A three-dimensional groundwater flow model (MODFLOW200-FMP1_1) of the Central Valley in California was developed to aid water managers in understanding how water moves through the aquifer system, to predict water-supply scenarios, and to address issues related to water competition. The USGS Groundwater Resources Program made a detailed assessment of groundwater availability of the Central Valley aquifer system, which includes: (1) the present status of groundwater resources; (2) how these resources have changed over time; and (3) tools to assess system responses to stresses from future human uses and climate variability and change. This effort builds on previous investigations, such as the USGS Central Valley Regional Aquifer System and Analysis (CV-RASA) project and several other groundwater studies in the Valley completed by Federal, State and local agencies at differing scales. The principal product of this new assessment is a tool referred to as the Central Valley Hydrologic Model (CVHM) that accounts for integrated, variable water supply and demand, and simulates surface-water and groundwater-flow across the entire Central Valley system. The current model was extended to incorporate a slightly larger geographic area, has a finer spatial and temporal discretization, uses a more-detailed depiction of subsurface geology. In addition, the model utilizes a modified version of MODFLOW2000 (version 1.15.03) to include an updated and refined Farm Process (FMP1) to simulate groundwater and surface-water flow, irrigated agriculture, land subsidence, and other key processes in the Central Valley on a monthly basis for April 1961 through September 2003. This USGS data release contains all of the input and output files for the simulation and calibration of the CVHM described in the associated model documentation report (https://pubs.er.usgs.gov/publication/pp1766).

A three-dimensional groundwater flow model (MODFLOW2000) of the Denver Basin bedrock aquifer system and overlying alluvial aquifer was developed to provide quantitative estimates of groundwater flow conditions and provide a useful tool for managers to analyze temporal changes to the hydrologic system in response to changing climatic conditions and future groundwater development. In 2004, the U.S. Geological Survey (USGS) initiated large-scale regional studies to provide updated assessments of groundwater availability in important principal aquifers across the United States, including the Denver Basin. The Denver Basin groundwater flow model includes several enhancements over previous modeling efforts because of the availability of additional data, improved modeling capabilities, and advanced computer technology. Additional data available include updated geologic mapping, additional geophysical logs, water-level, streamflow, precipitation, and irrigation data collected since previous studies; and updated estimates of pumping from Denver Basin bedrock and alluvial aquifers. Modeling capabilities and computer technology also have advanced such that additional features, hydrologic processes, and numerical techniques are included in the current model that were not possible in previous models. The Denver Basin groundwater flow model represents regional time-varying (transient) conditions prior to 1880 through 2003. The model was calibrated by primarily adjusting hydraulic conductivity and recharge parameters until a best fit was obtained between observed and simulated transient hydraulic heads and flows using PEST. The calibrated model was used to estimate the hydrologic system response to two pumping scenarios for the period 2004 through 2053. This USGS data release contains all of the input and output files for the simulation and calibration described in the associated model documentation report (https://pubs.er.usgs.gov/publication/pp1770).

A three-dimensional groundwater flow model (MODFLOW2000) of the Denver Basin bedrock aquifer system and overlying alluvial aquifer was developed to provide quantitative estimates of groundwater flow conditions and provide a useful tool for managers to analyze temporal changes to the hydrologic system in response to changing climatic conditions and future groundwater development. In 2004, the U.S. Geological Survey (USGS) initiated large-scale regional studies to provide updated assessments of groundwater availability in important principal aquifers across the United States, including the Denver Basin. The Denver Basin groundwater flow model includes several enhancements over previous modeling efforts because of the availability of additional data, improved modeling capabilities, and advanced computer technology. Additional data available include updated geologic mapping, additional geophysical logs, water-level, streamflow, precipitation, and irrigation data collected since previous studies; and updated estimates of pumping from Denver Basin bedrock and alluvial aquifers. Modeling capabilities and computer technology also have advanced such that additional features, hydrologic processes, and numerical techniques are included in the current model that were not possible in previous models. The Denver Basin groundwater flow model represents regional time-varying (transient) conditions prior to 1880 through 2003. The model was calibrated by primarily adjusting hydraulic conductivity and recharge parameters until a best fit was obtained between observed and simulated transient hydraulic heads and flows using PEST. The calibrated model was used to estimate the hydrologic system response to two pumping scenarios for the period 2004 through 2053. This USGS data release contains all of the input and output files for the simulation and calibration described in the associated model documentation report (https://pubs.er.usgs.gov/publication/pp1770).

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).

This data release contains a three-dimensional groundwater flow model with example applications using MODFLOW-2000. The calibrated model is able to simulate observed decadal-scale climate-driven fluctuations in the groundwater system as well as observed shorter-term pumping-related fluctuations. Example model simulations show that the timing and location of the effects of groundwater pumping vary markedly depending on the pumping location. The complete description for the models in Gannett et al., 2012.

