Jennifer (Jennie) Harkness
(she/her)Jennie Harkness is a Research Hydrologist with the USGS California Water Science Center
I work primarily on the California State Water Resources Control Board's Groundwater Ambient Monitoring and Assessment (GAMA) program. I use a suite of geochemical and isotope tracers, geochemical modeling, and age-dating to distinguish geogenic and anthropogenic process that affect the quality of groundwater resources. My current work focuses on characterizing the process by which historical development and on-going sustainable management of groundwater systems, particularly managed aquifer recharge, drive changes in concentrations of salts and trace elements in drinking water resources.
Professional Experience
2023 - present: Research Hydrologist, U.S. Geological Survey California Water Science Center
2019 - 2023: Hydrologist, U.S. Geological Survey California Water Science Center
2017-2019: Postdoctoral Scholar, School of Earth Science, The Ohio State University
2012-2017: Graduate Research Assistant, Division of Earth and Ocean Science, Duke University
2011-2012: Research Associate, Marine Science Institute, UC Santa Barbara
Education and Certifications
Ph.D. Earth and Ocean Science, Duke University, 2017
B.A. Chemistry, Vassar College, 2010
Science and Products
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
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 to identify
Authors
Jennifer S. Harkness, Patrick Michael McCarthy, Bryant Jurgens, Zeno Levy
Status and understanding of groundwater quality in the Redding–Red Bluff shallow aquifer study unit, 2019—California GAMA priority basin project
Groundwater quality in the north Sacramento Valley (NSV) was studied in the Redding–Red Bluff shallow aquifer study unit (referred to as the NSV shallow aquifer or NSV-SA) as part of the Priority Basin Project (PBP) of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is in Shasta and Tehama Counties and included two physiographic study areas: (1) the Redd
Authors
Jennifer S. Harkness
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
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 trend in flu
Authors
Jennifer S. Harkness, Bryant Jurgens
Groundwater quality in the Redding–Red Bluff shallow aquifer study unit of the northern Sacramento Valley, California
Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Private domest
Authors
Jennifer S. Harkness, Jennifer L. Shelton
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 program and
Potential Explanatory Variables for Groundwater Quality in the Redding-Red Bluff Shallow Aquifer Assessment Study Unit, 2018-2019: California GAMA Priority Basin Project
This data release codifies and attributes explanatory variables that could potentially influence groundwater quality at 50 groundwater wells used for domestic water supply and 43 groundwater sites used for public water supply in the U.S. Geological Survey’s Priority Basin Project Redding-Red Bluff shallow aquifer (NSV-SA) study unit in 2018-2019 and Northern Sacramento Valley public-supply (NSV-PA
Groundwater database for a regional assessment of groundwater salinity variations and sources in the Indio Subbasin of the Coachella Valley, California
Groundwater salinity presents a challenge to the management of water quality in the Indio subbasin of the Coachella Valley where a growing population is dependent primarily on groundwater for drinking water. The U.S. Geological survey, along with the Colorado River Basin regional water quality control board, are working to provide an assessment of salinity trends and sources in the Indio subbasin
Groundwater and surface water data for a regional assessment of groundwater salinity variations and sources in the Indio Subbasin of the Coachella Valley, California
The U.S. Geological Survey collected groundwater samples from 17 wells in the Indio subbasin (CA basin designation 7-21.01) of the Coachella Valley and surface water samples from two sites representing sources of recharge to the Indio subbasin in 2021. These samples are intended to provide inorganic water quality data, particularly total dissolved solids (TDS), within areas of the Indio subbasin n
Science and Products
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
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 to identify
Authors
Jennifer S. Harkness, Patrick Michael McCarthy, Bryant Jurgens, Zeno Levy
Status and understanding of groundwater quality in the Redding–Red Bluff shallow aquifer study unit, 2019—California GAMA priority basin project
Groundwater quality in the north Sacramento Valley (NSV) was studied in the Redding–Red Bluff shallow aquifer study unit (referred to as the NSV shallow aquifer or NSV-SA) as part of the Priority Basin Project (PBP) of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program. The study unit is in Shasta and Tehama Counties and included two physiographic study areas: (1) the Redd
Authors
Jennifer S. Harkness
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
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 trend in flu
Authors
Jennifer S. Harkness, Bryant Jurgens
Groundwater quality in the Redding–Red Bluff shallow aquifer study unit of the northern Sacramento Valley, California
Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Private domest
Authors
Jennifer S. Harkness, Jennifer L. Shelton
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 program and
Potential Explanatory Variables for Groundwater Quality in the Redding-Red Bluff Shallow Aquifer Assessment Study Unit, 2018-2019: California GAMA Priority Basin Project
This data release codifies and attributes explanatory variables that could potentially influence groundwater quality at 50 groundwater wells used for domestic water supply and 43 groundwater sites used for public water supply in the U.S. Geological Survey’s Priority Basin Project Redding-Red Bluff shallow aquifer (NSV-SA) study unit in 2018-2019 and Northern Sacramento Valley public-supply (NSV-PA
Groundwater database for a regional assessment of groundwater salinity variations and sources in the Indio Subbasin of the Coachella Valley, California
Groundwater salinity presents a challenge to the management of water quality in the Indio subbasin of the Coachella Valley where a growing population is dependent primarily on groundwater for drinking water. The U.S. Geological survey, along with the Colorado River Basin regional water quality control board, are working to provide an assessment of salinity trends and sources in the Indio subbasin
Groundwater and surface water data for a regional assessment of groundwater salinity variations and sources in the Indio Subbasin of the Coachella Valley, California
The U.S. Geological Survey collected groundwater samples from 17 wells in the Indio subbasin (CA basin designation 7-21.01) of the Coachella Valley and surface water samples from two sites representing sources of recharge to the Indio subbasin in 2021. These samples are intended to provide inorganic water quality data, particularly total dissolved solids (TDS), within areas of the Indio subbasin n