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Miranda Fram

Miranda Fram is a Program Chief, Statewide and National Water Quality Assessments at the California Water Science Center.

Science and Products

link
Map of Hydrogeologic provinces of California and distribution of wells

Groundwater Ambient Monitoring & Assessment (GAMA)

The Groundwater Ambient Monitoring and Assessment Program’s Priority Basin Project (GAMA-PBP) was established by the California State Water Resources Control Board (SWRCB) in response to the Ground-Water Quality Monitoring Act of 2001 (Sections 10780-10782.3 of the California Water Code). The USGS is the technical lead for the GAMA-PBP and between 2004-2012 focused on characterizing the quality of...
By
California Water Science Center
link

Groundwater Ambient Monitoring & Assessment (GAMA)

The Groundwater Ambient Monitoring and Assessment Program’s Priority Basin Project (GAMA-PBP) was established by the California State Water Resources Control Board (SWRCB) in response to the Ground-Water Quality Monitoring Act of 2001 (Sections 10780-10782.3 of the California Water Code). The USGS is the technical lead for the GAMA-PBP and between 2004-2012 focused on characterizing the quality of...
Learn More
link
USGS

Injection, storage, and extraction of water, Roseville, California

The purpose of this study is evaluate how vertical variations in aquifer properties and well hydraulics may affect the injection, storage, and extraction of water and the transport of associated disinfection by-products in the Mehrten Formation underlying the City of Roseville.
By
California Water Science Center
link

Injection, storage, and extraction of water, Roseville, California

The purpose of this study is evaluate how vertical variations in aquifer properties and well hydraulics may affect the injection, storage, and extraction of water and the transport of associated disinfection by-products in the Mehrten Formation underlying the City of Roseville.
Learn More

Predictions of PFAS in groundwater used as a source of drinking water and related data in the conterminous United States

An extreme gradient boosting ensemble tree model predicting per- and polyfluoroalkyl substances (PFAS) occurrence in groundwater at the depths typical of the bottom of public and domestic drinking water supplies across the conterminous United States was developed. PFAS data used to train the model were collected between 2019 and 2022 by the U.S. Geological Survey National Water Quality Network, Gr
By
New England Water Science Center

Data sets for: Status of Water Quality in Groundwater Resources Used for Drinking-Water Supply in the Southeastern San Joaquin Valley, 2013-2015 - California GAMA Priority Basin Project

This data release contains site information and potential explanatory factor data for 1,899 groundwater sites. These sites were used to assess groundwater quality in aquifers used for domestic and public drinking water supply in the southeastern San Joaquin Valley. The southeastern San Joaquin Valley (SESJV) study unit consists of five study areas whose boundaries are defined by the eponymous Cali
By
California Water Science Center

Data for volatile organic compounds in groundwater used for public supply across the United States, 2013-19, and data for associated quality-control samples

This data release includes tables and time-series plots of results for volatile organic compounds (VOCs) analyzed in samples of groundwater used for public supply that were collected by the USGS National Water-Quality Assessment (NAWQA) Project and the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) during 201
By
Water Resources Mission Area

Data for Machine Learning Predictions of Nitrate in Groundwater Used for Drinking Supply in the Conterminous United States

A three-dimensional extreme gradient boosting (XGB) machine learning model was developed to predict the distribution of nitrate in groundwater across the conterminous United States (CONUS). Nitrate was predicted at a 1-square-kilometer (km) resolution for two drinking water zones, each of variable depth, one for domestic supply and one for public supply. The model used measured nitrate concentrati
By
California Water Science Center

Water use information for sites sampled by the California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP), 2004-2021 (ver. 3.0, October 2023)

The U.S. Geological Survey collected water-quality samples from 3,199 sites between May 2004 and April 2022 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 quality of groundwa
By
California Water Science Center

Pesticide constituent data from the California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP), August 2013 - May 2018, schedule 2437 constituents

This Data release presents results for pesticide constituents in 460 samples collected from domestic and public-supply wells in August 2013-May 2018 for the California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP). The samples were analyzed for 225 pesticide constituents on USGS National Water Quality Laboratory analytical schedule 2437. Results from quali
By
California Water Science Center

