Publication Professional Paper 1770 Paschke, S.S. (editor), 2011, Groundwater availability of the Denver Basin Aquifer System: U.S. Geological Survey Professional Paper 1770, Chapters A-C, 274 p. https://pubs.er.usgs.gov/publication/pp1770 Data release Banta, E.R., Paschke, S.S., and Litke, D.W., 2017, MODFLOW2000 model used to simulate the groundwater flow of the Denver Basin Aquifer system, Colorado.: U.S. Geological Survey data release https://doi.org/10.5066/F77W69PQ MODEL ARCHIVE ------------- Archive originally created: September 15, 2010 by Suzanne Paschke and Edward Banta Archive modified: August 31 2011 by K.R. Watts Archive restructured for release on Water Node: May 2017 by M.K.Watt PP2011-1770/ Description: ----------- The purpose of this data release is to document the model archive for Professional Paper 1770 which describes the groundwater availability in the Denver Basin aquifer system. A basin-scale evaluation of groundwater resources in the Denver Basin aquifer system is provided that advances the understanding of system response to development. Specific objectives of this Denver Basin groundwater availability analysis were to: (1) Advance the understanding of the three-dimensional nature of the hydrogeologic framework including the extent and thickness of aquifers and confining units; (2) Advance the understanding of regional groundwater budgets and components including recharge, discharge, and aquifer storage for the entire system and separately for the bedrock and alluvial aquifers; (3) Evaluate recent and future system response to development at a scale relevant to basinwide water-management decisions; and (4) Explore the use of modeling to evaluate hydrologic monitoring of system changes. Professional Paper 1770 consists of three chapters describing groundwater availability in the Denver Basin. Chapter A presents the introduction, previous work, study methods, and a conceptualmodel of the hydrogeologic setting including the hydro- geologic framework and pre-development groundwater availability. Chapter B describes the land and groundwater-use changes in response to population growth and the effects of that development on groundwater availability. Chapter B also presents predictions of future hypothetical conditions and a discussion of monitoring data needs. The changes in land and groundwater use are used as input to the groundwater flow model as described in Chapter C, and the interpretations of the effects of development on the groundwater flow system are based largely on modeling results from this study. Effects included in the discussion are changes to recharge and discharge components of the groundwater budget (recharge, evapo-transpiration,pumping, groundwater/surface-water interaction, interaquifer flow, and storage), and the effects of those changes on groundwater levels and flow directions from 1880 through 2003. Chapter C presents details of the groundwater flow model used for the groundwater availability analysis including model setup, calibration results, parameter sensitivity, and future work. The underlying directories contain all of the input and output files for the simulations described in PP2011-1770, the MODFLOW and ZONE- BUDGET source codes, pre- and post-processing scripts, and supporting data files. Descriptions of the data in each subdirectory are given to facilitate understanding of this model archive. Files descriptions are provided for select files to provide additional information that may be of use for understanding this model archive. MODFLOW-2000 (Harbaugh and others, 2000; Hill and others, 2000) version '1.17.02 02/12/2007' with modifications documented in McAda and Barroll (2002) and Banta (2006) was used to simulate the Denver Basin aquifer system. The summarized modifications are as follows: 1. The Layer Property Flow (LPF) Package was modified to eliminate the vertical flow correction (McAda and Barroll, 2002). 2. The Recharge (RCH) Package was modified to allow recharge to apply to the uppermost active cell connected by active cells to the lowermost active cell in a stack of cells (Banta, 2006). 