Water-level measurements from 190 wells were used to develop a potentiometric-surface map of the east-central portion of the regional Great Basin carbonate and alluvial aquifer system in and around Snake Valley, eastern Nevada and western Utah. The map area covers approximately 9,000 square miles in Juab, Millard, and Beaver Counties, Utah, and White Pine and Lincoln Counties, Nevada. Recent (2007-2010) drilling by the Utah Geological Survey and U.S. Geological Survey has provided new data for areas where water-level measurements were previously unavailable. New water-level data were used to refine mapping of the pathways of intrabasin and interbasin groundwater flow. At 20 of these locations, nested observation wells provide vertical hydraulic gradient data and information related to the degree of connection between basin-fill aquifers and consolidated-rock aquifers. Multiple-year water-level hydrographs are also presented for 32 wells to illustrate the aquifer system’s response to interannual climate variations and well withdrawals.

A new version of previously published steady-state numerical groundwater flow models of the Great Basin carbonate and alluvial aquifer system (GBCAAS), and was developed in conjunction with U.S. Geological Survey (USGS) studies in Parowan, Pine, and Wah Wah Valleys, Utah. This version of the model is considered to be GBCAAS v. 3.0 and supersedes previous versions. This model added 15 transient calibration stress periods and 14 projection stress periods, aquifer storage properties, historical withdrawals in Parowan Valley, and observations of water-level changes in Parowan Valley to the previous steady-state versions. Recharge in Parowan Valley and withdrawal from wells in Parowan Valley and two nearby wells in Cedar City Valley vary for each calibration stress period representing conditions from March 1940 to November 2013. Stresses, including recharge, are the same in each stress period as in the steady-state stress period for all areas outside of Parowan Valley. This data release contains one calibration simulation and one projection simulation. The model is calibrated to transient conditions only in Parowan Valley. Simulated storage properties outside of Parowan Valley are set the same as the Parowan Valley properties and should not be considered calibrated. The projection simulation was used to estimate that reducing withdrawals in Parowan Valley from 35,000 to about 22,000 acre-feet per year should stabilize groundwater levels in the valley if recharge varies as it did from about 1950 to 2012 and that withdrawals of 15,000 acre-feet per year from Pine Valley and 6,500 acre-feet per year from Wah Wah Valley could ultimately (long-term steady-state) cause water-level declines of about 1,900 feet near the withdrawal wells and more than 5 feet over about 10,500 square miles. 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/sir20175072). This data release also contains source code needed to run the models. Model files presented in this data release were modified from an existing, calibrated, steady-state model of the Great Basin carbonate and alluvial aquifer system. SIR 2014-5213 (https://pubs.usgs.gov/sir/2014/5213/) and SIR 2017-5011 (https://doi.org/10.3133/sir20175011) document the construction and calibration of the previous versions of this model. Modifications that were made to the input files and discussion of model results are documented in SIR2017-5072 (https://doi.org/10.3133/sir20175072), which is associated with this data release. The model consists of a parent and a child model and must be run using MODFLOW-LGR. The child model is far removed from the area considered for this project, but is being kept with the model so that one model version exists of the Great Basin carbonate and alluvial aquifer system that incorporates all refinements and improvements. The model files documented in this data release should be used instead of previous versions.

A new version of previously published steady-state numerical groundwater flow models of the Great Basin carbonate and alluvial aquifer system (GBCAAS), and was developed in conjunction with U.S. Geological Survey (USGS) studies in Parowan, Pine, and Wah Wah Valleys, Utah. This version of the model is considered to be GBCAAS v. 3.0 and supersedes previous versions. This model added 15 transient calibration stress periods and 14 projection stress periods, aquifer storage properties, historical withdrawals in Parowan Valley, and observations of water-level changes in Parowan Valley to the previous steady-state versions. Recharge in Parowan Valley and withdrawal from wells in Parowan Valley and two nearby wells in Cedar City Valley vary for each calibration stress period representing conditions from March 1940 to November 2013. Stresses, including recharge, are the same in each stress period as in the steady-state stress period for all areas outside of Parowan Valley. This data release contains one calibration simulation and one projection simulation. The model is calibrated to transient conditions only in Parowan Valley. Simulated storage properties outside of Parowan Valley are set the same as the Parowan Valley properties and should not be considered calibrated. The projection simulation was used to estimate that reducing withdrawals in Parowan Valley from 35,000 to about 22,000 acre-feet per year should stabilize groundwater levels in the valley if recharge varies as it did from about 1950 to 2012 and that withdrawals of 15,000 acre-feet per year from Pine Valley and 6,500 acre-feet per year from Wah Wah Valley could ultimately (long-term steady-state) cause water-level declines of about 1,900 feet near the withdrawal wells and more than 5 feet over about 10,500 square miles. 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/sir20175072). This data release also contains source code needed to run the models. Model files presented in this data release were modified from an existing, calibrated, steady-state model of the Great Basin carbonate and alluvial aquifer system. SIR 2014-5213 (https://pubs.usgs.gov/sir/2014/5213/) and SIR 2017-5011 (https://doi.org/10.3133/sir20175011) document the construction and calibration of the previous versions of this model. Modifications that were made to the input files and discussion of model results are documented in SIR2017-5072 (https://doi.org/10.3133/sir20175072), which is associated with this data release. The model consists of a parent and a child model and must be run using MODFLOW-LGR. The child model is far removed from the area considered for this project, but is being kept with the model so that one model version exists of the Great Basin carbonate and alluvial aquifer system that incorporates all refinements and improvements. The model files documented in this data release should be used instead of previous versions.

