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: 20
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...
Data for karst groundwater vulnerability determined by modeled age and residence time tracers Data for karst groundwater vulnerability determined by modeled age and residence time tracers
Groundwater samples collected from the Edwards aquifer in south-central Texas were analyzed for water-quality data to assess aquifer susceptibility to contaminants. Water-quality data included environmental tracers of groundwater age (tritium, tritiogenic helium-3, sulfur hexafluoride, carbon-14, and radiogenic helium-4), calibrated to lumped parameter models (LPMs). Groundwater samples...
Data for Per- and Polyfluoroalkyl Substances (PFAS) in groundwater samples collected by the California Groundwater Ambient Monitoring and Assessment Priority Basin Project, 2019-2023 Data for Per- and Polyfluoroalkyl Substances (PFAS) in groundwater samples collected by the California Groundwater Ambient Monitoring and Assessment Priority Basin Project, 2019-2023
The California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) analyzed for 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...
Generalized use classification for groundwater sites in California with publicly available water-quality data in the U.S. Geological Survey National Water Information System (NWIS) data archive (ver. 1.1, April 2025) Generalized use classification for groundwater sites in California with publicly available water-quality data in the U.S. Geological Survey National Water Information System (NWIS) data archive (ver. 1.1, April 2025)
The U.S. Geological Survey Water Data for the Nation (WDFN; U.S. Geological Survey, 2025) data archive contains publicly available water-quality data for approximately 21,000 groundwater wells and springs in California. This data release publishes site type information and a generalized use classification for each site. The generalized use category is derived from, but is not equivalent...
Data for Distribution of Groundwater Age in Aquifers Used for Public Supply in the Continental United States, 2004 - 2017 (Version 1.1: June 2022) Data for Distribution of Groundwater Age in Aquifers Used for Public Supply in the Continental United States, 2004 - 2017 (Version 1.1: June 2022)
This data release documents seven tables that contain environmental tracer data and lumped parameter model (LPM) results that are used for assessing the distribution of groundwater age in 21 Principal Aquifers of the continental United States. Groundwater samples were collected from 1,279 sites and analyzed for environmental tracers: tritium, tritiogenic helium-3, sulfur hexafluoride...
Data for assessing the penetration depth post-1950s water in the Central Valley aquifer system, California (July 2022) Data for assessing the penetration depth post-1950s water in the Central Valley aquifer system, California (July 2022)
This dataset provides groundwater ages estimates that were used in an assessment of the penetration depth of modern groundwater in the Central Valley aquifer system (CVAL). Groundwater ages were estimated by calibration of environmental tracers (tritium, tritiogenic helium-3, chlorofluorocarbons, sulfur hexafluoride, carbon-14 and radiogenic helium-4) to lumped parameter models (LPMs)...
Water use information for sites sampled by the California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP), 2004-2021 (ver. 4.0, April 2025) Water use information for sites sampled by the California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP), 2004-2021 (ver. 4.0, April 2025)
The U.S. Geological Survey collected water-quality samples from 3,359 sites between May 2004 and November 2024 for the California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP). The GAMA-PBP is a cooperative project with the California State Water Resources Control Board (SWRCB). The primary objectives of the GAMA-PBP are: (1) to assess the...
Data for Time Scales of Arsenic Variability and the Role of High-Frequency Monitoring at Three Water-Supply Wells in New Hampshire, USA Data for Time Scales of Arsenic Variability and the Role of High-Frequency Monitoring at Three Water-Supply Wells in New Hampshire, USA
This data release consists of data (in four tables) for assessing the time scales of arsenic variability in three production wells in New Hampshire; tables that describe the data fields in the data tables are also included in the data release. High-frequency (every 5 to 15 minutes) and bi-monthly water-quality monitoring of a bedrock-aquifer domestic well (425651070573701), a bedrock...
Filter Total Items: 60
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 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 Lowenstern, Laura E. Clor, Andrew 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 Tokranov, Katherine Ransom, Laura Bexfield, Bruce Lindsey, Elise Watson, Danielle Dupuy, Paul Stackelberg, Miranda Fram, Stefan Voss, James Kingsbury, Bryant 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 Levy, Bryant Jurgens, Kirsten Faulkner, Jennifer Harkness, Miranda 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 Harkness, Patrick McCarthy, Bryant Jurgens, Zeno Levy
Karst groundwater vulnerability determined by modeled age and residence time tracers Karst groundwater vulnerability determined by modeled age and residence time tracers
Karst aquifers are a vital groundwater resource globally, but features such as rapid recharge and conduit flow make them highly vulnerable to land-surface contamination. We apply environmental age tracers to the south-central Texas Edwards aquifer, a karst resource in a rapidly urbanizing and drought-prone region, to assess vulnerability to land-surface contamination and risks unique to...
