A three-dimensional groundwater flow model, constructed in MODFLOW-NWT, was developed to evaluate the groundwater flow system of the Kitsap Peninsula, west-central Washington. A transient model was constructed to simulate groundwater flow for January 1985–December 2012 using annual stress periods for 1985–2004 and monthly stress periods for 2005–2012. The model was used to simulate six hydrologic scenarios, including simulations of a steady-state system, no-pumping and return flows, 15-percent increase in current withdrawals in all wells, 80-percent decrease in outdoor water to simulate effects of conservation efforts, 15-percent decrease in recharge from precipitation to simulate a drought, and particle tracking to determine flow paths. This data release contains the input and output files for the simulations described in the associated model documentation report (https://doi.org/10.3133/sir20165052).

A three-dimensional groundwater flow model, constructed in MODFLOW-NWT, was developed to evaluate the groundwater flow system of the Kitsap Peninsula, west-central Washington. A transient model was constructed to simulate groundwater flow for January 1985–December 2012 using annual stress periods for 1985–2004 and monthly stress periods for 2005–2012. The model was used to simulate six hydrologic scenarios, including simulations of a steady-state system, no-pumping and return flows, 15-percent increase in current withdrawals in all wells, 80-percent decrease in outdoor water to simulate effects of conservation efforts, 15-percent decrease in recharge from precipitation to simulate a drought, and particle tracking to determine flow paths. This data release contains the input and output files for the simulations described in the associated model documentation report (https://doi.org/10.3133/sir20165052).

A three-dimensional groundwater flow model, constructed in MODFLOW-NWT, was developed to evaluate the groundwater flow system near Puget Sound, Pierce and King Counties, Washington. A steady-state model version was constructed to simulate equilibrium conditions, while a transient model version was constructed to simulate monthly variability from January 2005 to December 2015. The model was used to simulate several hydrologic scenarios. This data release contains the input and output files for the simulations described in the associated model documentation report (https://doi.org/10.3133/sir20245026v2).

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).

This groundwater-flow model archive contains all of the input and output files for an inset MODFLOW-NWT model extracted from the northern (Wisconsin) half of a published USGS steady-state regional model of the Upper Fox River Basin in the U.S. Upper Midwest. The construction and details of the published USGS steady-state model of the Upper Fox River Basin is outlined in the U.S. Geological Survey Scientific Investigations Report 2018-5038 (https://doi.org/10.3133/sir20185038). The regional model is archived in the data release at https://doi.org/10.5066/F76D5R5V. The extracted model was used to demonstrate an innovative new method for delinating fen distribution and discharge using the MODFLOW UZF package. The extracted model incorporates the Mukwonago River Basin, a 10-digit hydrologic unit code (HUC10) basin occupying 86.2 mi2 (223 km2) in southeastern Wisconsin. The extracted model was used to demonstrate how regional and local flow patterns can be enhanced by adding a version of the UZF file that automatically inserts “seepage drains” in cells where the water table is near the land surface (within the “undulation depth”). Details on the extracted model construction and calibration, including preparation of the “stripped-down” UZF file central to the proposed fen delineation method can be found in the supporting information of the journal article in Groundwater (https://doi.org/10.1111/gwat.12931). This USGS data release contains all of the input and output files for the simulations described in the journal article in Groundwater (https://doi.org/10.1111/gwat.12931).

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)

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)

The U.S. Geological Survey, in cooperation with the National Park Service (NPS), developed a three-dimensional groundwater-flow model to simulate climate-change-related changes in depth to the water table and depth to freshwater/saltwater interfaces for the Fire Island National Seashore, New York. An existing SEAWAT three-dimensional variable-density groundwater flow and transport model (https://doi.org/10.3133/sir20095259) was converted to a MODFLOW–NWT three-dimensional finite-difference groundwater model with the Seawater Intrusion (SWI2) package and recalibrated using the UCODE_2005 automatic calibration software. A management goal for the Fire Island National Seashore is to increase the resiliency and capacity of coastal habitat and infrastructure to withstand storms and reduce the amount of damage caused by major storms. To facilitate management of ecohydrological effects and to increase understanding of the relation between sea-level rise and groundwater, as it relates to the ecology of the maritime forests and other vegetated areas on the island, the NPS requires hydrologic information. Accelerated sea-level rise, storms, rising temperatures, and changes in patterns of precipitation are all expected to drive considerable ecological changes. This model was used to evaluate three sea-level rise scenarios with 0.2-, 0.4-, and 0.6-meter increases above the 2015 level, applied to the existing topography. An additional high-recharge scenario, with the 0.6-meter increase, was created by increasing 2015 recharge rates by 10 percent. Understanding the possible effects of sea-level rise and changes in recharge on groundwater resources will allow the NPS to allocate scarce resources to best prepare for and manage climate-change-driven changes in the groundwater system and the subsequent effects on seashore ecosystems. 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/sir20205117).

The U.S. Geological Survey constructed a steady-state numerical groundwater flow model in cooperation with Des Moines Water Works (DMWW) to simulate groundwater flow conditions in the Des Moines River alluvial aquifer (DMRA) during winter low-flow conditions typical of December 2018-2020. The Des Moines River alluvial aquifer (DMRA) is an important source of water for Des Moines Water Works (DMWW), the municipal water utility that serves residential and commercial water needs in the city of Des Moines, Iowa and surrounding municipalities. A comprehensive understanding of groundwater flow processes in the DMRA is needed for DMWW to make decisions related to the management of this water resource. A three-layered model was constructed using MODFLOW-NWT to simulate an area of about 15 square kilometers near Prospect Park in Des Moines, Iowa. The model has 130 rows and 130 columns of cells within the model boundary. Parameter ESTimation software (PEST) was used for model calibration to assess and optimize performance of individual parameters including the horizontal and vertical hydraulic conductivity of the various units, evapotranspiration rate, and recharge rate. This USGS data release contains all the input and output files for the simulations described in the associated model documentation report (https://doi.org/10.3133/ofr20211110).

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.