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Levees: Information for Cooperating Technical Partners and Engineers

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Information for Cooperating Technical Partners, Engineers, Surveyors and Contractors 

Know Your Risk, Know Your Role, Take Action Today!

Flood readiness preparation meeting Community flanking a double levee system Flood amelioration measures

Identifying the Flood Risk

As the Federal agency that is responsible for administering the National Flood Insurance Program (NFIP), FEMA identifies risk levels through flood analyses and mapping projects and also establishes criteria for levee accreditation. The information developed through these flood analyses and projects is provided to communities in the form of maps, called Flood Insurance Rate Maps (FIRMs). FEMA does not build, own or certify levees. The U.S. Army Corps of Engineers (USACE) is responsible for building and maintaining USACE-owned levees and for inspecting those structures to determine their level of maintenance. States, communities, and private levee owners are responsible for maintaining and operating the levees they own according to specific design criteria.

Levee Assessment Requirements

Levees that are designed to provide protection from at least the 1%-annual-chance flood may be accredited by FEMA, and areas immediately behind them mapped as a moderate-risk zone on the FIRM. In order for a levee to be accredited by FEMA and shown on a FIRM as providing protection from the 1%-annual-chance flood, the levee must first be certified by a Professional Engineer or a Federal Agency that designs levees that it is in compliance with the requirements outlined in Section 65.10 of the NFIP regulations and the appropriate documentation included.

If FEMA does not receive the data and documentation required to show compliance with Section 65.10 of the NFIP regulations, FEMA will de-accredit the levee – that is, FEMA will not map the levee on the affected FIRM panel(s) as providing protection from the 1%-annual-chance flood.

Note that FEMA is currently assessing the approach used to analyze areas on the landward side of non-accredited levees on FIRMs and is developing more precise methods to identify flood hazards in these areas. To learn more, visit FEMA’s Revised Levee Analysis and Mapping Approach webpage.

Provisionally Accredited Levees

When a community with an existing accredited levee is being remapped, the levee owner must provide the proper documentation to certify that it still meets at least the minimum Federal requirements. To assist owners who cannot provide FEMA with the required professional engineer-certified data and/or documentation to show the levee continues to provide protection from at least the 1%-annual-chance flood, FEMA established the Provisionally Accredited Levee (PAL) designation to facilitate the levee accreditation process. Before FEMA will apply the PAL designation to a levee system, the community or levee owner must sign and submit an agreement indicating the data and documentation required for compliance with Section 65.10 will be provided within a specified time frame not to exceed 24 months. Additional information on PALs can be found in the Provisionally Accredited Levees Brochure and through the Levee Resources Library.

Finding More Information on Levee Accreditation and FEMA Guidance on Levees

FEMA has issued a number of publications providing guidance on the levee accreditation process, including the submittal of required data and documentation. To assist community officials and levee owners, FEMA has developed a “how-to” checklist for floodplain managers and engineers: Meeting the Criteria for Accrediting Levees on NFIP Flood Maps: How-To Guide for Floodplain Managers and Engineers.

FEMA Procedure Memorandum No. 34 (PM 34) helps clarify the responsibilities of community officials, levee owners, and other parties seeking recognition of a levee system that is identified during a study/mapping project. PM 34 clarifies the existing procedures to provide information on levee systems, which were provided in Appendix H of FEMA’s Guidelines and Standards for Flood Risk Mapping. The procedures in PM 34 were intended to minimize delays in near-term studies/mapping projects and to help FEMA mapping partners and contractors properly handle mapping issues in levee-impacted areas.

The FEMA Levee Procedure Memorandums fact sheet summarizes guidance delivered in all levee-related PMs issued by FEMA. These PMs are accessible at the links below.

  • PM 34 (Issued August 22, 2005): Interim Guidance for Studies including Levees
  • PM 43 (Issued March 16, 2007 - originally issued September 25, 2006): Guidelines for Identifying Provisionally Accredited Levees
  • PM 45 (Issued May 12, 2008): Revisions to Accredited Levee and Provisionally Accredited Levee Notation
  • PM 51 (Issued February 27, 2009): Guidance for Mapping of Non-Levee Embankments Previously Identified as Accredited
  • PM 52 (Issued April 24, 2009): Guidance for Mapping Processes Associated with Levee Systems
  • PM 53 (Issued April 24, 2009): Guidance for Notification and Mapping of Expiring Provisionally Accredited Levee Designations
  • PM 63 (Issued September 2, 2010): Guidance for Reviewing Levee Accreditation Submittals

A comprehensive catalog of levee-related publications and resources related to accreditation and other levee topics is available at the FEMA Levee Resources Library.

U.S. Army Corps of Engineers: Participation in Levee System Assessment

FEMA and USACE management and staff coordinate closely on levee system issues. On September 26, 2006, the USACE issued a memorandum that provides policy guidance for the inspection of levee systems in the USACE programs. The USACE memorandum helps clarify the responsibilities of USACE and FEMA staff for notifying levee owners of the condition of their levee systems. The USACE memorandum also explains the data required to credit levee systems with providing flood protection. FEMA and USACE staff collaboratively developed this memorandum and FEMA PM 43, which are intended to be companion documents to cover situations where levee systems in the USACE program are evaluated for accreditation on FIRMs.

On January 18, 2007, the USACE issued a memorandum to provide supplemental guidance for the inspection of levee systems in the USACE programs. The purpose of the memorandum is to provide a one-time-only “maintenance deficiency correction period” of 1 year, which will allow public sponsors of levee system projects time to correct maintenance deficiencies before the project is placed in an “inactive” status in the USACE Rehabilitation and Inspection Program and becomes ineligible for Public Law 84-99 rehabilitation assistance.

USACE Engineering Circular 1110-2-6067 (USACE Process for the National Flood Insurance Program Levee System Evaluation) issued August 31, 2010 comprehensively outlines the USACE’s policy for levee system evaluations performed by the USACE for FEMA NFIP accreditation of levees.

For a comprehensive listing of key USACE documents relating to levee assessment, visit the USACE’s Levee Safety Program webpage.

Mapping Requirements for Levee System Construction and Restoration Projects

In the interest of public safety, communities, State agencies, and Federal agencies sometimes construct new levee systems to address flood hazards and reduce flood risks to the people and structures in certain communities or areas within a state. In other situations, communities, State agencies, or Federal agencies will undertake a project to restore the flood protection capabilities of a levee system that had previously provided 1%-annual-chance flood protection, but which had been found to no longer provide this level of flood protection. FEMA has established regulatory and procedural requirements for the mapping of areas impacted by levee system construction and restoration projects. The Levee System Construction and Restoration Projects home page contains information and resources related to FEMA regulatory and procedural requirements. This page outlines the benefits of including FEMA flood protection restoration zones and adequate progress determinations, shown as Zone AR and Zone A99 respectively on FIRMs.

For More Information

For more information or additional assistance:

Last Updated: 
08/01/2012 - 14:05
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