S. Jerrod Smith John H. Ellis Nicole C. Paizis Carol J. Becker Derrick L. Wagner Jessica S. Correll R. Jacob Hernandez 2021 Groundwater model Reston, Virginia U.S. Geological Survey https://doi.org/10.5066/P927IAO1 S. Jerrod Smith John H. Ellis Nicole C. Paizis Carol J. Becker Derrick L. Wagner Jessica S. Correll R. Jacob Hernandez 2021 Publication Scientific Investigations Report 2021-5003 Reston, Virginia U.S. Geological Survey https://doi.org/10.3133/sir20215003 The U.S. Geological Survey, in cooperation with the Oklahoma Water Resources Board, constructed a finite-difference numerical groundwater-flow model of the Salt Fork Red River aquifer using MODFLOW with the Newton formulation solver (MODFLOW-NWT). The 1973 Oklahoma Water Law requires the Oklahoma Water Resources Board to conduct hydrologic investigations of the State’s aquifers to support a determination of the maximum annual yield (MAY) for each groundwater basin. The MAY is defined as the amount of fresh groundwater that can be withdrawn annually while ensuring a minimum 20-year life of the groundwater basin. For alluvium and terrace aquifers, the groundwater-basin-life requirement is satisfied if, after 20 years of MAY withdrawals, 50 percent of the groundwater basin retains a saturated thickness of at least 5 ft. When a MAY has been established, the amount of land owned or leased by a permit applicant determines the annual volume of water allocated to that permit applicant. The annual volume of water allocated per acre of land is known as the equal-proportionate-share (EPS) pumping rate. Because the MAY and EPS have not yet been established for the Salt Fork Red River aquifer, the U.S. Geological Survey, in cooperation with the Oklahoma Water Resources Board, conducted a hydrologic investigation and developed a calibrated numerical groundwater-flow model to evaluate the effects of potential groundwater withdrawals on groundwater availability in the Salt Fork Red River aquifer. The results of groundwater-availability scenarios run on the calibrated numerical groundwater-flow model could be used by the Oklahoma Water Resources Board to evaluate the maximum annual yield of groundwater from the Salt Fork Red River aquifer in Oklahoma. The numerical model was temporally discretized into 1 initial steady-state stress period representing average conditions during 1980-2015 and 432 monthly transient stress periods representing the period 1980-2015. This U.S. Geological Survey data release contains all of the input and output files for the simulations described in the associated model documentation report (https://doi.org/10.3133/sir20215003). This model was developed to (1) estimate the EPS pumping rate that ensures a minimum 20-, 40-, and 50-year life of the aquifer, (2) quantify the potential effects of projected well withdrawals on groundwater storage over a 50-year period, and (3) simulate the potential effects of a hypothetical (10-year) drought on groundwater storage. The results of these groundwater-availability scenarios could be used by the Oklahoma Water Resources Board to evaluate the maximum annual yield of groundwater from the Salt Fork Red River aquifer in Oklahoma. The development of the model input and output files included in this data release are documented in the U.S. Geological Survey Scientific Investigations Report 2021-5003 (https://doi.org/10.3133/sir20215003). 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://doi.org/10.3133/sir20215003) to understand the purpose, construction, and limitations of this model. The model will run successfully only if the original directory structure is correctly restored. The model archive is broken into several pieces to reduce the likelihood of download timeouts. Instructions for reconstructing the original directory structure and running the models included in this data release and described in the model documentation report can be found in the readme.txt ASCII file which can be downloaded as part of this data release. 19800101 20151231 publication date Complete Not planned -100.021833 -99.241149 34.960013 34.364727 USGS Thesaurus usgsgroundwatermodel MODFLOW-NWT MODFLOW Soil Water Balance Groundwater Groundwater Model Groundwater and surface-water interaction inlandWaters ISO 19115 Topic Category geoscientificInformation inlandWaters environment USGS Metadata Identifier USGS:84f8ee0d-8500-4dc2-8d80-6dee27c9092a Geographic Names Information System (GNIS) Salt Fork Red River Oklahoma Harmon County Greer County Jackson County None. Acknowledgement of the U.S. Geological Survey would be appreciated in products derived from this data release. Unless otherwise stated, all data, metadata 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 metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), 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. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Although these data have been processed successfully on a computer system at the U.S. Geological Survey (USGS), 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 USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. S. Jerrod Smith U.S. Geological Survey Oklahoma Water Science Center mailing and physical

