A groundwater-flow model was used to simulate zones of contribution to wells south of Naval Weapons Industrial Reserve Plant, Bethpage, New York. The model results will be used to demonstrate how the size and shape of zones of contribution may vary.

A three-dimensional groundwater flow model was developed to simulate the effects of withdrawals on the groundwater-flow systems of five aquifers in and around Ocean County, New Jersey—the unconfined Kirkwood-Cohansey aquifer system and Vincentown aquifer, and three confined aquifers--the Rio Grande water-bearing zone, the Atlantic City 800-foot sand, and the Piney Point aquifer. A transient model was used to simulate conditions that represent no groundwater withdrawals, 2000–2003 groundwater withdrawals, and maximum-allocation groundwater withdrawals. Particle-tracking analysis, using results from two steady-state simulations, determine flow paths and travel times to near-shore wells screened in the unconfined Kirkwood-Cohansey aquifer system, the Rio Grande water-bearing zone, and the Atlantic City 800-foot sand. Sources of water to wells in both unconfined and confined aquifers and travel times based on particle-tracking analysis are used to assess the susceptibility of selected wells to saltwater intrusion from bay or ocean water. This USGS 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/sir20165035).

The U.S. Geological Survey, in cooperation with the U.S. Department of the Navy, developed several 3-D groundwater flow models for used with MODFLOW-2005, MODFLOW-NWT, and SEAWAT model codes to evaluate variable-density groundwater flow and contaminant transport in Operable Unit 1 on Naval Base Kitsap in Keyport, Washington. Chlorinated volatile organic compounds (CVOCs) have migrated to groundwater beneath a former 9-acre landfill at Operable Unit 1 (OU-1). The three predominant ground-water contaminants are the chloroethene compounds trichloroethene (TCE), cis-1,2-dichloroethene (cis-DCE), and vinyl chloride (VC). A need for remedial action was identified because some of the contaminants present a potential risk to humans primarily through drinking contaminated groundwater or through ingesting seafood harvested from contaminated surface water. An ongoing effort with the U.S. Navy and U.S. Geological Survey (USGS) began in 1995 by evaluating the effectiveness of natural attenuation processes for removing and controlling the migration of CVOCs in ground water at OU-1. Additional collection of geochemical and contaminant concentration data demonstrated that biodegradation of CVOCs in shallow groundwater at OU-1 is substantial and prevents most of the mass of dissolved-phase CVOCs in groundwater beneath the landfill from discharging to surface water. However, dissolved-phase contaminant concentrations in the hundreds of milligrams per liter continue to persist in localized areas of OU-1. Data suggest that residual sources of chloroethenes in the form of non-aqueous phase liquid remain at the site, and that biodegradation is only partly effective at reducing the dissolved-phase contaminants that are generated from these sources. In 2018 an additional USGS effort was begun to simulate variable-density groundwater flow and contaminant transport in the vicinity of OU-1 using a revised hydrogeologic model of the site and a refined delineation of persistent contaminant sources. MODFLOW-2005 and MODFLOW-NWT model codes were used to calibrate a new model. Then groundwater flow and contaminant transport models were developed using SEAWAT-Version 4, a computer program based on MODFLOW and MT3DMS, to simulate three-dimensional variable-density groundwater flow coupled with multi-species solute transport. These models were used to simulate the direction and rate of groundwater flow near OU-1, estimate the CVOC mass in groundwater and the rate of mass loading, and assess possible remedial activities at OU-1. This USGS 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/sir20205066).

An existing three-dimensional model (MODFLOW-2000) by Petkewich and Campbell was modified to simulate potential changes in groundwater-level conditions caused by withdrawals from a proposed well in the Middendorf aquifer near Monocks, South Carolina. A single well was added to the existing model in the cell at row 67 and column 119 in layer 7 (the Middendorf aquifer). Two scenarios were created by modifying the Base Case simulation which is documented in the model documentation report (https://pubs.usgs.gov/sir/2009/5185/) and data release (https://doi.org/10.5066/F7JW8C1K). The proposed well was pumped at 0.5 million gallons per day for the 'proposed well 1.5 MGD' scenario and 1.5 million gallons per day for the 'proposed well 1.5 MGD' scenario. This was the only change made to the model for this data release. This data release was created at the request of Mount Pleasant Waterworks to document the effects of a proposed well. This data release contains all of the model input and out files needed to run the model simulations described above. Data tables and figures of the model output are included in the ancillary directory. The data release also includes MODFLOW-2000 source code used to run the model simulations.

An existing three-dimensional model (MODFLOW-2000) by Petkewich and Campbell was modified to simulate potential changes in groundwater-level conditions caused by withdrawals from a proposed well in the Middendorf aquifer near Monocks, South Carolina. A single well was added to the existing model in the cell at row 67 and column 119 in layer 7 (the Middendorf aquifer). Two scenarios were created by modifying the Base Case simulation which is documented in the model documentation report (https://pubs.usgs.gov/sir/2009/5185/) and data release (https://doi.org/10.5066/F7JW8C1K). The proposed well was pumped at 0.5 million gallons per day for the 'proposed well 1.5 MGD' scenario and 1.5 million gallons per day for the 'proposed well 1.5 MGD' scenario. This was the only change made to the model for this data release. This data release was created at the request of Mount Pleasant Waterworks to document the effects of a proposed well. This data release contains all of the model input and out files needed to run the model simulations described above. Data tables and figures of the model output are included in the ancillary directory. The data release also includes MODFLOW-2000 source code used to run the model simulations.

