Bryant C Jurgens
Groundwater is an important source of drinking water in the United States. In order to assess the status and long-term sustainability of this important resource, I use environmental tracers, geochemical modeling, and statistical methods to understand the age structure, geochemical processes, and trends affecting water-quality in aquifers.
Science and Products
Groundwater Age
The age of groundwater is key in predicting which contaminants it might contain. There are many tracers and techniques that allow us to estimate the age—or mix of ages—of the groundwater we depend on as a drinking water supply.
Filter Total Items: 21
Data for decadal shifts in groundwater age detected by environmental tracers across California, USA Data for decadal shifts in groundwater age detected by environmental tracers across California, USA
This data release documents seven tables containing environmental tracer data and lumped parameter model results used to evaluate temporal changes in groundwater age at 268 sites across California from 2004 to 2021. These sites are spatially distributed throughout the state and represent groundwater at depths used for public supply. Each site was sampled at least twice, with paired...
Data for Per- and Polyfluoroalkyl Substances (PFAS) in groundwater samples collected by the California Groundwater Ambient Monitoring and Assessment Priority Basin Project, 2019-2024 Data for Per- and Polyfluoroalkyl Substances (PFAS) in groundwater samples collected by the California Groundwater Ambient Monitoring and Assessment Priority Basin Project, 2019-2024
The California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) analyzed per-and polyfluoroalkyl substances (PFAS) in groundwater samples collected from domestic and public drinking water supply wells in California. GAMA-PBP is a cooperative program between the U.S. Geological Survey and the California State Water Resources Control Board. This...
Data for evaluating sustainable management of groundwater-quality and trends for groundwater basins in the Gilroy-Hollister Valley and northern San Joaquin Valley, California Data for evaluating sustainable management of groundwater-quality and trends for groundwater basins in the Gilroy-Hollister Valley and northern San Joaquin Valley, California
This data release documents five tables and one geographic information systems shapefile feature used to evaluate groundwater quality and concentration trends for groundwater basins in the Gilroy-Hollister Valley and northern San Joaquin Valley, California. This dataset provides a framework for evaluating groundwater quality data at the spatial scale of groundwater basins and the...
Data for assessing the susceptibility of groundwater used for domestic-supply, California Data for assessing the susceptibility of groundwater used for domestic-supply, California
This dataset provides groundwater age estimates for 175 wells used as domestic supply in four selected areas of California. Groundwater ages were estimated by calibration of environmental tracers (tritium, tritiogenic helium-3, sulfur hexafluoride, carbon-14 and radiogenic helium-4) to lumped parameter models (LPMs). Calibrated lumped parameter models provide the optimal mean age and...
DGMETA (Version 1): Dissolved Gas Modeling and Environmental Tracer Analysis Computer Program DGMETA (Version 1): Dissolved Gas Modeling and Environmental Tracer Analysis Computer Program
DGMETA (Dissolved Gas Modeling and Environmental Tracer Analysis) is a Microsoft Excel-based computer program that is used for modeling air-water equilibrium conditions from measurements of dissolved gases and for computing concentrations of environmental tracers that rely on air-water equilibrium model results. DGMETA can solve for the temperature, salinity, excess air, fractionation of...
Inverse Model Data for: Salinity trends in a groundwater system supplemented by 50 years of imported Colorado River water Inverse Model Data for: Salinity trends in a groundwater system supplemented by 50 years of imported Colorado River water
Data provided here describe the contribution of up to 7 different water sources to the major ion geochemistry of U.S. Geological Survey (USGS) and California State Water Resources Control Board Division of Drinking Water (CA-DDW) groundwater samples within the Indio Subbasin of the Coachella Valley, California. The Inverse Geochemical Modeling was performed in the USGS's PHREEQC ver. 3...
Filter Total Items: 61
Decadal shifts in groundwater age detected by environmental tracers across California, USA Decadal shifts in groundwater age detected by environmental tracers across California, USA
Groundwater age offers important insight into recharge, storage, and contamination risk. Although models predict age changes can be driven by pumping and climate variability, direct observational evidence remains limited. Here, we analyzed paired environmental tracer suites (tritium, carbon-14, and tritiogenic helium-3) collected a decade apart from 268 wells across California to assess...