202 NW 66th Street

Oklahoma City OK 73116 USA 405-810-4400 sjsmith@usgs.gov https://water.usgs.gov/GIS/browse/sir2021-5003Thumbnail.jpg Image showing the model domain with active and inactive areas of the numerical groundwater-flow model for the Salt Fork Red River aquifer in southwestern Oklahoma jpg The collection and analysis of these data were funded by the Oklahoma Water Resources Board. Environment as of Metadata Creation: Microsoft Windows 10.0 (Build 17763); Esri ArcGIS 10.7.0 (Build 11595) The numerical groundwater-flow model was calibrated to water-table-altitude observations at selected wells and monthly mean base-flow observations at selected streamgages. Only 302 water-table altitude observations from 63 wells were used as calibration targets for the transient simulation, most of which were measured during 1986-88 or during 2014-16. Water-table-altitude observations from March 2016, which fell outside of the model period (1980-2015), were assigned to December 31, 2015, so they could be used as model calibration targets. Water-table-altitude observations were averaged by well to derive calibration targets for the steady-state simulation because no observations were available at the beginning of the numerical model period (1980). The monthly mean base flow observations (864) at U.S. Geological Survey streamgages 07300500 Salt Fork Red River at Mangum, Okla., and 07301110 Salt Fork Red River near Elmer, Okla., were used as calibration targets for the transient simulation. The mean annual base flows for the two streamgages were used as calibration targets for the steady-state simulation. Base-flow observations from other selected streamgages weren’t used as calibration targets because they (1) were previously used to define inflows for the Streamflow-Routing package or (2) had periods of record that were too short to be representative of streamflow conditions during the study period The calibration process for the numerical model included both manual adjustment and automated adjustment of parameters. The manual calibration was primarily focused on aligning the numerical-model water budget, especially the recharge and streambed seepage components, to the conceptual-model water budget. The automated calibration approach focused solely on minimizing residuals and used the PEST++ Iterative Ensemble Smoother to reduce run times associated with the calibration of highly parameterized models. No formal logical accuracy tests were conducted Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the metadata record and the associated model documentation report for this data release (https://doi.org/10.3133/sir20215003) for additional details. No formal positional accuracy tests were conducted No formal positional accuracy tests were conducted The process used to develop, calibrate, and apply the groundwater flow model is fully described in the model documentation report (https://doi.org/10.3133/sir20215003) 2020 Raster Pixel Albers Conical Equal Area 29.5 45.5 -96.0 23.0 0.0 0.0 row and column 200 200 international feet North American Datum of 1983 Geodetic Reference System 80 (GRS 80) 6378137 298.257 North American Vertical Datum of 1988 1.0 feet Attribute values sir2021_5003.shp ESRI Polygon shapefile U.S. Geological Survey Area Text string indicating whether the model cell is active or inactive https://doi.org/10.3133/sir20215003 usgsgroundwatermodel Delineation of active or inactive areas in the model https://doi.org/10.3133/sir20215003 Smith, S.J., Ellis, J.H., Paizis, N.C., Becker, C.J., Wagner, D.L., Correll, J.S., and Hernandez, R.J., 2021, MODFLOW-NWT model used in simulation of groundwater availability in the Salt Fork Red River aquifer, southwestern Oklahoma, 1980-2015: U.S. Geological Survey data release https://doi.org/10.5066/P927IAO1 U.S. Geological Survey Michael Ierardi IT Specialist mailing and physical

445 National Center

Reston Virginia 20192 USA 1-888-275-8747 (1-888-ASK-USGS) mierardi@usgs.gov The data have been approved for release by the U.S. Geological Survey (USGS). Although the data have been subjected to rigorous review and are substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, the data are released on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from authorized or unauthorized use. Although the data, software, and related material have been processed successfully on a computer system at the USGS, 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 USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. readme.txt 1.0 ASCII text file This ASCII text file describes the model data release. This file also includes instructions on how to run the models contained in this data release. 0.048 https://water.usgs.gov/GIS/dsdl/gwmodels/SIR2021-5003/readme.txt modelgeoref.txt 1.0 ASCII text file This ASCII text file defines the four corners of the model domain in decimal degrees. Model data files are in a custom Albers Equal-Area projection with units of feet. Latitude and longitude coordinates are provided. 0.004 https://water.usgs.gov/GIS/dsdl/gwmodels/SIR2021-5003/modelgeoref.txt ancillary1.zip 1.0 ZIP This ZIP file contains ancillary data files that may aid in the interpretation of model results. The ancillary1 data files include final PEST files used to calibrate the final model and calculate observation sensitivities, and a Python script (CalculateStorage.py) with initialization (.ini) files to calculate storage. 97.2 https://water.usgs.gov/GIS/dsdl/gwmodels/SIR2021-5003/ancillary1.zip ancillary2.zip 1.0 ZIP This ZIP file contains ancillary data files that may aid in the interpretation of model results. The ancillary2 data files include inputs and outputs for the Soil-Water-Balance code. 2380 https://water.usgs.gov/GIS/dsdl/gwmodels/SIR2021-5003/ancillary2.zip bin.zip 1.0 ZIP This ZIP file contains the compiled executable codes used to run all simulation scenarios documented in the report. The compiled executable codes include MODFLOW-NWT 1.1.4, PEST 13, PEST++_IES 4.3.11, SWB 1.0.1, and Zonebudget 3.01. 10.0 https://water.usgs.gov/GIS/dsdl/gwmodels/SIR2021-5003/bin.zip georef.zip 1.0 ZIP This ZIP file contains a polygon shapefile showing the active and inactive areas of the Salt Fork Red River aquifer model domain. 0.100 https://water.usgs.gov/GIS/dsdl/gwmodels/SIR2021-5003/georef.zip model.zip 1.0 ZIP This ZIP file contains all of the model input files specific to each scenario (e.g. projected use, drought, final model, eps) and common files used by all models (externalfiles). Detailed information about these scenarios is provided in the model report. 976 https://water.usgs.gov/GIS/dsdl/gwmodels/SIR2021-5003/model.zip output.zip 1.0 ZIP This ZIP file contains all of the model output files specific to each scenario (e.g. projected use, drought, final model, eps). 970 https://water.usgs.gov/GIS/dsdl/gwmodels/SIR2021-5003/output.zip source.zip 1.0 ZIP This ZIP file contains standard model source codes and associated files for MODFLOW-NWT 1.1.4, PEST 13, PEST++_IES 4.3.11, SWB 1.0.1, and Zonebudget 3.01. 385 https://water.usgs.gov/GIS/dsdl/gwmodels/SIR2021-5003/source.zip None 20210322 U.S. Geological Survey Michael Ierardi IT Specialist mailing

445 National Center

Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) mierardi@usgs.gov FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998