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.      Ahmed, A.A. and G.E. Fogg. 2014. The impact of groundwater and agricultural expansion on the archaeological sites at Luxor, Egypt. Journal of African Earth Sciences, 2014. 95: p. 93-104.

2.      Miyasaka, S.C., McCulloch, C.E., Fogg, G.E., Hollyer, J.E. 2013. Optimum Plot Size for Field Trials of Taro (Colocasia esculenta). Hortscience, 48(4): p. 435-443.

3.      Engdahl, N.B., Ginn, T.R. and Fogg, G.E. 2013. Using groundwater age distributions to estimate the effective parameters of Fickian and non- Fickian models of solute transport. Advances in Water Resources (Elsevier Ltd.), 54: 11-21.

4.      Zhang, Y., Green, C.T., Fogg, G.E. 2013. The impact of medium architecture of alluvial settings on non-Fickian transport. Elsevier Ltd; Advances in Water Resources, 54: 78-99.

5.      Hornberger, G.M., E. Bernhardt, W.E. Dietrich, D. Entekhabi, G.E. Fogg, E. Foiufoula-Georgiou, W.J. Gutowski, W.B. Lyons, K.W. Potter, S.W. Tyler, H.J. Vaux, Jr., C.H. Vorosmarty, C. Welty, C.A. Woodhouse, C. Zheng. 2012. Challenges and Opportunities in Hydrologic Sciences, National Academy Press, 173 p.

6.      Boyle, D., King, A., Kourakos, G., Lockhart, K., Mayzelle, M., Fogg, G.E. & Harter, T., 2012. Groundwater Nitrate Occurrence. Technical Report 4, 277p., in: Addressing Nitrate in California’s Drinking Water with a Focus on Tulare Lake Basin and Salinas Valley Groundwater. Report for the State Water Resources Control Board Report to the Legislature. Center for Watershed Sciences, University of California, Davis (http://groundwaternitrate.ucdavis.edu/).

7.      Engdahl, N.B., Ginn, T.R. and Fogg,G.E. 2012, Non-Fickian dispersion of groundwater age, Water Resources Research, 48, W07508, doi:10.1029/2012WR012251.

8.      Rasa, E., S.W. Chapman, B. Bekins, G.E. Fogg, K.M. Scow, and D.M. Mackay. 2011. Role of back diffusion and biodegradation reactions in sustaining an MTBE/TBA plume in alluvial media, Journal of Contaminant Hydrology, http://dx.doi.org/10.1016/j.jconhyd.2011.08.006.

9.      Fleckenstein, J.H., R.G. Niswonger and G.E. Fogg. 2006. River-aquifer interactions, geologic heterogeneity, and low-flow management. 2006.; doi: 10.1111/j.1745-6584.2006.00190.x. Ground Water, 1-16.

10.  LaBolle, E.M. and G.E. Fogg. 2001. Role of molecular diffusion in contaminant migration and recovery in an alluvial aquifer system. Transport in Porous Media, Special Issue on Modeling Dispersion, 42: 155-179.

11.  Niswonger, R.G. and G.E. Fogg. 2008. Influence of perched groundwater on baseflow, Water Resources Research, 44, W03405, doi:10.1029/2007WR006160, Web access.

12.  Fogg, G.E. and E.M. LaBolle. 2006. Motivation of synthesis, with an example on groundwater quality sustainability, Water Resources Research (special forum on synthesis in the hydrologic sciences), 42, W03S05, doi:10.1029/2005WR004372, Web access.

Synergistic Activities:

1.  Research center leadership: PI of UC Davis IGERT Climate Change, Water, and Society, 2010-2017.

2.  Courses developed: Water, Power, Society (freshman course based on Cadillac Desert); Groundwater Hydrology; Hydrogeology and Contaminant Transport; Modeling of Groundwater Systems; Intro. to Geostatistics; Geostatistical Modeling of Geologic Systems (short course); Introduction to Groundwater Modeling (short course); Introduction to Hydrology (short course)

3.  Panels: Committee convened by Governor Brown of CA on Groundwater Resources and Climate Change; Chair of Characterization Panel, DOE Workshop on Basic Research Needs for Geosciences: Facilitating 21st Century Energy Systems, 2007 (focusing on CO₂ sequestration and nuclear waste isolation); Performance review of Geological Survey of Denmark and Greenland (2007); Davis-Woodland water resources advisory panel (current); Governor’s panel on management of low-level nuclear waste in CA (2000); Chair of Groundwater Committee for San Joaquin Valley Drainage Implementation Program (1999-2000).

4.  Curriculum Development: Developed Climate Change, Water, and Society IGERT curriculum at UCD; Co-founded and designed , new Graduate Group in Hydrologic Sciences (1990-92).

5.  Computational algorithms (that are now in wide use): Transition Probability Geostatistical Simulation (TPROGS) of geologic heterogeneity for more accurate, reliable modeling of groundwater phenomena; Random Walk Simulation in Heterogeneous Media (RWHET) for more accurate, reliable simulation of mass transport in groundwater.