Dubuque Levee and Floodwall System_Letter of Agreement FEMATO: The Honorable Mayor and City Council Members
FROM: Michael C. Van Milligen, City Manager
SUBJECT: Dubuque Levee and Floodwall System -Letter of Agreement with FEMA
DATE: April 28, 2009
Whenever new Federal Emergency Management Agency (FEMA) flood insurance rate
maps are produced, levees must be evaluated to see if they still provide protection from
a 100-year flood event (a 1 % annual chance flood).
The U.S. Corps of Engineers Rock Island District will conduct the evaluation in Dubuque
at no cost to the City. The Corps will provide a sample levee evaluation report to help
determine the level of effort needed by the City Engineering Department to certify the
levee using the Corps' report.
Planning Services Manager Laura Carstens recommends City Council authorization for
the Mayor, City Manager and City Engineer to execute the Provisionally Accredited
Levee Agreement with FEMA for Dubuque's levee and floodway system.
concur with the recommendation and respectfully request Mayor and City Council
approval.
Mi hael C. Van Milligen
MCVM/jh
Attachment
cc: Barry Lindahl, City Attorney
Cindy Steinhauser, Assistant City Manager
Laura Carstens, Planning Services Manager
THE CITY OF DUBUQUE
Masterpiece on the Mississippi
Dubuque
All-American City
2007
TO: Michael Van Milligen, City Manager
FROM: Laura Carstens, Planning Services Manager
SUBJECT: Dubuque Levee and Floodwall System -Letter of Agreement with FEMA
DATE: April 23, 2009
INTRODUCTION
This memorandum transmits correspondence from the Federal Emergency Management
Agency (FEMA) regarding the new federal program for levee certification and its application to
the Dubuque levee and floodwall system along the Mississippi River.
Attached area letter from FEMA, a Letter of Agreement and Request for Provisionally
Accredited Levee (PAL) Designation, handouts about this federal program, and a resolution
authorizing the Mayor, the City Manager, and the City Engineer to sign and submit the PAL
Agreement with FEMA on behalf of the City of Dubuque.
DISCUSSION
Whenever new FEMA flood insurance rate maps (FIRMS) are produced, levees must be
evaluated to see if they still provide protection from a 100 year flood event (a 1 % annual chance
flood). Prior to the Hurricane Katrina disaster, the U.S. Army Corps of Engineers evaluated and
re-certified the levees. Following Hurricane Katrina, the Corps no longer certifies the levees -
with the responsibility now placed on the communities protected by the levees.
FEMA representatives informed City staff that levees and floodwalls that are not certified as
providing protection from a 100 year flood event will be de-certified. If we lose levee
certification, new development and expansions in the Mississippi River floodplain would have to
comply with floodplain development standards, and existing structures in the Mississippi River
floodplain would be required to obtain flood insurance.
FEMA representatives informed City staff that preliminary FIRMS for Dubuque are scheduled for
June 2009. PAL Agreements need to be in place prior to the update of these FIRMS. PAL
Agreements are for two years.
The certification process begins with Dubuque receiving the attached PAL Agreement. The City
has until May 17, 2009 to return the signed PAL Agreement to FEMA, after having it approved
by the City Council.
Upon submittal of the completed PAL Agreement to FEMA, the City would have until May 17,
2011 to complete the certification process, make any necessary levee and floodwall system
improvements, and submit the necessary documentation for full accreditation of the levee and
floodwall system. If the certification process and documents show that our levee and floodwall
Dubuque Levee and Floodwall System -Letter of Agreement with FEMA Page 2
system still protects Dubuque from a 100 year flood event, the levee and floodwall system
would then be certified for approximately ten years.
At the end of the two year certification process, if the required certification forms and data have
not been submitted to FEMA, our floodwall will be de-certified. Alternatively, if the engineering
work required for certification is submitted on time but shows that the floodwall does not meet
FEMA's minimum standards, the floodwall will be de-certified if it is not brought up to FEMA's
standards within those same two years.
Corps representatives informed City staff that the Corps' Rock Island District will conduct the
evaluation of the Dubuque levee and floodwall system at no cost to the City. The Corps will
begin work sometime during the last quarter of this calendar year. The evaluation study will
take approximately 6 months to complete. The Corps will provide a sample levee evaluation
report to help us determine what effort would be necessary for the City's professional
engineering staff to certify the levee system based upon the evaluation.
