This data release documents three Microsoft Excel tables that contain data for understanding environmental tracer concentrations in groundwater of the Columbia Plateau aquifer system. Results of dissolved-gas modeling using environmental tracer concentrations (tritium, tritiogenic helium-3, and radiogenic helium-4), for the sample network (VPFS, vertical flow path study) are described. Dissolved gas modeling results (ModOut) contains detailed information on the calibration of dissolved gas models to measured dissolved-gas concentrations (neon, argon, krypton, xenon, and nitrogen). Calibration was done using methods described by Aeschbach-Hertig and others (1999 & 2000) with modifications to include nitrogen gas (Weiss, 1970). In most cases, a single set of noble-gas concentrations (neon, argon, krypton, and xenon) was used to solve for recharge conditions (recharge temperature, excess or entrapped air, and fractionation) using the unfractionated excess air (UA) and closed equilibration (CE) models (Aeschbach-Hertig and others, 1999 & 2000). In cases where noble gas data were not available, multiple analyses of nitrogen and argon (collected sequentially on the same sample date) were used to solve for recharge conditions. Environmental tracer results (TrcOut) contains detailed information on calculations of environmental tracer data. Dissolved gas models were paired with measured helium isotope ratios (3He/4He) and helium concentrations to calculate concentrations of tritiogenic helium-3 (the component of 3He derived from tritium decay; Solomon and Cook, 2000) and radiogenic helium-4 (the component of 4He derived from the decay of uranium and thorium in aquifer materials; Solomon, 2000). Tracer concentrations were computed for each combination of measure dissolved gas concentrations when sites had multiple measured gas results and analyses for helium isotopes. Average environmental tracer results (AvgTrcOut) contains average tracer concentrations for a given site used for determination of groundwater ages. Aeschbach-Hertig, W., F. Peeters, U. Beyerle, and R. Kipfer (1999), Interpretation of dissolved atmospheric noble gases in natural waters, Water Resour. Res., 35(9), 2779–2792,https://dx.doi.org/10.1029/1999WR900130. Aeschbach-Hertig, W., F. Peeters, U. Beyerle, and R. Kipfer (2000), Paleotemperature reconstruction from noble gases in ground water taking into account equilibration with entrapped air, Nature, v. 405, Iss. 6790, pg. 1040-1044, http://dx.doi.org/10.1038/35016542 Solomon, D.K., and P.G. Cook. 2000. 3H and 3He. In Environmental Tracers in Subsurface Hydrology, ed. P.G. Cook and A.L. Herczeg, 197-424. Boston: Kluwer Academic Publishers. Solomon, D.K. 2000. 4He in groundwater. In Environmental Tracers in Subsurface Hydrology, ed. P.G. Cook and A.L. Herczeg, 425-439. Boston: Kluwer Academic Publishers. Weiss, R. F., 1970, The solubility of nitrogen, oxygen, and argon in water and seawater, Deep Sea Research, vol. 17, pp. 721-735, https://doi.org/10.1016/0011-7471(70)90037-9.

This data release documents three Microsoft Excel tables that contain data for understanding environmental tracer concentrations in groundwater of the High Plains aquifer system. Results of dissolved-gas modeling using environmental tracer concentrations (tritium, tritiogenic helium-3, and radiogenic helium-4), for the sample network (VPFS, vertical flow path study) are described. Dissolved gas modeling results (ModOut) contains detailed information on the calibration of dissolved gas models to measured dissolved-gas concentrations (neon, argon, krypton, xenon, and nitrogen). Calibration was done using methods described by Aeschbach-Hertig and others (1999 & 2000) with modifications to include nitrogen gas (Weiss, 1970). In most cases, a single set of noble-gas concentrations (neon, argon, krypton, and xenon) was used to solve for recharge conditions (recharge temperature, excess or entrapped air, and fractionation) using the unfractionated excess air (UA) and closed equilibration (CE) models (Aeschbach-Hertig and others, 1999 & 2000). In cases where noble gas data were not available, multiple analyses of nitrogen and argon (collected sequentially on the same sample date) were used to solve for recharge conditions. Environmental tracer results (TrcOut) contains detailed information on calculations of environmental tracer data. Dissolved gas models were paired with measured helium isotope ratios (3He/4He) and helium concentrations to calculate concentrations of tritiogenic helium-3 (the component of 3He derived from tritium decay; Solomon and Cook, 2000) and radiogenic helium-4 (the component of 4He derived from the decay of uranium and thorium in aquifer materials; Solomon, 2000). Tracer concentrations were computed for each combination of measure dissolved gas concentrations when sites had multiple measured gas results and analyses for helium isotopes. Average environmental tracer results (AvgTrcOut) contains average tracer concentrations for a given site used for determination of groundwater ages. Aeschbach-Hertig, W., F. Peeters, U. Beyerle, and R. Kipfer (1999), Interpretation of dissolved atmospheric noble gases in natural waters, Water Resour. Res., 35(9), 2779–2792,https://dx.doi.org/10.1029/1999WR900130. Aeschbach-Hertig, W., F. Peeters, U. Beyerle, and R. Kipfer (2000), Paleotemperature reconstruction from noble gases in ground water taking into account equilibration with entrapped air, Nature, v. 405, Iss. 6790, pg. 1040-1044, http://dx.doi.org/10.1038/35016542 Solomon, D.K., and P.G. Cook. 2000. 3H and 3He. In Environmental Tracers in Subsurface Hydrology, ed. P.G. Cook and A.L. Herczeg, 197-424. Boston: Kluwer Academic Publishers. Solomon, D.K. 2000. 4He in groundwater. In Environmental Tracers in Subsurface Hydrology, ed. P.G. Cook and A.L. Herczeg, 425-439. Boston: Kluwer Academic Publishers. Weiss, R. F., 1970, The solubility of nitrogen, oxygen, and argon in water and seawater, Deep Sea Research, vol. 17, pp. 721-735, https://doi.org/10.1016/0011-7471(70)90037-9.