3. The Evapotranspiration Segments (ETS) Package (Banta, 2000) was modified to allow evapotranspiration to apply to the uppermost active cell connected by active cells to the lowermost active cell in a stack of cells (Banta, 2006). 4. The GMG solver was modified to support a new adaptive-damping option (Banta, 2006). Support is provided for correcting errors in the data release and clarification of the modeling conducted by the U.S. Geological Survey. Users are encouraged to review the model documentation report (https://pubs.er.usgs.gov/publication/pp1770) to understand the purpose, construction, and limitations of this model. Reconstructing the model archive from the online data release: ------------------------------------------------------------- The model archive is available as a data release from: https://doi.org/10.5066/F77W69PQ The models will run successfully only if the directory structure is correctly restored. The model archive is broken into several pieces to reduce the likelihood of download timeouts. Small files (readme.txt and modelgeoref.txt) are available as uncompressed files. All other files are zipped at the subdirectory level. For example, the files in the "georef" subdirectory are zipped into a zip file named "georef.zip". All zip files should be unzipped into a directory with the same name as the zip file name without the .zip extension. The highest-level directory structure of the original model archive is: PP2011-1770/ ancillary/ bin/ georef/ model/ output/ source/ The full directory structure of the model archive and the files within each subdirectory are listed below. Running the model(s): -------------------- Three simulations are included in this archive. SIMULATIONS DESCRIPTION OF SIMULATION TIME PERIOD SIMULATED TR_calibration Transient calibration 1880-2003 50yr_predict_base Transient conditions using 1880-2053 2003 recharge and pumping for simulation period 2004-2053 50yr_predict_reducepump Transient conditions using 1880-2053 the 2003 recharge and reduced pumping from the Lower Arapahoe aquifer in the South Denver metropolitan area for simulation period 2004-2053 To run a particular simulation, open a command line/terminal in the model directory of interest: model\TR_Calibration or model\50yr_predict_base or model\50yr_predict_reducepump Copy the MODFLOW-2000 executable file (mf2k-db-pcgn.exe) from the \bin directory to the model simulation directory When MODFLOW-2000 is executed, a single prompt is issued for the name file that specifies the input files to be used in the simulation, as well as,the output files that are created. Responding to this prompt with the name file listed below will initiate the corresponding simulation. Simulation Name file ---------- --------- TR_Calibration mod16_ssfix_wel2.nam 50yr_predict_base predict_base.nam 50yr_predict_reducepump pefict_redpump.nam Running batch files ------------------- A series of MS-DOS batch files also were created to run the Denver Basin model and auxiliary programs. The batch files and auxiliary programs are located in the model simulation subdirectory, as well as, in the /bin directory and are described below. run_tr.bat--Batch file that makes a forward model run of the base model. Copy dry.exe, gageinterp.exe, and j_osom.exe from the \bin directory. Execute run_tr.bat. run_predict.bat--Batch file that makes a forward model run of the 50yr_predict_base model. Copy dry.exe from the \bin directory. Execute run_predict.bat. run_predict_redpump.bat--Batch file that makes a forward model run of the 50yr_predict_reducepump model. Copy dry.exe from the \bin directory. Execute run_predict_redpump.bat. Run Zonebudget -------------- The ZONEBUDGET post-processing files for this model archive data release are in the ancillary directory. Each simulation has a subdirectory that contains the input and output files used to run ZONEBUDGET. These files are expalined in full detail below. ZONEBUDGET can be run by opening a command line/terminal in the model directory of interest and typing: ../../bin/Zonebud_cfs.exe for cubic feet per second ../../bin/Zonebud_dp.exe for double precision Files: ----- readme.txt : This file documents the structure, directories and files, and instructions on how to run the model of the data release. modelgeoref.txt : ASCII file with the four corners of the model domain in decimal degrees. ancillary/ Description: ----------- This directory contains ancillary data including ASCII model arrays of model input and output that were generated with the auxillary programs within the Macros_and_shell_programs subdirectory. Subdirectories of climate data, pumpage data, and an ArgusOne_Modflow GUI are included. Zonebudget post-processing input and output is included as well as .pdf files of the published report documenting the model and the work completed on the Denver Basin. Files: ----- modelgeoref.xlsx--This is an excel spreadsheet with the four corners of the model domain listed in northing and easting (feet and meters),latitude and longitude, and decimal degrees in NAD83. /ArgusONE-ModflowGUI - Description ----------- This directory contains an ArgusOneGui file. /ASCII_ModelArrays Description ----------- This directory contains input and output subdirectories of model arrays used in the MODFLOW models. /Input Description ----------- Subdirectory of ASCII files generated using the utilities DIS2RASTER and MULT2RASTER (Banta and others, 2008) Files ----- BOTM_000#.asc -- where L= layer number. # = 0 is the simulated land surface altitude or top of model, and # = 1-12 are the simulated bottom altitude of the layer #. MULT_IPY2FPD.asc -- Multiplier array to convert inches per year input to model units of feet per day MULT_k_aq_06.asc -- Multiplier array of hydraulic conductivity distribution for entire thickness of the Denver aquifer (L6), in ft/day. Equals K_sd_tkd*tkd_sdpct. MULT_k_aq_08.asc -- Multiplier array of hydraulic conductivity distribution for entire thickness of the Upper Arapahoe aquifer (L8), in ft/day. Equals K_sd_uka*uka_sdpct. MULT_k_aq_10.asc -- Multiplier array of hydraulic conductivity distribution for entire thickness of the Arapahoe aquifer (L10), in ft/day. Equals K_sd_lka*lka_sdpct. MULT_k_aq_12.asc -- Multiplier array of hydraulic conductivity distribution for entire thickness of the Laramie-Fox Hills aquifer (L12), in ft/day. Equals K_sd_klf*klf_sdpct. MULT_k_sd_klf.asc --Multiplier array of hydraulic conductivity distribution for the silt-plus-sand portion of the Laramie-Fox Hills aquifer, in ft/day MULT_k_sd_lka.asc -- Multiplier array of hydraulic conductivity distribution for the silt-plus-sand portion of the lower Arapahoe aquifer, in ft/day MULT_k_sd_tkd.asc -- Multiplier array of hydraulic conductivity distribution for the silt-plus-sand portion of the Denver aquifer, in ft/day MULT_k_sd_uka.asc -- Multiplier array of hydraulic conductivity distribution for the silt-plus-sand portion of the upper Arapahoe aquifer, in ft/day MULT_KLF_SDPCT.asc -- Multiplier array of percent silt- plus-sand for the Laramie-Fox Hills aquifer MULT_LKA_SDPCT.asc -- Multiplier array of percent silt- plus-sand for the lower Arapahoe aquifer MULT_LTDW_SDPCT.asc -- Multiplier array of percent silt- plus-sand for the lower Dawson aquifer MULT_P_YYYY_YY.asc -- Multiplier array of average precipitation distribution, (Years), in inches per year MULT_PPT_AVG.asc -- Multiplier array of long-term average precipitation distribution, in inches per year MULT_TKD_SDPCT.asc -- Multiplier array of percent silt-plus- sand for the Denver aquifer MULT_UKA_SDPCT.asc -- Multiplier array of percent silt-plus- sand for the upper Arapahoe aquifer MULT_UTDW_SDPCT.asc -- Multiplier array of percent silt-plus- sand for the upper Dawson aquifer /Output Description ----------- Subdirectory of ASCII files generated using the utilities MFBIN2RASTER (Banta and others, 2008). Output arrays are in subdirectories under the simulation name. Only the TR_calibration simulation contains all of the file types. The output for the scenario simulations only includes head and drawdown arrays. Files ----- DD_L00#_SP0##_TS005.asc -- Drawdown, in ft, where L= layer number, SP = stress period number, and TS = time step. Included in all 3 simulations