Authors
MaryLynn Musgrove, Bryant Jurgens, Stephen Opsahl
Modeling the dynamic penetration depth of post-1950s water in unconfined aquifers using environmental tracers: Central Valley, California Modeling the dynamic penetration depth of post-1950s water in unconfined aquifers using environmental tracers: Central Valley, California
The penetration depth of post-1950s recharge (D-1950) in aquifers is a marker that is frequently used to identify groundwater that is susceptible to anthropogenic contamination. Here, we compute D-1950 values at wells, interpolate them in space, and project them across time to map the moving front of modern recharge in four dimensions in the Central Valley aquifer system, California, USA...
Authors
Kirsten Faulkner, Bryant Jurgens, Stefan Voss, Danielle Dupuy, Zeno Levy
Quality of groundwater used for public supply in the continental United States: A comprehensive assessment Quality of groundwater used for public supply in the continental United States: A comprehensive assessment
The presence of contaminants in a source water can constrain its suitability for drinking. The quality of groundwater used for public supply was assessed in 25 principal aquifers (PAs) that account for 84% of groundwater pumped for public supply in the U.S. (89.6 million people on a proportional basis). Each PA was sampled across its lateral extent using an equal-area grid, typically...
Authors
Kenneth Belitz, Miranda Fram, Bruce Lindsey, Paul Stackelberg, Laura Bexfield, Tyler D. Johnson, Bryant Jurgens, James Kingsbury, Peter McMahon, Neil Dubrovsky
Over a third of groundwater in USA public-supply aquifers is Anthropocene-age and susceptible to surface contamination Over a third of groundwater in USA public-supply aquifers is Anthropocene-age and susceptible to surface contamination
The distribution of groundwater age is useful for evaluating the susceptibility and sustainability of groundwater resources. Here, we compute the aquifer-scale cumulative distribution function to characterize the age distribution for 21 Principal Aquifers that account for ~80% of public-supply pumping in the United States. The aquifer-scale cumulative distribution function for each...
Authors
Bryant Jurgens, Kirsten Faulkner, Peter McMahon, Andrew Hunt, Gerolamo Casile, Megan Young, Kenneth Belitz
Effects of imported recharge on fluoride trends in groundwater used for public supply in California Effects of imported recharge on fluoride trends in groundwater used for public supply in California
Fluoride is a naturally occurring element in groundwater that supports bone and dental health at low concentrations but can cause health problems at elevated concentrations in drinking water. This study investigates spatial and temporal trends for fluoride concentrations in untreated groundwater from over 20,000 public supply wells in California. The presence of a significant temporal...
Authors
Jennifer Harkness, Bryant Jurgens
Critical aquifer overdraft accelerates degradation of groundwater quality in California’s Central Valley during drought Critical aquifer overdraft accelerates degradation of groundwater quality in California’s Central Valley during drought
Drought-induced pumpage has precipitated dramatic groundwater-level declines in California’s Central Valley over the past 30 years, but the impacts of aquifer overdraft on water quality are poorly understood. This study coupled over 160,000 measurements of nitrate from ∼6,000 public-supply wells with a 30-year reconstruction of groundwater levels throughout the Central Valley to evaluate...
Authors
Zeno Levy, Bryant Jurgens, Karen Burow, Stefan Voss, Kirsten Faulkner, Jose Arroyo-Lopez, Miranda Fram
A multi-tracer and well-bore flow profile approach to determine occurrence, movement, and sources of perchlorate in groundwater A multi-tracer and well-bore flow profile approach to determine occurrence, movement, and sources of perchlorate in groundwater
The purpose of this study is to determine the occurrence, movement and sources of perchlorate in groundwater using a comprehensive set of environmental tracers coupled with discreet borehole data. Potential sources of perchlorate to groundwater at the study site have been attributed to waste disposal and industrial activities as well as to past agricultural operations. Perchlorate...
Authors
Michael Wright, John Izbicki, Bryant Jurgens
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: 20
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...