This data release documents three Microsoft Excel tables that contain data for understanding environmental tracer concentrations in groundwater of the High Plains aquifer system. Results of dissolved-gas modeling using environmental tracer concentrations (tritium, tritiogenic helium-3, and radiogenic helium-4), for the sample network (VPFS, vertical flow path study) are described. Dissolved gas modeling results (ModOut) contains detailed information on the calibration of dissolved gas models to measured dissolved-gas concentrations (neon, argon, krypton, xenon, and nitrogen). Calibration was done using methods described by Aeschbach-Hertig and others (1999 & 2000) with modifications to include nitrogen gas (Weiss, 1970). In most cases, a single set of noble-gas concentrations (neon, argon, krypton, and xenon) was used to solve for recharge conditions (recharge temperature, excess or entrapped air, and fractionation) using the unfractionated excess air (UA) and closed equilibration (CE) models (Aeschbach-Hertig and others, 1999 & 2000). In cases where noble gas data were not available, multiple analyses of nitrogen and argon (collected sequentially on the same sample date) were used to solve for recharge conditions. Environmental tracer results (TrcOut) contains detailed information on calculations of environmental tracer data. Dissolved gas models were paired with measured helium isotope ratios (3He/4He) and helium concentrations to calculate concentrations of tritiogenic helium-3 (the component of 3He derived from tritium decay; Solomon and Cook, 2000) and radiogenic helium-4 (the component of 4He derived from the decay of uranium and thorium in aquifer materials; Solomon, 2000). Tracer concentrations were computed for each combination of measure dissolved gas concentrations when sites had multiple measured gas results and analyses for helium isotopes. Average environmental tracer results (AvgTrcOut) contains average tracer concentrations for a given site used for determination of groundwater ages. Aeschbach-Hertig, W., F. Peeters, U. Beyerle, and R. Kipfer (1999), Interpretation of dissolved atmospheric noble gases in natural waters, Water Resour. Res., 35(9), 2779–2792,https://dx.doi.org/10.1029/1999WR900130. Aeschbach-Hertig, W., F. Peeters, U. Beyerle, and R. Kipfer (2000), Paleotemperature reconstruction from noble gases in ground water taking into account equilibration with entrapped air, Nature, v. 405, Iss. 6790, pg. 1040-1044, http://dx.doi.org/10.1038/35016542 Solomon, D.K., and P.G. Cook. 2000. 3H and 3He. In Environmental Tracers in Subsurface Hydrology, ed. P.G. Cook and A.L. Herczeg, 197-424. Boston: Kluwer Academic Publishers. Solomon, D.K. 2000. 4He in groundwater. In Environmental Tracers in Subsurface Hydrology, ed. P.G. Cook and A.L. Herczeg, 425-439. Boston: Kluwer Academic Publishers. Weiss, R. F., 1970, The solubility of nitrogen, oxygen, and argon in water and seawater, Deep Sea Research, vol. 17, pp. 721-735, https://doi.org/10.1016/0011-7471(70)90037-9.

This data release documents two Microsoft Excel tables that contain data for understanding tracer concentrations and groundwater age in the Columbia Plateau aquifer system. Results for geochemical correction of carbon-14, and lumped parameter modeling of groundwater age for the sample network (VPFS, vertical flow path study) are described. Geochemical carbon-14 correction results (RFG) describe geochemical correction of carbon-14 in dissolved inorganic carbon (DIC) for groundwater age dating. Datasets includes measured water parameters and chemistry, model parameter inputs, and final corrected carbon-14 in DIC. Geochemical correction was completed using the revised Fontes and Granier model of Han and Plummer (2013). Mean age and age distribution results (TracerLPM) contain final models of groundwater age by calibration of lumped parameter models to tracer concentrations (Jurgens and others, 2012). Please see the processing steps below for additional details on the results presented in this table.

