Item J4J.4
BOARD OF COUNTY COMMISSIONERS
C ounty of M onroe
Mayor Sylvia Murphy, District 5
Mayor Pro Tem Danny Kolhage, District 1
TheFloridaKeys
Michelle Coldiron, District 2
Heather Carruthers, District 3
David Rice, District 5
County Commission Meeting
February 20, 2019
Agenda Item Number: J.4
Agenda Item Summary #5175
BULK ITEM: No DEPARTMENT: Building
TIME APPROXIMATE: STAFF CONTACT: Mark Boone (305) 289-2505
N/A
AGENDA ITEM WORDING: Discussion and Direction on the impact of Coastal A Zone
designation on construction permitting and explanation of Limit of Moderate Wave Activity on
Flood Insurance Rate Maps.
ITEM BACKGROUND:
The National Flood Insurance Program (NFIP) maps flood risks geographically throughout the
United States. Historically, the program has designated three flood zones on Flood Insurance Rate
Maps (FIRM): X Flood Zones (geographic areas of minimal risk of flooding - .01% - .2% annual
chance), AE Flood Zones (1% annual chance), and VE Flood Zones (coastal high hazard areas
subject to wave action). As mapping technology has evolved, further definition of A-Zones has been
required for areas of A-Zone with wave action. Thus, in A-Zone coastal areas typically adjacent
(landward) of V--
determined. This refinement of risk
framework as well as the development, construction and insurance of structures mapped within
Coastal A designation.
How is a Coastal A Flood Zone determined?
As the NFIP continues to map and refine flood risks boundaries in FIRM panels, models now
include wave action, given the potential destructive nature of waves in a 1% flooding event. The
extent, or Limit of Moderate Wave Activity (LiMWA) is now drawn on map revisions. The LiMWA
shows wa-
storm investigations have shown that typical A-zone construction techniques are subject to damage
or destruction when exposed to less than 3' waves, which is the current threshold for V-zone
provided in A-Zone building code compliance. Thus, FEMA has introduced the designation of the
Coastal A flood zone.
FEMA defines a Coastal A Zone as an area with potential for breaking waves and erosion during the
1% Flood. Coastal A Zones, therefore, will see conditions in the Base Flood that are similar to, but
less severe than, those in a V Zone. Florida Building Code requires engineering and construction
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adherence to Coast A construction as described in ASCE 21-14, requiring Coastal A Zones be
constructed similarly to Coastal High Hazard Areas (V Zones) for the purposes of building design
and engineering standards. This means additional construction requirements including, but not
limited to:
Enclosed areas below BFE are required to be of breakaway construction and have flood
openings (vents) equal to one square inch per one square foot of enclosed area.
All residential buildings must have their lowest horizontal structural member (bottom of
the beam) elevated to or above the Design Flood Elevation.
Above ground pools are only permitted if the lowest horizontal structural member of the
pool is raised to or above the Design Flood Elevation.
required.
Dry Flood-proofing measures for nonresidential buildings and non-residential portions of
mixed-use buildings are not permitted.
Fill is required to be stable under conditions of flooding, including rapid rise and rapid
drawdown, prolonged inundation, and erosion and scour.
NFIP draft flood maps are expected to be issued in April 2019 followed by Preliminary and Adopted
Maps over time. Upon the issuance of Preliminary Flood Maps, staff recommends that the County
BOCC opt to regulate to the Preliminary Maps in all areas where the Flood Hazard has increased. In
areas where the Flood Hazard has decreased, the County would not regulate to a decreased standard
until the maps become effective. The Staff anticipate that Coastal A Zones will be indicated on the
Preliminary Maps.
The County may choose to regulate to the Coastal A Zone standards immediately upon receipt of the
Preliminary maps for properties within the boundaries of the LiMWA. This has the advantages and
disadvantages for the County as well as the property owners.
Advantages Disadvantages
preventing the construction of potential may potentially add significant
nonconforming structures construction costs to individual
structures
potentially lowering the cost of these
current permit applicants would need
pro
to revise designs to more stringent
Coastal A Zone standards* ROGO
applicants are currently required to
revise their permitted designs to be
redesigned and submit new plans to
meet the current Florida building code.
Section 138-25 would also need to be
amended to include a requirement for
ROGO applications to also amend their
designs to meet Coastal A Flood Zone
construction requirements.
