Information about the groundwater model files in this archive file is below this
disclaimer.

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DISCLAIMER:
The files contained herein are provided as an archive of the groundwater flow
simulations described in the publications MBMG Open-File Report (OFR) 771 by
Zeiler and others (2025) and MBMG OFR 772 by Meredith and others (2025), which
can be freely downloaded in PDF format from the MBMG website where these files
were downloaded (https://mbmg.mtech.edu/WaterEnvironment/GWIP/reports.asp).
Notably, OFR 771 describes the model assumptions and limitations. Groundwater
flow model and particle tracking simulations are based on available data at the
time of development. Users are advised to read the associated reports for
additional details. Output files are also provided as a convenience to those who
wish to replicate simulations and repeat the modeling workflow. Any changes made
to the model input/output or other files could have unintended, undesirable
consequences. These consequences could include, but may not be limited to:
erroneous model output, numerical instabilities, and violations of the
underlying assumptions about the subject hydrologic system that are inherent in
results presented in the associated reports. Montana Bureau of Mines and Geology
[MBMG] assumes no responsibility for the consequences of any changes made to
these files. If changes are made to the model, the onus is on the user for
documenting the changes and justifying the results and conclusions. Unless
otherwise stated, all data and related materials are considered to satisfy the
quality standards relative to the purpose for which the data were collected.
Although these data and associated materials have been reviewed for accuracy and
completeness, and approved for release by the MBMG, no warranty expressed or
implied is made regarding the display or utility of the data for other purposes,
nor on all computer systems, nor shall the act of distribution constitute any
such warranty. The users of these data and associated materials assume all risk.
The MBMG, Montana Technological University, University of Montana, Montana
University System, or the State of Montana shall not be held liable for improper
or incorrect use of the data described and/or contained herein.

These groundwater flow model constructs and particle tracking simulations are
not designed for use as a primary regulatory tool in permitting, siting, or
other regulatory decisions, but may be used as a reference source. This is
public information and may be interpreted by organizations, agencies, units of
government, or others based on needs; however, they are solely responsible for
the appropriate application. Federal, state, or local regulatory bodies are not
to reassign any authority to the MBMG any authority for their decisions. The
MBMG may perform evaluations of these models for purposes related to regulatory
programs; however, any regulatory decisions would be the authority and
responsibility of the applicable regulatory bodies.

Any use of trade, firm, or product names is for descriptive purposes only and
does not imply endorsement by MBMG, Montana Technological University, University
of Montana, Montana University System, or the State of Montana.

This disclaimer may be updated at any time.
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MBMG GWIP Upper Gallatin Aquifer groundwater flow model and particle tracking
files - otential broad additional septic system effluent discharge predictive
scenario

This archive contains directories with the following contents:
* UG_SS_CalibrationFall20_Spring21_AddlSeptPTs_FallOnly - contains MODFLOW-USG
input and output files for the potential broad additional septic system effluent
discharge predictive scenario model for the low-flow ("fall") period with mod-
PATH3DU particle tracking input and output files.

* UG_SS_CalibrationFall20_Spring21_AddlSeptPTs_SpringOnly - contains MODFLOW-USG
input and output files for the potential broad additional septic system effluent
discharge predictive scenario model for the high-flow ("spring") period with
mod-PATH3DU particle tracking input and output files.


Executables in each directory include:
* mfusg_x64.exe - 64-bit MODFLOW-USG 1.5 executable from standard USGS software
distribution

* mp3du.exe - mod-PATH3DU version 2.1.8 executable from the S.S. Papadopulos &
Associates, Inc. (SSP&A) mod-PATH3DU software distribution

* writep3dgsf.exe - mod-PATH3DU version 2.1.8 utility executable for handling
grid-specification files from the mod-PATH3DU software distribution

* writep3doutput.exe - mod-PATH3DU version 2.1.8 utility executable for writing
binary particle tracking output files to ASCII text files from the mod-PATH3DU
software distribution


The MODFLOW-USG files are in standard USGS MODFLOW-USG formats, and the ASCII
text files (those without the file extensions ".hds" and ".cbb") can be read
with any text editor.

The mod-PATH3DU files are in ASCII text files, except the output binary
(extension .bin) file and the shapefiles of initial particle locations and
output particle pathlines, which can be read with any standard GIS software.

These files can be read into any commercial MODFLOW graphical user interface,
including (but not limited to) Groundwater Vistas (TM), Groundwater Modeling
Software (GMS) (TM), or Visual MODFLOW Flex (TM). These can also be read into
FloPy, available freely from the USGS or on GitHub.


The following Groundwater Vistas (GWV) (TM) files are also included in this
archive for the user's convenience, but because the model utilizes a quadtree
unstructured grid, a Professional License is required:

* UG_SS_CalibrationFall20_Spring21_AddlSeptPTs_FallOnly.gwf
* UG_SS_CalibrationFall20_Spring21_AddlSeptPTs_SpringOnly.gwf

These GWV files produced the input files in the directories of the same name.
Note that for the low-flow ("fall") period, the GWV file is using the option to
create input files for only the first stress period (Model-->MODFLOW-->Package
Options-->Simulate a subset of stress periods). For the high-flow ("spring")
period, the GWV file creates input files for only the second stress period using
the same stress period subset option.
