FRANKLIN COUNTY,
FLORIDA
AND INCORPORATED AREAS
COMMUNITY NAME
APALACHICOLA, CITY OF
CARRABELLE, CITY OF
FRANKLIN COUNTY
(UNINCORPORATED AREAS)
COMMUNITY NUMBER
120089
120090
120088
REVISED:
FEBRUARY 5, 2014
Federal Emergency Management Agency
FLOOD INSURANCE STUDY NUMBER
12037CV000A
NOTICE TO
FLOOD INSURANCE STUDY USERS
Communities participating in the National Flood Insurance Program have established repositories
of flood hazard data for floodplain management and flood insurance purposes. This Flood
Insurance Study (FIS) may not contain all data available within the repository. It is advisable to
contact the community repository for any additional data.
Part or all of this FIS may be revised and republished at any time. In addition, part of this FIS may
be revised by the Letter of Map Revision process, which does not involve republication or
redistribution of the FIS. It is, therefore, the responsibility of the user to consult with community
officials and to check the community repository to obtain the most current FIS components.
Initial Countywide FIS Effective Date: June 17, 2002
Revised Countywide FIS Date: February 5, 2014
TABLE OF CONTENTS
Page
1.0
INTRODUCTION
1.1
Purpose of Study
1.2
Authority and Acknowledgments
1.3
Coordination
1
1
1
2
2.0
AREA STUDIED
2.1
Scope of Study
3
3
2.2
2.3
2.4
4
4
7
Community Description
Principal Flood Problems
Flood Protection Measures
3.0
ENGINEERING METHODS
3.1
Riverine Hydrologic Analyses
3.2
Riverine Hydraulic Analyses
3.3
Coastal Hydrologic Analyses
3.4
Coastal Hydraulic Analyses
3.5
Vertical Datum
7
8
9
11
18
40
4.0
FLOODPLAIN MANAGEMENT APPLICATIONS
4.1
Floodplain Boundaries
4.2
Floodways
41
41
42
5.0
INSURANCE APPLICATIONS
46
6.0
FLOOD INSURANCE RATE MAP
47
7.0
OTHER STUDIES
48
8.0
LOCATION OF DATA
50
9.0
BIBLIOGRAPHY AND REFERENCES
50
i
TABLE OF CONTENTS – continued
Page
FIGURES
Figure 1 – Transect Schematic
18
Figure 2– Transect Location Map
39
Figure 3– Floodway Schematic
45
TABLES
Table 1 - Summary of Discharges
9
Table 2 – Summary of Stillwater Elevations
15-17
Table 3 – Transect Descriptions
21-29
Table 4 – Transect Data
30-37
Table 5 – Floodway Data
44
Table 6 – Community Map History
49
EXHIBITS
Exhibit 1 - Flood Profiles
Apalachicola River
Ochlockonee River
Panels 01P-05P
Panels 06P-07P
Exhibit 2 - Flood Insurance Rate Map Index
Flood Insurance Rate Map
ii
FLOOD INSURANCE STUDY
FRANKLIN COUNTY, FLORIDA AND INCORPORATED AREAS
1.0
INTRODUCTION
1.1
Purpose of Study
This countywide Flood Insurance Study (FIS) investigates the existence and
severity of flood hazards in, or revises and updates previous FISs/Flood Insurance
Rate Maps (FIRMs) for the geographic area of Franklin County, Florida, including:
the Cities of Apalachicola and Carrabelle, and the unincorporated areas of Franklin
County (hereinafter referred to collectively as Franklin County).
This FIS aids in the administration of the National Flood Insurance Act of 1968 and
the Flood Disaster Protection Act of 1973. This FIS has developed flood risk data
for various areas of the county that will be used to establish actuarial flood
insurance rates. This information will also be used by Franklin County to update
existing floodplain regulations as part of the Regular Phase of the National Flood
Insurance Program (NFIP), and will also be used by local and regional planners to
further promote sound land use and floodplain development. Minimum floodplain
management requirements for participation in the NFIP are set forth in the Code of
Federal Regulations at 44 CFR, 60.3.
In some States or communities, floodplain management criteria or regulations may
exist that are more restrictive or comprehensive than the minimum Federal
requirements. In such cases, the more restrictive criteria take precedence and the
State (or other jurisdictional agency) will be able to explain them.
