SIR2017-5014\readme.txt Publication: Senior, L.A., and Goode, D.J., 2017, Effects of changes in pumping on regional groundwater-flow paths, 2005 and 2010, and areas contributing recharge to discharging wells, 1990-2010, in the vicinity of North Penn Area 7 Superfund site, Montgomery County, Pennsylvania: U.S. Geological Survey Scientific Investigations Report 2017-5014 https://doi.org/10.3133/sir20175014 Data Release: Goode, D.J., and Senior, L.A., 2017, MODFLOW-2000 and MODPATH5 model data sets used to evaluate the effects of changes in pumping on regional groundwater-flow paths, 2005 and 2010, and areas contributing recharge to discharging wells, 1990-2010, in the vicinity of North Penn Area 7 Superfund site, Montgomery County, Pennsylvania: U.S. Geological Survey data release https://doi.org/10.5066/F7FN14BQ Archive created: 2017-01-27 --------------------------------------------------------------------------------- DISCLAIMER- THE FILES CONTAINED HEREIN ARE PROVIDED AS A CONVENIENCE TO THOSE WHO WISH TO REPLICATE SIMULATIONS OF GROUNDWATER FLOW THAT ARE DESCRIBED IN U.S. GEOLOGICAL SURVEY SCIENTIFIC INVESTIGATIONS REPORT 2017-5014. ANY CHANGES MADE TO THESE FILES COULD HAVE UNINTENDED, UNDESIRABLE CONSEQUENCES. THESE CONSEQUENCES COULD INCLUDE, BUT MAY NOT BE LIMITED TO: ERRONEOUS MODEL OUTPUT, NUMERICAL INSTABILITIES, AND VIOLATIONS OF UNDERLYING ASSUMPTIONS ABOUT THE SUBJECT HYDROLOGIC SYSTEM THAT ARE INHERENT IN RESULTS PRESENTED IN U.S. GEOLOGICAL SURVEY SCIENTIFIC INVESTIGATIONS REPORT 2017-5014. THE U.S. GEOLOGICAL SURVEY ASSUMES NO RESPONSIBILITY FOR THE CONSEQUENCES OF ANY CHANGES MADE TO THESE FILES. IF CHANGES ARE MADE TO THE MODEL, THE USER IS RESPONSIBLE FOR DOCUMENTING THE CHANGES AND JUSTIFYING THE RESULTS AND CONCLUSIONS. --------------------------------------------------------------------------------- The underlying directories contain all of the input and output files for the simulations described in the report, input and output data files for the particle-tracking analysis, and the MODFLOW and MODPATH source codes. BACKGROUND OF MODEL The model used for the simulations in this report was developed by, and documented in the report by, Senior and Goode (2013). Minor updates to the model stresses and particle source locations are documented in the current report. Refer to Senior and Goode (2013) for full explanation of the model construction and calibration, and other information necessary to understand and use these model files. It is recommended that the model construction be explored using the model preprocessor in order to visualize the model structure. The model datasets were developed using MODFLOW-GUI (version 4.35.0.0), a GIS-based graphical user interface linked to Argus Numerical Environments (ARGUS; version 4.2.0w) software (Winston, 2000). Groundwater flow was simulated using MODFLOW-2000 (Harbaugh and others, 2000; version 1.19.01) and MODPATH (Pollock, 1994; version 5.0), a particle-tracking program commonly used to delineate contributing recharge areas and flow paths from contaminant sources. The three-dimensional finite-difference grid was constructed in the preprocessor using geo-referenced shapefiles for 10- and 30-m DEMs and NHD medium-resolution streams. All the MODFLOW-2000 data sets were generated using ARGUS, except for the initial head binary file, which was produced using a previous modflow model run. Model Viewer (Hsieh and Winston, 2000; version 1.6) was used to visualie the MODPATH flow paths in three dimensions. As described by Senior and Goode (2013), this model uses dipping model layers to represent dipping geologic units. The model has 2 subhorizontal layers at the top. Because of the dip, underylying layers subcrop into the bottom of layer 2. When this occurs, the subcropping layers are assigned a very small thickness, a large vertical hydraulic conductivity (Kz), and zero horizontal Kx and Ky. This allows the upper subhorizontal layers to interact with the 'active' lower layers of the model by passing water through the subcropped 'inactive' model cells. This is explained in detail by Senior and Goode (2013). In the upper (low number) rows, only the upper 4 or 5 layers are active, and the underlying layers are inactive (ibound=0). In the bottom rows, the upper 2 subhorizontal layers are active, then there are several 'inactive' or pseudo inactive layers that are handled as described, but are still ibound=1. Below those, there are the 'real' active layers that have positive Kx and Ky, and realistic Kz. The stream (STR) elevations were assigned from a gridded data set derived from a DEM. This results in some small variations in the elevations along the stream segments, and the elevation may increase in the downstream direction. The stream stage for the model is not calculated, but it is specified by input from the DEM. That gridded DEM does not always align well with the actual stream elevation in the cell. These elevations affect the gradient between the stream and the aquifer, but the gradient along the segments of the stream is NOT used to compute the streamflow in this model. There may be some abrupt differences in the stream loss/gain due to these abrupt elevation changes. However, the model adequately captures the overall interaction between the streams and the aquifer for the purpose of determining the regional groundwater-flow paths. MODFLOW-2000 includes algorithms for model sensitivity and calibration. These algorithms were used by Senior and Goode (2013), but this model archive does not include the files for those model calibration and sensitity simulations. However, the