This data release documents two Microsoft Excel tables that contain data for understanding tracer concentrations and groundwater age in the Columbia Plateau aquifer system. Results for geochemical correction of carbon-14, and lumped parameter modeling of groundwater age for the sample network (VPFS, vertical flow path study) are described. Geochemical carbon-14 correction results (RFG) describe geochemical correction of carbon-14 in dissolved inorganic carbon (DIC) for groundwater age dating. Datasets includes measured water parameters and chemistry, model parameter inputs, and final corrected carbon-14 in DIC. Geochemical correction was completed using the revised Fontes and Granier model of Han and Plummer (2013). Mean age and age distribution results (TracerLPM) contain final models of groundwater age by calibration of lumped parameter models to tracer concentrations (Jurgens and others, 2012). Please see the processing steps below for additional details on the results presented in this table.

This data release documents 155 sets of dissolved noble gas analyses (neon, argon, krypton, xenon) and 153 modeled recharge temperatures for groundwater sampled from domestic water supply wells and springs throughout the northern Sierra Nevada foothills as part of the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment (GAMA) Program in 2015-2017. Data from two of the U.S. Geological Survey’s Priority Basin Project Shallow Aquifer Assessment study units are presented here: The Yuba and Bear Watersheds (YB) Shallow Aquifer Study Unit (sampled in 2015-2016) and the Mokelumne, Cosumnes, and American River Watersheds (MCAW) Shallow Aquifer Study Unit (sampled in 2016-2017). The YB and MCAW study units include domestic well and spring sites within watersheds overlying fractured rock aquifer systems of the Sierra Nevada hydrogeologic province of California in Nevada, Yuba, Sierra, Placer, El Dorado, Amador, and Calaveras Counties. Study design and site attributes for the YB and MCAW study units are presented by Jasper and others (2017) and Shelton and others (2018), respectively. This data release contains one tab-delimited text file containing Table 1, which reports the results of dissolved noble gas analyses for environmental samples from 72 sites in the YB study unit in addition to eight field replicates (80 samples total) and environmental samples from 67 sites in the MCAW study unit in addition to eight field replicates (75 samples total). Table 1 also contains groundwater recharge temperatures for 153 samples that were modeled using measured dissolved noble gas concentrations, land surface elevation at the sample site, and sample salinity. Model inputs and outputs including Monte Carlo simulations to estimate model parameter errors are also included in Table 1. Detailed descriptions for Table 1 column fields are provided in an additional tab-delimited text file of Table 1 column definitions. Abbreviations used in this data release are explained in an additional tab-delimited text file of abbreviations. These data support the following publications: Jasper, M., Bennett, G.L., and Fram, M.S., 2017, Groundwater-Quality Data in the Yuba and Bear Watersheds Shallow Aquifer Study Unit, 2015-2016: Results from the California GAMA Priority Basin Project: U.S. Geological Survey data release, https://doi.org/10.5066/F73F4MS9. Levy, Z.F., Fram, M.S., Faulkner, K.E., Alpers, C.N., Soltero, E.M., and Taylor, K.A., 2020, Effects of montane watershed development on vulnerability of domestic groundwater supply during drought: Journal of Hydrology, v. 583, https://doi.org/10.1016/j.jhydrol.2020.124567. Shelton, J.L., Fram, M.S., Goldrath, D.A., Bennett, G.L., V, and Jasper, M., 2018, Groundwater-quality data in the Mokelumne, Cosumnes, and American River Watersheds Shallow Aquifer Study Unit, 2016-2017: Results from the California GAMA Priority Basin Project: U.S. Geological Survey data release, https://doi.org/10.5066/F78G8JXP.