Water quality and ancillary data for assessment of uranium concentrations in groundwater, San Joaquin Valley, CA (ver. 1.1, December, 2019)

High concentrations of uranium were detected in samples from wells used for domestic drinking water supplies in the San Joaquin Valley. Of 163 domestic wells sampled by the California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) and the National Water Quality Program (NWQP) in 2008-2015, 26 percent had uranium concentrations greater than the U.S. Environm
By
California Water Science Center

Groundwater-Quality Data in the Tule-Tulare-Highlands-Kaweah Shallow Aquifer Study Unit, 2014-2015

The U.S. Geological Survey collected groundwater samples from 95 domestic wells in Tulare and Kings Counties, California in 2014-2015. The wells were sampled for the Tulare Shallow Aquifer Study Unit of the California State Water Resources Control Board Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Projects assessment of the quality of groundwater resources used for d
By
California Water Science Center
Map of the US shaded by principal aquifer. Wells that were sampled are symbolized with circles
Principal aquifers and wells assessed in nationwide NAWQA/GAMA groundwater quality study
Principal aquifers and wells assessed in nationwide NAWQA/GAMA groundwater quality study
Map of the US shaded by principal aquifer. Wells that were sampled are symbolized with circles

Principal aquifers and wells assessed in nationwide NAWQA/GAMA groundwater quality study

Principal aquifers and wells assessed in nationwide NAWQA/GAMA groundwater quality study

Map showing principal aquifers (PAs) and wells that were sampled as part of a Nationwide assessment of the quality of groundwater used for public supply.  

By
California Water Science Center
Map of the US shaded by principal aquifer. Wells that were sampled are symbolized with circles

Principal aquifers and wells assessed in nationwide NAWQA/GAMA groundwater quality study

Principal aquifers and wells assessed in nationwide NAWQA/GAMA groundwater quality study

Map showing principal aquifers (PAs) and wells that were sampled as part of a Nationwide assessment of the quality of groundwater used for public supply.  

By
California Water Science Center
Filter Total Items: 80

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, particularly in dom
Authors
Andrea K. Tokranov, Katherine Marie Ransom, Laura M. Bexfield, Bruce D. Lindsey, Elise Watson, Danielle Dupuy, Paul Stackelberg, Miranda S. Fram, Stefan Voss, James A. Kingsbury, Bryant Jurgens, Kelly Smalling, Paul M. Bradley
By
Water Resources Mission Area, National Water Quality Program, California Water Science Center, New England Water Science Center, New Jersey Water Science Center, New Mexico Water Science Center, South Atlantic Water Science Center (SAWSC), Lower Mississippi-Gulf Water Science Center

Status and understanding of groundwater quality in the Mojave Basin Domestic-Supply Aquifer study unit, 2018—California GAMA Priority Basin Project

Groundwater quality in the western part of the Mojave Desert in San Bernardino County, California, was investigated in 2018 as part of the California State Water Resources Control Board Groundwater Ambient Monitoring and Assessment Program Priority Basin Project. The Mojave Basin Domestic-Supply Aquifer study unit (MOBS) region was divided into two study areas—floodplain and regional—to assess dif
Authors
Krishangi D. Groover, Miranda S. Fram, Zeno F. Levy
By
Water Resources Mission Area, California Water Science Center

Status of water quality in groundwater resources used for drinking-water supply in the southeastern San Joaquin Valley, 2013–15—California GAMA Priority Basin Project

The California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) investigated water quality of groundwater resources used for drinking-water supplies in the Madera-Chowchilla, Kings, Kaweah, Tule, and Tulare Lake groundwater subbasins of the southeastern San Joaquin Valley during 2013–15. The study focused primarily on groundwater resources used for domestic-s
Authors
Karen R. Burow, Jennifer L. Shelton, Miranda S. Fram
By
Water Resources Mission Area, California Water Science Center

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 of time-ser
Authors
Zeno Levy, Bryant Jurgens, Kirsten Faulkner, Jennifer S. Harkness, Miranda S. Fram
By
Water Resources Mission Area, California Water Science Center

