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Date: April 24, 2009
Contacts: Jennifer Walsh, Media Relations Officer
William Kearney, Director of Media of Relations
Alison Burnette, Media Relations Assistant
Office of News and Public Information
202-334-2138; e-mail <news@nas.edu>
For immediate release
Levees Cannot Fully Eliminate Risk of Flooding to
The report is the fifth and final one to provide recommendations to the Interagency Performance Evaluation Task Force (IPET), formed by the U.S. Army Corps of Engineers to examine why
Although some of the report's recommendations to enhance hurricane preparedness have been widely acknowledged for years, many have not been adequately implemented, said the committee that wrote the report. For instance, levees and floodwalls should be viewed as a way to reduce risks from hurricanes and storm surges, not as measures that completely eliminate risk. As with any structure built to protect against flooding, the
Comprehensive flood planning and risk management should be based on a combination of structural and nonstructural measures, including the option of voluntary relocations, floodproofing and elevation of structures, and evacuation, the committee urged. Rebuilding the
For structures in hazardous areas and residents who do not relocate, the committee recommended major floodproofing measures -- such as elevating the first floor of buildings to at least the 100-year flood level and strengthening electric power, water, gas, and telecommunication supplies. Also, a comprehensive evacuation program should be established that includes well-designed and tested evacuation plans; improved local and regional shelters that would make evacuations less imposing; and long-term strategies that could enhance the efficiency of evacuations, such as locating facilities for the ill and elderly away from hazardous areas.
Furthermore, the 100-year flood level -- which is a crucial flood insurance standard -- is inadequate for flood protection structures in heavily populated areas such as
Regarding IPET's draft final report, the committee concluded that it contained important advances in characterizing and understanding the nature of Gulf hurricane storm surges and waves -- in particular explaining the storm surge generated by Hurricane Katrina, how waters from the surge entered the
However, the final IPET report should provide a better explanation of its methods to evaluate flood risks, the committee said. The final report also should be written in a more clear and organized manner, using layman's terminology that can be understood by the public and officials. Such clarity is lacking in Volume VIII, which was the principal focus of the final two years of IPET's study. This volume assesses the risks posed by future tropical storms and contains inundation maps that show the areas at most risk for future flooding. These maps are important to citizens, businesses, and government agencies for planning resettlement and redevelopment in the region, but the volume contains limited discussion of the implications of these maps. Moreover, at times the extensive technical information presented in the volume overshadows key results.
The committee also recommended that a professional technical firm prepare a second document for the public and officials that would be shorter and focus on explaining IPET report results and implications for reconstruction and resettlement.
The National Academy of Sciences, National Academy of Engineering,
Copies of The New Orleans Hurricane Protection System: Assessing Pre-Katrina Vulnerability and Improving Mitigation and Preparedness are available from the National Academies Press; tel. 202-334-3313 or 1-800-624-6242 or on the Internet at http://www.nap.edu. Reporters may obtain a copy from the Office of News and Public Information (contacts listed above).
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[ This news release and report are available at http://national-academies.org ]
NATIONAL RESEARCH COUNCIL
Division on Earth and Life Studies
Division on Engineering and Physical Sciences
Committee on
G. Wayne Clough* (chair)
Secretary
Smithsonian Institution
Rafael L. Bras*
Dean and Distinguished Professor
John T. Christian*
Consulting Engineer
Jos Dijkman
Flood Management Engineer
WL/Delft Hydraulics
Robin L. Dillon-Merrill
Associate Professor
Delon
Chairman of the Board
Delon Hampton and Associates, Chartered
Greg J. Holland
Director
Mesoscale and Microscale Meteorology Division
Richard A. Luettich Jr.
Director
Peter Marshall
Consulting Engineer
David H. Moreau
Professor
Departments of City and Regional Planning and Environmental Sciences and Engineering
Thomas D. O'Rourke*
Thomas R. Briggs Professor of Engineering
Kenneth W. Potter
Professor
Department of Civil and Environmental Engineering
Y. Peter Sheng
Professor
Department of Civil and Coastal Engineering
Robert H. Weisberg
Professor of Physical Oceanography
Andrew J. Whittle
Professor
Department of Civil and Environmental Engineering
Massachusetts Institute of Technology
RESEARCH COUNCIL STAFF
Jeffrey Jacobs
Study Director