This dataset was created in support of a U.S. Geological Survey (USGS) study focusing on groundwater resources in the Great Basin carbonate and alluvial aquifer system (GBCAAS). The GBCAAS is a complex aquifer system comprised of both unconsolidated and bedrock formations covering an area of approximately 110,000 square miles. The aquifer system is situated in the eastern portion of the Great Basin Province of the western United States. The eastern Great Basin is experiencing rapid population growth and has some of the highest per capita water use in the Nation. These factors, combined with the arid setting, have levied intensive demand upon current groundwater resources and, thus, predictions of future shortages. Because of the large regional extent of the aquifer system, rapid growth in the region, and the reliance upon groundwater for urban populations, agriculture, and native habitats, the GBCAAS was selected by the USGS Water Resources program as part of the National Water Census Initiative to evaluate the Nation's groundwater availability. This dataset consists of potentiometric contours, control points used to guide the creation of the contours, and a grid of 2 square-mile cells used to average the water-level value of selected control points. Control points are based on water-level measurements at well and spring locations from the USGS National Water Information System (NWIS, Mathey, 1998). Additional control points were derived from estimates of water-level altitudes in perennial mountain streams based on National Hydrography Dataset (NHD, 1999) stream reaches. References cited: Mathey, Sharon B., ed., 1998, National Water Information System (NWIS): U.S. Geological Survey Fact Sheet 027-98, 2 p., Accessed January 14, 2009 at U.S. Geological Survey, 1999, National Hydrography Dataset: U.S. Geological Survey Fact Sheet 106-99, accessed March 2007 at http://erg.usgs.gov/isb/pubs/factsheets/fs10699.html

This dataset was created in support of a U.S. Geological Survey (USGS) study focusing on groundwater resources in the Great Basin carbonate and alluvial aquifer system (GBCAAS). The GBCAAS is a complex aquifer system comprised of both unconsolidated and bedrock formations covering an area of approximately 110,000 square miles. The aquifer system is situated in the eastern portion of the Great Basin Province of the western United States. The eastern Great Basin is experiencing rapid population growth and has some of the highest per capita water use in the Nation. These factors, combined with the arid setting, have levied intensive demand upon current groundwater resources and, thus, predictions of future shortages. Because of the large regional extent of the aquifer system, rapid growth in the region, and the reliance upon groundwater for urban populations, agriculture, and native habitats, the GBCAAS was selected by the USGS Water Resources program as part of the National Water Census Initiative to evaluate the Nation's groundwater availability. This dataset consists of potentiometric contours, control points used to guide the creation of the contours, and a grid of 2 square-mile cells used to average the water-level value of selected control points. Control points are based on water-level measurements at well and spring locations from the USGS National Water Information System (NWIS, Mathey, 1998). Additional control points were derived from estimates of water-level altitudes in perennial mountain streams based on National Hydrography Dataset (NHD, 1999) stream reaches. References cited: Mathey, Sharon B., ed., 1998, National Water Information System (NWIS): U.S. Geological Survey Fact Sheet 027-98, 2 p., Accessed January 14, 2009 at U.S. Geological Survey, 1999, National Hydrography Dataset: U.S. Geological Survey Fact Sheet 106-99, accessed March 2007 at http://erg.usgs.gov/isb/pubs/factsheets/fs10699.html

This data set consists of sub delineations of the hydrographic area (HA) boundaries and polygons drawn at 1:1,000,000 scale for the Great Basin supplemented by information from HA drawn at 1:750,000 scale where necessary. See the process steps for more information.

This data set consists of sub delineations of the hydrographic area (HA) boundaries and polygons drawn at 1:1,000,000 scale for the Great Basin supplemented by information from HA drawn at 1:750,000 scale where necessary. See the process steps for more information.