Quality of groundwater used for domestic drinking-water supply in the Coachella Valley, 2020

Groundwater is the primary source of drinking water in the Coachella Valley in the desert region of southern California. Although most people in Coachella Valley are served by public drinking-water systems, about 20,000 people rely on private domestic or small-system wells (referred to herein as domestic wells). Recently, the U.S. Geological Survey (USGS) found that 39 percent of the groundwater r
Authors
Andrew L. Soldavini, Jennifer S. Harkness, Zeno F. Levy, Miranda S. Fram
By
Water Resources Mission Area, California Water Science Center

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 with 60 wells

Authors
Kenneth Belitz, Miranda S. Fram, Bruce D. Lindsey, Paul Stackelberg, Laura M. Bexfield, Tyler D. Johnson, Bryant Jurgens, James A. Kingsbury, Peter B. McMahon, Neil M. Dubrovsky
By
Water Resources Mission Area, California Water Science Center, Colorado Water Science Center, New Mexico Water Science Center

Volatile organic compounds in groundwater used for public supply across the United States: Occurrence, explanatory factors, and human-health context

This systematic assessment of occurrence for 85 volatile organic compounds (VOCs) in raw (untreated) groundwater used for public supply across the United States (U.S.), which includes 43 compounds not previously monitored by national studies, relates VOC occurrence to explanatory factors and assesses VOC detections in a human-health context. Samples were collected in 2013 through 2019 from 1537 pu
Authors
Laura M. Bexfield, Kenneth Belitz, Miranda S. Fram, Bruce D. Lindsey
By
Water Resources Mission Area, California Water Science Center, New Mexico Water Science Center

Machine learning predictions of nitrate in groundwater used for drinking supply in the conterminous United States

Groundwater is an important source of drinking water supplies in the conterminous United State (CONUS), and presence of high nitrate concentrations may limit usability of groundwater in some areas because of the potential negative health effects. Prediction of locations of high nitrate groundwater is needed to focus mitigation and relief efforts. A three-dimensional extreme gradient boosting (XGB)
Authors
Katherine Marie Ransom, Bernard T. Nolan, Paul Stackelberg, Kenneth Belitz, Miranda S. Fram
By
Water Resources Mission Area, California Water Science Center

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 dynamic r
Authors
Zeno Levy, Bryant Jurgens, Karen R. Burow, Stefan Voss, Kirsten Faulkner, Jose Alfredo Arroyo-Lopez, Miranda S. Fram
By
Water Resources Mission Area, California Water Science Center

Status and understanding of groundwater quality in the northern Sierra Nevada foothills domestic-supply aquifer study units, 2015–17—California GAMA Priority Basin Project

Groundwater quality in the northern Sierra Nevada foothills region of California was investigated as part of California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring Assessment Priority Basin Project (GAMA-PBP). The region was divided into two study units: the Yuba-Bear watersheds (YBW) study unit and the American-Cosumnes-Mokelumne watersheds (ACMW) study unit. The GA
Authors
Zeno F. Levy, Miranda S. Fram
By
Water Resources Mission Area, California Water Science Center

Geologic influences on the quality of groundwater used for domestic supply in the northern Sierra Nevada Foothills

Approximately 2 million California residents depend on groundwater from domestic wells for their drinking-water supply. The State of California, in collaboration with the U.S. Geological Survey, created the Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) to assess the quality of groundwater used for domestic supply throughout the state and determine regional
Authors
Zeno F. Levy, Miranda S. Fram
By
Water Resources Mission Area, California Water Science Center

Identifying areas of degrading and improving groundwater-quality conditions in the State of California, USA, 1974-2014

Areas of improving and degrading groundwater-quality conditions in the State of California were assessed using spatial weighting of a new metric for scoring wells based on constituent concentrations and the direction and magnitude of a trend slope (Sen). Individual well scores were aggregated across 2135 equal-area grid cells covering the entire groundwater resource used for public supply in the s
Authors
Bryant Jurgens, Miranda S. Fram, Jeffrey Rutledge, George L. Bennett
By
Water Resources Mission Area, California Water Science Center

