Analysis and Mapping Procedures for Non-Accredited Levees - New Approach

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This document outlines the new process used by the Federal Emergency Management Agency (FEMA) to analyze and map areas on the landward side of non-accredited levee systems that are shown on FEMA’s Flood Insurance Rate Maps.  Under FEMA’s prior levee approach, a levee system that did not meet the National Flood Insurance Program requirements was analyzed and mapped as if it had no effect on the landward side of the levee system during the base (1-percent-annual-chance) flood.  This was known as the “without levee” approach.  Given recent technological advances in data collection and hydrologic and hydraulic modeling, FEMA is able to implement a more refined approach to mapping flood hazards in areas landward of levee systems.  The suite of procedures discussed in this document will better meet the needs of the public and provide results that are more refined. 

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Icon for file of type application/pdfAnalysis and Mapping Procedures for Non-Accredited Levees - New Approach
3.07MJuly 1, 2013
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