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4 Levee Analysis and Mapping Procedure
Pages 57-62

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From page 57...
... and would be subject to the mandatory purchase requirements of the NFIP. In response to congressional requests, the administrator directed FEMA staff to develop an approach to mapping nonaccredited levees that would reflect any risk reduction and the commensurate rates that nonaccredited levees might afford the communities.
From page 58...
... If so, the remaining area is designated as Zone D, except for any portions subject to flooding due to interior drainage. The Sound Reach Procedure is applied to continuous sections of levee that have been designed, constructed, and maintained to withstand and reduce the flood hazards posed by a one percent annual chance flood.
From page 59...
... Suggestions were made to use the Zone X designation which carries less of a negative connotation. 2 Technical comments addressed such issues as the failure of the Natural Valley method to account for local backwater effects caused by flow impediments such as levee tiebacks, confusion over the definition of a reach, use of the Freeboard Deficient Procedure believing that it "would remove elevation and insurance requirements behind a levee that has only one inch of freeboard and no armoring," and failure in the Overtopping Procedure "to consider that the true one percent chance flood stage may be substantially higher than the median one percent stage," suggesting that the Overtopping Procedure be replaced by the Structural-Based Procedure which does not appear to use a factor of safety.
From page 60...
... and will have a negative impact with respect to public engagement, risk communication, and NFIP viability and public acceptance of the program. FEMA should move directly to a modern risk-based analysis for dealing with areas behind levees and not implement the Levee Analysis and Mapping Procedure.
From page 61...
... Where a participating community has within its geographic bounds and within the SFHA levees that do not currently meet NFIP standards and that have never been proposed for certification, it would be possible, on completion of the development of risk-based analysis, for these communities to request, at community expense, FEMA evaluation of the levees to determine risk-based SFHA insurance pricing for properties affected by these levees. A CAUTION Levees were introduced into the NFIP because, at the time, decision makers reasoned that because new construction within the SFHA would be required to be at or above one percent annual chance flood level in order to be removed from the mandatory purchase requirement, equity dictated that those protected by a one percent annual chance "flood control" structure should also be removed from the requirements of mandatory insurance and land management behind the structures.
From page 62...
... 2006. The Evaluation of the National Flood Insurance Program: Final Report.


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