Data for karst groundwater vulnerability determined by modeled age and residence time tracers Data for karst groundwater vulnerability determined by modeled age and residence time tracers
Groundwater samples collected from the Edwards aquifer in south-central Texas were analyzed for water-quality data to assess aquifer susceptibility to contaminants. Water-quality data included environmental tracers of groundwater age (tritium, tritiogenic helium-3, sulfur hexafluoride, carbon-14, and radiogenic helium-4), calibrated to lumped parameter models (LPMs). Groundwater samples...
Data for Per- and Polyfluoroalkyl Substances (PFAS) in groundwater samples collected by the California Groundwater Ambient Monitoring and Assessment Priority Basin Project, 2019-2023 Data for Per- and Polyfluoroalkyl Substances (PFAS) in groundwater samples collected by the California Groundwater Ambient Monitoring and Assessment Priority Basin Project, 2019-2023
The California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) analyzed for 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...
Generalized use classification for groundwater sites in California with publicly available water-quality data in the U.S. Geological Survey National Water Information System (NWIS) data archive (ver. 1.1, April 2025) Generalized use classification for groundwater sites in California with publicly available water-quality data in the U.S. Geological Survey National Water Information System (NWIS) data archive (ver. 1.1, April 2025)
The U.S. Geological Survey Water Data for the Nation (WDFN; U.S. Geological Survey, 2025) data archive contains publicly available water-quality data for approximately 21,000 groundwater wells and springs in California. This data release publishes site type information and a generalized use classification for each site. The generalized use category is derived from, but is not equivalent...
Data for Distribution of Groundwater Age in Aquifers Used for Public Supply in the Continental United States, 2004 - 2017 (Version 1.1: June 2022) Data for Distribution of Groundwater Age in Aquifers Used for Public Supply in the Continental United States, 2004 - 2017 (Version 1.1: June 2022)
This data release documents seven tables that contain environmental tracer data and lumped parameter model (LPM) results that are used for assessing the distribution of groundwater age in 21 Principal Aquifers of the continental United States. Groundwater samples were collected from 1,279 sites and analyzed for environmental tracers: tritium, tritiogenic helium-3, sulfur hexafluoride...
Data for assessing the penetration depth post-1950s water in the Central Valley aquifer system, California (July 2022) Data for assessing the penetration depth post-1950s water in the Central Valley aquifer system, California (July 2022)
This dataset provides groundwater ages estimates that were used in an assessment of the penetration depth of modern groundwater in the Central Valley aquifer system (CVAL). Groundwater ages were estimated by calibration of environmental tracers (tritium, tritiogenic helium-3, chlorofluorocarbons, sulfur hexafluoride, carbon-14 and radiogenic helium-4) to lumped parameter models (LPMs)...
Water use information for sites sampled by the California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP), 2004-2021 (ver. 4.0, April 2025) Water use information for sites sampled by the California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP), 2004-2021 (ver. 4.0, April 2025)
The U.S. Geological Survey collected water-quality samples from 3,359 sites between May 2004 and November 2024 for the California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP). The GAMA-PBP is a cooperative project with the California State Water Resources Control Board (SWRCB). The primary objectives of the GAMA-PBP are: (1) to assess the...
Data for Time Scales of Arsenic Variability and the Role of High-Frequency Monitoring at Three Water-Supply Wells in New Hampshire, USA Data for Time Scales of Arsenic Variability and the Role of High-Frequency Monitoring at Three Water-Supply Wells in New Hampshire, USA
This data release consists of data (in four tables) for assessing the time scales of arsenic variability in three production wells in New Hampshire; tables that describe the data fields in the data tables are also included in the data release. High-frequency (every 5 to 15 minutes) and bi-monthly water-quality monitoring of a bedrock-aquifer domestic well (425651070573701), a bedrock...
Filter Total Items: 60
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 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 Lowenstern, Laura E. Clor, Andrew 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 Tokranov, Katherine Ransom, Laura Bexfield, Bruce Lindsey, Elise Watson, Danielle Dupuy, Paul Stackelberg, Miranda Fram, Stefan Voss, James Kingsbury, Bryant 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 Levy, Bryant Jurgens, Kirsten Faulkner, Jennifer Harkness, Miranda 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 Harkness, Patrick McCarthy, Bryant Jurgens, Zeno Levy
Karst groundwater vulnerability determined by modeled age and residence time tracers Karst groundwater vulnerability determined by modeled age and residence time tracers
Karst aquifers are a vital groundwater resource globally, but features such as rapid recharge and conduit flow make them highly vulnerable to land-surface contamination. We apply environmental age tracers to the south-central Texas Edwards aquifer, a karst resource in a rapidly urbanizing and drought-prone region, to assess vulnerability to land-surface contamination and risks unique to...
