Zeno Levy, Ph.D.
I am a groundwater hydrologist and geochemist at the California Water Science Center specializing in drinking-water resources.
I work primarily on the California State Water Resources Control Board's Groundwater Ambient Monitoring and Assessment (GAMA) program. My research deals with understanding hydrologic and geochemical factors driving changes in groundwater-resource quality over time. To accomplish this, I develop novel research integrating basic hydrogeochemical methods with “big data” statistical learning techniques. I develop computational tools to query large, geochemical databases and characterize regional drivers of groundwater-quality trends. I am interested in identifying specific processes with broad transfer value that can help to forecast the fate drinking-water resources to extreme precipitation and drought.
Science and Products
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...
Data for Analysis of Decadal Trends in the Quality of Groundwater Used for Public Drinking-Water Supply in California, 2004-2023, California GAMA Priority Basin Project Data for Analysis of Decadal Trends in the Quality of Groundwater Used for Public Drinking-Water Supply in California, 2004-2023, California GAMA Priority Basin Project
This data release documents datasets supporting analysis of decadal trends in the quality of groundwater resources used for public drinking-water supply across California. The analysis primarily utilizes samples collected by the U.S. Geological Survey's Groundwater Ambient Monitoring and Assessment Priority Basin Project (GAMA-PBP) during 2004-2023 as part of a cooperative research...
Example Groundwater-Level Datasets and Benchmarking Results for the Automated Regional Correlation Analysis for Hydrologic Record Imputation (ARCHI) Software Package Example Groundwater-Level Datasets and Benchmarking Results for the Automated Regional Correlation Analysis for Hydrologic Record Imputation (ARCHI) Software Package
This data release provides two example groundwater-level datasets used to benchmark the Automated Regional Correlation Analysis for Hydrologic Record Imputation (ARCHI) software package (Levy and others, 2024). The first dataset contains groundwater-level records and site metadata for wells located on Long Island, New York (NY) and some surrounding mainland sites in New York and...
Groundwater-Quality Time-Series Analyses and Potential Explanatory Factors of Drought-Response Patterns at Public-Supply Wells, San Joaquin Valley, California, 2000-2022 Groundwater-Quality Time-Series Analyses and Potential Explanatory Factors of Drought-Response Patterns at Public-Supply Wells, San Joaquin Valley, California, 2000-2022
This data release documents time-series analyses of aqueous-chemistry data from public-supply wells (PSWs) and associated potential explanatory factors to characterize responses of groundwater quality to drought and recovery periods in California’s San Joaquin Valley (SJV) during 2000-2022. Annual median nitrate values were computed for PSWs throughout the SJV during the period of study...
Environmental chemistry from selected sites in Lakeport, Lake County, California (version 1.1, August 2023) Environmental chemistry from selected sites in Lakeport, Lake County, California (version 1.1, August 2023)
This data release documents chemical analyses of environmental samples collected by the U.S. Geological Survey (USGS) in Lakeport (Lake County, California) during July 11-12, 2022. Environmental samples were collected at selected sites to assess the effects of lead-based paint on soil chemistry. This sampling was made as part of a broader study to attribute sources of lead in soils in...
Compilation of Public-Supply Well Construction Depths in California Compilation of Public-Supply Well Construction Depths in California
This data release is a compilation of construction depth information for 12,383 active and inactive public-supply wells (PSWs) in California from various data sources. Construction data from multiple sources were indexed by the California State Water Resources Control Board Division of Drinking Water (DDW) primary station code (PS Code). Five different data sources were compared with the...
