New Approaches to Sustainable Water Management
Across California—from farms, to communities, to industry—water plays a vital role.
Yet managing this finite resource is a complex process that involves understanding where water comes from, how it moves through the environment, and how this precious resource is replenished. Information about this dynamic, complex system enables policymakers, water agencies, and other stakeholders to implement solutions aimed at meeting California’s need for clean, fresh water.
LLNL combines cutting-edge analytical techniques and expertise to deliver timely information regarding water management options to government entities, resource managers, industry partners, and other stakeholders.
LLNL scientists use isotope hydrology to trace the movement of water, which enables them to identify the sources of local fresh water, how quickly it is replenished, and whether it is at risk of contamination.
About Isotope Hydrology
How it works
Isotope hydrology involves the use of environmental isotopes to trace the movement of water throughout the hydrological cycle, from precipitation, through surface runoff and evaporation, to the flow of surface water and groundwater.
As water molecules move through this cycle, they are naturally tagged with isotopic “fingerprints,” offering clues about the water’s origin and its history of movement.
Hydrologists can use these naturally occurring isotopic tracers to map sources of groundwater, identify how quickly water resources are recharged (replenished), and determine the risk of saltwater intrusion or other contamination. In addition, noble gas tracers can be introduced into managed aquifer recharge facilities or aquifer storage and recovery wells to provide detailed information regarding the flow rates in the aquifer and the recovery of recharged water.
What we can learn
Isotopic analysis of surface water and groundwater can generate a broad range of data to facilitate informed decision making regarding how to address water management challenges, such as:
- How fast water travels through an ecosystem, which can help identify where the geology supports fast flow paths that are beneficial for intentional, managed recharge of aquifers.
- The age of existing groundwater, which helps explain trends in groundwater flow and geochemistry, and provides insight regarding future trends.
- How groundwater interacts with surface water, including where and when those interactions occur, providing insight regarding the vulnerability of ecosystems that are dependent on groundwater.
- How potential changes in groundwater management, such as altering flow paths, might impact the availability of future water resources.
- The cause of any contamination or pollution detected in water sources.
Answering key questions
Stakeholders need actionable information that can help them answer questions like those provided below—and make informed decisions regarding managing future water needs.
- What data do I need when making decisions regarding water management policies and legislation?
- How will water management decisions impact groundwater reserves, wells, reservoirs, and other resources?
Water Resource Managers
- Where does local groundwater come from, and how quickly is it replenished?
- What risks threaten the local water supply, and how can I mitigate those risks?
- Can I use managed aquifer recharge techniques to augment the local water supply?
- How sustainable are water sources used for irrigation in a changing climate?
- Over what time scale can we expect water management practices to improve water quality?
LLNL’s Unique Capabilities
LLNL’s comprehensive suite of analytical techniques enables our scientists to study a broad range of water management challenges across the hydrological cycle. Our experts collect water samples and use one-of-a-kind, high-precision mass spectrometry and nuclear counting facilities at LLNL to conduct isotopic analyses of the samples. We also develop new isotope tracer techniques to understand evolving water management challenges.
LLNL Analysis of San Joaquin Valley Groundwater Recharge
With funding from the California State Water Resources Control Board, LLNL scientists used isotope hydrology to study a groundwater basin in the south-eastern portion of the San Joaquin Valley and understand how this important water resource is replenished.
Investigators learned that river water provides nearly 50% of the groundwater recharge in this predominantly agricultural area. However, this recharge mechanism fluctuates significantly throughout the year, as the major source of river water is snowmelt from the Sierra Nevada mountains. In addition, all of the region’s major rivers are dammed, and water is diverted for agricultural irrigation and drinking water in other parts of California.
Based on their findings, LLNL scientists recommended groundwater banking of seasonal surface water, along with expansion of managed aquifer practices, to increase the resilience of San Joaquin Valley’s water system.