This dataset was created in support of a U.S. Geological Survey (USGS) study focusing on groundwater resources in the Great Basin carbonate and alluvial aquifer system (GBCAAS). The GBCAAS is a complex aquifer system comprised of both unconsolidated and bedrock formations covering an area of approximately 110,000 square miles. The aquifer system is situated in the eastern portion of the Great Basin Province of the western United States. The eastern Great Basin is experiencing rapid population growth and has some of the highest per capita water use in the Nation. These factors, combined with its arid setting, have levied intensive demand upon current groundwater resources and, thus, predictions of future shortages. Because of the large regional extent of the aquifer system, rapid growth in the region, and the reliance upon groundwater for urban populations, agriculture, and native habitats, the GBCAAS was selected by the USGS Water Resources program as part of the National Water Census Initiative to evaluate the nation's groundwater availability. This dataset contains hydrographic area (HA) boundaries and polygons for the GBCAAS study area. The study area consists of 165 HAs based on Great Basin HAs defined by the USGS in 1988 (Harrill and others, 1988; Buto, 2009). The study area is characterized by north-south trending alluvial basins separated by intervening mountain ranges. HA boundaries generally coincide with the topographic highs separating these basins but may also contain arbitrary divisions that have no topographic control. HAs generally consist of thick layers of unconsolidated geologic deposits in the basins and consolidated bedrock in the mountain ranges. The basins are underlain by bedrock at varying depths. Much of the bedrock in the study area consists of permeable carbonate and volcanic rock strata, both of which allow some degree of hydraulic connection between hydrographic areas. The hydrographic area boundaries in this dataset have been assigned a code identifying each boundary as a potential barrier, conduit, or neutral zone to groundwater flow between basins. References cited: Buto, S.G., 2009, Digital representation of 1:1,000,000-scale Hydrographic Areas of the Great Basin: U.S. Geological Survey Digital Data Report 457, 5 p., Harrill, J.R., Gates, J.S., and Thomas, J.M., 1988, Major ground-water flow systems in the Great Basin region of Nevada, Utah, and adjacent states: U.S. Geological Survey Hydrologic Investigations Atlas HA-694-C, 2 sheets, scale 1:1,000,000.

This dataset was created in support of a U.S. Geological Survey (USGS) study focusing on groundwater resources in the Great Basin carbonate and alluvial aquifer system (GBCAAS). The GBCAAS is a complex aquifer system comprised of both unconsolidated and bedrock formations covering an area of approximately 110,000 square miles. The aquifer system is situated in the eastern portion of the Great Basin Province of the western United States. The eastern Great Basin is experiencing rapid population growth and has some of the highest per capita water use in the Nation. These factors, combined with its arid setting, have levied intensive demand upon current groundwater resources and, thus, predictions of future shortages. Because of the large regional extent of the aquifer system, rapid growth in the region, and the reliance upon groundwater for urban populations, agriculture, and native habitats, the GBCAAS was selected by the USGS Water Resources program as part of the National Water Census Initiative to evaluate the nation's groundwater availability. This dataset contains hydrographic area (HA) boundaries and polygons for the GBCAAS study area. The study area consists of 165 HAs based on Great Basin HAs defined by the USGS in 1988 (Harrill and others, 1988; Buto, 2009). The study area is characterized by north-south trending alluvial basins separated by intervening mountain ranges. HA boundaries generally coincide with the topographic highs separating these basins but may also contain arbitrary divisions that have no topographic control. HAs generally consist of thick layers of unconsolidated geologic deposits in the basins and consolidated bedrock in the mountain ranges. The basins are underlain by bedrock at varying depths. Much of the bedrock in the study area consists of permeable carbonate and volcanic rock strata, both of which allow some degree of hydraulic connection between hydrographic areas. The hydrographic area boundaries in this dataset have been assigned a code identifying each boundary as a potential barrier, conduit, or neutral zone to groundwater flow between basins. References cited: Buto, S.G., 2009, Digital representation of 1:1,000,000-scale Hydrographic Areas of the Great Basin: U.S. Geological Survey Digital Data Report 457, 5 p., Harrill, J.R., Gates, J.S., and Thomas, J.M., 1988, Major ground-water flow systems in the Great Basin region of Nevada, Utah, and adjacent states: U.S. Geological Survey Hydrologic Investigations Atlas HA-694-C, 2 sheets, scale 1:1,000,000.

This data set consists of digital hydraulic conductivity values for the alluvial and terrace deposits along the Beaver-North Canadian River from the panhandle to Canton Lake in northwestern Oklahoma. Ground water in 830 square miles of the Quaternary-age alluvial and terrace aquifer is an important source of water for irrigation, industrial, municipal, stock, and domestic supplies. The aquifer consists of poorly sorted, fine to coarse, unconsolidated quartz sand with minor amounts of clay, silt, and basal gravel. The hydraulically connected alluvial and terrace deposits unconformably overlie the Tertiary-age Ogallala Formation and Permian-age formations. Six zones of ranges of hydraulic conductivity values for the alluvial and terrace deposits reported in a ground-water modeling report are used in this data set. The hydraulic conductivity values range from 0 to 160 feet per day, and average 59 feet per day. The features in the data set representing aquifer boundaries along geological contacts were extracted from a published digital surficial geology data set based on a scale of 1:250,000. The geographic limits of the aquifer and zones representing ranges of hydraulic conductivity values were digitized from folded paper maps, at a scale of 1:250,000 from a ground-water modeling report. Ground-water flow models are numerical representations that simplify and aggregate natural systems. Models are not unique; different combinations of aquifer characteristics may produce similar results. Therefore, values of hydraulic conductivity used in the model and presented in this data set are not precise, but are within a reasonable range when compared to independently collected data.