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BOCC may choose to regulate to the elevations indicated on the Preliminary maps and/or to the
the Preliminary elevations, if not both the elevation and the flood zone. Even if the BOCC directs
staff to appeal certain maps, panels or models, Staff are held to a high standard of regulating to best
available data, which includes the Florida Building Code and the mapping of Coastal A Zones where
applicable.
Alternatively, the County could decide to wait until finalized maps are adopted to begin regulating to
the new standards. This could potentially reduce construction costs; however, doing so would cause
those structures be rendered nonconforming by the adopted maps. Furthermore, these properties
would only be eligible for the subsidized flood insurance rate offered to Pre-FIRM structures and
potentially for a limited time.
The County plans to create a Fact Sheet once the Preliminary Maps are made public that advises the
BOCC and property owners of the existing Flood Zones, the proposed Flood Zones, and the
differential between the two. These Fact Sheets will include an acknowledgment stating that the
building permit applicants have been informed that the Flood Zone designation on their property
may potentially change.
County floodplain program staff are required to regulate to the best available data and will advise the
BOCC as maps are issued. The designation of Coastal A Zone may
Green Keys Initiative.
PREVIOUS RELEVANT BOCC ACTION:
CONTRACT/AGREEMENT CHANGES:
N/A
STAFF RECOMMENDATION: Staff recommends the Board of County Commissioners examine
the information presented and offer Staff direction to proceed with a land development code
amendment to Chapter 122 (floodplain) and Chapter 138 (ROGO) to potentially regulate to
preliminary maps, pending staff review of draft maps to ensure technical accuracy.
DOCUMENTATION:
coastal_a_zones
FPM_1_Page_LiMWA
LIMWA_and_Higher_Construction_Standards_fact_sheet_12_18_17_reviewed.2_CLEAN
New_Coastal_Flood_Risk_Information_-_LIMWA
Staff Research on FBC ASCE 24-14
Staff Research LDC Chapter 138 25 and 52
Staff Research on FEMA Guidance Best Available Data and Regulating to Preliminary Maps
FINANCIAL IMPACT:
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Effective Date:
Expiration Date:
Total Dollar Value of Contract:
Total Cost to County:
Current Year Portion:
Budgeted:
Source of Funds:
CPI:
Indirect Costs:
Estimated Ongoing Costs Not Included in above dollar amounts:
Revenue Producing: If yes, amount:
Grant:
County Match:
Insurance Required:
Additional Details:
N/A
REVIEWED BY:
Rick Griffin Completed 02/05/2019 1:27 PM
Assistant County Administrator Christine Hurley Completed
02/05/2019 1:21 PM
Mark Boone Completed 02/05/2019 1:23 PM
Rick Griffin Completed 02/05/2019 1:27 PM
Emily Schemper Completed 02/05/2019 3:56 PM
Steve Williams Completed 02/05/2019 4:00 PM
Budget and Finance Completed 02/05/2019 4:13 PM
Maria Slavik Completed 02/05/2019 4:14 PM
Kathy Peters Completed 02/05/2019 4:34 PM
Board of County Commissioners Pending 02/20/2019 9:00 AM
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Attachment: coastal_a_zones (Floodplain Mapping: Limit of Moderate Wave Activity modeling and Coastal A Zone)
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Attachment: coastal_a_zones (Floodplain Mapping: Limit of Moderate Wave Activity modeling and Coastal A Zone)
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Attachment: coastal_a_zones (Floodplain Mapping: Limit of Moderate Wave Activity modeling and Coastal A Zone)
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Attachment: coastal_a_zones (Floodplain Mapping: Limit of Moderate Wave Activity modeling and Coastal A Zone)
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Fact Sheet
Using the Limit of Moderate Wave Action (LiMWA) to Build Safer and Stronger CoastalCommunities
Zone VE Building Standards for Coastal
The National Flood Insurance Program (NFIP) depicts
Communities
coastal flood hazards in two different zones on Flood
Insurance Rate Maps (FIRMs):
Communities that adopt Zone VE standards in the
Coastal A Zone can receive Community Rating
Zone VE, also known as the Coastal High Hazard
System (CRS) credits, which could lower flood
Area (CHHA), where flood hazards include wave
insurance premiums for residents and business
heights equal to or greater than 3feet; and
owners.
Zone AE, where flood hazards include wave heights
less than 3feet.
1.Buildings must be elevated on pile, post, pier, or
Due to the high risk of structural damage, buildings within
column foundations.
Zone VE must adhere to more stringent building
2.Buildings must be adequately anchored to the
requirements. Communities should also be adopting the
foundation.
most up-to-date building codes to ensure buildings are
protected from the potential hazards of high-risk floods.
