An experienced leader of multidisciplinary research teams, Dr. Scott L. Painter currently leads the Watershed Systems Modeling Group at Oak Ridge National Laboratory (ORNL). He has extensive experience in modeling flow, heat transport, and solute transport on the surface of the Earth and in the shallow and deep subsurface. He has used those tools in multiple application areas including groundwater resource management, climate change impact studies, and radioactive waste disposal. Prior to joining ORNL, Painter had senior research positions at Los Alamos National Laboratory (LANL) and Southwest Research Institute. After joining ORNL in 2014, Painter helped develop several multi-institution DOE-funded research projects. He is currently on the leadership team for four multilab projects and co-leads the ExaSheds project, which is using machine learning and high performance computing to extend high-resolution, physics-based watershed models to river basin scales. He launched the Watershed Systems Modeling Group in 2020. The group is developing the state-of-the-art open-source simulation tool Amanzi-ATS to better understand the impacts of a changing climate on natural and human-managed environmental systems. Dr. Painter's group also works with observationalists at ORNL and other labs to compare models and observations. Painter was a senior member of the subsurface flow and transport modeling team at LANL from early 2010 to late 2014. Painter expanded the research profile for that team to include discrete fracture network modeling, which is now one of that team's signature capabilities. As principal investigator for a laboratory-directed research and development project, he led the development of new multiphysics simulation tools to predict future Arctic carbon releases to the atmosphere from a thawing, deforming, and topographically reorganizing landscape. Dr. Painter has a long history in developing new simulation tools and computational strategies to analyze risks of migrating radionuclides in the subsurface. From 1998 to 2010 he was with the Center for Nuclear Waste Regulatory Analyses at Southwest Research Institute where he provided independent technical advice on geologic disposal of nuclear waste to the Nuclear Regulatory Commission. He also led several subsurface modeling projects for a variety of industry and government clients. He continues work on nuclear waste disposal as an independent consultant. Painter has received 3 R&D 100 Awards for surface and subsurface modeling software: MARFA (formerly TDRW), dfnWorks, and Amanzi-ATS.