Authors
Bryant C. Jurgens, Zeno F. Levy
Quality of groundwater used for domestic supply in the Gilroy-Hollister basin and surrounding areas, California, 2022 Quality of groundwater used for domestic supply in the Gilroy-Hollister basin and surrounding areas, California, 2022
More than 2 million Californians rely on groundwater from domestic wells for drinking-water supply. This report summarizes a 2022 California Groundwater Ambient Monitoring and Assessment Priority Basin Project (GAMA-PBP) water-quality survey of 33 domestic and small-system drinking-water supply wells in the Gilroy-Hollister Valley groundwater basin and the surrounding areas, where more...
Authors
Kirsten E. Faulkner, Bryant C. Jurgens
The systematics of stable hydrogen (δ2H) and oxygen (δ18O) isotopes and tritium (3H) in the hydrothermal system of the Yellowstone Plateau volcanic field, USA The systematics of stable hydrogen (δ2H) and oxygen (δ18O) isotopes and tritium (3H) in the hydrothermal system of the Yellowstone Plateau volcanic field, USA
To improve our understanding of hydrothermal activity on the Yellowstone Plateau volcanic field, we collected and analyzed a large data set of δ2H, δ18O, and the 3H concentrations of circum-neutral and alkaline waters. We find that (a) hot springs are fed by recharge throughout the volcanic plateau, likely focused through fractured, permeable tuff units. Previous work had stressed the...
Authors
Shaul Hurwitz, R. Blaine McCleskey, Bryant Jurgens, Jacob B. Lowenstern, Laura E. Clor, Andrew G. Hunt
Predictions of groundwater PFAS occurrence at drinking water supply depths in the United States Predictions of groundwater PFAS occurrence at drinking water supply depths in the United States
Per- and polyfluoroalkyl substances (PFAS), known colloquially as “forever chemicals”, have been associated with adverse human health effects and have contaminated drinking water supplies across the United States owing to their long-term and widespread use. People in the United States may unknowingly be drinking water that contains PFAS because of a lack of systematic analysis...
Authors
Andrea K. Tokranov, Katherine Marie Ransom, Laura M. Bexfield, Bruce D. Lindsey, Elise Watson, Danielle Dupuy, Paul E. Stackelberg, Miranda S. Fram, Stefan Voss, James A. Kingsbury, Bryant C. Jurgens, Kelly Smalling, Paul M. Bradley
Basin-scale responses of groundwater-resource quality to drought and recovery, San Joaquin Valley, California Basin-scale responses of groundwater-resource quality to drought and recovery, San Joaquin Valley, California
Groundwater-resource quality is assumed to be less responsive to drought compared to that of surface water due to relatively long transit times of recharge to drinking-supply wells. Here, we evidence dynamic perturbations in aquifer pressure dynamics during drought and subsequent recovery periods cause dramatic shifts in groundwater quality on a basin scale. We used a novel application...
Authors
Zeno F. Levy, Bryant C. Jurgens, Kirsten Faulkner, Jennifer S. Harkness, Miranda S. Fram
Salinity trends in a groundwater system supplemented by 50 years of imported Colorado River water Salinity trends in a groundwater system supplemented by 50 years of imported Colorado River water
The Indio subbasin of the Coachella Valley is a desert area of southern California where a growing population depends primarily on groundwater for drinking and agricultural uses. The aquifer system has been supplemented with Colorado River water through managed recharge and widespread irrigation since the mid-20th century. We use a combination of geochemical modeling and trend analysis...
Authors
Jennifer S. Harkness, Patrick Michael McCarthy, Bryant C. Jurgens, Zeno F. Levy
DGMETA (Version 1): Dissolved Gas Modeling and Environmental Tracer Analysis Computer Program DGMETA (Version 1): Dissolved Gas Modeling and Environmental Tracer Analysis Computer Program
DGMETA (Dissolved Gas Modeling and Environmental Tracer Analysis) is a Microsoft Excel-based computer program that is used for modeling air-water equilibrium conditions from measurements of dissolved gases and for computing concentrations of environmental tracers that rely on air-water equilibrium model results. DGMETA can solve for the temperature, salinity, excess air, fractionation of...
Groundwater Age Mixtures & Contaminant Trends Tool (GAMACTT) Groundwater Age Mixtures & Contaminant Trends Tool (GAMACTT)
Use this Groundwater Age Mixtures and Contaminant Trends Tool (GAMACTT) to explore the effects of basic aquifer properties and well configurations on groundwater age mixtures in groundwater discharge and on contaminant trends from varying nonpoint-source contaminant input scenarios.