Authors
MaryLynn Musgrove, Bryant Jurgens, Stephen Opsahl
Modeling the dynamic penetration depth of post-1950s water in unconfined aquifers using environmental tracers: Central Valley, California Modeling the dynamic penetration depth of post-1950s water in unconfined aquifers using environmental tracers: Central Valley, California
The penetration depth of post-1950s recharge (D-1950) in aquifers is a marker that is frequently used to identify groundwater that is susceptible to anthropogenic contamination. Here, we compute D-1950 values at wells, interpolate them in space, and project them across time to map the moving front of modern recharge in four dimensions in the Central Valley aquifer system, California, USA...
Authors
Kirsten Faulkner, Bryant Jurgens, Stefan Voss, Danielle Dupuy, Zeno Levy
Quality of groundwater used for public supply in the continental United States: A comprehensive assessment Quality of groundwater used for public supply in the continental United States: A comprehensive assessment
The presence of contaminants in a source water can constrain its suitability for drinking. The quality of groundwater used for public supply was assessed in 25 principal aquifers (PAs) that account for 84% of groundwater pumped for public supply in the U.S. (89.6 million people on a proportional basis). Each PA was sampled across its lateral extent using an equal-area grid, typically...
Authors
Kenneth Belitz, Miranda Fram, Bruce Lindsey, Paul Stackelberg, Laura Bexfield, Tyler D. Johnson, Bryant Jurgens, James Kingsbury, Peter McMahon, Neil Dubrovsky
Over a third of groundwater in USA public-supply aquifers is Anthropocene-age and susceptible to surface contamination Over a third of groundwater in USA public-supply aquifers is Anthropocene-age and susceptible to surface contamination
The distribution of groundwater age is useful for evaluating the susceptibility and sustainability of groundwater resources. Here, we compute the aquifer-scale cumulative distribution function to characterize the age distribution for 21 Principal Aquifers that account for ~80% of public-supply pumping in the United States. The aquifer-scale cumulative distribution function for each...
Authors
Bryant Jurgens, Kirsten Faulkner, Peter McMahon, Andrew Hunt, Gerolamo Casile, Megan Young, Kenneth Belitz
Effects of imported recharge on fluoride trends in groundwater used for public supply in California Effects of imported recharge on fluoride trends in groundwater used for public supply in California
Fluoride is a naturally occurring element in groundwater that supports bone and dental health at low concentrations but can cause health problems at elevated concentrations in drinking water. This study investigates spatial and temporal trends for fluoride concentrations in untreated groundwater from over 20,000 public supply wells in California. The presence of a significant temporal...
Authors
Jennifer Harkness, Bryant Jurgens
Critical aquifer overdraft accelerates degradation of groundwater quality in California’s Central Valley during drought Critical aquifer overdraft accelerates degradation of groundwater quality in California’s Central Valley during drought
Drought-induced pumpage has precipitated dramatic groundwater-level declines in California’s Central Valley over the past 30 years, but the impacts of aquifer overdraft on water quality are poorly understood. This study coupled over 160,000 measurements of nitrate from ∼6,000 public-supply wells with a 30-year reconstruction of groundwater levels throughout the Central Valley to evaluate...
Authors
Zeno Levy, Bryant Jurgens, Karen Burow, Stefan Voss, Kirsten Faulkner, Jose Arroyo-Lopez, Miranda Fram
A multi-tracer and well-bore flow profile approach to determine occurrence, movement, and sources of perchlorate in groundwater A multi-tracer and well-bore flow profile approach to determine occurrence, movement, and sources of perchlorate in groundwater
The purpose of this study is to determine the occurrence, movement and sources of perchlorate in groundwater using a comprehensive set of environmental tracers coupled with discreet borehole data. Potential sources of perchlorate to groundwater at the study site have been attributed to waste disposal and industrial activities as well as to past agricultural operations. Perchlorate...
Authors
Michael Wright, John Izbicki, Bryant Jurgens
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