NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.
This study was supported by the U.S. Nuclear Regulatory Commission, award number NRC-04-96-078, and the U.S. Department of Energy, DE-FG08-97NV12056. The opinions, findings, conclusions, and recommendations expressed herein are those of the authors and do not necessarily reflect the view of the Nuclear Regulatory Commission or the U.S. Department of Energy.
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Cover: Illustrations courtesy of David A. Feary (photographs from Yucca Mountain and Busted Butte), and Peters, R. R., and E. A. Klavetter, 1988, a continuum model for water movement in an unsaturated fractured rock mass, Water Resources Research 24(3): 416-430, copyright by American Geophysical Union (for schematic figure showing fluid in fractures).
Copyright 2001 by the National Academy of Sciences. All rights reserved.
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PANEL ON CONCEPTUAL MODELS OF FLOW AND TRANSPORT IN THE FRACTURED VADOSE ZONE
PAUL A. HSIEH, Chair,
U.S. Geological Survey, Menlo Park, California
JEAN M. BAHR,
University of Wisconsin, Madison
THOMAS W. DOE,
Golder Associates, Inc., Redmond, Washington
ALAN L. FLINT,
U.S. Geological Survey, Sacramento, California
GLENDON GEE,
Battelle Pacific Northwest Laboratory, Richland, Washington
LYNN W. GELHAR,
Massachusetts Institute of Technology, Cambridge
D. KIP SOLOMON,
University of Utah, Salt Lake City
MARTINUS VAN GENUCHTEN,
U.S. Salinity Laboratory, Riverside, California
STEPHEN W. WHEATCRAFT,
University of Nevada, Reno
NRC Staff
DAVID A. FEARY, Senior Program Officer (beginning 3/2000)
THOMAS M. USSELMAN, Senior Program Officer (through 2/2000)
JENNIFER T. ESTEP, Administrative Associate
U. S. NATIONAL COMMITTEE FOR ROCK MECHANICS
HERBERT H. EINSTEIN, Chair,
Massachusetts Institute of Technology, Cambridge
RONALD P. STEIGER, Vice-Chair,
Exxon Production Research Co., Houston, Texas
CATHERINE T. AIMONE-MARTIN,
New Mexico Institute of Mining and Technology, Socorro
JAAK J.K. DAEMEN,
University of Nevada, Reno
EMMANUEL DETOURNAY,
University of Minnesota, Minneapolis
JOANNE T. FREDRICH,
Sandia National Laboratories, Albuquerque, New Mexico
RICHARD E. GOODMAN,
University of California, Berkeley
PAUL A. HSIEH, U.S.
Geological Survey, Menlo Park, California
JAMES E. MONSEES,
Parsons Brinckerhoff, Inc., Orange, California
LAURA J. PYRAK-NOLTE,
Purdue University, West Lafayette, Indiana
NRC Staff
DAVID A. FEARY, Senior Program Officer
JENNIFER T. ESTEP, Administrative Associate
BOARD ON EARTH SCIENCES AND RESOURCES
RAYMOND JEANLOZ, Chair,
University of California, Berkeley
JOHN J. AMORUSO,
Amoruso Petroleum Company, Houston, Texas
PAUL BARTON, JR., U.S.
Geological Survey (emeritus), Reston, Virginia
BARBARA L. DUTROW,
Louisiana State University, Baton Rouge
ADAM M. DZIEWONSKI,
Harvard University, Cambridge, Massachusetts
RICHARD S. FISKE,
Smithsonian Institution, Washington, D.C.
JAMES M. FUNK,
Shell Continental Companies, Houston, Texas (retired)
WILLIAM L. GRAF,
Arizona State University, Tempe
SUSAN M. KIDWELL,
University of Chicago, Illinois
SUSAN KIEFFER,
Kieffer & Woo, Inc., Palgrave, Ontario, Canada
PAMELA E. LUTTRELL,
Dallas, Texas
ALEXANDRA NAVROTSKY,
University of California, Davis
DIANNE R. NIELSON,
Utah Department of Environmental Quality, Salt Lake City
JONATHAN PRICE,
Nevada Bureau of Mines & Geology, Reno
NRC Staff
ANTHONY R. DE SOUZA, Director
TAMARA L. DICKINSON, Senior Program Officer
DAVID A. FEARY, Senior Program Officer
ANNE M. LINN, Senior Program Officer
LISA M. VANDEMARK, Program Officer
JENNIFER T. ESTEP, Administrative Associate
VERNA J. BOWEN, Administrative Assistant
REBECCA E. SHAPACK, Research Assistant
TERESIA K. WILMORE, Project Assistant
COMMISSION ON GEOSCIENCES, ENVIRONMENT, AND RESOURCES
GEORGE M. HORNBERGER, Chair,
University of Virginia, Charlottesville
RICHARD A. CONWAY,
Union Carbide Corporation (retired), South Charleston, West Virginia
LYNN GOLDMAN,
Johns Hopkins School of Hygiene and Public Health, Baltimore, Maryland
THOMAS E. GRAEDEL,
Yale University, New Haven, Connecticut
THOMAS J. GRAFF,
Environmental Defense Fund, Oakland, California
EUGENIA KALNAY,
University of Maryland, College Park
DEBRA KNOPMAN,
Progressive Policy Institute, Washington, D.C.