3.Structural fill is prohibited.
Over the past decade, post-storm surveys of damage and
4.The bottom of the lowest horizontal structural
laboratory tests have confirmed that wave heights as small
member must be at or above the Base Flood
as 1.5 feet can cause significant damage to coastal structures
Elevation (BFE).
thatare not built to withstand these hazards. This fact sheet
describes how to use the information that is available to
5.The area below the BFE must be built of flood-
improve construction standards in coastal communities that
resistant materials and free of obstructions. If
have not adopted the most recent International Building
enclosed, the enclosure must be made of
Codes (I-Codes).
lightweight wood lattice, insect screening, or
breakaway walls.
On a FIRM, FEMA identifies where waves can reach
heights of 1.5 feet or greater usinga line called the Limit of
6.The building design and method of construction
Moderate Wave Action (LiMWA). Throughthe LiMWA
must be certified by a design professional.
shown on the FIRMs, homeowners and communities can
better understand which portions of Zone AE are at risk of
For specific requirements, refer to Title 44 of the
Code of Federal Regulations, Section 60.3.
highwave energy. These portions, which make upthearea
between the LiMWA and Zone VE, arereferred to
collectively as the Coastal A Zone.
While FEMA does not impose floodplain management
requirements based on the LiMWA, the LiMWA
communicates that a greater risk of flood damage is present
in the Coastal A Zone.
FEMA encourages the practice of buildingto Zone VE
standardswithin the Coastal A Zone, andmany local
building codes require that buildings in the Coastal A Zone
be built to ZoneVE standards to be better protected from
the dangers posed by waves.
“FEMA’s mission is to support our citizens and first responders to ensure that as a nation we work together to build,
sustain, and improve our capability to prepare for, protect against, respond to, recover from, and mitigate all hazards.”
December 2017
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Effects on FloodplainManagement
For their safety, communities are encouraged to adopt the most
Requiring design and construction within the
recent I-Codes,but at minimum, to adopt construction standards
Coastal A Zone to meet Zone VE standards
in the Coastal A Zone similar to those for Zone VE. (Refer to the
is a minimum requirement under widely
sidebaron page 1 for a summary.)
adopted,consensus model building codes
Many communities adopt a requirement fora structure tobe built
(International Building Code and
a few feet above the BFE, which is the potential height of a 1-
International Residential Code) as well as
percent-annual-chance flood. This added elevation, called
FEMA assistance programs.
freeboard,has at least two benefits: it adds a factor of safety to
protect against flooding damage, and itreduces flood insurance
premium costs.
CRS credits are available for participating communities that adopt Zone VE building standards in the
Coastal A Zone. For more information on CRS, visit: www.fema.gov/national-flood-insurance-program-
community-rating-system.
Effects on PropertyOwners
Residents and business owners living or working in the Coastal A Zone should be aware that potential wave
action and floating debris could cause significant damage to their property. Property owners are encouraged
to exceed theminimum requirements and build “safer and higher” to reduce the risk to life and property.
Although the risk of damage is higher in the Coastal A Zone than in other Zone AE areas, NFIP rates for
properties in the Coastal A Zone do not differ from those in other Zone AE areas.
A federal requirement to purchaseflood insuranceapplies in Zones V, VE, A, and AE. Property owners are
encouraged to carry coverage equivalent to the replacement cost of their building and to include additional
coverage for the contents of their property.
Options for Communities to Account for Coastal A Zones inConstruction
The following paragraphs provideoptions and sample ordinance language that communities can consider to
implement higher standards in the Coastal A Zone.Ideally, communities should adopt the most recent I-Codes,
which recognize the Coastal A Zone and provide construction requirements for those areas. Building codes
represent the most comprehensive approach to addressing construction within the Coastal A Zone. The options
below provide varying levels of increased protection, and communities canchoose what ismost suitable for their
needs. Communities should consult their legal departments to ensure the ordinance language complies with other
community standards and regulations.
Substantial Damagerefers to the damage
Adopt Zone VE standards for all properties(most protective option)
sustained by a building where the cost of
With this option, all development in the Coastal A Zone would be subject restoring the building to its pre-damaged
to the same building requirements enforced by the community in Zone condition would equal or exceed 50
VE. These requirements would include the building standards highlighted percent of the building’s market value
on the first page of this fact sheet and apply to all new construction, before the damage occurred.
substantially damaged buildings, and buildings undergoing substantial
Substantial Improvementrefers to
improvements.
enhancements or repairs that will cost 50
percent or more of the building’s pre-
improvement market value (unless
otherwise specified by the community).
