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
Filter Total Items: 21
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...
Filter Total Items: 61
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 P. 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 F. 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 S. Fram, Bruce D. Lindsey, Paul E. Stackelberg, Laura M. Bexfield, Tyler D. Johnson, Bryant C. Jurgens, James A. Kingsbury, Peter B. McMahon, Neil M. 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 C. Jurgens, Kirsten Faulkner, Peter B. McMahon, Andrew G. Hunt, Gerolamo C. Casile, Megan B. 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 S. Harkness, Bryant C. 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 F. Levy, Bryant C. Jurgens, Karen R. Burow, Stefan Voss, Kirsten Faulkner, Jose Alfredo Arroyo-Lopez, Miranda S. Fram
Science and Products
Filter Total Items: 21
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...
Filter Total Items: 61
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 P. 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 F. 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 S. Fram, Bruce D. Lindsey, Paul E. Stackelberg, Laura M. Bexfield, Tyler D. Johnson, Bryant C. Jurgens, James A. Kingsbury, Peter B. McMahon, Neil M. 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 C. Jurgens, Kirsten Faulkner, Peter B. McMahon, Andrew G. Hunt, Gerolamo C. Casile, Megan B. 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 S. Harkness, Bryant C. 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 F. Levy, Bryant C. Jurgens, Karen R. Burow, Stefan Voss, Kirsten Faulkner, Jose Alfredo Arroyo-Lopez, Miranda S. Fram