JOHN B. MOONEY, JR.,
J. Brad Mooney Associates, Ltd., Arlington, Virginia
HUGH C. MORRIS,
El Dorado Gold Corporation, Vancouver, British Columbia
H. RONALD PULLIAM,
University of Georgia, Athens
MILTON RUSSELL,
University of Tennessee (retired), Knoxville
ROBERT J. SERAFIN,
National Center for Atmospheric Research, Boulder, Colorado
ANDREW R. SOLOW,
Woods Hole Oceanographic Institution, Massachusetts
E-AN ZEN,
University of Maryland, College Park
NRC Staff
ROBERT M. HAMILTON, Executive Director
GREGORY H. SYMMES, Associate Executive Director
JEANETTE SPOON, Administrative and Financial Officer
CHRISTINE HENDERSON, Scientific Reports Officer
SANDI FITZPATRICK, Administrative Associate
Preface
The purpose of this study is to describe the processes through which conceptual models of flow and transport in the fractured vadose zone are developed, tested, refined, and reviewed. The Panel convened a two-day workshop in March 1999, during which a large group of specialists from the hydrogeologic, geochemical, soil science, and related fields discussed the current state of knowledge, lessons learned from field investigations, and needs for future research. A series of invited presentations provided the basis for much of the discussion at this workshop. Individually authored papers based on these presentations are presented as Chapter 2, Chapter 3, Chapter 4, Chapter 5, Chapter 6, Chapter 7, Chapter 8, Chapter 9, Chapter 10 and Chapter 11 in the second part of this volume.
The Panel was charged with preparing a consensus report on the development and testing of conceptual models for fluid flow and transport in the fractured vadose zone. The Panel's conclusions and recommendations were based in large part on the workshop presentations and discussions. This report is intended to describe the present status of conceptual model building in the fractured vadose zone; to provide guidance to regulatory agencies on the review process for conceptual models developed for site licensing; to compile knowledge and experiences from related disciplines so that technical communities can benefit from advances in related fields; and to identify future research needed to advance the technical basis for developing and evaluating vadose zone conceptual models.
In its consideration of transport in the vadose zone, the Panel focused on the application of environmental tracers (such as tritium and chlorine-36) because they provide integrated responses that are difficult to determine by point measurements of fluid potential or moisture content. The Panel briefly reviewed
approaches for modeling transport of conservative solutes, but the scope of the study did not include reactive solutes or water-rock interactions.
The Panel report (Chapter 1) is composed of three main sections. First, we discuss general considerations applicable to the development and testing of conceptual models. Second, we summarize the current state of knowledge of flow and transport processes in the fractured vadose zone. Third, we present our conclusions and recommendation.
This report has been reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the NRC's Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their review of this report:
John D. Bredehoeft, The Hydrodynamics Group, Story, Wyoming
June T. Fabryka-Martin, Environmental Technology, Los Alamos National Laboratory, New Mexico
Jane C. S. Long, Mackay School of Mines, University of Nevada, Reno
Mark Person, Department of Geology and Geophysics, University of Minnesota, Minneapolis
Daniel B. Stephens, Daniel B. Stephens and Associates, Inc., Albuquerque, New Mexico
Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations nor did they see the final draft of the report before its release. The review of this report was overseen by George Hornberger, University of Virginia, Charlottesville, appointed by the Commission on Geosciences, Environment, and Resources, who was responsible for making certain that an independent examination of this report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the authoring committee and the institution.
In addition, we acknowledge peer reviews provided by the following for the invited papers (Chapter 2, Chapter 3, Chapter 4, Chapter 5, Chapter 6, Chapter 7, Chapter 8, Chapter 9, Chapter 10 and Chapter 11): S. Bradford, J. D. Bredehoeft, J. Fabryka-Martin, R. Healy, D. L. Hughson, V. Kapoor, K. Karasaki, K. Keller, S. Kung, E. Kwicklis, L. D. McKay, J. W. Mercer, R. L. Michel, B. Mohanty, J-V. Parlange, L. Pyrak-Nolte, E. H. Roseboom Jr., B. R. Scanlon, D. B. Stephens, T. K. Tokunaga, and E. P. Weeks. Although these papers have undergone peer review,
Contents
Note: Color plates are located after p. 184.