Science and Products

link
Map of Hydrogeologic provinces of California and distribution of wells

Groundwater Ambient Monitoring & Assessment (GAMA)

The Groundwater Ambient Monitoring and Assessment Program’s Priority Basin Project (GAMA-PBP) was established by the California State Water Resources Control Board (SWRCB) in response to the Ground-Water Quality Monitoring Act of 2001 (Sections 10780-10782.3 of the California Water Code). The USGS is the technical lead for the GAMA-PBP and between 2004-2012 focused on characterizing the quality of...
By
California Water Science Center
link

Groundwater Ambient Monitoring & Assessment (GAMA)

The Groundwater Ambient Monitoring and Assessment Program’s Priority Basin Project (GAMA-PBP) was established by the California State Water Resources Control Board (SWRCB) in response to the Ground-Water Quality Monitoring Act of 2001 (Sections 10780-10782.3 of the California Water Code). The USGS is the technical lead for the GAMA-PBP and between 2004-2012 focused on characterizing the quality of...
Learn More
link
USGS

Injection, storage, and extraction of water, Roseville, California

The purpose of this study is evaluate how vertical variations in aquifer properties and well hydraulics may affect the injection, storage, and extraction of water and the transport of associated disinfection by-products in the Mehrten Formation underlying the City of Roseville.
By
California Water Science Center
link

Injection, storage, and extraction of water, Roseville, California

The purpose of this study is evaluate how vertical variations in aquifer properties and well hydraulics may affect the injection, storage, and extraction of water and the transport of associated disinfection by-products in the Mehrten Formation underlying the City of Roseville.
Learn More

Predictions of PFAS in groundwater used as a source of drinking water and related data in the conterminous United States

An extreme gradient boosting ensemble tree model predicting per- and polyfluoroalkyl substances (PFAS) occurrence in groundwater at the depths typical of the bottom of public and domestic drinking water supplies across the conterminous United States was developed. PFAS data used to train the model were collected between 2019 and 2022 by the U.S. Geological Survey National Water Quality Network, Gr
By
New England Water Science Center

Data sets for: Status of Water Quality in Groundwater Resources Used for Drinking-Water Supply in the Southeastern San Joaquin Valley, 2013-2015 - California GAMA Priority Basin Project

This data release contains site information and potential explanatory factor data for 1,899 groundwater sites. These sites were used to assess groundwater quality in aquifers used for domestic and public drinking water supply in the southeastern San Joaquin Valley. The southeastern San Joaquin Valley (SESJV) study unit consists of five study areas whose boundaries are defined by the eponymous Cali
By
California Water Science Center

Data for volatile organic compounds in groundwater used for public supply across the United States, 2013-19, and data for associated quality-control samples

This data release includes tables and time-series plots of results for volatile organic compounds (VOCs) analyzed in samples of groundwater used for public supply that were collected by the USGS National Water-Quality Assessment (NAWQA) Project and the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) during 201
By
Water Resources Mission Area

Data for Machine Learning Predictions of Nitrate in Groundwater Used for Drinking Supply in the Conterminous United States

A three-dimensional extreme gradient boosting (XGB) machine learning model was developed to predict the distribution of nitrate in groundwater across the conterminous United States (CONUS). Nitrate was predicted at a 1-square-kilometer (km) resolution for two drinking water zones, each of variable depth, one for domestic supply and one for public supply. The model used measured nitrate concentrati
By
California Water Science Center

Water use information for sites sampled by the California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP), 2004-2021 (ver. 3.0, October 2023)

The U.S. Geological Survey collected water-quality samples from 3,199 sites between May 2004 and April 2022 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 quality of groundwa
By
California Water Science Center

Pesticide constituent data from the California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP), August 2013 - May 2018, schedule 2437 constituents

This Data release presents results for pesticide constituents in 460 samples collected from domestic and public-supply wells in August 2013-May 2018 for the California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP). The samples were analyzed for 225 pesticide constituents on USGS National Water Quality Laboratory analytical schedule 2437. Results from quali
By
California Water Science Center

