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FEMA Finalized Analysis and Mapping Procedures for Non-Accredited Levees

posted Jul 12, 2013, 1:22 PM by mary presnail

The Federal Emergency Management Agency (FEMA), today, released its updated procedures for analyzing and mapping flood hazards in the vicinity of non-accredited levee systems.  These updated procedures are a part of an on-going effort to reform the National Flood Insurance Program (NFIP).  The new procedures are repeatable, flexible, and comply with statutory and regulatory requirements.


FEMA recognizes that levee systems that do not fully meet the requirements for accreditation may still provide a measure of flood risk reduction; for that reason, the Agency has developed a new approach and procedures for providing a more refined depiction of flood risks. The adopted procedures have gone through an extensive process of scientific review and public input.  These new procedures allow a levee system to be broken down into multiple reaches, or sections of levee, to allow the risks due to identified deficiencies to be better understood and determined.  A levee reach is a continuous length of a portion of the levee system where a single new procedure may be applied.  Levees are not always considered one single structure, but instead, often comprised of multiple levee reaches.  The new procedures will provide a more realistic depiction of flood risks in the vicinity of the nation’s levee systems.


This new approach, accompanied by operating guidance, will be applied to a limited number (approximately 25) of projects during Fiscal Year 2013 that were selected considering a number of factors including data availability and to select a wide range of levee scenarios to properly pilot the new process. Future mapping projects will be prioritized as the first phase of projects are completed.  The first phase will begin the process of compiling the necessary additional data that FEMA has available in the coming weeks.


FEMA will continue to tailor its existing approach, guidance and engagement materials to support this new process and incorporate the lessons learned in the pilot projects.  To that end, FEMA will periodically issue operating guidance and standards to document updates and improvements to the approach.  These materials will provide communities, levee owners, and local project sponsors with a clear understanding of how their participation will be sought and valued throughout the new process.  As with other recently-adopted tools that have increased FEMA mapping accuracy, the new levee analysis and mapping procedures add to FEMA’s overall continually improving flood mapping and analysis capabilities.


To review the final approach document, visit: