Integrated Use of Data and Numerical Models for Site Conceptual Model Development In Complex Hydrogeologic Systems
Tuesday, September 24, 2019: 10:10 a.m.
Donald Reeves, Ph.D.
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Department of Geological and Environmental Sciences, Western Michigan University
Rishi Parashar, Ph.D.
,
Division of Hydrologic Sciences, Desert Research Institute, Reno, NV
Eric M. LaBolle, Ph.D.
,
Hydrologic Sciences, University of California, Davis, Davis, CA
Yong Zhang, Ph.D.
,
Department of Geological Sciences, University of Alabama, Tuscaloosa, AL
Karl Pohlmann
,
Division of Hydrologic Sciences, Desert Research Institute, Las Vegas, NV
Chuck Russell
,
Division of Hydrologic Sciences, Desert Research Institute, Las Vegas, NV
Jenny Chapman
,
Division of Hydrologic Sciences, Desert Research Institute, Las Vegas, NV
Rainier Mesa is a tuffaceous plateau located on the Nevada National Security Site that has been subjected to a numerous subsurface nuclear tests conducted in a series of tunnel complexes. The tunnels are constructed near the middle of an 800 m thick Tertiary volcanic sequence of faulted, low-permeability welded and non-welded bedded, vitric and zeolitized tuff units that overlie a regional groundwater flow system within densely fractured carbonates. This presentation will focus on the multi-year development and iterative testing of a comprehensive site conceptual model that forms a basis for fluid flow and radionuclide transport simulations in support of the monitored natural attenuation strategy employed by the U.S. DOE. The hydrogeologic complexity of the site necessitated a comprehensive analysis of all available data to first explain and then properly develop numerical models that reasonably represent the dominant flow characteristics of the site which include an upper perched zone of saturated overlying a regional flow system separated by a thin unsaturated zone, and perplexing patterns and trends of fluid drainage from faults and fractures observed during tunnel excavation and operation. Emphasis will be placed on how seemingly disparate datasets and numerical modeling exercises were critical for successful site conceptualization.
Donald Reeves, Ph.D., Department of Geological and Environmental Sciences, Western Michigan University
Dr. Matt Reeves is an associate professor of hydrogeology, director of the graduate and undergraduate certificate programs in applied hydrogeology, and director of the Hydrogeology Field Course at Western Michigan University. Dr. Reeves’ research involves applied and theoretical investigations of fluid flow, heat and solute transport in various types of porous media, with a specialty in fractured rock systems. His research has been applied to various problems, including assessing climate change impacts on water resources, contaminant transport, geological waste disposal, geothermal energy, groundwater-to-surface water interaction and hydraulic fracturing for oil and gas.
Rishi Parashar, Ph.D., Division of Hydrologic Sciences, Desert Research Institute, Reno, NV
My research interest is in the area of developing models to characterize movement of water and entities such as contaminants, microbes, and heat on a continuum of scales in porous and fractured media. I use discrete fracture network (DFN) modeling tools to understand influence of network-scale hydraulic and geometric properties on plume migration in fractured rock formations. My co-researchers and I are interested in developing techniques for upscaling transport in fracture networks which can effectively account for correlations and connectivity structures. I am also interested in employing coupled thermo-hydro-mechanical models for enhanced geothermal systems and other fields of research where faults and fractures play an important role. Outside of fracture media related topics, I have interest in the wider research field of anomalous transport, particularly in relation to motile microbes and their implications for in-situ bioremediation.
Eric M. LaBolle, Ph.D., Hydrologic Sciences, University of California, Davis, Davis, CA
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Yong Zhang, Ph.D., Department of Geological Sciences, University of Alabama, Tuscaloosa, AL
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Karl Pohlmann, Division of Hydrologic Sciences, Desert Research Institute, Las Vegas, NV
Mr. Pohlmann's experience and interests include characterization and analysis of hydrogeologic frameworks, groundwater flow, and contaminant transport through field data collection, interpretation and modeling. Field investigations focus on delineation of local and regional groundwater flow systems in the Great Basin and Mojave Deserts. The modeling emphasizes a stochastic approach, incorporating spatial variability in hydrogeologic parameters and the uncertainty in estimating these parameters, and has been used for development of conceptual models, site characterization and closure, delineation of wellhead protection areas, and development of risk assessments.
Chuck Russell, Division of Hydrologic Sciences, Desert Research Institute, Las Vegas, NV
Mr. Russell's research interests are centered on hydrogeologic studies that combine hydrologic and geochemical parameters to solve hydrologic problems, on both a local and regional scale. Other areas of focus are the development of improved methods for the field-based determination of hydrologic parameters, the development of improved methods for monitoring and remediation techniques.
Jenny Chapman, Division of Hydrologic Sciences, Desert Research Institute, Las Vegas, NV
Ms. Chapman is interested in helping solve problems related to waste disposal, contaminant tranpsort, and water supply in arid regions where paleoclimates may continue to influence flow systems or pose uncertainties for the future. Previous and current work rely heavily on isotopic (stable and radiogenic) and geochemical tracers for evaluating recharge and paleohydrologic systems. Borehole logging, time-domain reflectometry, and analytic solute-flux modeling are other techniques that have been useful in her work.