The Corps will provide this evaluation at no cost to the City because the agency is evaluating
the Upper Mississippi River levee systems that provide or potentially provide protection from the
100 year flood. The goal of this project is to complete rigorous evaluations of all qualifying levee
systems according to current Corps engineering technical standards. In accomplishing these
evaluations, site visits will be made, levee cross sections will be studied, and seepage analysis
computations and historic performance information will be reviewed. Project results will be
documented in comprehensive assessment reports on the engineering adequacy of the
evaluated levee systems to withstand the 100 year flood. These levee system evaluations will
not result in the certification of levees, nor constitute a warranty of performance; however, they
will be of significant value to City Engineering staff for certification of Dubuque's levee and
floodwall system.
RECOMMENDATION
Staff recommends that the City Council adopt the attached resolution authorizing the Mayor, the
City Manager, and the City Engineer to sign the PAL Agreement with FEMA for Dubuque's
levee and floodwall system, on behalf of the City of Dubuque.
Attachments
cc: Don Vogt, Public Works Director
Gus Psihoyos, City Engineer
John Klostermann, Streets & Sewers Supervisor
Deron Muehring, Civil Engineer
Kyle Kritz, Associate Planner
Prepared by: Laura Carstens, City Planner Address: City Hall. 50 W. 13th St Telephone: 589-4210
Return to: Jeanne Schneider, City Clerk Address: City Hall- 50 W. 13 St Telephone: 589-4121
RESOLUTION NO. 140 -09
RESOLUTION AUTHORIZING EXECUTION OF A PROVISIONALLY
ACCREDITED LEVEE (PAL) LETTER OF AGREEMENT WITH THE FEDERAL
EMERGENCY MANAGEMENT AGENCY FOR THE DUBUQUE LEVEE AND
FLOODWALL SYSTEM
Whereas, the Federal Emergency Management Agency (FEMA) has provided a
Letter of Agreement and Request for Provisionally Accredited Levee (PAL) Designation
to the City of Dubuque for the Dubuque levee and floodwall system along the
Mississippi River; and
Whereas, the City of Dubuque has identified that the accreditation of this City-
owned facility is a community priority.
NOW THEREFORE, BE IT RESOLVED BY THE CITY COUNCIL OF THE CITY
OF DUBUQUE, IOWA:
Section 1. The City Council does hereby authorize the Mayor, the City
Manager, and the City Engineer to sign and submit the Letter of Agreement and
Request for Provisionally Accredited Levee (PAL) Designation with FEMA on behalf of
the City of Dubuque.
Passed, approved and adopted this 4tn day of May 2009.
Roy D. BSI, Mayor
Attest:: Jeanne F. Schneider, City Clerk
U.S. Department of Homeland Security
Region VII
9221 Ward Parkway, Suite 300
Kansas City, MO 64114-3372
FEMA
February 19, 2009
Ms. Laura Carstens
Planning Services Manager
City of Dubuque
50 West 13th Street
Dubuque, Iowa 52001-4805
Dear Ms. Carstens:
This letter is in regard to the Dubuque Local Flood Protection Project Levee shown on the
effective Flood Insurance Rate Map (FIRM) and in the effective Flood Insurance Study (FIS)
report for the City of Dubuque in Dubuque County, Iowa. The Department of Homeland Security,
Federal Emergency Management Agency (FEMA), is producing a countywide FIS report and
Digital Flood Insurance Rate Map (DFIRM) for Dubuque County, Iowa, as part of FEMA's
Flood Map Modernization (Map Mod) program.
During the DFIRM production, FEMA determined that the flood hazard information presented on
the effective FIRM and in the FIS report is based, in some areas, on flood protection provided by
the Dubuque Local Flood Protection Project Levee. Based on the information available and on
the mapping standards of the National Flood Insurance Program (NFIP) when the FIS was
performed, FEMA accredited the levee with providing protection from the flood that has a
1-percent-chance of being equaled or exceeded in any given year. This 1-percent-annual-chance
flood is also referred to as the "base flood."
For FEMA to continue to accredit the identified levee with providing protection from the base
flood, the levee must meet the requirements of the Code of Federal Regulations, Title 44, Section
65.10 (44 CFR 65.10), entitled "Mapping of Areas Protected by Levee Systems" (copy enclosed).
In accordance with 44 CFR 65.10(a), the community or other party seeking recognition of a levee
system is responsible for providing the data defined and outlined within the regulation. Please
note, the design and construction data provided must be certified by a registered professional
engineer or by a federal agency with responsibility for levee design.