A. Deinhart, R. Bibby, A. Visser, M. Thaw, K. Thomas, Simplified Method for the In Situ Collection and Laboratory Analysis of Cosmogenic Tracers (Sulfur-35 and Sodium-22) to Determine Residence Time Distributions and Water Ages, Analytical Chemistry 93, 4472 (2021).
M. Thaw, A. Visser, R. Bibby, A. Deinhart, E. Oerter, M. Conklin, Vegetation water sources in California’s Sierra Nevada (USA) are young and change over time, a multi-isotope (𝛿18O, 𝛿2H, 3H) tracer approach, Hydrological Processes 35, e14249 (2021).
A. Visser, M. Thaw, A. Deinhart, R. Bibby, M. Safeeq, M. Conklin, B. Esser, Y. Van der Velde, Cosmogenic Isotopes Unravel the Hydrochronology and Water Storage Dynamics of the Southern Sierra Critical Zone, Water Resources Research 55, 1429 (2019).
M. de Jong, J.E. Moran, A. Visser, Identifying paleowater in California drinking water wells, Quaternary International , (2019).
N. Veale, A. Visser, B. Esser, M.J. Singleton, J.E. Moran, Nitrogen Cycle Dynamics Revealed Through δ18O-NO3− Analysis in California Groundwater, Geosciences 9, 95 (2019).
E. Oerter, G. Siebert, D. Bowling, G. Bowen, Soil water vapor isotopes identify missing water source for streamside trees, Ecohydrology 12, e2083 (2019).
E. Oerter, G. Bowen, Spatiotemporal heterogeneity in soil water stable isotopic composition and its ecohydrologic implications in semi-arid ecosystems, Hydrological Processes 33, 1724 (2019).
C. Gomez-Navarro, D. Pataki, G. Bowen, E. Oerter, Spatiotemporal variability in water sources of urban soils and trees in the semiarid, irrigated Salt Lake Valley, Ecohydrology 12, e2154 (2019).
E. Oerter, M. Singleton, M. Thaw, L. Davisson, Water vapor exposure chamber for constant humidity and hydrogen and oxygen stable isotope composition, Rapid Communications in Mass Spectrometry 33, 89 (2019).
A. Visser, M. Thaw, B. Esser, Analysis of air mass trajectories to explain observed variability of tritium in precipitation at the Southern Sierra Critical Zone Observatory, California, USA, Journal of Environmental Radioactivity 181, 42 (2018).
A. Visser, J.E. Moran, M.J. Singleton, B.K. Esser, Importance of river water recharge to the San Joaquin Valley groundwater system, Hydrological Processes 32, 1202 (2018).
E. Oerter, M. Singleton, L. Davisson, Hydrogen and oxygen stable isotope dynamics of hyper-saline and salt-saturated aqueous solutions, Geochimica et Cosmochimica Acta 238, 316 (2018).
G. Bowen, A. Putman, J.R. Brooks, D. Bowling, E. Oerter, S. Good, Inferring the source of evaporated waters using stable H and O isotopes, Oecologia 187, 1025 (2018).
E. Avery, R. Bibby, A. Visser, B. Esser, J. Moran, Quantification of Groundwater Discharge in a Subalpine Stream Using Radon-222, Water 10, 100 (2018).
E. Peters, A. Visser, B. Esser, J. Moran, Tracers Reveal Recharge Elevations, Groundwater Flow Paths and Travel Times on Mount Shasta, California, Water 10, 97 (2018).
E. Oerter, M. Malone, A. Putman, L. Stark, D. Drits, G. Bowen, Every apple has a voice: Using stable isotopes to teach about food sourcing and the water cycle, Hydrology and Earth System Sciences 21, 3799 (2017).
E. Oerter, M. Singleton, L. Davisson, Hydrogen and oxygen stable isotope signatures of goethite hydration waters by thermogravimetry-enabled laser spectroscopy, Chemical Geology 475, 14 (2017).
E. Oerter, G. Bowen, In situ monitoring of H and O stable isotopes in soil water reveals ecohydrologic dynamics in managed soil systems, Ecohydrology 10, e1841 (2017).