Groundwater-quality data in the Modesto-Turlock-Merced Domestic-Supply Aquifer Study Unit, 2020-2021: Results from the California GAMA Priority Basin Project Groundwater-quality data in the Modesto-Turlock-Merced Domestic-Supply Aquifer Study Unit, 2020-2021: Results from the California GAMA Priority Basin Project
The U.S. Geological Survey collected groundwater samples from 71 wells used for domestic and small system drinking water supplies in Stanislaus and Merced counties of California during 2020-2021. The wells were sampled for the Modesto-Turlock-Merced Domestic-Supply Aquifer Study Unit of the State Water Resources Control Board Groundwater Ambient Monitoring and Assessment (GAMA) Program...
Filter Total Items: 20
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
Decadal trends in the quality of groundwater used for public drinking-water supply in California, 2004–2023, California groundwater ambient monitoring and assessment program, priority basin project Decadal trends in the quality of groundwater used for public drinking-water supply in California, 2004–2023, California groundwater ambient monitoring and assessment program, priority basin project
This study provides a comprehensive assessment of decadal changes in the quality of groundwater used for public drinking-water supply at 444 monitoring sites across California during 2004–2023. We assessed decadal step trends in groundwater quality for 145 water-quality constituents and geochemical indicators statewide and across geographic and land-use based network groups. We evaluated...
Authors
Zeno F. Levy, Andrew Lee Soldavini
ARCHI: A new R package for automated imputation of regionally correlated hydrologic records ARCHI: A new R package for automated imputation of regionally correlated hydrologic records
Missing data in hydrological records can limit resource assessment, process understanding, and predictive modeling. Here, we present ARCHI (Automated Regional Correlation Analysis for Hydrologic Record Imputation), a new, open-source software package in R designed to aggregate, impute, cluster, and visualize regionally correlated hydrologic records. ARCHI imputes missing data in “target”...
Authors
Zeno F. Levy, Robin L. Glas, Timothy J. Stagnitta, Neil Terry
Status and understanding of groundwater quality in the Mojave Basin Domestic-Supply Aquifer study unit, 2018—California GAMA Priority Basin Project 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...
Authors
Krishangi D. Groover, Miranda S. Fram, Zeno F. Levy
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
Non-USGS Publications**
Levy ZF, Rosenberry DO, Moucha R, Mushet DM, Goldhaber MB, LaBaugh JW, Fiorentino AJ, Siegel DI. 2018. Drought-induced recharge promotes long-term storage of porewater salinity beneath a prairie wetland. Journal of Hydrology 557: 391-406, https://doi.org/10.1016/j.jhydrol.2017.12.005.
Levy ZF, Mills CT, Lu Z, Goldhaber MB, Rosenberry DO, Mushet DM, Lautz LK, Zhou X, Siegel DI. 2018. Using halogens (Cl, Br, I) to understand the hydrogeochemical evolution of drought-derived saline porewater beneath a prairie wetland. Chemical Geology 476: 191-207, https://doi.org/10.1016/j.chemgeo.2017.11.017.
Levy ZF, Siegel DI, Glaser PH, Samson SD, Dasgupta SS. 2016. Peat porewaters have contrasting geochemical fingerprints for groundwater recharge and discharge due to matrix diffusion in a large, northern bog-fen complex. Journal of Hydrology 541: 941-951, https://dx.doi.org/10.1016/j.jhydrol.2016.08.001.
Levy ZF, Smardon RC, Bays JS, Meyer D. 2014. A Point Source of a Different Color: Identifying a Gap in United States Regulatory Policy for “Green” CSO Treatment Using Constructed Wetlands. Sustainability 6(5): 2392-2412, https://dx.doi.org/10.3390/su6052392.
Levy ZF, Siegel DI, Dasgupta SS, Glaser PH, Welker JM. 2014. Stable isotopes of water show deep seasonal recharge in northern bogs and fens. Hydrological Processes 228: 4938-4952, https://dx.doi.org/10.1002/hyp.9983.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
ARCHI: Automated Regional Correlation Analysis for Hydrologic Record Imputation, v1.0.0 ARCHI: Automated Regional Correlation Analysis for Hydrologic Record Imputation, v1.0.0
Welcome to Automated Regional Correlation Analysis for Hydrologic Record Imputation (ARCHI). ARCHI provides a workflow and interactive platform for regional-scale hydrologic record imputation. ARCHI allows users to aggregate, visualize, and impute records with irregular monitoring frequency at annual, seasonal, monthly, weekly, and daily timesteps. Missing data at “target” sites are...
