Introduction to MODFLOW, specifically file formats

[JHaas]

Is there any "easy" introduction to Modflow available?

Or more specifically on the various files it needs and on their
structure.
At the moment i am working through the USGS ofr00-92 pdf, and it is
quite helpful (especially the Input Instructions section), but i am
still having a hard time to get to a working model.

I am not sure which files i always need (as far as i understand GLOBAL
or LIST is always needed) and which i only need for specific packages
(such as RIV). For exapmle stuff like DIS or BAS6 seem to be something
that i always need.

I guess i can work that out, by working through the mentionend pdf,
but any "shortcuts" to get to a working example model to play around
with and get a feeling for what is what and then get into the details
would be appreciated.

Another problem i have is "producing" the needed files.

It seems to me that Modflow is quite choosy in which files it accepts.
As written above, i do not have a running Modflow model, but i do have
played around in PMWIN, and it often produces errors, when i use files
with it that i have exported from excel, or written with MATLAB.
Generally that stuff that works, is the easy stuff that i have
handwritten in notepad, whereas the complicated stuff that does not
work does look "mangled" in notepad. However in useable editors such
as notepad++, Kate or gedit they do look fine.

One problem was the fact that i use linux for most stuff, whereas
PMWIN runs on windows, but even with files produced on a windows
machine i often get the above problems.

Are there any specifications on how the files have to look like?
encoding? End of line? tab vs. spaces between values? What format do
numbers need to have?

Regards
JHaas

[ashutosh singh]

Hi Jhaas,

I am also a newbie in modflow. But I got good help from ModelMuse. It has a GUI which makes easy to make files automatically from the program itself.

Once you run a small easy model using modelmuse you can see the output files and for complex problems you can produce the output files using matlab or any other programming language. I started with it 2 weeks back and I have learned a lot.

May be you can try it. ModelMuse is really an easy way to learn modflow. There are plenty of videos on the website which makes it far easier to learn the software.

Ashutosh

--
You received this message because you are subscribed to the Google Groups "MODFLOW Users Group" group.
To post to this group, send email to mod...@googlegroups.com.
To unsubscribe from this group, send email to modflow+u...@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/modflow?hl=en.

--

Ashutosh Singh

Center for Applied Geoscience (ZAG)

Eberhard-Karls-University Tübingen

Hölderlinstr. 12

72076 Tübingen

Germany

 

Phone: +49-(0)7071-29 73174

Mobil: +49(0)176-890 22926

[Prashanth Khambhammettu]

JHaas,

The LIST and GLOBAL files are the output files produced by MODFLOW.

The DIS package contains the model discretization (spatial and temporal) info and the BAS6 file contains the Initial conditions and some of the boundary conditions.

The online guide to MODFLOW  has most of the information you are looking for like formatting and variable descriptions.
http://water.usgs.gov/nrp/gwsoftware/modflow2000/MFDOC/index.html

I believe the documentation has a number of test problems that could use.

Also, as you may have realized notepad is not good enough to view large files. So you may want to use a more heavy-duty text editor that is compatible with linux. I use textpad on windows but any good editor would suffice.

Regards,
Prashanth Khambhammettu
SS Papadopulos & Associates

--
You received this message because you are subscribed to the Google Groups "MODFLOW Users Group" group.
To post to this group, send email to mod...@googlegroups.com.
To unsubscribe from this group, send email to modflow+u...@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/modflow?hl=en.

--
------------------------------------------------------------------------------
It's not who you are underneath, but what you do that defines you.
------------------------------------------------------------------------------

[Edward Banta]

Johannes,

You always need to list in the name file:

LIST (or GLOBAL, or both.  Starting out, just use LIST)
BAS6
DIS
A flow package (one of LPF, BCF, or HUF2)
A solver package (one of SIP, DE4, SOR, PCG2, or GMG)

Other files are listed to activate stress packages or if you want to provide array data in separate files or to use various other options.

In general, prepare all input files as ASCII text files.  Spreadsheet files in their native format will not be read correctly.  Your text editors should be able to "Save As" in ASCII.  The line-ending convention is operating-system dependent...use the native convention for your operating system.  For most predictable results, do not use tab characters; separate input values with spaces.

Formats for numeric inputs vary, but most input can be in "free" format if you specify the FREE option in the Basic Package (BAS6) input file.

In the MODFLOW-2000 distribution, the test-run directory contains test data sets, which you may find instructive.

For getting started in MODFLOW-2000, you also may find MFI2K useful, although it only runs under Windows.  Find MFI2K at http://water.usgs.gov/nrp/gwsoftware/MFI2K/MFI2K.html

========================
Ned Banta
Hydrologist (GW Modeler)
U.S. Geological Survey
Denver Federal Center          
P.O. Box 25046, M.S. 415
Denver, CO 80225-0046
303-236-6871

[Richard B. Winston]

As others have suggested, you might find ModelMuse helpful.
http://water.usgs.gov/nrp/gwsoftware/ModelMuse/ModelMuse.html

The Global file is not required. You can use the global file with
MODFLOW-2000 but not MODFLOW-2005.

When transferring text files from Windows to Linux, you need to make
sure that the line endings get converted properly because Windows and
Linux use different conventions for marking the end of the line.
EditPad Lite is one program that can make the conversion for you.
http://www.editpadlite.com/

It is important to set the Options data set in the basic package
properly. Of you include "FREE" in the options you can use free format
for most of the data in MODFLOW. Otherwise, most of the numeric fields
are 10 spaces long.

[JHaas]

Thanks for the replies.

I will have a look at model muse. Maybe it is better than the PMWIN
GUI i am using at the moment.

>Also, as you may have realized notepad is not good enough to view large
>files. So you may want to use a more heavy-duty text editor that is
>compatible with linux. I use textpad on windows but any good editor would
>suffice.

I think you misunderstood me. I am already using a "heavy duty" editor
(notepad++ in my case), but the problem seems to be that this editor
is "intelligent" enough to read about any file correctly, no matter
which operating system or program it came from.
Windows stock notepad however does often show "artifacts" such as
missing line breaks, and those files are the ones i run into trouble
with in modflow/PMWIN.

> When transferring text files from Windows to Linux, you need to make
> sure that the line endings get converted properly because Windows and
> Linux use different conventions for marking the end of the line.  
> EditPad Lite is one program that can make the conversion for you.http://www.editpadlite.com/

Yes, i think that might be one of my problems. However Matlab on
windows can also produce files that wont get read correctly. So i will
have also to look into tab vs. space, and if they are encoded in
ASCII.

> It is important to set the Options data set in the basic package
> properly.  Of you include "FREE" in the options you can use free format
> for most of the data in MODFLOW. Otherwise, most of the numeric fields
> are 10 spaces long.

I guess this has to do with the fact that modflow is written in
Fortran? From the documentation i have read so far, it seems like it
is assumed that people who want to use Modflow are fluent in Fortran.

So if I understand this correctly, with nonfree format every value
hast to use a field of ten spaces length. That means "1" would become
"space space space space space space space space space 1" and
"10000000000" "10000000E3", whereas free format would simply allow me
to use "1" and "100000000"?

JHaas

[Richard B. Winston]

JHaas wrote:
> So if I understand this correctly, with nonfree format every value
> hast to use a field of ten spaces length. That means "1" would become
> "space space space space space space space space space 1" and
> "10000000000" "10000000E3", whereas free format would simply allow me
> to use "1" and "100000000"?
>
> JHaas
>
>

You are correct that with non-free format 1 would be written as
" 1". However, if 1000000000 represents a real number rather
than an integer it could be written as "10000000000", "10000000E3",
" 1.0E3", or a number of other variants.