E. Oerter, A. Perelet, E. Pardyjak, G. Bowen, Membrane inlet laser spectroscopy to measure H and O stable isotope compositions of soil and sediment pore water with high sample throughput, Rapid Communications in Mass Spectrometry 31, 75 (2017).
S.H. Urióstegui, R.K. Bibby, B.K. Esser, J.F. Clark, Quantifying annual groundwater recharge and storage in the central Sierra Nevada using naturally occurring 35S, Hydrological Processes 31, 1382 (2017).
H.J. Schenk, S. Espino, A. Visser, B.K. Esser, Dissolved atmospheric gas in xylem sap measured with membrane inlet mass spectrometry, Plant, Cell & Environment 39, 944 (2016).
P.A. Harms, A. Visser, J.E. Moran, B.K. Esser, Distribution of tritium in precipitation and surface water in California, Journal of Hydrology 534, 63 (2016).
A. Visser, J.E. Moran, D. Hillegonds, M.J. Singleton, J.T. Kulongoski, K. Belitz, B.K. Esser, Geostatistical analysis of tritium, groundwater age and other noble gas derived parameters in California, Water Research 91, 314 (2016).
J. Alikhani, A.L. Deinhart, A. Visser, R.K. Bibby, R. Purtschert, J.E. Moran, A. Massoudieh, B.K. Esser, Nitrate vulnerability projections from Bayesian inference of multiple groundwater age tracers, Journal of Hydrology 543, 167 (2016).
J. Clark, S. Urióstegui, R. Bibby, B. Esser, G. Tredoux, Quantifying Apparent Groundwater Ages near Managed Aquifer Recharge Operations Using Radio-Sulfur (35S) as an Intrinsic Tracer, Water 8, 474 (2016).
S.H. Urióstegui, R.K. Bibby, B.K. Esser, J.F. Clark, Quantifying groundwater travel time near managed recharge operations using 35S as an intrinsic tracer, Journal of Hydrology 543, 145 (2016).
C.T. Green, B.C. Jurgens, Y. Zhang, J.J. Starn, M.J. Singleton, B.K. Esser, Regional oxygen reduction and denitrification rates in groundwater from multi-model residence time distributions, San Joaquin Valley, USA, Journal of Hydrology 543, 155 (2016).
M.F. Verce, V.M. Madrid, S.D. Gregory, Z. Demir, M.J. Singleton, E.P. Salazar, P.J. Jackson, R.U. Halden, A. Verce, A Long-Term Field Study of In Situ Bioremediation in a Fractured Conglomerate Trichloroethene Source Zone, Bioremediation Journal 19, 18 (2015).
S.H. Urióstegui, R.K. Bibby, B.K. Esser, J.F. Clark, Analytical Method for Measuring Cosmogenic 35S in Natural Waters, Analytical Chemistry 87, 6064 (2015).
A. Benson, M. Zane, T. Becker, A. Visser, S. Uriostegui, E. DeRubeis, J. Moran, B. Esser, J. Clark, Quantifying Reaeration Rates in Alpine Streams Using Deliberate Gas Tracer Experiments, Water 6, 1013 (2014).
D.C. Segal, J.E. Moran, A. Visser, M.J. Singleton, B.K. Esser, Seasonal variation of high elevation groundwater recharge as indicator of climate response, Journal of Hydrology 519, 3129 (2014).
A. Visser, M.J. Singleton, D.J. Hillegonds, C.A. Velsko, J.E. Moran, B.K. Esser, A membrane inlet mass spectrometry system for noble gases at natural abundances in gas and water samples, Rapid Communications in Mass Spectrometry 27, 2472 (2013).
J.T. Kulongoski, D.R. Hilton, P.H. Barry, B.K. Esser, D. Hillegonds, K. Belitz, Volatile fluxes through the Big Bend section of the San Andreas Fault, California: Helium and carbon-dioxide systematics, Chemical Geology 339, 92 (2013).
