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Energy and Environment Directorate

Frederick Day-Lewis

Frederick Day-Lewis

(509) 371-6734


Fred Day-Lewis joined PNNL in 2021 as a Chief Geophysicist in the Environmental Subsurface Science Group within the Earth Systems Science Division. Prior to coming to PNNL, Fred worked for the U.S. Geological Survey for 18 years as a Research Hydrologist. Fred has worked on a variety of applied-research projects related to subsurface characterization and monitoring, groundwater remediation, groundwater/surface-water exchange, geophysical inverse problems, thermal methods, hydrologic parameter estimation, and petrophysics. Fred currently serves as an associate editor for the journal Groundwater. He previously served as an associate editor for Water Resources Research, Geosphere, and Hydrogeology Journal, and he co-edited the American Geophysical Union monograph Subsurface Hydrology: Data Integration for Properties and Processes. Fred is a past president of the American Geophysical Union Near Surface Geophysics Section, and past Vice President of the Environmental and Engineering Geophysics Society. He was elected Fellow of the Geological Society of America in 2015 for seminal contributions to hydrogeophysics.

Research Interests

  • Hydrogeophysics
  • Groundwater/surface-water exchange
  • Real-time geophysical monitoring
  • Predictive data analytics; inverse modeling; parameter estimation
  • Digital signal processing

Education and Credentials

  • Ph.D., Hydrogeology, Stanford University
  • B.S., Hydrology, U. New Hampshire
  • B.A., English, U. New Hampshire

Affiliations and Professional Service

  • American Geophysical Union
  • Geological Society of America
  • Society of Exploration Geophysicists
  • National Groundwater Association

Awards and Recognitions

  • Fellow, Geological Society of America

PNNL Publications


  • Thompson J.H., A.R. Mangel, and F.D. Day-Lewis. 2023. "A Geophysical Remediation Monitoring Method Selection Tool (GRM-MST)." Groundwater 61, no. 1:8-10. PNNL-SA-177934. doi:10.1111/gwat.13268


  • Day-Lewis F.D., P.D. Royer, L.A. Placzek, and K.E. Markham. 2022. "A Multi-Scale Temperature-Based Strategy to Map Hydrologic Exchange Flows in Highly Dynamic Systems." Frontiers in Water 10. PNNL-SA-178043. doi:10.3389/feart.2022.1070393
  • McAliley W.A., F.D. Day-Lewis, D.A. Rey, M. Briggs, A.M. Shapiro, and D. Werkema. 2022. "Application of Recursive Estimation to Heat Tracing for Groundwater/Surface-Water Exchange." Water Resources Research 58, no. 6:e2021WR030443. PNNL-SA-165706. doi:10.1029/2021WR030443
  • Robinson J.L., J.N. Thomle, D.P. McFarland, K.A. Deters, M.L. Rockhold, F.D. Day-Lewis, and V.L. Freedman. 2022. "Integration of Large-Scale Electrical Imaging into Geological Framework Development and Refinement." Environmental Processes 9, no. 2:Art. No. 21. PNNL-SA-166767. doi:10.1007/s40710-022-00570-2
  • Singha K., T.C. Johnson, F.D. Day-Lewis, and L. Slater. 2022. "Electrical Imaging for Hydrogeology." In Groundwater Geophysics. Guelph:The Groundwater Project. PNNL-SA-159896.


  • Shapiro A.M., and F.D. Day-Lewis. 2021. "Estimating and Forecasting Time-Varying Groundwater Recharge in Fractured Rock: A State-Space Formulation with Preferential and Diffuse Flow to the Water Table." Water Resources Research 57, no. 9:Article No. e2020WR029110. PNNL-SA-165293. doi:10.1029/2020WR029110


  • Johnson T.C., R. Versteeg, F.D. Day-Lewis, W. Major, and J.W. Lane. 2015. "Time-Lapse Electrical Geophysical Monitoring of Amendment-Based Biostimulation." Groundwater 53, no. 6:920-932. PNNL-SA-115558. doi:10.1111/gwat.12291
  • Singha K., F.D. Day-Lewis, T.C. Johnson, and L.D. Slater. 2015. "Advances in interpretation of subsurface processes with time-lapse electrical imaging." Hydrological Processes 29, no. 6:1549-1576. PNNL-SA-110809. doi:10.1002/hyp.10280


  • Johnson T.C., L. Slater, D. Ntarlagiannis, F.D. Day-Lewis, and M. Elwaseif. 2012. "Monitoring groundwater-surface water interaction using time-series and time-frequency analysis of transient three-dimensional electrical resistivity changes." Water Resources Research 48. PNNL-SA-85275. doi:10.1029/2012WR011893


  • Johnson T.C., R.J. Versteeg, A.L. Ward, F.D. Day-Lewis, and A. Revil. 2010. "Improved hydrogeophysical characterization and monitoring through parallel modeling and inversion of time-domain resistivity andinduced-polarization data." Geophysics 75, no. 4:WA27-WA41. PNNL-SA-69316. doi:10.1190/1.3475513
  • Slater L., D. Ntarlagiannis, F.D. Day-Lewis, K. Mwakanyamale, R.J. Versteeg, A.L. Ward, and C.E. Strickland, et al. 2010. "Use of Electrical Imaging and Distributed Temperature Sensing Methods to Characterize Surface Water-Groundwater Exchange Regulating Uranium Transport at the Hanford 300 Area, Washington." Water Resources Research 46, no. 10:Paper No. W10533. PNNL-SA-69319. doi:10.1029/2010WR009110

Energy and Environment

Core Research Areas