directories. ETS_SP00#_TS00#.asc -- ETS rate, in ft/d, from uppermost layer where SP= stress period, TS = time step HD_L00#_SP00#_TS00#.asc -- Head elevation, in ft, where L= layer number, and SP = stress period number, TS = time step. Included in all 3 simulations directories. RCH_SP00#_TS00#.asc -- Recharge rate, in ft/d, for uppermost layer where SP= stress period, TS = time step SFR_SP00#_TS00#.asc -- Streamflow routing flux, in ft3/d where SP= stress period, TS = time step. WEL_SP00#_TS00#_L0##.asc -- Well pkg flux, in ft3/d, where SP= stress period, TS = time step, and L= layer number. /Climate_data - Description ----------- This directory contains files used for the precipitation recharge /Macros_and_shell_programs - Description ----------- This directory contains macros and other programs for model development and post-processing. Files ----- fac2r.bat - ASCII MS-DOS batch file to generate 2-D arrays of HK values for model layers 2, 4, 6, 8, 10, and 12 (calls fac2real) model.bat - ASCII MS-DOS batch file to interpolate K values at pilot points and run the transient model (calls fac2r.bat and run_tr.bat) run_predict.bat - ASCII MS-DOS batch file to run the base prediction model. (calls dry auxillary program) run_predict_redpump.bat - ASCII MS-DOS batch file to run the reduced pumping prediction model. (calls dry auxillary program) run_tr.bat - ASCII MS-DOS batch file to run the transient calibrated model (calls dry, gageinterp, and j_osom auxillary programs) modeldata.txt - ASCII file containing model coordinates /Pumping_database Description ----------- This directory contains files used for pumping estimates. /Report Description ----------- This directory contains Adobe .pdf files of Chapters A, B, and C of Professional Paper 1770, including tables and figures. Approval memos and an excel spreadsheet for the appendix also are included. /Zonebudget_post_processing Description ----------- This directory contains files used for Zonebudget and GWCHART water-budget analysis. Zonebudget input and output are in subdirectories under the simulation name. For each simulation, Zonebudget was run for the 4 different zone analysis: Subdirectory name Zones Zone description File prefix ----------------------------------------------------------------------- 3Zones_SouthMetro 3 zones Zone 1 = Alluvial aquifer, 3zone_smetro Zone 2 = all other bedrock, Zone 3 = south metro area. All_layers 12 zones One zone for each hydro- all_layers stratigraphic unit in model. One_zone entire one_zone model Two_zones_AL1_BR2 2 zones Zone 1 = Alluvial aquifer, al1_br2 Zone 2 = All Bedrock units combined. Files ----- zonbud-dp.exe - Zonebudget v3 double-precision executable zonbud_cfs.exe - Zonebudget version converts units to cfs .dis - DIS file for GWCHART to convert zonebud files .bud - MODFLOW binary budget file (double precision) .zblst - Zonebudget output file in cubic ft/day _cfd.zbz - Zonebudget input file for cubic ft/day calculation _cfd_gwchart.txt - GWCHART output file in cubic ft/day and cumulative budget _cfs.zblst - Zonebudget output file in cubic ft/second _cfs.zbz - Zonebudget input file for cubic ft/second calculation _cfs_gwchart.txt - GWCHART output file in cubic ft/second for plotting rates bin/ Description: ----------- This directory contains the modified MODFLOW2000 64-bit executable used to do the analysis documented in the report https://pubs.er.usgs.gov/publication/pp1770, as well as, auxillary programs for post-processing. MODFLOW-2000 (Harbaugh and others, 2000; Hill and others, 2000)version '1.17.02 02/12/2007' with modifications documented in McAda and Barroll (2002) and Banta (2006) was used to simulate the Denver Basin aquifer system. The summarized modifications are as follows: 1. The Layer Property Flow (LPF) Package was modified to eliminate the vertical flow correction (McAda and Barroll, 2002). 2. The Recharge (RCH) Package was modified to allow recharge to apply to the uppermost active cell connected by active cells to the lowermost active cell in a stack of cells (Banta, 2006). 