D.R. O’Leary, J.A. Izbicki, J.E. Moran, T. Meeth, B. Nakagawa, L. Metzger, C. Bonds, M.J. Singleton, Movement of Water Infiltrated from a Recharge Basin to Wells, Ground Water 50, 242 (2011).
M.K. Landon, C.T. Green, K. Belitz, M.J. Singleton, B.K. Esser, Relations of hydrogeologic factors, groundwater reduction-oxidation conditions, and temporal and spatial distributions of nitrate, Central-Eastside San Joaquin Valley, California, USA, Hydrogeology Journal 19, 1203 (2011).
M.J. Singleton, J.E. Moran, Dissolved noble gas and isotopic tracers reveal vulnerability of groundwater in a small, high-elevation catchment to predicted climate changes, Water Resour. Res. 46, W00F06 (2010).
B.D. Cey, G.B. Hudson, J.E. Moran, B.R. Scanlon, Evaluation of Noble Gas Recharge Temperatures in a Shallow Unconfined Aquifer, Ground Water 47, 646 (2009).
B.D. Cey, G.B. Hudson, J.E. Moran, B.R. Scanlon, Impact of Artificial Recharge on Dissolved Noble Gases in Groundwater in California, Environ. Sci. Technol. 42, 1017 (2008).
W.W. McNab, M.J. Singleton, J.E. Moran, B.K. Esser, Assessing the impact of animal waste lagoon seepage on the geochemistry of an underlying shallow aquifer, Environmental Science and Technology 41, 753 (2007).
M.J. Singleton, B.K. Esser, J.E. Moran, G.B. Hudson, W.W. Mcnab, T. Harter, Saturated zone denitrification: Potential for natural attenuation of nitrate contamination in shallow groundwater under dairy operations, Environmental Science and Technology 41, 759 (2007).
S.F. Carle, B.K. Esser, J.E. Moran, High-resolution simulation of basin scale nitrate transport considering aquifer system heterogeneity, Geosphere 2, 195 (2006).
K.B. Moore, B. Ekwurzel, B.K. Esser, G.B. Hudson, J.E. Moran, Sources of groundwater nitrate revealed using residence time and isotope methods, Applied Geochemistry 21, 1016 (2006).
M.J. Singleton, K.N. Woods, M.E. Conrad, D.J. DePaolo, P.E. Dresel, Tracking Sources of Unsaturated Zone and Groundwater Nitrate Contamination Using Nitrogen and Oxygen Stable Isotopes at the Hanford Site, Washington, Environmental Science & Technology 39, 3563 (2005).
K.A. Surano, G.B. Hudson, R.A. Failor, J.M. Sims, R.C. Holland, S.C. MacLean, J.C. Garrison, Helium-3 mass spectrometry for low-level tritium analysis of environmental samples, Journal of Radioanalytical and Nuclear Chemistry 161, 443 (1992).
GAMA Special Studies Project Reports
LLNL was the project technical lead of the Special Studies Project, as part of the California Waterboards Groundwater Ambient Monitoring and Assessment Program. The Special Studies Project focused on specific groundwater quality studies, using state-of-the-art scientific techniques and methods that help researchers and public policy planners to better understand how groundwater contamination occurs and behaves. Since 2004, studies have focused on sources of nitrate, wastewater indicators, groundwater recharge, detection of pharmaceutical compounds and personal care products using low-level anthropogenic compounds as tracers, and isotopic composition as a contamination source tool. Expand the section below to view LLNL Special Studies reports to the Waterboards.
Water and Nitrate Isotopic Data for San Diego County—November 2012
Nitrate and Water Isotopic Data for Tulare County—January 2011
LLNL’s Isotope Hydrology Group includes experts in hydrology, reactive transport, radiochemistry, nuclear counting, and mass spectrometry. Rooted in more than five decades of national leadership in environmental radiochemistry, our multidisciplinary team studies water management scenarios and delivers timely answers to sponsors, academic and industry partners, and other stakeholders.