FEMA understands that it may take time to acquire and/or assemble the documentation necessary
to fully comply with 44 CFR 65.10. Therefore, FEMA has incorporated a process into the
aggressive schedule of Map Mod that, if needed, will provide you with additional time to submit
all the necessary documentation. Initiation of this process can take place only if you, the levee
owner, and a representative of each impacted community sign and return the enclosed agreement
within 90 days of the date of this letter (before May 17, 2009). Completion and submittal of the
enclosed agreement will officially request that FEMA label the levee as a Provisionally
Accredited Levee (PAL) on the DFIRM and will serve as your agreement that, to the best of your
knowledge, the levee meets the requirements of 44 CFR 65.10. The completed agreement must
be submitted before May 17, 2009 for the levee to receive the PAL designation.
www.fema.gov
By endorsing the agreement, you agree to provide all the necessary documentation to comply
with 44 CFR 65.10 before May 17, 2011. If you are unable to submit all of the documentation
necessary to meet the requirements of 44 CFR 65.10 before this date, FEMA will initiate a map
revision which will show certain areas on the landward side of the levee as flood-prone.
The levee will be labeled as PAL during the 24-month period to convey to map users that levee
certification verification is underway. FEMA recommends that you, the levee owner, and the
impacted communities implement outreach efforts to inform affected property owners that an
assessment of the levee is underway. FEMA also encourages the purchase of flood insurance,
even though coverage is not federally required.
If the documentation necessary to fully comply with 44 CFR 65.10, including an existing
operation and maintenance plan and record of an on-site inspection by a registered professional
engineer, is readily available, please submit the data to this office within 30 days of the date of
this letter. Upon receipt of your submittal, FEMA will review the data and determine whether the
levee will continue to be accredited with providing protection from the base flood.
If you have additional questions regarding the specific submittal requirements, please contact
Dawn Kinsey of my staff at (816) 283-7055. We look forward to working with you and
community officials to address this important matter. If there is anything we can do to facilitate
the submittal process, please let us know.
Sincerely,
Robert G. Bissell •
Director, Mitigation Division
Enclosures:
PAL Agreement
"Requirements of 44 CFR Section 65.10: Mapping of Areas Protected by Levee Systems"
"Meeting the Criteria for Accrediting Levees on Flood Maps: How-to-Guide for Floodplain Managers
and Engineers"
cc: Ray Buol, Mayor, City of Dubuque
Bill Cappuccio, State of Iowa NFIP Coordinator
Jerry Skalak, U.S. Army Corps of Engineers, Rock Island District
Senator Chuck Grassley
Senator Tom Harkin
Representative Bruce Braley
Letter of Agreement and Request for Provisionally Accredited Levee (PAL) Designation and
Agreement to Provide Adequate Compliance with the
Code of Federal Regulations, Title 44, Section 65.10 (44 CFR 65.10)
We, the undersigned, have received the letter from FEMA dated February 16, 2009, and the enclosed
document entitled "44 CFR Section 65.10: Mapping of Areas Protected by Levee Systems." We
understand that FEMA is in the process of providing updated flood maps for Dubuque County, Iowa, and
that the area behind the levee known as the Dubuque Local Flood Protection Project Levee remapped to
reflect that the levee has been designated as a PAL.
To the best of our knowledge, the Dubuque Local Flood Protection Project Levee meets the requirements
of 44 CFR 65.10. We hereby submit to FEMA, within 90 days (before May 17, 2009) our agreement to
provide FEMA with all the necessary information to show that the Dubuque Local Flood Protection
Project Levee complies with 44 CFR 65.10. We understand that this documentation will be required
before May 17, 2011. This information will allow FEMA to move forward with the flood mapping for
Dubuque County, Iowa. We fully understand that if complete documentation of compliance with
44 CFR 65.10 is not provided within the designated timeframe of 24 months, FEMA will initiate a
revision to the Flood Insurance Rate Map to redesignate the area as flood-prone.
City of Dubuque Representative
(signature)
Roy D. Buol (print)
Mayo r
Date: Mav 4. 200
Community CEO (signature)
Michael Van Mi 11 igen (print)
ity anager
Date: May 4, 2009
Other (if applicable)
(signature)
Gus Ps i hoyos (print)
City Engineer
Date: May 4 , 2009
As part of a mapping project, it is the levee owner's or community's responsibility to provide data and documentation to
show that a levee meets the requirements of Section 65.10 ofthe National Flood Insurance Program (NFIP) regulations.
Links to Section 65.10 and many other documents are available on FEMA's Web site at
www.fema.~ov/plan/prevent/fhm/ly fpm.shtm.
The FEMA requirements in Section 65.10 are separated into five categories:
1. General criteria;
2. Design criteria;
3. Operations plans and criteria;
4. Maintenance plans and criteria; and
5. Certification requirements.
The requirements for each of these areas are summarized below.