When using Zone VE standards in the Coastal AZone, breakaway walls should include the appropriate number of flood openings to
equalize hydrostatic loads in the enclosure.If the flood openings are not required by code, the lack of flood openings for the enclosure
will result in increased flood insurance premiums.
“FEMA’s mission is to support our citizens and first responders to ensure that as a nation we work together to build,
sustain, and improve our capability to prepare for, protect against, respond to, recover from, and mitigate all hazards.”
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Federal Emergency Management Agency
Adopt Zone VE standards for residential structures, but continue to apply Zone AE requirements for non-
residential structures
With this option, all new residential construction, including substantial improvements and substantial damage
repairs, would be subject to the same building requirements enforced by the community in Zone VE. Sample
language includes:
All new residential construction, substantial improvements, and repairs to substantially damaged buildings
must comply with the building standards for Zone VE; and
All new non-residential construction, substantial improvements, and repairs to substantially damaged
buildings must comply with the community floodplain ordinance for development in Zone AE.
Additionally, communities could consider applying Zone VE standards to “light-framed construction” in the
Coastal A Zone. (Wave damage isexpected to be greaterin buildings constructed using wood framing or light-
gauge metal framing.)
Adopt Zone VE standards for new construction only*
For this option, Zone VE standards would apply only to new construction. Sample language for this option
includes:
All new construction must comply with the building standards for Zone VE; and
All residential and non-residential buildings undergoing substantial improvement/repair must comply with
the community’s floodplain ordinance for Zone AE development.
Adopt Zone VE standards for critical facilities only*
Sample language for this option includes:
All new construction and substantial improvement or repair of critical facilities or those undergoing
substantial improvements in the Coastal A Zone must comply with the building standards for Zone VE.
Adopt increased elevation requirements above the BFE—freeboard(least protectiveoption)*
While this option should reduce damage to a building’s floor system and walls, the foundation system will need to
be designed to resist the hazards posed by waves and address scour and erosion.
Open foundations are recommended, with theoption of a designed stemwall foundation (a continuous wall
foundation with structural fill placed behind the wall system and the building constructed on a continuous
slab, which caps the structural fill). The slab elevation should meet the freeboard requirements.Continuous
wall foundations with a crawlspace should be avoided unless they are designed to resist breaking wave
loads.
All foundations should besufficiently deep to resist scour and erosion.
Scour around continuous foundation walls can be significantly deeper
For More Information
than around pile foundations (open and deep foundations).
To obtain model ordinances,
check with your State NFIP
Pier foundations should also be designed to resist breaking wave loads
Coordinator.
and impactloads. Footings should account for scour and erosion.
For more information on NFIP
Communities that only adopt increased freeboard requirements should expect
floodplain management
buildings constructed in Coastal A Zones to experience more damage during a
requirements, visit:
flood than buildings designed to Zone VE requirements.
https://www.fema.gov/media-
library/assets/documents/902
When using Zone VE standards in the Coastal A Zone, breakaway walls should include the appropriate number of flood openings
to equalize hydrostatic loads in the enclosure.Even if the flood openings are not required by code, the lack of flood openings for
the enclosure will result in increased flood insurance premiums.
“FEMA’s mission is to support our citizens and first responders to ensure that as a nation we work together to build,
sustain, and improve our capability to prepare for, protect against, respond to, recover from, and mitigate all hazards.”
3
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Florida Building Code mandates Coastal A Construction. The following quotations from ASCE 24-14,
which is adopted by the Florida Building Code 6th Edition, which the County adopted prior to it taking
effect in 2018 require us to regulate to the new standard and FBC 6th Edition:
ASCE 24-14 Chapter 3, Section 3.7, Subsection 3.7.1, "New construction and substantial
improvements shall not be constructed in Coastal High Hazard Areas and Coastal A Zones unless
the design and construction meet the requirements of Chapter 4."
ASCE 24-14 Chapter 4, Section 4.1.1,
(1) Landward of the V Zone or shoreline and seaward of the Limits of Moderate
Wave Action (LiMWA) if the LiMWA is delineated on a FIRM, or
(2) Designated by the authority having jurisdiction.
ASCE 24-14, Chapter 4 details all the requirements that will be enforced for Coastal A Zones.
FBC 6th Edition, Section R322.2: Areas that have been determined to be prone to flooding and
that are not subject to high-velocity wave action shall be designated as flood hazard areas.