Science and Products
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...
Data for Analysis of Decadal Trends in the Quality of Groundwater Used for Public Drinking-Water Supply in California, 2004-2023, California GAMA Priority Basin Project Data for Analysis of Decadal Trends in the Quality of Groundwater Used for Public Drinking-Water Supply in California, 2004-2023, California GAMA Priority Basin Project
This data release documents datasets supporting analysis of decadal trends in the quality of groundwater resources used for public drinking-water supply across California. The analysis primarily utilizes samples collected by the U.S. Geological Survey's Groundwater Ambient Monitoring and Assessment Priority Basin Project (GAMA-PBP) during 2004-2023 as part of a cooperative research...
Example Groundwater-Level Datasets and Benchmarking Results for the Automated Regional Correlation Analysis for Hydrologic Record Imputation (ARCHI) Software Package Example Groundwater-Level Datasets and Benchmarking Results for the Automated Regional Correlation Analysis for Hydrologic Record Imputation (ARCHI) Software Package
This data release provides two example groundwater-level datasets used to benchmark the Automated Regional Correlation Analysis for Hydrologic Record Imputation (ARCHI) software package (Levy and others, 2024). The first dataset contains groundwater-level records and site metadata for wells located on Long Island, New York (NY) and some surrounding mainland sites in New York and...
Groundwater-Quality Time-Series Analyses and Potential Explanatory Factors of Drought-Response Patterns at Public-Supply Wells, San Joaquin Valley, California, 2000-2022 Groundwater-Quality Time-Series Analyses and Potential Explanatory Factors of Drought-Response Patterns at Public-Supply Wells, San Joaquin Valley, California, 2000-2022
This data release documents time-series analyses of aqueous-chemistry data from public-supply wells (PSWs) and associated potential explanatory factors to characterize responses of groundwater quality to drought and recovery periods in California’s San Joaquin Valley (SJV) during 2000-2022. Annual median nitrate values were computed for PSWs throughout the SJV during the period of study...
Environmental chemistry from selected sites in Lakeport, Lake County, California (version 1.1, August 2023) Environmental chemistry from selected sites in Lakeport, Lake County, California (version 1.1, August 2023)
This data release documents chemical analyses of environmental samples collected by the U.S. Geological Survey (USGS) in Lakeport (Lake County, California) during July 11-12, 2022. Environmental samples were collected at selected sites to assess the effects of lead-based paint on soil chemistry. This sampling was made as part of a broader study to attribute sources of lead in soils in...
Compilation of Public-Supply Well Construction Depths in California Compilation of Public-Supply Well Construction Depths in California
This data release is a compilation of construction depth information for 12,383 active and inactive public-supply wells (PSWs) in California from various data sources. Construction data from multiple sources were indexed by the California State Water Resources Control Board Division of Drinking Water (DDW) primary station code (PS Code). Five different data sources were compared with the...
Groundwater-quality data in the Modesto-Turlock-Merced Domestic-Supply Aquifer Study Unit, 2020-2021: Results from the California GAMA Priority Basin Project Groundwater-quality data in the Modesto-Turlock-Merced Domestic-Supply Aquifer Study Unit, 2020-2021: Results from the California GAMA Priority Basin Project
The U.S. Geological Survey collected groundwater samples from 71 wells used for domestic and small system drinking water supplies in Stanislaus and Merced counties of California during 2020-2021. The wells were sampled for the Modesto-Turlock-Merced Domestic-Supply Aquifer Study Unit of the State Water Resources Control Board Groundwater Ambient Monitoring and Assessment (GAMA) Program...
