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.