(A) GENERAL CRITERIA
For purposes of the NFIP, FEMA will only recognize in its flood hazard and risk mapping effort those levee systems that
meet, and continue to meet, minimum design, operation, and maintenance standards that are consistent with the level of
protection sought through the comprehensive floodplain management criteria established by Section 60.3 of the NFIP
regulations. Section 65.10 of the NFIP regulations describes the types of information FEMA needs to recognize, on NFIP
maps, that a levee system provides protection from the flood that has a 1-percent chance of being equaled or exceeded in
any give year (base flood). This information must be supplied to FEMA by the community or other party seeking
recognition of a levee system at the time a study or restudy is conducted, when a map revision under the provisions of Part
65 of the NFIP regulations is sought based on a levee system, and upon request by the Administrator during the review of
previously recognized structures. The FEMA review is for the sole purpose of establishing appropriate risk zone
determinations for NFIP maps and does not constitute a determination by FEMA as to how a structure or system will
perform in a flood event.
(B) DESIGN CRITERIA
For the purposes of the NFIP, FEMA has established levee design criteria for freeboard, closures, embankment protection,
embankment and foundation stability, settlement, interior drainage, and other design criteria. These criteria are
summarized in subsections below.
(B)(1) FREEBOARD
For riverine levees:
• A minimum freeboard of 3 feet above the water-surface level of the base flood must be provided.
• An additional 1 foot above the minimum is required within 100 feet on either side of structures (e.g., bridges)
riverward of the levee or wherever the flow is constricted.
~" FEMA November 2008 PAGE 1
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• An additiona10.5 foot above the minimum at the upstream end of the levee, tapering to not less than the minimum
at the downstream end of the levee, is also required.
Exceptions to the minimum riverine freeboard requirements above may be approved if the following criteria are met:
• Appropriate engineering analyses demonstrating adequate protection with a lesser freeboard must be
submitted.
• The material presented must evaluate the uncertainty in the estimated base flood elevation profile and include,
but not necessarily be limited to:
o An assessment of statistical confidence limits of the 1-percent-annual-chance discharge;
o Changes in stage-discharge relationships; and
o Sources, potential, and magnitude of debris, sediment, and ice accumulation.
• It must be also shown that the levee will remain structurally stable during the base flood when such additional
loading considerations are imposed.
Under no circumstances will freeboard of less than 2 feet be accepted.
For coastal levees, the freeboard must be established at 1 foot above the height of the 1-percent-annual-chance wave or
the maximum wave runup (whichever is greater) associated with the 1-percent-annual-chance stillwater surge elevation at
the site.
Exceptions to the minimum coastal freeboard requirements above may be approved if the following criteria are met:
• Appropriate engineering analyses demonstrating adequate protection with a lesser freeboard must be
submitted.
• The material presented must evaluate the uncertainty in the estimated base flood loading conditions.
Particular emphasis must be placed on the effects of wave attack and overtopping on the stability of the levee.
Under no circumstances will a freeboard of less than 2 feet above the 1-percent-annual-chance stillwater surge elevation
be accepted.
(B)(2) CLOSURES
The levee closure requirement is that all openings must be provided with closure devices that are structural parts of the
system during operation and design according to sound engineering practice.
(B)(3) EMBANKMENT PROTECTION
Engineering analyses must be submitted to demonstrate that no appreciable erosion of the levee embankment can be
expected during the base flood, as a result of either currents or waves, and that anticipated erosion will not result in failure
of the levee embankment or foundation directly or indirectly through reduction of the seepage path and subsequent
instability.
The factors to be addressed in such analyses include, but are not limited to:
• Expected flow velocities (especially in constricted areas);
• Expected wind and wave action;
November 2008 PAGE 2
• Ice loading;
• Impact of debris;
• Slope protection techniques;
• Duration of flooding at various stages and velocities;
• Embankment and foundation materials;
• Levee alignment, bends, and transitions; and
• Levee side slopes.
(B)(4) EMBANKMENT AND FOUNDATION STABILITY
Engineering analyses that evaluate levee embankment stability must be submitted.
The analyses provided shall evaluate expected seepage during loading conditions associated with the base flood and shall
demonstrate that seepage into or through the levee foundation and embankment will not jeopardize embankment or
foundation stability.
An alternative analysis demonstrating that the levee is designed and constructed for stability against loading conditions for
Case IV as defined in U.S. Army Corps of Engineers (USAGE) Engineering Manual 1110-2-1913, Chapter 6, Section II,
may be used.
The factors that shall be addressed in the analyses include:
• Depth of flooding;
• Duration of flooding;
• Embankment geometry and length of seepage path at critical locations;
• Embankment and foundation materials;
• Embankment compaction;
• Penetrations;
• Other design factors affecting seepage (e.g., drainage layers); and
• Other design factors affecting embankment and foundation stability (e.g., berms).