This data release documents 155 sets of dissolved noble gas analyses (neon, argon, krypton, xenon) and 153 modeled recharge temperatures for groundwater sampled from domestic water supply wells and springs throughout the northern Sierra Nevada foothills as part of the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment (GAMA) Program in 2015-2017. Data from two of the U.S. Geological Survey’s Priority Basin Project Shallow Aquifer Assessment study units are presented here: The Yuba and Bear Watersheds (YB) Shallow Aquifer Study Unit (sampled in 2015-2016) and the Mokelumne, Cosumnes, and American River Watersheds (MCAW) Shallow Aquifer Study Unit (sampled in 2016-2017). The YB and MCAW study units include domestic well and spring sites within watersheds overlying fractured rock aquifer systems of the Sierra Nevada hydrogeologic province of California in Nevada, Yuba, Sierra, Placer, El Dorado, Amador, and Calaveras Counties. Study design and site attributes for the YB and MCAW study units are presented by Jasper and others (2017) and Shelton and others (2018), respectively. This data release contains one tab-delimited text file containing Table 1, which reports the results of dissolved noble gas analyses for environmental samples from 72 sites in the YB study unit in addition to eight field replicates (80 samples total) and environmental samples from 67 sites in the MCAW study unit in addition to eight field replicates (75 samples total). Table 1 also contains groundwater recharge temperatures for 153 samples that were modeled using measured dissolved noble gas concentrations, land surface elevation at the sample site, and sample salinity. Model inputs and outputs including Monte Carlo simulations to estimate model parameter errors are also included in Table 1. Detailed descriptions for Table 1 column fields are provided in an additional tab-delimited text file of Table 1 column definitions. Abbreviations used in this data release are explained in an additional tab-delimited text file of abbreviations. These data support the following publications: Jasper, M., Bennett, G.L., and Fram, M.S., 2017, Groundwater-Quality Data in the Yuba and Bear Watersheds Shallow Aquifer Study Unit, 2015-2016: Results from the California GAMA Priority Basin Project: U.S. Geological Survey data release, https://doi.org/10.5066/F73F4MS9. Levy, Z.F., Fram, M.S., Faulkner, K.E., Alpers, C.N., Soltero, E.M., and Taylor, K.A., 2020, Effects of montane watershed development on vulnerability of domestic groundwater supply during drought: Journal of Hydrology, v. 583, https://doi.org/10.1016/j.jhydrol.2020.124567. Shelton, J.L., Fram, M.S., Goldrath, D.A., Bennett, G.L., V, and Jasper, M., 2018, Groundwater-quality data in the Mokelumne, Cosumnes, and American River Watersheds Shallow Aquifer Study Unit, 2016-2017: Results from the California GAMA Priority Basin Project: U.S. Geological Survey data release, https://doi.org/10.5066/F78G8JXP.

These data are solubility calculations for dissolved gases in groundwater samples collected to support a U.S. Geological Survey study to estimate the timing and source of recharge to the basalt groundwater system in the Umatilla River basin, Oregon. The software package Dissolved Gas Modeling and Environmental Tracer Analysis (DGEMTA; Jurgens and others, 2020) was used to develop the solubility calculations. DGMETA produces estimates of dissolved gas concentrations during recharge as well as estimates of recharge temperature, excess air, and excess nitrogen gas concentrations by optimizing the solutions of solubility equations for multiple gases dissolved in samples of groundwater. These data were collected during August 26, 2014 – April 16, 2019. Data are in .csv file format. Reference cited: Jurgens, B.C., Böhlke, J., Haase, K., Busenberg, E., Hunt, A.G., and Hansen, J.A., 2020, DGMETA (version 1) - Dissolved gas modeling and environmental tracer analysis computer program: U.S. Geological Survey Techniques and Methods 4-F5, 50 p., https://doi.org/10.3133/tm4F5.

These data are solubility calculations for dissolved gases in groundwater samples collected to support a U.S. Geological Survey study to estimate the timing and source of recharge to the basalt groundwater system in the Umatilla River basin, Oregon. The software package Dissolved Gas Modeling and Environmental Tracer Analysis (DGEMTA; Jurgens and others, 2020) was used to develop the solubility calculations. DGMETA produces estimates of dissolved gas concentrations during recharge as well as estimates of recharge temperature, excess air, and excess nitrogen gas concentrations by optimizing the solutions of solubility equations for multiple gases dissolved in samples of groundwater. These data were collected during August 26, 2014 – April 16, 2019. Data are in .csv file format. Reference cited: Jurgens, B.C., Böhlke, J., Haase, K., Busenberg, E., Hunt, A.G., and Hansen, J.A., 2020, DGMETA (version 1) - Dissolved gas modeling and environmental tracer analysis computer program: U.S. Geological Survey Techniques and Methods 4-F5, 50 p., https://doi.org/10.3133/tm4F5.

This dataset contains measurements of dissolved hydrocarbons in from groundwater samples collected in the shale gas producing regions of West Virginia, USA, between June and August of 2018. The target analytes in this study were: methane (CH4), ethane (C2H6), ethene (C2H4), ethyne (C2H2), propane (C3H8), propene (C3H6), i-butane (C4H10), n-butane (C4H10), 1-butene (C4H8), propyne (C3H4), i-pentane (C5H12), n-pentane (C5H12), 2-methyl-pentane (C6H14), 3-methyl-pentane (C6H14), hexane (C6H14), and benzene (C6H6). This dataset also contains corresponding measurements of chlorofluorocarbons (CFCs), Sulfurhexafluoride (SF6), dissolved permanent gases (N2/Ar), tritium, the isotope ratio of helium dissolved in water, the concentration of neon dissolved in water, the isotope ratios of hydrogen-2 and oxygen-18 in water, and the isotope ratio of carbon-13 in dissolved inorganic carbon (DIC).