Tying Flood Insurance to
Flood Risk for Low-Lying
Structures in the Floodplain
Committee on Risk-Based Methods for Insurance Premiums of
Negatively Elevated Structures in the National Flood Insurance Program
Water Science and Technology Board
Division on Earth and Life Studies
Board on Mathematical Sciences and Their Applications
Division on Engineering and Physical Sciences
NATIONAL RESEARCH COUNCIL
OF THE NATIONAL ACADEMIES
THE NATIONAL ACADEMIES PRESS
Washington, D.C.
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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.
Support for this study was provided by Federal Emergency Management Agency under contract number HSHQDC-11-D-0009/HSFE60-13-J-0026. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that provided support for the project.
International Standard Book Number-13: 978-0-309-37166-7
International Standard Book Number-10: 0-309-37166-X
Cover Illustration: Photo of an inundated downtown riverfront in Davenport, Iowa, when the Mississippi River overflowed its banks on May 4, 2001. The building is a negatively elevated structure in the Special Flood Hazard Area. SOURCE: Photo by David Teska, FEMA.
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COMMITTEE ON RISK-BASED METHODS FOR
INSURANCE PREMIUMS OF NEGATIVELY ELEVATED STRUCTURES
IN THE NATIONAL FLOOD INSURANCE PROGRAM
DAVID T. FORD, Chair, David Ford Consulting Engineers, Sacramento, California
ROSS B. COROTIS, University of Colorado, Boulder
WEI DU, CoreLogic Spatial Solutions, Springfield, Virginia
CLIVE Q. GOODWIN, FM Global Insurance Company, Johnston, Rhode Island
LARRY LARSON, Association of State Floodplain Managers, Madison, Wisconsin
HOWARD LEIKIN, Independent consultant, Silver Spring, Maryland
MARTIN W. MCCANN, Jack R. Benjamin & Associates, Menlo Park, California
LAURA A. MCLAY, University of Wisconsin, Madison
ERWANN MICHEL-KERJAN, University of Pennsylvania, Philadelphia
LINDENE PATTON, CoreLogic Spatial Solutions, Springfield, Virginia*
PATRICIA TEMPLETON-JONES, Wright National Flood Insurance Company, St. Petersburg, Florida
SUSAN E. VOSS, American Enterprise Group, Inc., Des Moines, Iowa
National Research Council Staff
ANNE M. LINN, Study Director, Board on Earth Sciences and Resources
SCOTT T. WEIDMAN, Director, Board on Mathematical Sciences and Their Applications
ANITA A. HALL, Senior Program Associate, Water Science and Technology Board
____________________
* Since October 2014; previously at Zurich Insurance Group, Washington, DC
WATER SCIENCE AND TECHNOLOGY BOARD
GEORGE M. HORNBERGER, Chair, Vanderbilt University, Nashville, Tennessee
EDWARD J. BOUWER, Johns Hopkins University, Baltimore, Maryland
YU-PING CHIN, Ohio State University, Columbus
DAVID A. DZOMBAK, Carnegie Mellon University, Pittsburgh, Pennsylvania
M. SIOBHAN FENNESSY, Kenyon College, Gambier, Ohio
BEN GRUMBLES, Clean Water America Alliance, Washington, D.C.
GEORGE R. HALLBERG, The Cadmus Group, Watertown, Massachusetts
CATHERINE L. KLING, Iowa State University, Ames
DEBRA S. KNOPMAN, RAND Corporation, Arlington, Virginia
LARRY LARSON, Association of State Floodplain Managers, Madison, Wisconsin
RITA P. MAGUIRE, Maguire & Pearce PLLC, Phoenix, Arizona
DAVID I. MAURSTAD, OST, Inc., McLean, Virginia
ROBERT SIMONDS, The Robert Simonds Company, Culver City, California
FRANK H. STILLINGER, Princeton University, Princeton, New Jersey
GEORGE VALENTIS, Veolia Institute, Paris, France
MARYLYNN V. YATES, University of California, Riverside
JAMES W. ZIGLAR, SR., Van Ness Feldman, Washington, D.C.