This data release contains a three-dimensional groundwater flow model with example applications using MODFLOW-2000. The calibrated model is able to simulate observed decadal-scale climate-driven fluctuations in the groundwater system as well as observed shorter-term pumping-related fluctuations. Example model simulations show that the timing and location of the effects of groundwater pumping vary markedly depending on the pumping location. The complete description for the models in Gannett et al., 2012.

An existing three-dimensional model (MODFLOW-2000) by Fine, Petkewich, and Campbell (2017) (https://doi.org/10.3133/sir20175128) was used to evaluate 7 water-management scenarios and predict the effects on the groundwater flow and groundwater-level conditions in the Mount Pleasant, South Carolina area. This model was originally developed in 2007, by Petkewich and Campbell (https://pubs.er.usgs.gov/publication/sir20075126), then updated and recalibrated to conditions from 1900 to 2015. Results of six previous scenario simulations (scenarios 1-6) for the Mount Pleasant Water Works are published in a U.S. Geological Survey (USGS) Scientific Investigations Report (https://doi.org/10.3133/sir20175128). The archived model input and output files are available in a USGS data release (https://doi.org/10.5066/F7S181FC). Seven additional MODFLOW-2000 scenarios (numbered 7-13), using this updated and recalibrated model, were developed to evaluate different withdrawal strategies which are included in this data release: (7) Mount Pleasant Waterworks bringing online a new well (located at the old well 5 location) at 3.51 million gallons per day (Mgal/d) in 2025; (8) Maximizing withdrawals from Mount Pleasant Waterworks wells 2 and 5 (3.51 Mgal/d each) in 2020 and 2025, respectively; (9) Same as Scenario 7, but removing well 3 from production in 2025; (10) Same as Scenario 9, but removing well 4 from production in 2025 (11) Same as Scenario 7, but converting well 3 to an injection well in 2025 (12) Same as Scenario 11, but converting well 4 to an injection well in 2030; and (13) Same as scenario 8, but with two injection wells added (one in 2025 and one in 2035) to Mount Pleasant Waterworks well field. Nine alternate simulations for scenarios 11-13 (three MODFLOW and six MODPATH) were done to evaluate the effects of different porosity on the groundwater flow system, water levels, and the time-of-travel of particles from injection wells to the main water source. This USGS data release contains all the input and output files for the simulations described above and in the readme.txt file of this data release (https://doi.org/10.5066/P9GZEE4E).

An existing three-dimensional model (MODFLOW-2000) by Fine, Petkewich, and Campbell (2017) (https://doi.org/10.3133/sir20175128) was used to evaluate 7 water-management scenarios and predict the effects on the groundwater flow and groundwater-level conditions in the Mount Pleasant, South Carolina area. This model was originally developed in 2007, by Petkewich and Campbell (https://pubs.er.usgs.gov/publication/sir20075126), then updated and recalibrated to conditions from 1900 to 2015. Results of six previous scenario simulations (scenarios 1-6) for the Mount Pleasant Water Works are published in a U.S. Geological Survey (USGS) Scientific Investigations Report (https://doi.org/10.3133/sir20175128). The archived model input and output files are available in a USGS data release (https://doi.org/10.5066/F7S181FC). Seven additional MODFLOW-2000 scenarios (numbered 7-13), using this updated and recalibrated model, were developed to evaluate different withdrawal strategies which are included in this data release: (7) Mount Pleasant Waterworks bringing online a new well (located at the old well 5 location) at 3.51 million gallons per day (Mgal/d) in 2025; (8) Maximizing withdrawals from Mount Pleasant Waterworks wells 2 and 5 (3.51 Mgal/d each) in 2020 and 2025, respectively; (9) Same as Scenario 7, but removing well 3 from production in 2025; (10) Same as Scenario 9, but removing well 4 from production in 2025 (11) Same as Scenario 7, but converting well 3 to an injection well in 2025 (12) Same as Scenario 11, but converting well 4 to an injection well in 2030; and (13) Same as scenario 8, but with two injection wells added (one in 2025 and one in 2035) to Mount Pleasant Waterworks well field. Nine alternate simulations for scenarios 11-13 (three MODFLOW and six MODPATH) were done to evaluate the effects of different porosity on the groundwater flow system, water levels, and the time-of-travel of particles from injection wells to the main water source. This USGS data release contains all the input and output files for the simulations described above and in the readme.txt file of this data release (https://doi.org/10.5066/P9GZEE4E).

A three-dimensional groundwater flow model, MODFLOW-OWHM, was developed to provide a better understanding of the hydrogeology of the Lucerne Valley Groundwater Basin, California. The model was used to investigate the historical groundwater storage loss and subsidence associated with anthropogenic groundwater demands. The model was calibrated to 1942 through 2016 conditions. This USGS data release contains all of the input and output files for the simulation described in the associated model documentation report https://doi.org/10.3133/sir20225048