Water quality and ancillary data for assessment of uranium concentrations in groundwater, San Joaquin Valley, CA (ver. 1.1, December, 2019)

High concentrations of uranium were detected in samples from wells used for domestic drinking water supplies in the San Joaquin Valley. Of 163 domestic wells sampled by the California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) and the National Water Quality Program (NWQP) in 2008-2015, 26 percent had uranium concentrations greater than the U.S. Environm
By
California Water Science Center

Groundwater-Quality Data in the Tule-Tulare-Highlands-Kaweah Shallow Aquifer Study Unit, 2014-2015

The U.S. Geological Survey collected groundwater samples from 95 domestic wells in Tulare and Kings Counties, California in 2014-2015. The wells were sampled for the Tulare Shallow Aquifer Study Unit of the California State Water Resources Control Board Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Projects assessment of the quality of groundwater resources used for d
By
California Water Science Center
Map of the US shaded by principal aquifer. Wells that were sampled are symbolized with circles
Principal aquifers and wells assessed in nationwide NAWQA/GAMA groundwater quality study
Principal aquifers and wells assessed in nationwide NAWQA/GAMA groundwater quality study
Map of the US shaded by principal aquifer. Wells that were sampled are symbolized with circles

Principal aquifers and wells assessed in nationwide NAWQA/GAMA groundwater quality study

Principal aquifers and wells assessed in nationwide NAWQA/GAMA groundwater quality study

Map showing principal aquifers (PAs) and wells that were sampled as part of a Nationwide assessment of the quality of groundwater used for public supply.  

By
California Water Science Center
Map of the US shaded by principal aquifer. Wells that were sampled are symbolized with circles

Principal aquifers and wells assessed in nationwide NAWQA/GAMA groundwater quality study

Principal aquifers and wells assessed in nationwide NAWQA/GAMA groundwater quality study

Map showing principal aquifers (PAs) and wells that were sampled as part of a Nationwide assessment of the quality of groundwater used for public supply.  

By
California Water Science Center
Filter Total Items: 80

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, particularly in dom
Authors
Andrea K. Tokranov, Katherine Marie Ransom, Laura M. Bexfield, Bruce D. Lindsey, Elise Watson, Danielle Dupuy, Paul Stackelberg, Miranda S. Fram, Stefan Voss, James A. Kingsbury, Bryant Jurgens, Kelly Smalling, Paul M. Bradley
By
Water Resources Mission Area, National Water Quality Program, California Water Science Center, New England Water Science Center, New Jersey Water Science Center, New Mexico Water Science Center, South Atlantic Water Science Center (SAWSC), Lower Mississippi-Gulf Water Science Center

Status and understanding of groundwater quality in the Mojave Basin Domestic-Supply Aquifer study unit, 2018—California GAMA Priority Basin Project

Groundwater quality in the western part of the Mojave Desert in San Bernardino County, California, was investigated in 2018 as part of the California State Water Resources Control Board Groundwater Ambient Monitoring and Assessment Program Priority Basin Project. The Mojave Basin Domestic-Supply Aquifer study unit (MOBS) region was divided into two study areas—floodplain and regional—to assess dif
Authors
Krishangi D. Groover, Miranda S. Fram, Zeno F. Levy
By
Water Resources Mission Area, California Water Science Center

Status of water quality in groundwater resources used for drinking-water supply in the southeastern San Joaquin Valley, 2013–15—California GAMA Priority Basin Project

The California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) investigated water quality of groundwater resources used for drinking-water supplies in the Madera-Chowchilla, Kings, Kaweah, Tule, and Tulare Lake groundwater subbasins of the southeastern San Joaquin Valley during 2013–15. The study focused primarily on groundwater resources used for domestic-s
Authors
Karen R. Burow, Jennifer L. Shelton, Miranda S. Fram
By
Water Resources Mission Area, California Water Science Center

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 of time-ser
Authors
Zeno Levy, Bryant Jurgens, Kirsten Faulkner, Jennifer S. Harkness, Miranda S. Fram
By
Water Resources Mission Area, California Water Science Center