(B)(5) SETTLEMENT
Engineering analyses must be submitted that assess the potential and magnitude of future losses of freeboard as a result of
levee settlement and demonstrate that freeboard will be maintained within the minimum freeboard standards set forth in
B(1).
This analysis must address:
• Embankment loads,
• Compressibility of embankment soils,
• Compressibility of foundation soils,
November 2008 PAGE 3
• Age of the levee system, and
• Construction compaction methods.
A detailed settlement analysis using procedures such as those described in USACE Engineering Manual EM 1110-1-1904
must be submitted.
(B)(6) INTERIOR DRAINAGE
An analysis must be submitted that identifies the source(s) of such flooding; the extent of the flooded azea; and, if the
average depth is greater than 1 foot, the water-surface elevation(s) of the base flood. This analysis must be based on the
joint probability of interior and exterior flooding and the capacity of facilities (such as drainage lines and pumps) for
evacuating interior floodwaters. Interior drainage systems usually include storage azeas, gravity outlets, pumping stations,
or a combination thereof.
For areas of interior drainage that have average depths greater than 1 foot, mapping must be provided depicting the
extents'of the interior flooding, along with supporting documentation.
(B)(7) OTHER DESIGN CRITERIA
In unique situations, such as those where the levee system has relatively high vulnerability, FEMA may require that other
design criteria and analyses be submitted to show that the levees provide adequate protection. In such situations, sound
engineering practice will be the standard on which FEMA will base its determinations. FEMA also will provide the
rationale for requiring this additional information.
(C) OPERATIONS PLANS AND CRITERIA
For a levee system to be recognized, the operational criteria must be as described below. All closure devices or
mechanical systems for internal drainage, whether manual or automatic, must be operated in accordance with an officially
adopted operation manual, a copy of which must be provided to FEMA by the operator when levee or drainage system
recognition is being sought or when the manual for a previously recognized system is revised in any manner. All
operations must be under the jurisdiction of a Federal or State agency, an agency created by Federal or State law, or an
agency of a community participating in the NFIP.
(C)(1) CLOSURES
Operation plans for closures must include the following:
• Documentation of the flood warning system, under the jurisdiction of Federal, State, or community officials, that
will be used to trigger emergency operation activities and demonstration that sufficient flood warning time exists
for the completed operation of all closure structures, including necessary sealing, before floodwaters reach the
base of the closure;
• A formal plan of operation, including specific actions and assignments of responsibility by individual name or
title; and
• Provisions for periodic operation, at not less than 1-year intervals, of the closure structure(s) for testing and
training purposes.
November 2008 PAGE 4
(C)(2) INTERIOR DRAINAGE SYSTEMS
Interior drainage systems associated with levee systems usually include storage areas, gravity outlets, pumping stations, or
a combination thereof. FEMA will recognize these drainage systems on NFIP maps for flood protection purposes only if
the following minimum criteria are included in the operation plan:
• Documentation of the flood warning system, under the jurisdiction of Federal, State, or community officials, that
will be used to trigger emergency operation activities and demonstration that sufficient flood warning time exists
to permit activation of mechanized portions of the drainage system;
• A formal plan of operation, including specific actions and assignments of responsibility by individual name or
title;
• Provision for manual backup for the activation of automatic systems; and
• Provisions for periodic inspection of interior drainage systems and periodic operation of any mechanized portions
for testing and training purposes; no more than 1 year shall elapse between either the inspections or the
operations.
(C)(3) OTHER OPERATION PLANS AND CRITERIA
FEMA may require other operating plans and criteria to ensure that adequate protection is provided in specific situations.
In such cases, sound emergency management practice will be the standard upon which FEMA determinations will be
based.
(D) MAINTENANCE PLANS AND CRITERIA
For levee systems to be recognized as providing protection from the base flood, the following maintenance criteria must
be met:
• Levee systems must be maintained in accordance with an officially adopted maintenance plan, and a copy of this
plan must be provided to FEMA by the owner of the levee system when recognition is being sought or when the
plan for a previously recognized system is revised in any manner.
• All maintenance activities must be under the jurisdiction of a(n):
o Federal or State agency;
o Agency created by Federal or State law; or
o Agency of a community participating in the NFIP that must assume ultimate responsibility for
maintenance.
• The maintenance plan must document the formal procedure that ensures that the stability, height, and overall
integrity of the levee and its associated structures and systems are maintained.
• At a minimum, the maintenance plan shall specify:
o Maintenance activities to be performed;
o Frequency of their performance; and
o Person by name or title responsible for their performance.