National Research Council Staff
JEFFREY JACOBS, Director
LAURA J. EHLERS, Senior Program Officer
STEPHANIE E. JOHNSON, Senior Program Officer
EDMOND J. DUNNE, Program Officer
M. JEANNE AQUILINO, Financial and Administrative Associate
MICHAEL J. STOEVER, Research Associate
ANITA A. HALL, Senior Program Associate
BRENDAN R. MCGOVERN, Senior Program Assistant
BOARD ON MATHEMATICAL SCIENCES AND THEIR APPLICATIONS
DONALD G. SAARI, Chair, University of California, Irvine
DOUGLAS N. ARNOLD, University of Minnesota, Minneapolis
JOHN B. BELL, E.O. Lawrence Berkeley National Laboratory, Berkeley, California
VICKI M. BIER, University of Wisconsin, Madison
JOHN R. BIRGE, The University of Chicago, Illinois
L. ANTHONY COX, JR, Cox Associates, Denver, Colorado
MARK L. GREEN, University of California, Los Angeles
JOSEPH A. LANGSAM, University of Maryland, College Park
BRYNA KRA, Northwestern University, Evanston, Illinois
ANDREW W. LO, Massachusetts Institute of Technology, Cambridge, Massachusetts
DAVID MAIER, Portland State University, Portland, Oregon
WILLIAM A. MASSEY, Princeton University, Princeton, New Jersey
JUAN C. MEZA, University of California, Merced
CLAUDIA NEUHAUSER, University of Minnesota, Minneapolis
FRED S. ROBERTS, Rutgers University, Piscataway, New Jersey
GUILLERMO SAPIRO, Duke University, Durham, North Carolina
CARL P. SIMON, University of Michigan, Ann Arbor
KATEPALLI SREENIVASAN, New York University, New York
ELIZABETH A. THOMPSON, University of Washington, Seattle
National Research Council Staff
SCOTT T. WEIDMAN, Director
NEAL D. GLASSMAN, Senior Program Officer
MICHELLE K. SCHWALBE, Program Officer
RODNEY HOWARD, Administrative Assistant
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Acknowledgments
The report was reviewed in draft form by individuals chosen for their breadth of perspectives and technical expertise in accordance with the procedures approved by the National Academies’ Report Review Committee. The purpose of this independent review was to provide candid and critical comments to assist the institution in ensuring that its published report is scientifically credible and that it 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:
Jeroen C.J.H. Aerts, VU University Amsterdam, The Netherlands
Gregory B. Baecher, University of Maryland, College Park
Wouter Botzen, VU University Amsterdam, The Netherlands
Patrick L. Brockett, University of Texas, Austin
W. Hans de Moel, VU University Amsterdam, The Netherlands
Robert E. Hoyt, University of Georgia, Athens
Christopher Jones, Professional Engineer, Durham, NC
David R. Maidment, University of Texas, Austin
Edward T. Pasterick, FEMA, retired, Bowie, MD
Jery R. Stedinger, Cornell University, Ithaca, NY
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 Gerald Galloway, University of Maryland, College Park, and Robin McGuire, Lettis Consultants International, Inc., Boulder, Colorado. Appointed by the National Research Council, they were 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 NRC.
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Contents
1 THE NATIONAL FLOOD INSURANCE PROGRAM AND THE NEED FOR ACCURATE RATES
National Flood Insurance Program
2 NFIP PROCEDURES FOR ANALYZING FLOOD HAZARD AND CALCULATING INSURANCE RATES
Floodplain Analysis and Mapping
3 METHODS FOR ASSESSING FLOOD RISK
Assessing the Components of Flood Risk
U.S. Army Corps of Engineers Method
Refinements to Current Methods
4 FACTORS THAT AFFECT RISK-BASED PREMIUMS FOR NEGATIVELY ELEVATED STRUCTURES