ASCEM contacts & Leadership

ASCEM is overseen by the Department of Energy’s Office of Environmental Management (DOE-EM).  A DOE-ASCEM Program Manager oversees the program.  A Multi-Lab Program Manager supervises ASCEM operations, while each of the three ASCEM thrust areas has a Thrust Lead, managing progress toward particular goals.


Thrust Area Leads



ASCEM Organization Chart

Leadership ContaCTS

Thrust area contacts

Paul Dixon

Paul Dixon PortraitASCEM Multi-Lab Program Manager, Los Alamos National Laboratory (LANL)

For the past 25 years, Dr. Paul Dixon has performed research and has been a technical manager in a variety of energy, non-proliferation and environmental programs at Los Alamos National Laboratory.  Some of his key research efforts have included development of atom-level chemical separation techniques for Pu, Tc, Np, U and I from organic and inorganic materials, natural analog studies for nuclear waste disposal, and non-proliferation research for the IAEA.

Dr. Dixon has 17 years' experience in nuclear waste disposal program management.  Since 1997, he has held senior management roles on the Yucca Mountain Project through three M&O’s: TRW, BSC and Sandia National Laboratory.   Dr. Dixon is currently the Multi-Lab Program Manager leading the Advanced Simulation Capability for Environmental Management (ASCEM) effort within DOE-EM.  In this role, he manages the a multi-lab team of geochemists, hydrologists, mathematicians and computer scientists from multiple National Laboratories.  In addition, Dr. Dixon spends a significant portion of his time interfacing with other DOE agencies to coordinate their efforts with those of ASCEM.

Dr. Dixon has been a member of the American Chemical Society for over 20 years.  He was also appointed to the Clark County Wildlife Advisory Board in 2008 and has served as Chairman of that board since April 2009. 

Dr. Dixon received his B.A. from Albion College in Geology & Chemistry in 1983, his M.Phil in Geochemistry from Yale University in 1985, and his Ph.D. in Geochemistry from Yale in 1989.

Roger Seitz

Roger Seitz

Senior Advisory Scientist

Radiological Performance Assessment Group

Environmental Stewardship Directorate

Savannah River National Laboratory (SRNL)

Roger Seitz is currently providing technical and strategic support to the Department of Energy, Office of Environmental Management (DOE-EM) and multiple DOE sites on topics related to modeling, design and performance and risk assessment to consider the long-term safety of waste disposal, tank closure and other site restoration activities. He is also a frequent consultant to the International Atomic Energy Agency (IAEA), including currently serving as Chair for an International Project related to assessments for disposal facilities and supporting development of waste management aspects of the IAEA Fukushima Report.

Roger’s career began in 1985 and has included activities at seven DOE sites and in more than 10 different countries, including five years as a staff member at the IAEA. These activities involved a variety of research, applied and policy aspects related to modeling and supporting efforts for the design and assessment of disposal facilities for low-level, high-level and mixed radioactive waste, remediation of contaminated sites, and decommissioning of reactors and other large facilities. During his career, he has also served as a consultant and peer reviewer on assessment-related topics for the U.S. Nuclear Regulatory Commission, served as a peer reviewer for a U.S. National Research Council report on mixed waste forms, and served on the U.S. National Council on Radiation Protection and Measurements Scientific Committee that produced guidance for disposal facility performance assessments.

Timothy Scheibe

Timothy Scheibe

Staff Scientist, Hydrology,
Pacific Northwest National Laboratory (PNNL)

Dr. Scheibe’s primary research focus is on multiscale modeling of biogeochemically reactive transport in groundwater systems, including microbial transport in groundwater and bioremediation of metals and radionuclides. He collaborates with computational scientists, microbiologists, and geochemists to apply high-performance computation to simulate coupled flow, transport, and biogeochemical processes at cellular, pore and continuum scales. Dr. Scheibe serves on the editorial board of the scientific journal Ground Water, is active in several scientific organizations, and in 2010 served as the Henry Darcy Distinguished Lecturer (sponsored by the National Ground Water Association). He is currently also the interim director of the Molecular Sciences Computing Facility at the Environmental Molecular Sciences Laboratory (EMSL) at PNNL, which operates the world’s 13th largest supercomputer in support of the mission of DOE’s Biological and Environmental Research office.

Timothy Scheibe's PNNL staff page

Stefan Finsterle

Stefan Finsterle

Staff Geological Scientist, Hydrogeology Department,
Earth Sciences Division,
Lawrence Berkeley National Laboratory (LBNL)

Dr. Finsterle has 20 years of experience in the application of multiphase flow and transport simulators to various, complex subsurface systems. He received his doctorate in environmental engineering from the Swiss Federal Institute of Technology (ETH) in Zürich, Switzerland, before he moved to Berkeley, California, where he performs applied research in geothermal reservoir engineering, nuclear waste isolation, carbon sequestration, and environmental remediation projects. Dr. Finsterle is the main developer of the iTOUGH2 simulation-optimization code. He is interested in the analysis of laboratory and field data through a formal model calibration procedure, specifically using the joint inversion of hydrogeological and geophysical data for the characterization of heterogeneous subsurface systems.

Stefan Finsterle's LBNL staff page

David Moulton

David Moulton

Mathematical Modeling and Analysis, Computing Division,
Los Alamos National Laboratory (LANL)

Dr. J. David Moulton is a team leader in the Applied Mathematics and Plasma Physics Group in the Theoretical Division at the Los Alamos National Laboratory, and he is the Multi-Process HPC Simulator Thrust lead for ASCEM. He received his B.Eng and M.Eng in Physics from McMaster University and a Ph.D in Applied Mathematics from the University of British Columbia. His current research focuses on advanced discretizations and multilevel algorithms for flow and reactive transport in highly heterogeneous porous media. In addition, he is investigating a variety of model reduction techniques that target enhanced efficiency and accuracy of uncertainty quantification in multiscale systems, in conjunction with new approaches to ensemble-based data assimilation. Dr. Moulton continues to work on parallel scalable implementations of robust variationally based multigrid solvers for logically structured grids, which have significant advantages on emerging architectures. He has developed robust and efficient preconditioners for various mixed finite element and mimetic finite difference discretizations on severely distorted meshes with highly discontinuous coefficients.

