1. WHAT IS A LEVEE?
levee is a manmade structure, usually an earthen embankment, designed and
constructed in accordance with sound engineering practices to contain or
control the flow of water so as to provide protection from flooding during
high water events.
2. WHY IS LEVEE SAFETY BEING ADDRESSED AS PART OF THE FEDERAL
EMERGENCY MANAGEMENT AGENCY’S (FEMA’s) FLOOD MAP MODERNIZATION PROGRAM?
Levees present an unusual and extreme hazard. While they modify flood risk,
levee systems do not provide protection from the largest floods and tend to
lull people into a false sense of security. Levees do have limitations and
they are susceptible to sudden and catastrophic overtopping and failure. In
addition, information on levee location, structural integrity, and
certification often is outdated or missing altogether. This information is
important for preparing reliable flood hazard maps.
3. HOW DOES FEMA
EVALUATE LEVEES THAT SHOW AS PROVIDING 100-YEAR PROTECTION ON THEIR DIGITAL
FLOOD INSURANCE RATE MAPS (“DFIRMs”)
FEMA evaluates levees based on documentation submitted by the levee owner or
operator (a reclamation district or other flood control agency). The
documentation must demonstrate the levee is in compliance with the criteria
in Title 44 of the Code of Federal Regulations Section 65.10, which includes
criteria for levee design, operations plans, maintenance plans, and
certification by a registered civil engineer.
IS A PROVISIONALLY ACCREDITED LEVEE (“PAL”)?
provisionally accredited levee is a levee for which all the documentation
necessary to gain full accreditation is not readily available. The
community and maintaining agency submit a signed letter to FEMA stating that
the documentation will be provided by a specific date. Provisionally
accredited levees are shown as providing 1% annual chance (100-year) flood
protection on the Digital Flood Insurance Rate Maps (“DFIRMs”), with notes
indicating that the levee is only provisionally accredited.
5. WHY DOES FEMA USE PROVISIONALLY ACCREDITED LEVEE STATUS AS PART OF
THE MAP MODERNIZATION PROGRAM?
FEMA uses provisionally accredited levee status as part of the Map
Modernization program in order to issue DFIRMs which provide the community
with current flood risk information while the documentation necessary for
the levees to gain full accreditation is being gathered.
6. WILL THE
FLOOD INSURANCE RATE MAPS CHANGE?
Yes, more map changes are expected within the next two years. The October
16, 2009 FIRMs have some land areas that are marked as "PROTECTED...BY A
LEVEE SYSTEM THAT HAS BEEN PROVISIONALLY ACCREDITED..." Some of the levees
will become accredited levees, others might lose accreditation by FEMA. All
or some of the land behind de-accredited levees will then be shown on a new
map as Special Flood Hazard Area. Your Floodplain Administrator will notify
you before the maps change.
7. WHAT MUST BE DONE TO GAIN FULL ACCREDITATION FOR PROVISIONALLY
order for a provisionally accredited levee to gain full accreditation,
documentation must be submitted to FEMA demonstrating that the levee is in
compliance with Title 44 of the Code of Federal Regulations Section 65.10
(44 CFR 65.10), which includes criteria for levee design, operations plans,
maintenance plans, and certification by a registered civil engineer.
8. WHAT HAPPENS IF THE PAL EXPIRES BEFORE THE COMMUNITY CAN PROVE THE
LEVEES ARE IN COMPLIANCE WITH ACCREDITATION REQUIREMENTS?
the PAL expires before the community can demonstrate the levees are
compliant with 44 CFR 65.10, FEMA will de-accredit the levee and begin the
map revision process to show the area behind the levees in a Special Flood
Hazard Area (SFHA), where flood insurance is mandatory for any property with
a federally-regulated mortgage. The map revision process takes a minimum of
nine months to complete, and may take longer. As part of the revision
process, the public is notified that the maps will be changing.
9. WHEN IS THE DEADLINE FOR THE COMMUNITY TO PROVE THE PROVISIONALLY
ACCREDITED LEVEES ARE IN COMPLIANCE WITH THE ACCREDITATION REQUIREMENTS?
The deadline for the community to prove the levees are in compliance with
the accreditation requirements (the PAL expiration date) varies between
levee systems depending on when the PAL letter was submitted by the
community and accepted by FEMA. In San Joaquin County, PALs expire in
August 2009, March 2010, and August 2010. For the expiration date of a
particular area, see the "Notes to User" on the DFIRM, located at
10. WHICH AREAS WOULD BE AFFECTED IF THESE PROVISIONALLY ACCREDITED
LEVEES ARE DE-ACCREDITED?
The areas affected by the de-accreditation of a provisionally accredited
levee can be viewed on the DFIRMs and on the “Flood Zone Changes Map,” both
www.sjgov.org/pubworks/flood_info.htm. The DFIRMs have areas with a
note that states, "THIS AREA IS SHOWN AS BEING PROTECTED FROM THE
1-PERCENT-ANNUAL-CHANCE OR GREATER FLOOD HAZARD BY A LEVEE SYSTEM THAT HAS
BEEN PROVISIONALLY ACCREDITED..." On the "Flood Zone Changes Map,"
yellow-highlighted areas represent areas currently protected from the
1-percent-annual-chance flood hazard. (To see the yellow areas more
clearly, increase the magnification on the Flood Zone Changes Map.) These
areas include Lathrop, Weston Ranch, Twin Creeks, Boggs Tract, Brookside,
Quail Lakes, Lincoln Village West, Country Club, Rough & Ready Island, and a
portion of western Manteca.
11. DO I NEED FLOOD INSURANCE IF I LIVE IN AN AREA PROTECTED BY A
PROVISIONALLY ACCREDITED LEVEE?
While mandatory flood insurance requirements do not apply in areas protected
by provisionally accredited levees, there is still a risk of flooding.
Levees and other flood control structures can only be designed and
constructed to provide a degree of protection from flooding; should they
overtop or fail, the results could be disastrous. All property owners in
areas protected by levees are strongly encouraged to purchase flood
12. HOW CAN I FIND OUT IF MY PROPERTY IS WITHIN AN AREA PROTECTED BY A
PROVISIONALLY ACCREDITED LEVEE?
The new Digital Flood Insurance Rate Maps showing PAL-protected areas went
into effect on October 16, 2009. You can find out if your property is
located in an area protected by a provisionally accredited levee by viewing
the DFIRMs dated October 16, 2009, available at
www.sjgov.org/pubworks/firmpanels.htm. Also on this website, there is a
“Flood Zone Viewer” application that can help you find your specific parcel
If you have any questions or need any clarification regarding the flood zone
changes that occurred in October, please contact your community floodplain