Filter Total Items: 20
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
Decadal trends in the quality of groundwater used for public drinking-water supply in California, 2004–2023, California groundwater ambient monitoring and assessment program, priority basin project Decadal trends in the quality of groundwater used for public drinking-water supply in California, 2004–2023, California groundwater ambient monitoring and assessment program, priority basin project
This study provides a comprehensive assessment of decadal changes in the quality of groundwater used for public drinking-water supply at 444 monitoring sites across California during 2004–2023. We assessed decadal step trends in groundwater quality for 145 water-quality constituents and geochemical indicators statewide and across geographic and land-use based network groups. We evaluated...
Authors
Zeno F. Levy, Andrew Lee Soldavini
ARCHI: A new R package for automated imputation of regionally correlated hydrologic records ARCHI: A new R package for automated imputation of regionally correlated hydrologic records
Missing data in hydrological records can limit resource assessment, process understanding, and predictive modeling. Here, we present ARCHI (Automated Regional Correlation Analysis for Hydrologic Record Imputation), a new, open-source software package in R designed to aggregate, impute, cluster, and visualize regionally correlated hydrologic records. ARCHI imputes missing data in “target”...
Authors
Zeno F. Levy, Robin L. Glas, Timothy J. Stagnitta, Neil Terry
Status and understanding of groundwater quality in the Mojave Basin Domestic-Supply Aquifer study unit, 2018—California GAMA Priority Basin Project 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...
Authors
Krishangi D. Groover, Miranda S. Fram, Zeno F. Levy
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
Non-USGS Publications**
Levy ZF, Rosenberry DO, Moucha R, Mushet DM, Goldhaber MB, LaBaugh JW, Fiorentino AJ, Siegel DI. 2018. Drought-induced recharge promotes long-term storage of porewater salinity beneath a prairie wetland. Journal of Hydrology 557: 391-406, https://doi.org/10.1016/j.jhydrol.2017.12.005.
Levy ZF, Mills CT, Lu Z, Goldhaber MB, Rosenberry DO, Mushet DM, Lautz LK, Zhou X, Siegel DI. 2018. Using halogens (Cl, Br, I) to understand the hydrogeochemical evolution of drought-derived saline porewater beneath a prairie wetland. Chemical Geology 476: 191-207, https://doi.org/10.1016/j.chemgeo.2017.11.017.
Levy ZF, Siegel DI, Glaser PH, Samson SD, Dasgupta SS. 2016. Peat porewaters have contrasting geochemical fingerprints for groundwater recharge and discharge due to matrix diffusion in a large, northern bog-fen complex. Journal of Hydrology 541: 941-951, https://dx.doi.org/10.1016/j.jhydrol.2016.08.001.
Levy ZF, Smardon RC, Bays JS, Meyer D. 2014. A Point Source of a Different Color: Identifying a Gap in United States Regulatory Policy for “Green” CSO Treatment Using Constructed Wetlands. Sustainability 6(5): 2392-2412, https://dx.doi.org/10.3390/su6052392.
Levy ZF, Siegel DI, Dasgupta SS, Glaser PH, Welker JM. 2014. Stable isotopes of water show deep seasonal recharge in northern bogs and fens. Hydrological Processes 228: 4938-4952, https://dx.doi.org/10.1002/hyp.9983.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
ARCHI: Automated Regional Correlation Analysis for Hydrologic Record Imputation, v1.0.0 ARCHI: Automated Regional Correlation Analysis for Hydrologic Record Imputation, v1.0.0
Welcome to Automated Regional Correlation Analysis for Hydrologic Record Imputation (ARCHI). ARCHI provides a workflow and interactive platform for regional-scale hydrologic record imputation. ARCHI allows users to aggregate, visualize, and impute records with irregular monitoring frequency at annual, seasonal, monthly, weekly, and daily timesteps. Missing data at “target” sites are...