com-mon errors.
R.B. Winston / Computers & Geosciences 25 (1999) 377±382380
Environmental Simulations, Inc. (http://www.groundwatermodels.com/) has converted the
MODFLOW documentation to a pair of WindowsHelp Files. Strictly, these ®les are not sharewarebecause they cost US$25.00. These help ®les are
included with their preprocessor Groundwater Vistas,but may also be purchased separately.
5. Summary
MODFLOW is popular as a groundwater modelingprogram. This popularity stems from its power, and
excellent documentation, among othe factors. Not onlymay MODFLOW be obtained free from the USGS,but enhanced versions are also available from a varietyof other sites. Free, and low-cost, MODFLOW pre-
and postprocessors are available, as well as a numberof public domain models that use MODFLOW andprovide additional modeling capabilities. A variety of
free or low-cost documentation is also available.
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