As part of the Isotope Hydrology Group at LLNL, my work focuses on water security, quality, and sustainability. Using our suite of isotopic and geochemical tracers, we investigate the sources, residence times, recharge conditions, and flowpaths of water and can apply this information to better understand a variety of water resource concerns in California.

I earned my Master’s in Environmental Geosciences at California State University, East Bay where my research used isotopic and geochemical tracer data from LLNL and the GAMA project to assess vulnerability of domestic groundwater wells in California’s San Joaquin Valley to contamination and declining groundwater levels.

M.S., Environmental Geosciences, California State University, East Bay, Hayward, California, 2023

• Lerback, J. C., Oerter, E., Visser, A., & Harm, A. J. (2026). California Trees Seasonally Use Augmented Water Sources: Water Isotope Tracking in a Groundwater‐Dependent Ecosystem. Ecohydrology, 19(1), e70166. https://doi.org/10.1002/eco.70166
• Visser, A., Harm, A. J., Lerback, J. C., Moran, J. E. (2025). California GAMA Special Study: A Well Vulnerability Assessment Tool [White paper]. California State Water Resources Control Board. https://gispublic.waterboards.ca.gov/portal/sharing/rest/content/items/717ab7e49c9041078e830ead9059c799/data
• Lerback, J., Bibby, R., Danielsen, J., Garguilo, M., Grande, E., Harm, A. J., Minn, K., Moran, J., Oerter, E., & Visser, A. (2024). How Rains and Floods Become Groundwater: Understanding Recharge Pathways With Stable and Cosmogenic Isotopes. Hydrological Processes, 38(12), e70020. https://doi.org/10.1002/hyp.70020

For a full list, see: Google Scholar | ResearchGate | Scopus | ORCID

• Physical and Life Sciences Directorate Award for contributions to establishing a contamination mitigation strategy during demolition of an LLNL building, 2024