学术报告题目：Connectivity of Heterogeneous Geologic Media: From Complexity to Simplification of Groundwater Contaminant Transport Analysis

报告人： Graham E. Fogg

报告时间：2018年6月29日上午10:00

报告地点：国家重点实验室301会议室

报告简介

The need for new theories of transport that account for effects of complex, heterogeneous porous media arises from fundamental hydrogeologic characteristics of porous media. The typically large values of Ln-K variance (e.g., 5-25) result in juxtaposed fast and slow velocity zones wherein the latter can be dominated by diffusion processes. Moreover, empirical and theoretical studies of the last 15 years demonstrate that in the absence of spatially persistent unconformities, the percolation threshold in 3D will be small, at about 13 to 20%. In other words, without unconformities that might systematically interrupt connectivity, in 3D the upper 13 to 20% of K values will produce percolating paths that connect fully in all three dimensions. In contrast, human intuition is much more comfortable with the notion of a 50% percolation threshold, which applies to the 2D but not the 3D case. The high variance and tendency for interconnection of the high-K fraction leads to a connected-network paradigm of the subsurface that is consistent with field observations, wherein tracer first breakthroughs can occur much sooner than conventional models would predict, and late-time tailing can persist decades to centuries longer than conventional models would predict (e.g., the ubiquitous difficulty of pump-and-treat even for non-reactive contaminants). These fundamentals provide a solid foundation for new, non-Fickian theories of transport while also providing a logical explanation for the extreme scale-dependent behavior of dispersivity. Such research must lead to work on another grand challenge that should eclipse the challenges of plume scale phenomena – the modeling of regional scale groundwater quality sustainability of systems subjected to centuries of contaminant sources or to non-point sources.

报告人简介

Graham E. Fogg

Professor of Hydgrology

Department of Land, Air, and Water Resources

237 Veihmeyer Hall

University of California, Davis

Davis, CA 95616 530-752-6810 / gefogg@ucdavis.edu

Research and Professional Experience:

2006-11           Chair, Hydrologic Sciences Graduate Group, Univ. of CA, Davis

1996-present Professor of Hydrogeology, Dept. of Land, Air, and Water Resources, University of California, Davis

1998-01 Vice-Chair for Hydrology, Dept. of Land, Air and Water Resources, University of California, Davis

1993-98 Chair, Hydrologic Sciences Graduate Group, University of California, Davis 1989-96 Associate Professor of Hydrogeology, Dept. of Land, Air, and Water Resources,

University of California, Davis

1978-89 Research Scientist/Associate, Bureau of Economic Geology, The University of Texas at Austin

Awards

Fellow of Geological Society of America, awarded 2002

Geological Society of America Birdsall-Dreiss Distinguished Lecturer, 2002 O.E. Meinzer Award for 2011, Geological Society of America

University of Texas at Austin Bur. of Econ. Geology Alumni of the Year, 2012

Publications:

1.     

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