This model archive provides the necessary documentation of the numerical models developed for the Central Sands Lake study in central Wisconsin and will be included as a technical appendix (Appendix C) in the report to the Wisconsin State Legislature by the Wisconsin Department of Natural Resources (WDNR) in response to 2017 Wisconsin Act 10. This legislation directed DNR to determine whether existing and potential groundwater withdrawals are causing or are likely to cause significant reduction of mean seasonal water levels at Pleasant Lake, Long Lake, and Plainfield Lake (s. 281.34(7m)(2)(b), Wis. Stats.) in Waushara County, Wisconsin. To evaluate the potential hydrologic connection between groundwater withdrawals and the nearby study lakes, hydrologic models were created that focused on the lakes of interest and yet were large enough to cover a broad enough region to extend to the major hydrologic boundaries of the natural flow system. The areas near the lakes require finer-scale grid discretization (or spacing) to better represent the lakes and streams in the model, but also need to cover a large enough area to include the groundwater withdrawal locations that have the potential to cause reduction in water levels in the lakes. To accomplish these goals, three groundwater models were created: a regional model extending to major hydrologic boundaries; and two inset models, inheriting boundaries from the regional model but focused near the lakes. Each of the inset models, in turn, included a detailed area close to the lakes surrounded by an area at the same spatial scale as the regional model. To support WDNR in evaluating the connection between groundwater withdrawals and lake levels, a representative time period was required over which to compare land use with and without irrigated agriculture and for WDNR to evaluate potential lake stage and flux changes related to irrigated agriculture. WDNR chose the climate period of 1981-2018 to be representative of a typical period and provided two land use scenarios—one with no irrigated agriculture and one with assumed crop rotations similar to current conditions—to simulate with groundwater models to, then, compare lake responses with. As a result, simulations over this climate record are not intended to recreate the history of 1981-2018 because land use changed over that time. These runs are, instead, intended to provide a basis on which to compare land use with and without irrigation-related groundwater withdrawals based on the current arrangement of land use and a varied climatic record. Groundwater withdrawals focused on irrigated-agriculture-related water use because greater than 95% of groundwater withdrawal in the two inset models around the study lakes is for irrigated agriculture water use. The period of 2012-2018 was used for parameter estimation (synonymously referred to as “history matching”) for the groundwater models. This time period was chosen because it includes the most complete water use records to simulate groundwater withdrawals. History matching was performed using groundwater elevations, lake stages, and streamflow observations over the 2012-2018 time period and processed observations derived from those raw data. Climatic data were incorporated into the model using a soil-water balance approach. A soil water balance model (Westenbroek and others, 2021) was constructed at the scale of the regional groundwater model to both calculate recharge based on land use and climate, and in the long-term climate-period runs, to estimate water use required by irrigated agriculture to apply as well boundary conditions in the groundwater model in the absence of reported water use values over that period. The model archive presents all the inputs needed to run the models, the model software, information on history matching to estimate parameters of the model, model scenario files, and model outputs that the user should be able to recreate using the model files in this archive.

This model archive provides the necessary documentation of the numerical models developed for the Central Sands Lake study in central Wisconsin and will be included as a technical appendix (Appendix C) in the report to the Wisconsin State Legislature by the Wisconsin Department of Natural Resources (WDNR) in response to 2017 Wisconsin Act 10. This legislation directed DNR to determine whether existing and potential groundwater withdrawals are causing or are likely to cause significant reduction of mean seasonal water levels at Pleasant Lake, Long Lake, and Plainfield Lake (s. 281.34(7m)(2)(b), Wis. Stats.) in Waushara County, Wisconsin. To evaluate the potential hydrologic connection between groundwater withdrawals and the nearby study lakes, hydrologic models were created that focused on the lakes of interest and yet were large enough to cover a broad enough region to extend to the major hydrologic boundaries of the natural flow system. The areas near the lakes require finer-scale grid discretization (or spacing) to better represent the lakes and streams in the model, but also need to cover a large enough area to include the groundwater withdrawal locations that have the potential to cause reduction in water levels in the lakes. To accomplish these goals, three groundwater models were created: a regional model extending to major hydrologic boundaries; and two inset models, inheriting boundaries from the regional model but focused near the lakes. Each of the inset models, in turn, included a detailed area close to the lakes surrounded by an area at the same spatial scale as the regional model. To support WDNR in evaluating the connection between groundwater withdrawals and lake levels, a representative time period was required over which to compare land use with and without irrigated agriculture and for WDNR to evaluate potential lake stage and flux changes related to irrigated agriculture. WDNR chose the climate period of 1981-2018 to be representative of a typical period and provided two land use scenarios—one with no irrigated agriculture and one with assumed crop rotations similar to current conditions—to simulate with groundwater models to, then, compare lake responses with. As a result, simulations over this climate record are not intended to recreate the history of 1981-2018 because land use changed over that time. These runs are, instead, intended to provide a basis on which to compare land use with and without irrigation-related groundwater withdrawals based on the current arrangement of land use and a varied climatic record. Groundwater withdrawals focused on irrigated-agriculture-related water use because greater than 95% of groundwater withdrawal in the two inset models around the study lakes is for irrigated agriculture water use. The period of 2012-2018 was used for parameter estimation (synonymously referred to as “history matching”) for the groundwater models. This time period was chosen because it includes the most complete water use records to simulate groundwater withdrawals. History matching was performed using groundwater elevations, lake stages, and streamflow observations over the 2012-2018 time period and processed observations derived from those raw data. Climatic data were incorporated into the model using a soil-water balance approach. A soil water balance model (Westenbroek and others, 2021) was constructed at the scale of the regional groundwater model to both calculate recharge based on land use and climate, and in the long-term climate-period runs, to estimate water use required by irrigated agriculture to apply as well boundary conditions in the groundwater model in the absence of reported water use values over that period. The model archive presents all the inputs needed to run the models, the model software, information on history matching to estimate parameters of the model, model scenario files, and model outputs that the user should be able to recreate using the model files in this archive.