Flood hazard areas that have been delineated as subject to wave heights between 1 ½ feet
(457mm) and 3 feet (914 mm) or otherwise designated by the jurisdiction shall be designated
Coastal A Zones and are subject to the requirements of Section R322.3.
FBC 6th Edition, Section R322.3: -Hazard Areas (including V Zones and Coastal A
heights between 1 ½ feet (457mm) and 3 feet (914 mm) or otherwise designated by the
jurisdiction shall be designated Coastal A Zones and are subject to the requirements of Section
R322.3. Buildings and structures constructed in whole or in part in coastal high-hazard areas
and Coastal A Zones, where designated, shall be designed and constructed in accordance with
Sections R322.3.1 through R322.3.7.
Karl W. Bursa, AICP, CFM
Chief of Floodplain Regulatory Operations
Monroe County Building Department
Key Largo Office
Bursa-Karl@MonroeCounty-FL.Gov
(305) 453-8759
Attachment: Staff Research on FBC ASCE 24-14 (Floodplain Mapping: Limit of Moderate Wave Activity modeling and Coastal A Zone)
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Below are sections from ROGO and NROGO regarding updated plans.
Attachment: Staff Research LDC Chapter 138 25 and 52 (Floodplain Mapping: Limit of Moderate Wave Activity modeling and Coastal A Zone)
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Tiffany Stankiewicz
Development Administrator
Monroe County Planning & Environmental Resources
2798 Overseas Hwy., Suite 410
Marathon, FL 33050
305-289-2513
Attachment: Staff Research LDC Chapter 138 25 and 52 (Floodplain Mapping: Limit of Moderate Wave Activity modeling and Coastal A Zone)
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Quick reference to FEMA/NFIP on using Best Available Data, an ethical agreement for Floodplain
Managers and any NFIP floodplain reviewer/manager.
Taken from: https://www.fema.gov/use-flood-insurance-study-data-available-data
Snippets:
“Communities are required to reasonably utilize the data from a draft or preliminary FIS under the
section of their ordinance that applies to this paragraph. A community is allowed discretion in using this
data only to the extent that the technical or scientific validity of the data in the draft or preliminary FIS is
questioned.”
“For Zones AE, A1-30, AH, AO, VE, and V1-30:
The NFIP floodplain management criteria do not require communities to use BFE and flood way data
from a draft or preliminary Flood Insurance Restudy in Zones AE, A1-30, AH, AO, VE, and V1-30 in lieu of
using the BFE and floodway data contained in an existing effective FIS and FIRM. Because communities
are afforded the opportunity to appeal BFE data from a restudy in accordance with Section 1363 of the
National Flood Insurance Act of 1968, as amended, a presumption of validity is given to existing effective
BFE data that has gone through the formal statutory appeals process and which has been adopted by
the community. However, in cases where BFEs increase in the restudied area, communities have the
responsibility to ensure that new or substantially improved structures are protected, particularly if
the increases in BFEs are significant. While FEMA cannot mandate or require a community to use BFE
and floodway data in a draft or preliminary FIS as available data or to use the data at the time FEMA
issues the LFD to the community, FEMA encourages communities to reasonably utilize this
information in instances where BFEs increase and floodways are revised to ensure that the health,
safety, and property of their citizens are protected.”
For Zones AE, A1-30, AH, AO, VE, V1-30, B, C, and X:
Communities are given six months from the date of the LFD in which to adopt the revised FIS and FIRM.
This is in keeping with FEMA's statutory obligation to provide a reasonable time for the community to
adopt floodplain management regulations consistent with the final flood elevation determinations.
Subparagraph 44 CFR 59.24(a) of the NFIP Regulations provides for a six month compliance period in
which the community must adopt the effective FIS and FIRM and amend existing regulations to
incorporate any additional requirements under 44 CFR 60.3.
Floodplain management ordinances generally contain a section entitled "Basis for Establish-ing the
Areas of Special Flood Hazard" in which the current effective FIS and FIRM are cited. Language in the
ordinance may include any subsequent amendments thereto (i.e., to include any subsequent revised FIS
and FIRM); however, this language should not be used as the basis for a community to use the
preliminary FIS prior to the issuance of the LFD. If a community chooses to use BFE and floodway data
from a preliminary FIS prior to the LFD being issued or use the data after a LFD is issued but before the
effective date of the FIS and FIRM, it is advised that the community adopt this information before its
use.
Attachment: Staff Research on FEMA Guidance Best Available Data and Regulating to Preliminary Maps (Floodplain Mapping: Limit of
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