David Moulton's LANL staff page 

Carl Steefel

Carl Steefel

Staff Scientist, Earth Sciences Division,
Lawrence Berkeley National Laboratory (LBNL)

Carl Steefel has over 21 years of experience in developing models for multicomponent reactive transport in porous media and applying them to topics in reactive contaminant transport and water-rock interaction.  The reactive transport software CrunchFlow, for which he is the principal developer, is the culmination of this work.  He investigated geochemical self-organization and complexity theory in water-rock interaction (Steefel and Lasaga, 1990), while also developing the first routine for multicomponent nucleation and crystal size distributions in the Earth Sciences (Steefel and Van Cappellen, 1990).  Soon after, he presented  the first multicomponent, multi-dimensional  code for simulating water-rock interaction in non-isothermal environments (Steefel and Lasaga, 1994).  Steefel applies reactive transport modeling to such diverse settings as hydrothermal, contaminant, chemical weathering, and marine environments.  Recently, he has been involved in experimental studies of cation exchange (Steefel et al., 2003) and mineral dissolution and precipitation (Yang and Steefel, 2008), as well as modeling studies of field systems  focused on contaminant transport, microbially-mediated biogeochemical reactions, and chemical weathering (Giambalvo et al., 2002; Steefel, 2004; Maher et al., 2009; Li et al., 2009; Steefel and Maher, 2009).

Carl Steefel's LBNL staff page

CrunchFlow software website

Mark Freshley

Mark Freshley

Senior Project Manager, Hydrology Group,
Environmental Sustainability Division,
Energy and Environmental Directorate,
Pacific Northwest National Laboratory

Mark Freshley presently manages the Groundwater Remediation and Closure Assessment Projects which includes groundwater monitoring, science and technology, and modeling projects. The Groundwater Performance Assessment Project characterizes and monitors current conditions in the environment, assesses current impact from past waste disposals and provides the information necessary to allow the continued operation of Hanford’s waste management facilities. The Hanford Site-Wide Impact Assessments Project performs assessments to estimate future conditions and the effect of remedial options on those conditions using broad collection of assessment and analytical tools and provides a calibrated groundwater model of Hanford for all projects. The Remediation and Closure Science Project uses fundamental and applied science to investigate waste site inventories, to develop our understanding of the basic mechanisms controlling contaminant movement and the impact of those contaminants on receptors, and to develop the technical basis for new remediation technologies.

Mr. Freshley joined Battelle-Pacific Northwest Division in 1982 as a Scientist and has participated in both field and modeling studies in ground-water hydrology. Mr. Freshley has focused his own work on modeling the movement of water and contaminants in the unsaturated zone and saturated zone for high-level and low-level radioactive waste disposal, predicting the movement of ground-water flow and contami¬nant transport in the unconfined aquifer at the Hanford Site, reconstructing the potential dose from radioactive waste discharges to the ground during the more than 40 years of operations at the Hanford Site.

Mark Freshley's PNNL staff page

Susan hubbard

Susan Hubbard

 Earth Sciences Division Director and Senior Scientist (LBNL)
Senior Technical Advisor for the ASCEM

Dr. Susan S. Hubbard is the Director of the Earth Sciences Division and a Senior Scientist at Lawrence Berkeley National Laboratory.  Susan received her B.S in Geology from UC Santa Barbara; her M.S. in Geophysics from Virginia Tech; and her Ph.D. in Engineering from UC Berkeley in 1998.  She has previously worked at the U.S. Geological Survey and for the petroleum industry. Her research focuses on advancing the use of geophysical methods for shallow subsurface characterization and monitoring, with a particular emphasis on development of data integration methods and application of those methods to water resources, carbon cycling, and environmental remediation problems. She co-edited the first book on hydrogeophysics and has published over 100  papers on this topic. Dr. Hubbard is  on several scientific advisory boards and serves or has served on several editorial boards (including the Vadose Zone Journal, Journal of Hydrology, Water Resources and JGR-Biosciences). She leads the DOE Sustainable Systems SFA 2.0 at LBNL and co leads NGEE-Arctic.  She is the recipient of the 2009 Frank Frischknecht award for leadership and innovation in near-surface geophysics, was the Birdsall-Dreiss Distinguished lecturer for 2010, and is a Fellow of the Geological Society of America.

Susan Hubbard's LBNL staff page

Haruko wainwright

Haruko Wainwright PortraitPostdoctoral Researcher, Earth Sciences Division,
Lawrence Berkeley National Laboratory (LBNL)

Haruko Murakami Wainwright is currently a postdoctoral fellow at Lawrence Berkeley National Laboratory. She earned MS in nuclear engineering (2006), MA in statistics (2010), and PhD in nuclear engineering (2010) at University of California, Berkeley. Her dissertation focused on geostatistical hydrological inversion for subsurface characterization at the DOE Hanford site. Her research interests include geostatistics, stochastic inverse modeling, hydrogeological modeling and uncertainty quantification related to environmental remediation, CO2 sequestration and terrestrial ecosystem modeling. Her postdoctoral research includes the development of Bayesian multscale data integration methods for jointly inverting hydrogeological and geophysical datasets, and uncertainty quantification for reactive transport modeling and multiphase flow modeling.

Haruko Wainwright's Earth Science staff page