November 2008 PAGE 5
(E) CERTIFICATIONREQUIREMENTS
Data submitted to support that a given levee system complies with the structural requirements set forth in B(1) through
B(7) above must be certified by a Registered Professional Engineer. Also, certified as-built plans of the levee must be
submitted. Certifications are subject to the definition given in Section 65.2 of the NFIP regulations. In lieu of these
structural requirements, a Federal agency with responsibility for levee design may certify that the levee has been
adequately designed and constructed to provide protection against the base flood.
November 2008 PAGE 6
A levee system is a flood
protection system that consists of a
levee, or levees, and associated
structures, such as closure and
drainage devices, which are
constructed and operated in
accordance with sound engineering
practices. A levee is a manmade
structure, usually an earthen
embankment, designed and
constructed in accordance with
sound engineering practices to
contain, control, or divert the flow
of water so as to provide protection
from temporary flooding.
As part of the flood mapping
process, the Department of
Homeland Security, Federal
Emergency Management Agency
(FEMA) and its State and local
mapping partners review levee
system data and documentation.
It is the levee owner's or
community's responsibility to
provide data and documentation to
demonstrate that a levee system
meets National Flood Insurance
Program (NFIP) requirements as
described in Title 44, Chapter 1,
Section 65.10 of the Code of
Federal Regulations (44 CFR
Section 65.10), which you may
view on the FEMA Web site at
www. fema.gov/plan/prevent/
flan/lv_fpm. shtm.
To be recognized as providing a
1-percent-annual-chance level of
flood protection on the modernized
NFIP maps, called Digital Flood
Insurance Rate Maps (DFIRMs),
levee systems must meet and
continue to meet the minimum
design, operation, and maintenance
standards (44 CFR Section 65.10)..
To help clarify the responsibilities
of community officials, levee
owners, or other parties seeking
recognition of a levee system
identified during astudy/mapping
project, FEMA issued Procedure
Memorandum No. 34 (PM 34),
Interim Guidance for Studies
Including Levees, on
August 22, 2005. PM 34 provided
clarification of the procedures
provided in Appendix H of
FEMA's Guidelines and
Specifications for Flood Hazard
Mapping Partners.
FEMA issued Revised Procedure
Memorandum No. 43, Guidelines
for Identifying Provisionally
Accredited Levees, on March 16,
2007, which allows issuance of
preliminary and, in some cases,
effective DFIRMs while
communities/levee owners compile
and submit required data and
documentation. FEMA issued
Procedure Memorandum No. 45,
Revisions to Accredited Levee and
Provisionally Accredited Levee
Notations, in Apri12008 to clarify
map notes for accredited and
provisionally accredited levee
systems.
This document provides
information regarding the types of
data and documentation that must
be submitted for levee systems to
be accredited on DFIRMs,
including a checklist and an index
of further resources you may wish
to consult.
~~F
~~.,~ FEMA
LIA'p S f/
November 2008 PAGE 1
HOW FEMA WILL MAP LEVEE SYSTEMS
FEMA mapping requirements are designed to provide the people living and working behind levee systems with accurate,
up-to-date flood hazard and risk information so that they may make wise decisions to minimize damage and loss of life.
FEMA does not evaluate the performance of a levee system-this is the responsibility of the levee owner. FEMA is
responsible for establishing levee system evaluation and mapping standards, determining flood insurance risk zones, and
reflecting these determinations on DFIRMs.
Accredited Levee System
NOTE: THIS AREA IS SHOWN AS BEING
PROTECTED FRO1N THE 1~ERCENT,AtiNUAL-
CHANCE DRGREATER FLOOD HAZARD BY A
FVEE SYSTEIr( THAT HAS BEEN PROVISIONALLY
ACCREDRED. OVERTOPPING DR FAILURE OF
ANY LEVEE SYSTEM IS POSSIBLE. FOR
ADDI1lONAL INFORMATION PLEASE SEE THE
°PROVISIONALLYACCREDITED LEVEE NOTE" iN
NOTES TO USERS.
An accredited levee system is a system that FEMA has determined
can be shown on a DFIRM as providing a 1-percent-annual-chance
or greater level of flood protection. This determination is based on
the submittal of data and documentation required by 44 CFR
Section 65.10. The area landward of an accredited levee system is
shown as a moderate-risk area, labeled Zone X (shaded), on the
DFIRM except for areas of residual flooding, such as ponding
areas, which will be shown as high-risk areas, called Special Flood
Hazard Areas (SFHAs). Flood insurance is not mandatory in
Zone X (shaded) areas, but is mandatory in SFHAs. FEMA
strongly encourages flood insurance for all structures in levee-
impacted areas.
