Thomas Nicholson is a Senior Technical Advisor in the Division of Risk Analysis of the Office of Nuclear Regulatory Research (RES) within the U.S. Nuclear Regulatory Commission (NRC). He has worked at the NRC for 36 years, primarily in RES. His principal responsibility is to provide technical advice to NRC senior management concerning radionuclide migration in the subsurface at NRC-licensed facilities. His work focuses on research in hydrology, principally ground-water and surface-water issues such as flood assessments, radionuclide transport in the environment, and evaluation of accidental releases at nuclear facilities. He has formulated and directed numerous research studies, as a senior project manager, involving estimation of extreme flood probabilities in watersheds; radionuclide transport in fractured rock; and integration of subsurface monitoring and modeling. He chairs the Work Group on Extreme Storm Events under the Federal Subcommittee on Hydrology (SOH) of the Advisory Committee on Water Information (ACWI). He is the NRC member of SOH. He is also the co-chair of Federal Work Group on Parameter Estimation and Uncertainty under the Memorandum of Understanding on Research in Multimedia Environmental Modeling (ISCMEM). He recently chaired the Workshop on Probabilistic Flood Hazard Assessment.
He holds a B.S. in geological sciences from Pennsylvania State University, and a M.S. in geology from Stanford University. At Stanford, he was a student of Professors Ray Linsley and Joseph Franzini in the hydrology program completing the core courses in hydrology. He is a registered Professional Geologist in Indiana, and certified Professional Hydrogeologist in the American Institute of Hydrology. He is an active member of the American Geophysical Union, Geological Society of America, International Association of Hydrological Sciences, the International Hydrogeologic Society, and the National Ground-Water Association.