Quality of groundwater used for domestic drinking-water supply in the Coachella Valley, 2020

Groundwater is the primary source of drinking water in the Coachella Valley in the desert region of southern California. Although most people in Coachella Valley are served by public drinking-water systems, about 20,000 people rely on private domestic or small-system wells (referred to herein as domestic wells). Recently, the U.S. Geological Survey (USGS) found that 39 percent of the groundwater r
Authors
Andrew L. Soldavini, Jennifer S. Harkness, Zeno F. Levy, Miranda S. Fram
By
Water Resources Mission Area, California Water Science Center

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 with 60 wells

Authors
Kenneth Belitz, Miranda S. Fram, Bruce D. Lindsey, Paul Stackelberg, Laura M. Bexfield, Tyler D. Johnson, Bryant Jurgens, James A. Kingsbury, Peter B. McMahon, Neil M. Dubrovsky
By
Water Resources Mission Area, California Water Science Center, Colorado Water Science Center, New Mexico Water Science Center

Volatile organic compounds in groundwater used for public supply across the United States: Occurrence, explanatory factors, and human-health context

This systematic assessment of occurrence for 85 volatile organic compounds (VOCs) in raw (untreated) groundwater used for public supply across the United States (U.S.), which includes 43 compounds not previously monitored by national studies, relates VOC occurrence to explanatory factors and assesses VOC detections in a human-health context. Samples were collected in 2013 through 2019 from 1537 pu
Authors
Laura M. Bexfield, Kenneth Belitz, Miranda S. Fram, Bruce D. Lindsey
By
Water Resources Mission Area, California Water Science Center, New Mexico Water Science Center

Machine learning predictions of nitrate in groundwater used for drinking supply in the conterminous United States

Groundwater is an important source of drinking water supplies in the conterminous United State (CONUS), and presence of high nitrate concentrations may limit usability of groundwater in some areas because of the potential negative health effects. Prediction of locations of high nitrate groundwater is needed to focus mitigation and relief efforts. A three-dimensional extreme gradient boosting (XGB)
Authors
Katherine Marie Ransom, Bernard T. Nolan, Paul Stackelberg, Kenneth Belitz, Miranda S. Fram
By
Water Resources Mission Area, California Water Science Center

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 dynamic r
Authors
Zeno Levy, Bryant Jurgens, Karen R. Burow, Stefan Voss, Kirsten Faulkner, Jose Alfredo Arroyo-Lopez, Miranda S. Fram
By
Water Resources Mission Area, California Water Science Center

Status and understanding of groundwater quality in the northern Sierra Nevada foothills domestic-supply aquifer study units, 2015–17—California GAMA Priority Basin Project

Groundwater quality in the northern Sierra Nevada foothills region of California was investigated as part of California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring Assessment Priority Basin Project (GAMA-PBP). The region was divided into two study units: the Yuba-Bear watersheds (YBW) study unit and the American-Cosumnes-Mokelumne watersheds (ACMW) study unit. The GA
Authors
Zeno F. Levy, Miranda S. Fram
By
Water Resources Mission Area, California Water Science Center

Geologic influences on the quality of groundwater used for domestic supply in the northern Sierra Nevada Foothills

Approximately 2 million California residents depend on groundwater from domestic wells for their drinking-water supply. The State of California, in collaboration with the U.S. Geological Survey, created the Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) to assess the quality of groundwater used for domestic supply throughout the state and determine regional
Authors
Zeno F. Levy, Miranda S. Fram
By
Water Resources Mission Area, California Water Science Center

Identifying areas of degrading and improving groundwater-quality conditions in the State of California, USA, 1974-2014

Areas of improving and degrading groundwater-quality conditions in the State of California were assessed using spatial weighting of a new metric for scoring wells based on constituent concentrations and the direction and magnitude of a trend slope (Sen). Individual well scores were aggregated across 2135 equal-area grid cells covering the entire groundwater resource used for public supply in the s
Authors
Bryant Jurgens, Miranda S. Fram, Jeffrey Rutledge, George L. Bennett
By
Water Resources Mission Area, California Water Science Center
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