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.
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...
Levy, Zeno; Jurgens, Bryant; Burow, Karen R.; Voss, Stefan; Faulkner, Kirsten; Arroyo-Lopez, Jose Alfredo; Fram, Miranda S.
Groundwater development leads to decreasing arsenic concentrations in the San Joaquin Valley, California
In the San Joaquin Valley (SJV), California, about 10% of drinking water wells since 2010 had arsenic concentrations above the US maximum contaminant level of 10 μg/L. High concentrations of arsenic are often associated with high pH (greater than 7.8) or reduced geochemical conditions. Although most wells have low arsenic (<3 μg/L)...
Haugen, Emily; Jurgens, Bryant; Arroyo-Lopez, Jose Alfredo; Bennett, George L.
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...
Jurgens, Bryant C.; Böhlke, J.K.; Haase, Karl; Busenberg, Eurybiades; Hunt, Andrew G.; Hansen, Jeffrey A. Geochemistry and age of groundwater in the Williston Basin, USA: Assessing potential effects of shale-oil production on groundwater quality
Thirty water wells were sampled in 2018 to understand the geochemistry and age of groundwater in the Williston Basin and assess potential effects of shale-oil production from the Three Forks-Bakken petroleum system (TBPS) on groundwater quality. Two geochemical groups are identified using hierarchical cluster analysis. Group 1 represents the...
McMahon, Peter B.; Galloway, Joel M.; Hunt, Andrew; Belitz, Kenneth; Jurgens, Bryant; Johnson, Tyler D. 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...
Jurgens, Bryant; Fram, Miranda S.; Rutledge, Jeffrey; Bennett, George L. Evaluation of soil zone processes and a novel radiocarbon correction approach for groundwater with mixed sources
Estimates of groundwater age based on 14C is often limited by the uncertainty in geochemical processes that alter the 14C concentration measured in water and the composition (δ13C and 14C) of carbon sources needed to appropriately parametrize 14C adjustment models. Estimated ages for samples that contain a mixture of young and old groundwater will...
Solder, John E.; Jurgens, Bryant Environmental tracer evidence for connection between shallow and bedrock aquifers and high intrinsic susceptibility to contamination of the conterminous U.S. glacial aquifer
Covering a large portion of the northern conterminous United States (1.87 x 106 km2), the glacial aquifer serves as the primary water supply for 39 million public and domestic water users. Mean groundwater age, groundwater age distribution, and susceptibility to land surface contamination, using a new metric (Susceptibility Index; SI) based on the...
Solder, John E.; Jurgens, Bryant; Stackelberg, Paul; Shope, Christopher L. Time scales of arsenic variability and the role of high-frequency monitoring at three water-supply wells in New Hampshire, USA
Groundwater geochemistry, redox process classification, high-frequency physicochemical and hydrologic measurements, and climate data were analyzed to identify controls on arsenic (As) concentration changes. Groundwater was monitored in two public-supply wells (one glacial aquifer and one bedrock aquifer), and one bedrock-aquifer domestic well in...
Degnan, James R.; Levitt, Joseph P.; Erickson, Melinda; Jurgens, Bryant C.; Lindsey, Bruce D.; Ayotte, Joseph D. History and sources of co-occurring pesticides in an abstraction well unravelled by age distributions of depth specific groundwater samples
When groundwater-based drinking water supply becomes contaminated, the timing and source of contamination are obvious questions. However, contaminants often have diffuse sources and different contaminants may have different sources even in a single groundwater well, making these questions complicated to answer. Age dating of groundwater has been...
Jakobsen, Rasmus ; Hinsby, Klaus ; Aamand, Jens ; van der Keur, Peter ; Kidmose, Jacob ; Purtschert, Roland ; Jurgens, Bryant; Sultenfuss, Jurgen ; Albers, Christian N.
Delineation of spatial extent, depth, thickness, and potential volume of aquifers used for domestic and public water-supply in the Central Valley, California
Identification of the groundwater resources used for drinking-water supplies is essential for the design of strategies to manage those resources. In this study, the spatial extent, depths, thicknesses, and volumes of groundwater aquifers used for domestic and public drinking-water supply were estimated from locations and well-construction data...
Voss, Stefan; Jurgens, Bryant C.; Fram, Miranda S.; Bennett, George L.
Tritium as an indicator of modern, mixed, and premodern groundwater age
Categorical classification of groundwater age is often used for the assessment and understanding of groundwater resources. This report presents a tritium-based age classification system for the conterminous United States based on tritium (3H) thresholds that vary in space and time: modern (recharged in 1953 or later), if the measured value is...
Lindsey, Bruce D.; Jurgens, Bryant C.; Belitz, Kenneth Hydrocarbons in upland groundwater, Marcellus Shale Region, Northeastern Pennsylvania and Southern New York, USA
Water samples from 50 domestic wells located <1 km (proximal) and >1 km (distal) from shale-gas wells in upland areas of the Marcellus Shale region were analyzed for chemical, isotopic, and groundwater-age tracers. Uplands were targeted because natural mixing with brine and hydrocarbons from deep formations is less common in those areas...
McMahon, Peter B.; Lindsey, Bruce D.; Conlon, Matthew D.; Hunt, Andrew G.; Belitz, Kenneth; Jurgens, Bryant; Varela, Brian A.
DGMETA (Dissolved Gas Modeling and Environmental Tracer Analysis)
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.
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
An Excel® Workbook for Interpreting Groundwater Age Distributions from Environmental Tracer Data
California Groundwater Wells Receive Grades for Improvement and Degradation
In California, groundwater is a major source for drinking and other uses. Identifying where groundwater quality is getting better or worse is essential for managing groundwater resources.
USGS Hydrologist Collaborates with Danish Scientists on Groundwater Research
Groundwater provides much of the world's drinking water. When a supply of groundwater becomes contaminated, determining the timing and source of the contamination is an obvious concern. But the answers aren’t always clear. Contaminants may have different sources, even in a single groundwater well.
Domestic groundwater wells in the eastern and southeastern U.S. at risk of lead contamination
About one-third of more than 8,300 wells tested across the U.S. had groundwater with chemical characteristics that could cause lead, if present in plumbing, to leach into tap water at levels above the EPA Action Level, according to a new study by the U.S. Geological Survey National Water Quality Program. These...