TracerLPM TracerLPM
An Excel® Workbook for Interpreting Groundwater Age Distributions from Environmental Tracer Data
Science and Products
Groundwater Age
The age of groundwater is key in predicting which contaminants it might contain. There are many tracers and techniques that allow us to estimate the age—or mix of ages—of the groundwater we depend on as a drinking water supply.
Filter Total Items: 21
Data for decadal shifts in groundwater age detected by environmental tracers across California, USA Data for decadal shifts in groundwater age detected by environmental tracers across California, USA
This data release documents seven tables containing environmental tracer data and lumped parameter model results used to evaluate temporal changes in groundwater age at 268 sites across California from 2004 to 2021. These sites are spatially distributed throughout the state and represent groundwater at depths used for public supply. Each site was sampled at least twice, with paired...
Data for Per- and Polyfluoroalkyl Substances (PFAS) in groundwater samples collected by the California Groundwater Ambient Monitoring and Assessment Priority Basin Project, 2019-2024 Data for Per- and Polyfluoroalkyl Substances (PFAS) in groundwater samples collected by the California Groundwater Ambient Monitoring and Assessment Priority Basin Project, 2019-2024
The California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) analyzed per-and polyfluoroalkyl substances (PFAS) in groundwater samples collected from domestic and public drinking water supply wells in California. GAMA-PBP is a cooperative program between the U.S. Geological Survey and the California State Water Resources Control Board. This...
Data for evaluating sustainable management of groundwater-quality and trends for groundwater basins in the Gilroy-Hollister Valley and northern San Joaquin Valley, California Data for evaluating sustainable management of groundwater-quality and trends for groundwater basins in the Gilroy-Hollister Valley and northern San Joaquin Valley, California
This data release documents five tables and one geographic information systems shapefile feature used to evaluate groundwater quality and concentration trends for groundwater basins in the Gilroy-Hollister Valley and northern San Joaquin Valley, California. This dataset provides a framework for evaluating groundwater quality data at the spatial scale of groundwater basins and the...
Data for assessing the susceptibility of groundwater used for domestic-supply, California Data for assessing the susceptibility of groundwater used for domestic-supply, California
This dataset provides groundwater age estimates for 175 wells used as domestic supply in four selected areas of California. Groundwater ages were estimated by calibration of environmental tracers (tritium, tritiogenic helium-3, sulfur hexafluoride, carbon-14 and radiogenic helium-4) to lumped parameter models (LPMs). Calibrated lumped parameter models provide the optimal mean age and...
DGMETA (Version 1): Dissolved Gas Modeling and Environmental Tracer Analysis Computer Program DGMETA (Version 1): Dissolved Gas Modeling and Environmental Tracer Analysis Computer Program
DGMETA (Dissolved Gas Modeling and Environmental Tracer Analysis) is a Microsoft Excel-based computer program that is used for modeling air-water equilibrium conditions from measurements of dissolved gases and for computing concentrations of environmental tracers that rely on air-water equilibrium model results. DGMETA can solve for the temperature, salinity, excess air, fractionation of...
Inverse Model Data for: Salinity trends in a groundwater system supplemented by 50 years of imported Colorado River water Inverse Model Data for: Salinity trends in a groundwater system supplemented by 50 years of imported Colorado River water
Data provided here describe the contribution of up to 7 different water sources to the major ion geochemistry of U.S. Geological Survey (USGS) and California State Water Resources Control Board Division of Drinking Water (CA-DDW) groundwater samples within the Indio Subbasin of the Coachella Valley, California. The Inverse Geochemical Modeling was performed in the USGS's PHREEQC ver. 3...
Filter Total Items: 61
Decadal shifts in groundwater age detected by environmental tracers across California, USA Decadal shifts in groundwater age detected by environmental tracers across California, USA
Groundwater age offers important insight into recharge, storage, and contamination risk. Although models predict age changes can be driven by pumping and climate variability, direct observational evidence remains limited. Here, we analyzed paired environmental tracer suites (tritium, carbon-14, and tritiogenic helium-3) collected a decade apart from 268 wells across California to assess...