3. The Evapotranspiration Segments (ETS) Package (Banta, 2000) was modified to allow evapotranspiration to apply to the uppermost active cell connected by active cells to the lowermost active cell in a stack of cells (Banta, 2006). 4. The GMG solver was modified to support a new adaptive-damping option (Banta, 2006). Files: ----- cbc2raster_dp.exe - auxillary program to read budget data from unformatted MODFLOW output files and prepares text files for ArcGIS import. dis2raster.exe - auxillary program to read MODFLOW2000 .dis file and prepares file of datasets to be read into Arc GIS dry.exe - auxillary program to count the number of dry cells FAC2REAL.EXE - auxillary program to generate 2-D arrays of HK values by interpolating from pilot point values gageinterp.exe - auxillary program to output simulated gage values to ASCII files j_osom.exe - auxillary program to count number of missing observation caused by dry cells mf2k-db-pcgn.exe – MODFLOW-2000 executable used for Denver Basin model calibration Mf2k-db.exe – current version of MODFLOW-2000 executable mfbin2raster_dp.exe - Program MFBIN2RASTER double precision executable file writewell.exe - auxillary program to write WELL package input file from well tabulation zonbud-dp.exe - Zonebudget v3 double-precision executable zonbud_cfs.exe - Zonebudget version converts units to cfs georef/ Description: ----------- This directory contains a shapefile defining the active and inactive areas of the model documented in the report. https://pubs.er.usgs.gov/publication/pp1770 Files: ----- PP2011_1770.<#> : <#> parts (.cpg, .dbf, .prj, .sbn, .sbx, .shp, .shp.xml, and .shx) of the PP2011_1770 shapefile model/ Description: ----------- This directory contains all of the input files for the transient calibration and 2 scenario simulations documented in USGS Professional Paper 1770. https://pubs.er.usgs.gov/publication/pp1770 Scenarios Model subdirectory --------- ------------------ Base conditions TR_calibration 50 year prediction 50yr_predict_base 50 year prediction with reduced pumpage 50yr_predict_reducepump Files: ----- None externalfiles/ Description: ----------- This directory contains the shared or common files used to run the simulations documented in the report https://pubs.er.usgs.gov/publication/pp1770 Files: ----- db_weldona.fhb - FHB pkg input defines FHB cells at downstream end of South Platte QAL K_sd_klf.txt - Hydraulic-conductivity array for silt-plus-sand fraction of layer 12 K_sd_lka.txt - Hydraulic-conductivity array for silt-plus-sand fraction of layer 10 K_sd_tkd.txt - Hydraulic-conductivity array for silt-plus-sand fraction of layer 6 K_sd_uka.txt - Hydraulic-conductivity array for silt-plus-sand fraction of layer 8 mod16.gag - GAG pkg input defines Gage numbers mod16_a.gmg - GMG pkg input defines solver settings mod16_endheads.bhd -Binary head file for end of calibration period. Used as starting heads for predictions mod16pest.mul - MULT pkg input defines multiplier arrays mod16pest.zon- ZON pkg input defines active model zones for each layer mod16pest_ssfix.lpf - LPG pkg input mod16pest_ssfix.sen – SEN pkg input new300.txt - Land-surface altitude array, in feet new301.txt - Base altitude array for layer 1, in feet new302.txt - Base altitude array for layer 2, in feet new303.txt - Base altitude array for layer 3, in feet new304.txt - Base altitude array for layer 4, in feet new305.txt - Base altitude array for layer 5, in feet new306.txt - Base altitude array for layer 6, in feet new307.txt - Base altitude array for layer 7, in feet new308.txt - Base altitude array for layer 8, in feet new309.txt - Base altitude array for layer 9, in feet new310.txt - Base altitude array for layer 10, in feet new311.txt - Base altitude array for layer 11, in feet new312.txt - Base altitude array for layer 12, in feet predict_base.bas - BAS pkg input for the scenarios predict_base.dis - DIS pkg input for the scenarios predict_base.drn - DRN pkg input for the scenarios predict_base.ets - ETS pkg input for the scenarios predict_base.ghb - GHB pkg input for the scenarios predict_base.mnw - MNW pkg input for the scenarios predict_base.oc - OC pkg input for the scenarios TR_calibration/ Description: ----------- This directory contains the MODFLOW2000 name file and all of the unique input files used to run the transient calibration documented in the report. https://pubs.er.usgs.gov/publication/pp1770 Files: ----- db.mnw - MNW (Multi-Node Well) pkg input db.odr - Drain observations for historical flowing wells and springs db_new2.wel - WEL pkg input defines pumping history for calibration period fac2r_##.rsp - Interpolation factor file for layer # hydraulic conductivity gage##.flows - Flow observations for Gage # HeadObsTransient_wAlternatives.hob- Transient head observations interp_fac0#.txt - Hydraulic-conductivity array for layer # lsfixedsfr3tr.dis - DIS pkg input mod16.obs - OBS input defines output files for obs mod16_AgIrr_all.rch - RCH pkg input mod16_coop_new.ets - ETS pkg input mod16_spheads_tsflux.oc - OC pkg input mod16m.bas - BAS pkg input mod16m.drn - DRN pkg input mod16m.ghb - GHB pkg input defines GHB cells at downstream end of Black Squirrel Creek and Nussbaum Alluvium mod16m.riv - RIV pkg input mod16m.sfr - SFR pkg input mod16trosom._om - josom.exe output- listing of missing observations usgs.model.reference : temporal and spatial reference for the model 50yr_predict_base/ Description: ----------- This directory contains the MODFLOW2000 file and all of the input files used to run the scenario 1 predictive simulation documented in the report. https://pubs.er.usgs.gov/publication/pp1770 Files: ----- predict_base.nam - MODFLOW name file that contains input and output files for this simulation predict_base.wel - WEL pkg input predict_stress_period.txt - time discretization for predictive simulations run_predict.bat - Batch file to run scenario 1 prediction using MODFLOW2000 usgs.model.reference : temporal and spatial reference for the model 50yr_predict_reducepump/ Description: ----------- This directory contains the MODFLOW2000 file and all of the input files used to run the scenario 2 predictive simulation documented in the report. https://pubs.er.usgs.gov/publication/pp1770 Files: ----- predict_redpump.nam - MODFLOW name file that contains input and output files for this simulation predict_redpump2.wel - WEL pkg input predict_stress_period.txt - time discretization for predictive simulations run_predict_redpump.bat - Batch file to run the scenario 2 prediction using MODFLOW2000 usgs.model.reference : temporal and spatial reference for the model output/ Description: ----------- This directory contains the output files from the MODFLOW-2000 ground-water flow model documented in USGS Professional Paper 1770. https://pubs.er.usgs.gov/publication/pp1770 Files: ----- None output.TR_calibration/ Description: ----------- This directory contains all of the output files for the transient calibration model simulation documented in the report. https://pubs.er.usgs.gov/publication/pp1770 Files: ----- db_mnw.bynode- mnw output files db_mnw.qsum - mnw output files mod16_ssfix_wel2.bdn - Binary drawdown output mod16_ssfix_wel2.bhd - Binary head output mod16_ssfix_wel2.bsf2 - ASCII SFR output mod16_ssfix_wel2.bud - Binary water budget output mod16_ssfix_wel2.lst - ASCII MODFLOW LST file mod16_tsfluxhc.csv - Excel spreadsheet of maximum head change per stress period mod16mf2k._nm - Weighted residuals and probability plotting positions mod16mf2k._os - Unweighted simulated equivalents and unweighted observations mod16mf2k._r - Unweighted residuals mod16mf2k._w - Weighted residuals mod16mf2k._ws - Weighted simulated equivalents and weighted residuals mod16mf2k._ww - Weighted simulated equivalents and weighted observations mod16mf2k.gage## - Simulated flows for Gage ## output.predict_base/ Description: ----------- This directory contains all of the output files for the scenario 1 predictive simulation documented in the report https://pubs.er.usgs.gov/publication/pp1770 Files: ----- db_mnw.bynode- mnw output files db_mnw.qsum - mnw output files mod16mf2k.gage## - Simulated flows for Gage ## pred_base_out.bdn - Binary drawdown output pred_base_out.bhd - Binary head output pred_base_out.bsf2 - ASCII SFR output pred_base_out.bud - Binary water budget output pred_base.lst - ASCII MODFLOW LST file pred_base_out_mhc.csv - Excel spreadsheet of maximum head change per stress period output.predict_reducepump/ Description: ----------- This directory contains all of the output files for the scenario 2 predictive simulation documented in the report https://pubs.er.usgs.gov/publication/pp1770 Files: ----- db_mnw.bynode- mnw output files db_mnw.qsum - mnw output files mod16mf2k.gage## - Simulated flows for Gage ## pred_redpump_out.bdn - Binary drawdown output pred_redpump_out.bhd - Binary head output mod16.bsf2 - ASCII SFR output pred_redpump_out.bud - Binary water budget output pred_redpump.lst - ASCII MODFLOW LST file mod16_mhc.csv - Excel spreadsheet of maximum head change per stress period source/ Description: ----------- This directory contains the Fortran source code for MODFLOW-2000 and the support programs used with MODFLOW-2000: CBC2RASTER, DIS2RASTER, Dry, fac2real,gageinterp, j_osom, MFBIN2RASTER, MULT2RASTER, zonbud_cfs. The version of MODFLOW-2000 in this archive is derived from MODFLOW-2000 version '1.17.02 02/12/2007' and incorporates the following modifications: 1. Version "X" of LPF1, which eliminates the vertical flow correction 2. RCH supports NRCHOP=4 3. EVT supports NEVTOP=4 4. ETS supports NETSOP=4 5. PCGN solver by Naff, ver. 0.1, 11/16/2006 Files: ----- source_code_readme.txt - file that describes the version of MODFLOW used to run the simulations documented in the report https://pubs.er.usgs.gov/publication/pp1770 Directories ----------- CBC2RASTER - Source code for the program that converts cell-by-cell binary file into ASCII files for raster display in ARCGIS DIS2RASTER - Source code for the program that converts discretization file arrays into ASCII files for raster display in ARCGIS Documentation - Pdf files documenting the new damping capabilities of the GMG solver and documentation of MODFLOW modifications. Dry - Source code for the program that counts number of dry cells in model fac2real - Source code for the program that generate hydraulic conductivity arrays for model gageinterp - Source code for the program that outputs simulated gage values to ASCIIfiles j_osom - Source code for the program that counts number of missing observation caused by dry cells MFBIN2RASTER - Source code for the program that converts binary head file into ASCII files for raster display in ARCGIS MODFLOW2000 - Source code for the version of MODFLOW used to run the simulations documented in the report https://pubs.er.usgs.gov/publication/pp1770 MULT2RASTER - Source code for the program that converts multiplier file arrays into ASCII files for raster display in ARCGIS Write_wellfile - Source code for the program that writes WELL pkg input file from well tabulation zonbud_cfs - Source code for the program that Converts from model units of ft/day to cubic ft/second . ---------- REFERENCES ---------- Banta, E.R., 2006, Modifications to MODFLOW boundary conditions and an adaptive-damping scheme for Picard iterations for a highly nonlinear regional model, in Poeter, Eileen, Hill, Mary, and Zheng, Chunmiao, eds., MODFLOW and more,2006-Managing ground-water systems: International Groundwater Modeling Center and Colorado School of Mines, 2006 [Proceedings, Golden, Colo.], p. 596-600. Banta, E.R., Paschke, S.S., and Litke, D.W., 2008, User guide and documentation for five MODFLOW ground-water modeling utility programs: U.S. Geological Survey Techniques and Methods 6-A28, 24 p. Banta, E.R., Paschke, S.S., and Litke, D.W.., 2009, Groundwater flow simulation of the Denver Basin aquifer system, Chapter C: U.S. Geological Survey Professional Paper 1770-C,94 p. Paschke, S.S., Banta, E.R., and Litke, D.W., 2010, Effects of development on groundwater availability of the Denver Basin aquifer system, Colorado, Chapter B: U.S. Geological Survey Professional Paper 1770-B, 87 p. Paschke, S.S., Banta, E.R., Webbers, Ank, and Capesius, J.P., 2010, Introduction, conceptual model, hydrogeologic framework, and predevelopment groundwater availability of the Denver Basin aquifer system, Colorado, Chapter A: U.S. Geological Survey Professional Paper 1770-A, 93 p.