Provisionally Accredited Levee (PAL) System
The PAL designation may be used for a levee system that FEMA has
previously accredited with providing 1-percent-annual-chance flood
protection on an effective FIRM/DFIRM, and for which FEMA is
awaiting data and/or documentation that will show the levee system is
compliant with 44 CFR Section 65.10. Before FEMA will apply the
PAL designation to a levee system, the community or levee owner will
need to sign and return an agreement indicating the data and
documentation required for compliance with 44 CFR Section 65.10 will
be provided within a specified timeframe. The impacted area landward
of a PAL system also is shown as a moderate-risk area, labeled Zone X
(shaded). Therefore, flood insurance is not mandatory for insurable
structures in the levee-impacted area; however, it is strongly
encouraged by FEMA as are other protective measures.
Levee System Not Accredited or De-accredited
If the levee system is not shown as providing 1-percent-annual-
chance flood protection on an effective FIRM, the system is
considered "not accredited" and the levee-impacted area is mapped
as Zone AE or Zone A on a DFIRM, depending on the type of study
performed for the area. If the levee system was previously shown
as providing 1-percent-annual-chance flood protection on an
effective FIRM or DFIRM, but does not meet the PAL
requirements or is no longer eligible for the PAL designation,
FEMA will de-accredit the levee system and re-map the levee-
impacted area as an SFHA, labeled Zone AE or Zone A depending
on the type of study performed . Flood insurance will be required
for insurable structures with federally backed mortgages in SFHAs.
November 2008
Description: For levee systems to be recognized (i.e., accredited) by FEMA, evidence that adequate design and operation
and maintenance systems are in place to provide reasonable assurance that protection from the base flood exists must be
provided. The following requirements must be met:
1
Freeboard. Minimum freeboard required 3 feet above the Base Flood Elevation (BFE) all along
length, and an additional 1 foot within 100 feet of structures (such as bridges) or wherever the flow is
^
restricted. Additiona10.5 foot at the upstream end of a levee. Coastal levees have special freeboard
requirements (see Paragraphs 65.10(b)(1)(iii) and (iv)).
^ Closures. All openings must be provided with closure devices that are structural parts of the system
during operation and designed according to sound engineering practice.
Embankment Protection. Engineering analyses must be submitted that demonstrate that no
appreciable erosion of the levee embankment can be expected during the base flood, as a result of eithe
^ currents or waves, and that anticipated erosion will not result in failure of the levee embankment or
foundation directly or indirectly through reduction of the seepage path and subsequent instability.
Embankment and Foundation Stability Analyses. Engineering analyses that evaluate levee
embankment stability must be submitted. The analyses provided must evaluate expected seepage
during loading conditions associated with the base flood and must demonstrate that seepage into or
^ through the levee foundation and embankment will not jeopardize embankment or foundation stability.
An alternative analysis demonstrating that the levee is designed and constructed for stability against
loading conditions for Case IV as defined in the U.S. Army Corps of Engineers (USAGE) Engineer
Manual 1110-2-1913, Design and Construction of Levees, (Chapter 6, Section II), may be used.
Settlement Analyses. Engineering analyses must be submitted that assess the potential and magnitude
of future losses of freeboard as a result of levee settlement and demonstrate that freeboard will be
maintained. This analysis must address embankment loads, compressibility of embankment soils,
^ compressibility of foundation soils, age of the levee system, and construction compaction methods. In
addition, detailed settlement analysis using procedures such as those described in USAGE Engineer
Manual 1110-1-1904, Soil Mechanics Design- Settlement Analysis, must be submitted.
Interior Drainage. An analysis must be submitted that identifies the source(s) of such flooding, the
^ extent of the flooded area, and, if the average depth is greater than 1 foot, the water-surface elevation(s)
of the base flood. This analysis must be based on the joint probability of interior and exterior flooding
and the capacity of facilities (such as drainage lines and pumps) for evacuating interior floodwaters.
November 2008
Description: For a levee system to be recognized (i.e., accredited), the operational criteria must be as described below.
All closure devices or mechanical systems for internal drainage, whether manual or automatic, must be operated in
accordance with an officially adopted operation manual, a copy of which must be provided to FEMA by the operator
when levee or drainage system recognition is being sought or when the manual for a previously recognized system is
revised in any manner. All operations must be under the jurisdiction of a Federal or State agency, an agency created by
Federal or State law, or an agency of a community participating in the NFIP.
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Flood Warning System. Documentation of the flood warning system, under the jurisdiction of
Federal, State, or community officials that will be used to trigger emergency operation activities; and
^
demonstration that sufficient flood warning time exists for the completed operation of all closure
structures, including necessary sealing, before floodwaters reach the base of the closure.
^ Plan of Operation. A formal plan of operation including specific actions and assignments of
responsibility by individual name or title.
Periodic Operation of Closures. Provisions for periodic operation, at not less than one-year
^ intervals, of the closure structure for testing and training purposes.