parameter values used for the simulations here are contained in the sensitivity (.sen) input files, and these values may not match the values in the input files associated with various flow and boundary condition modflow packages. SOFTWARE AND MODEL LAYOUT The modeling was done on a personal computer using Microsoft Windows 8.1 Enterprise 64-bit operating system with 8 Gb of ram. The modeling used the Argus ONE software (version 4.2.0w) and a graphical user interface (MFGUI version 40i_4_35) for MODFLOW developed by USGS. Argus ONE is proprietary commercial software that can be purchased from http://www.argusint.com/index.html. The USGS MODFLOW GUI can be obtained free from https://water.usgs.gov/nrp/gwsoftware/mfgui4/modflow-gui.html. The version of the GUI used for this modeling is attached in the ancillary directory as zipped file mfgui40i_4_35.zip dated 29 November 2013. MODFLOW-2000 (version 1.19.01 25 March 2010) was used to compute head and drawdown for all modeling simulations. The particle-tracking program MODPATH (version 5.0) was used to compute flow paths and delineate areas contributing recharge to pumping wells and streams. Water budget calculations were performed using ZONEBUDGET version 3.01 (Harbaugh, 1990). These programs are packaged with the MODFLOW GUI that can be obtained from the USGS web page listed above, or in the source directory. The model was constructed in units of meters and days. Geographic information in the model is in: Datum -- NAD27 Projection – NAD27 UTM N 18 Units -- Meters Origin -- (x=0,y=0) or northwest corner of row 1, col 1 xcoord= 466073.04 m, ycoord= 4451115.04 m Southeast corner of row 112, col 137 xcoord= 483760.35 m, ycoord= 4452830.30 m Grid at angle of -45 degrees (negative angle is rotation counter-clockwise (up from horizontal axis)) DIRECTORY STRUCTURE The highest-level directory structure of the original model archive is: SIR2017-5014/ ancillary/ bin/ georef/ model/ output/ source/ webrelease/ ancillary directory: Argus Modflow GUI preprocessor files and software. ArgusONE_PC_Installer.EXE = Self-extracting zip file that installs ArgusOne program. Purchase of Argus ONE software is needed to run this program. mfgui4.0i.zip = Self-extracting zip file that installs the USGS GUI for MODFLOW that is used by the Argus ONE software. This program contains MFGUI (version 4.35.0.0), MODFLOW-2000 (version 1.19.01), and ZONEBUDGET (version 3.01; Harbaugh, 1990) that were used in this modeling study. Purchase of Argus ONE software is needed to run this program. bin directory: This directory contains the compiled code that was used in the study. georef directory: This directory contains a polygon shapefile showing the active and inactive extent of the model domain. The text attribute "Active" defines the active (True) and inactive (False) areas of the model domain. model directory: This directory contains model input files. SIMULATED SCENARIOS -- PATHLINES AND CONTRIBUTING AREAS 7 model simulation folders have been archived (see table below) corresponding to simulations presented in the report. In each directory are files to run modflow-2000 and modpath. TO RUN THE ARCHIVED SIMULATIONS, DOUBLE-CLICK ON THE “.BAT” FILE IN EACH DIRECTORY TABLE Hydrologic conditions and purposes for models in simulation folders: Model Directory Names Hydrologic conditions Purpose 1990_WS 1990 Groundwater discharge delineation 2000_WS 2000 “” 2005_WS 2005 “” 2010_WS 2010 “” NoPump_WS No pumping “” 2005_Srcs 2005 Pathlines from contaminant Sources 2010_Srcs 2010 “” 2010_Srcs_3D 2010 Single pathlines from contaminant sources for 3D display This directory structure is also used in the output directory, in which each directory contains the model output associated with that simulation. The prefix 'output.' is added before the directory names in the Table above. This directory structure is also used in ancillary/PreprocessorFiles, where each directory contains the ARGUS MODFLOW-GUI file to produce the modflow and modpath files. It is recommended that the model preprocessor software and files be used to understand and use the model. source directory: MODFLOW-2000 - version of modflow used in the study MODPATH 5.0 – version of modpath/modpath plot used in the modeling Model Viewer 1.6 – version of Model Viewer used to display flow paths in 3D. webrelease directory: This directory contains 2 files for use in external model archive database systems to indicate the spatial coverage of the model. REFERENCES 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., Banta, E.R., Hill, M.C., and McDonald, M.G., 2000, MODFLOW-2000, the U.S. Geological Survey modular ground-water model --User guide to modularization concepts and the Ground-Water Flow Process: U.S. Geological Survey Open-File Report 00-92, 121 p. Hsieh, P.A., and Winston, R.B., 2002, User’s Guide To Model Viewer, A Program For Three-Dimensional Visualization of Ground-water Model Results: U.S. Geological Survey Open-File Report 02-106, 18 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 finite-difference ground-water flow model: U.S. Geological Survey Open-File Report 94-464, 234 p. Senior, L.A., and Goode, D.J., 2013, Investigations of groundwater system and simulation of regional groundwater flow for North Penn Area 7 Superfund site, Montgomery County, Pennsylvania: U.S. Geological Survey Scientific Investigations Report 2013–5045, 95 p., available only at https://pubs.usgs.gov/sir/2013/5045/. Winston, R.B., 2000, Graphical User Interface for MODFLOW, Version 4: U.S. Geological Survey Open-File Report 00-315, 27 p. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.