Authors
Bryant C. Jurgens, Zeno F. Levy
Quality of groundwater used for domestic supply in the Gilroy-Hollister basin and surrounding areas, California, 2022 Quality of groundwater used for domestic supply in the Gilroy-Hollister basin and surrounding areas, California, 2022
More than 2 million Californians rely on groundwater from domestic wells for drinking-water supply. This report summarizes a 2022 California Groundwater Ambient Monitoring and Assessment Priority Basin Project (GAMA-PBP) water-quality survey of 33 domestic and small-system drinking-water supply wells in the Gilroy-Hollister Valley groundwater basin and the surrounding areas, where more...
Authors
Kirsten E. Faulkner, Bryant C. Jurgens
The systematics of stable hydrogen (δ2H) and oxygen (δ18O) isotopes and tritium (3H) in the hydrothermal system of the Yellowstone Plateau volcanic field, USA The systematics of stable hydrogen (δ2H) and oxygen (δ18O) isotopes and tritium (3H) in the hydrothermal system of the Yellowstone Plateau volcanic field, USA
To improve our understanding of hydrothermal activity on the Yellowstone Plateau volcanic field, we collected and analyzed a large data set of δ2H, δ18O, and the 3H concentrations of circum-neutral and alkaline waters. We find that (a) hot springs are fed by recharge throughout the volcanic plateau, likely focused through fractured, permeable tuff units. Previous work had stressed the...
Authors
Shaul Hurwitz, R. Blaine McCleskey, Bryant Jurgens, Jacob B. Lowenstern, Laura E. Clor, Andrew G. Hunt
Predictions of groundwater PFAS occurrence at drinking water supply depths in the United States Predictions of groundwater PFAS occurrence at drinking water supply depths in the United States
Per- and polyfluoroalkyl substances (PFAS), known colloquially as “forever chemicals”, have been associated with adverse human health effects and have contaminated drinking water supplies across the United States owing to their long-term and widespread use. People in the United States may unknowingly be drinking water that contains PFAS because of a lack of systematic analysis...
Authors
Andrea K. Tokranov, Katherine Marie Ransom, Laura M. Bexfield, Bruce D. Lindsey, Elise Watson, Danielle Dupuy, Paul E. Stackelberg, Miranda S. Fram, Stefan Voss, James A. Kingsbury, Bryant C. Jurgens, Kelly Smalling, Paul M. Bradley
Basin-scale responses of groundwater-resource quality to drought and recovery, San Joaquin Valley, California Basin-scale responses of groundwater-resource quality to drought and recovery, San Joaquin Valley, California
Groundwater-resource quality is assumed to be less responsive to drought compared to that of surface water due to relatively long transit times of recharge to drinking-supply wells. Here, we evidence dynamic perturbations in aquifer pressure dynamics during drought and subsequent recovery periods cause dramatic shifts in groundwater quality on a basin scale. We used a novel application...
Authors
Zeno F. Levy, Bryant C. Jurgens, Kirsten Faulkner, Jennifer S. Harkness, Miranda S. Fram
Salinity trends in a groundwater system supplemented by 50 years of imported Colorado River water Salinity trends in a groundwater system supplemented by 50 years of imported Colorado River water
The Indio subbasin of the Coachella Valley is a desert area of southern California where a growing population depends primarily on groundwater for drinking and agricultural uses. The aquifer system has been supplemented with Colorado River water through managed recharge and widespread irrigation since the mid-20th century. We use a combination of geochemical modeling and trend analysis...
Authors
Jennifer S. Harkness, Patrick Michael McCarthy, Bryant C. Jurgens, Zeno F. Levy
DGMETA (Version 1): Dissolved Gas Modeling and Environmental Tracer Analysis Computer Program DGMETA (Version 1): Dissolved Gas Modeling and Environmental Tracer Analysis Computer Program
DGMETA (Dissolved Gas Modeling and Environmental Tracer Analysis) is a Microsoft Excel-based computer program that is used for modeling air-water equilibrium conditions from measurements of dissolved gases and for computing concentrations of environmental tracers that rely on air-water equilibrium model results. DGMETA can solve for the temperature, salinity, excess air, fractionation of...
Groundwater Age Mixtures & Contaminant Trends Tool (GAMACTT) Groundwater Age Mixtures & Contaminant Trends Tool (GAMACTT)
Use this Groundwater Age Mixtures and Contaminant Trends Tool (GAMACTT) to explore the effects of basic aquifer properties and well configurations on groundwater age mixtures in groundwater discharge and on contaminant trends from varying nonpoint-source contaminant input scenarios.
TracerLPM TracerLPM
An Excel® Workbook for Interpreting Groundwater Age Distributions from Environmental Tracer Data