An existing three-dimensional model (MODFLOW-2000) by Petkewich and Campbell (2007) (https://pubs.usgs.gov/sir/2007/5126/) was updated to simulate six predictive water-management scenarios that were created to simulate potential changes in groundwater flow and groundwater-level conditions in the Mount Pleasant, South Carolina area. The model was recalibrated to conditions from 1900 to 2015. Simulations included six scenarios: (1) maximize Mount Pleasant Waterworks reverse-osmosis plant capacity by increasing groundwater withdrawals from 3.9 million gallons per day (Mgal/d) in 2015 to 8.6 Mgal/d from the Middendorf aquifer; (2) same as Scenario 1, but with the addition of a 0.5 Mgal/d supply well in the Middendorf aquifer near Moncks Corner, SC; (3) same as Scenario 1, but with the addition of a 1.5 Mgal/d supply well in the Middendorf aquifer near Moncks Corner, SC; (4) maximize Mount Pleasant Waterworks well capacity by increasing withdrawals from the Middendorf aquifer from 3.9 Mgal/d in 2015 to 10.2 Mgal/d (5) minimizing Mount Pleasant Waterworks surface-water purchase from the Charleston Water System by adding supply wells and increasing withdrawals from the Middendorf aquifer from 3.9 Mgal/d in 2015 to 12.2 Mgal/d; and (6) same as Scenario 1, but with the addition of quarterly model stress periods to simulate seasonal variations in the groundwater withdrawals. This USGS 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/sir20175128).

An existing three-dimensional model (MODFLOW-2000) by Petkewich and Campbell (2007) (https://pubs.usgs.gov/sir/2007/5126/) was updated to simulate six predictive water-management scenarios that were created to simulate potential changes in groundwater flow and groundwater-level conditions in the Mount Pleasant, South Carolina area. The model was recalibrated to conditions from 1900 to 2015. Simulations included six scenarios: (1) maximize Mount Pleasant Waterworks reverse-osmosis plant capacity by increasing groundwater withdrawals from 3.9 million gallons per day (Mgal/d) in 2015 to 8.6 Mgal/d from the Middendorf aquifer; (2) same as Scenario 1, but with the addition of a 0.5 Mgal/d supply well in the Middendorf aquifer near Moncks Corner, SC; (3) same as Scenario 1, but with the addition of a 1.5 Mgal/d supply well in the Middendorf aquifer near Moncks Corner, SC; (4) maximize Mount Pleasant Waterworks well capacity by increasing withdrawals from the Middendorf aquifer from 3.9 Mgal/d in 2015 to 10.2 Mgal/d (5) minimizing Mount Pleasant Waterworks surface-water purchase from the Charleston Water System by adding supply wells and increasing withdrawals from the Middendorf aquifer from 3.9 Mgal/d in 2015 to 12.2 Mgal/d; and (6) same as Scenario 1, but with the addition of quarterly model stress periods to simulate seasonal variations in the groundwater withdrawals. This USGS 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/sir20175128).

MODFLOW-2005 groundwater flow models were developed to simulate 47 pumping tests conducted for a hydraulic tomography experiment in fractured rocks underlying the former Naval Air Warfare Center, West Trenton, New Jersey. These flow models simulate the change in water level during the pumping tests, which range from about 45 to 60 minutes in duration. MODFLOW-2005 models were also developed to simulate groundwater flow in different directions across the hydraulic conductivity field estimated by the hydraulic tomography, and MODPATH simulations were conducted to identify flow paths in these simulations. This USGS data release contains all of the input and output files for the simulations described in the associated journal article (https://doi.org/10.1111/gwat.12915)