^ Interior Drainage Plan. See below.
Description: Interior drainage systems associated with levee systems usually include storage areas, gravity outlets,
pumping stations, or a combination thereof. These drainage systems will be recognized by FEMA on NFIP maps for
flood protection purposes only if the following minimum criteria are included in the operation plan.
Flood Warning System. Documentation of the flood warning system, under the jurisdiction of
Federal, State, or community officials that will be used to trigger emergency operation activities; and
^
demonstration that sufficient flood warning time exists to permit activation of mechanized portions
of the drainage system.
^ Plan of Operation. A formal plan of operation including specific actions and assignments of
responsibility by individual name or title.
November 2008
^ Manual Backup. Provision for manual backup for the activation of automatic systems.
^ Periodic Inspection. Provisions for periodic inspection of interior drainage systems and periodic
operation of any mechanized portions for testing and training purposes. No more than 1 year shall
elapse between either the inspections or the operations.
Description: For levee systems to be recognized as providing protection from the base flood (i.e., accredited by FEMA),
the maintenance criteria must be as described herein.
Levee systems must be maintained in accordance with an officially adopted maintenance plan, and a
^
copy of this plan must be provided to FEMA by the owner of the levee system when recognition is
being sought or when the plan for a previously recognized system is revised in any manner.
All maintenance activities must be under the jurisdiction of a Federal or State agency, an agency
^ created by Federal or State law, or an agency of a community participating in the NFIP that must
assume ultimate responsibility for maintenance.
This plan must document the formal procedure that ensures that the stability, height, and overall
^ integrity of the levee and its associated structures and systems are maintained. At a minimum, the
plan shall specify the maintenance activities to be performed, the frequency of their performance, and
the person by name or title responsible for their performance.
~ ~ I ~
Description: Data submitted to support that a given levee system complies with the structural requirements set forth in
"Design Criteria" (Paragraphs 65.10(b)(1) through (7) of the regulations) must be certified by a Registered Professional
Engineer. Also, certified "as-built" plans of the levee must be submitted. Certifications are subject to the definition given
in Section 65.2 of the NFIP regulations. In lieu of these structural requirements, a Federal agency with responsibility for
levee design may certify that the levee has been adequately designed and constructed to provide protection from the base
flood.
~ ~
^ All data submitted is certified by Professional Engineer or certified by a Federal agency.
^ Certified as-built levee plans are included in the submittal.
November 2008
CHECKLIST INFORMATION
The checklist provided in this fact sheet is meant to assist local community officials
and levee owners in gathering the data and documentation that will be required for
FEMA to show a levee system as providing 1-percent-annual-chance flood
protection on the community's DFIRM. Where possible, text from the actual NFIP
regulations (44 CFR Section 65.10) was used.
The checklist is set up according to the appropriate paragraph of 44 CFR Section
65.10. For example, Design Criteria can be found in Paragraph 65.10(b):
Desciipiion: For levee systems to be recognized (i. e., accredited) by FEMA,
evidence that adequate design and operation and maintenance systems arc in
place to provide reasonable assurance that protectdon from the base flood exists
must be provided.
For a comprehensive description of each item in this checklist, please see
Appendix H of the Guidelines and Specifications for Flood Hazard Mapping
Partners. Locations of this resource, and other useful resources, are provided
below.
INDEX OF RESOURCES
This fact sheet is accessible, along with an assortment of other levee-related
resources, through a dedicated portion of the FEMA Web site. The gateway to the
FEMA-provided levee information, which is organized by stakeholder group to
assist levee owners, community officials, and other stakeholders, is
www.fema.gov/plan/prevent/fhm/lv intro.shtm. The FEMA resources referenced
in this fact sheet, listed below, are directly accessible through
www.fema. ov/plan/prevent/fhm/ly fpm.shtm.
• Procedure Memorandum No. 34, Interim Guidance for Studies Including
Levees
• Revised Procedure Memorandum No. 43, Guidelines for Identifying
Provisionally Accredited Levees.
• Procedure Memorandum No. 45, Revisions to Accredited Levee and
Provisionally Accredited Levee Notations
• Appendix H, "Mapping of Areas Protected by Levee Systems," of Guidelines
and Specifications for Flood Hazard Mapping Partners.
• Section 65.10. Mapping of Areas Protected by Levee Systems of the NFIP
regulations.
Flood insurance information can be found at www.fema.¢ov/business/nfip or on
the NFIP's consumer Web site, www.FloodSmart.gov.
Links to the USACE Web site also are provided on the levee-dedicated pages; the
resources discussed in this fact sheet are accessible through the USACE Web page
at www.usace.army.miUpublications/en~-manuals.
November 2008