1.2
Authority and Acknowledgments
The sources of authority for this FIS are the National Flood Insurance Act of 1968
and the Flood Disaster Protection Act of 1973.
This FIS was prepared to include the unincorporated areas of, and incorporated
communities within, Franklin County in a countywide format. Information on the
authority and acknowledgments for each jurisdiction included in this countywide
FIS, as compiled from their previously printed FIS reports, is shown below.
Apalachicola, City of:
the hydrologic and
hydraulic analyses for the FIS report dated January
18, 1983, were prepared by Gee & Jensen Engineers,
Architects, & Planners (EAP), Inc., for the Federal
Emergency Management Agency (FEMA) under
Contract No. H-4625. That work was completed in
November 1980.
1
Carrabelle, City of:
the hydrologic and
hydraulic analyses for the FIS report dated January
18, 1983, were prepared by Gee & Jensen EAP Inc.,
for FEMA under Contract No. H-4625. That work
was completed in March 1980.
Franklin County
(Unincorporated Areas):
the hydrologic and
hydraulic analyses for the FIS report dated January
18, 1983, were prepared by Gee & Jensen EAP Inc.,
for FEMA under Contract No. H-4625. That work
was completed in November 1980.
For the June 17, 2002 countywide FIS, the coastal analyses were revised by
Dewberry and Davis LLC. The extent of the revised coastal hydrologic and
hydraulic analyses were limited to the barrier island portions of the county: St.
Vincent Island, St. George Island, Little St. George Island, and Dog Island, as well
as portions of the Alligator Point area, up to the confluence of the Ochlockonee Bay
with the Gulf of Mexico. This work was completed in August 1999.
For this revision to the countywide FIS dated February 5, 2014, the revised coastal
analysis for the Gulf of Mexico, including the entire shoreline of Franklin County
has been prepared for FEMA by the Northwest Florida Water Management District
(NFWMD) under Contract No. EMA-2008-CA-5886. Additionally, the floodplain
for the Apalachicola River has been redelineated using updated topographic data.
Existing data for St. James Bay and the area in the vicinity of Eastpoint has also
been incorporated as a part of this revision. This work was completed in 2011.
Base map information for this FIRM was developed from high resolution digital
orthoimagery provided by the Florida Department of Revenue. This information
was produced at a scale of 1:200 from photography dated 2010.
The coordinate system used for the production of this FIRM is Florida State Plane
North (FIPS 0903) feet, referenced to the North American Datum of 1983
(NAD83) HARN. Corner coordinates shown on the FIRM are in latitude and
longitude referenced to the State Plane projection, NAD 83 HARN. Differences in
the datum and spheroid used in the production of FIRMs for adjacent counties
may result in slight positional differences in map features at the county
boundaries. These differences do not affect the accuracy of information shown on
the FIRM.
1.3
Coordination
Consultation Coordination Officer’s (CCO) meetings may be held for each
jurisdiction in this countywide FIS. An initial CCO meeting is held typically with
representatives of FEMA, the community, and the study contractor to explain the
nature and purpose of a FIS, and to identify the streams to be studied by detailed
2
methods. A final CCO meeting is held typically with representatives of FEMA, the
community, and the study contractor to review the results of the study.
The dates of the initial and final CCO meetings held prior to the countywide FIS for
Franklin County and the incorporated communities within its boundaries are in the
following tabulation:
Community Name
Initial CCO Date
Final CCO Date
Apalachicola, City of
Carrabelle, City of
Franklin County
(Unincorporated Areas)
March 21, 1978
March 21, 1978
July 26, 1982
July 22, 1982
March 28, 1978
July 1982
For the June 17, 2002, countywide FIS, Franklin County and the Cities of
Apalachicola and Carrabelle were notified of the revision by FEMA in a letter dated
July 20, 1999.
For this revision to the countywide FIS, final CCO meetings were held September
12, 2012. These meetings were attended by representatives of the study
contractors, the communities, and the State of Florida.
2.0
AREA STUDIED
2.1
Scope of Study
This FIS covers the geographic area of Franklin County, Florida, located on the
Gulf of Mexico in northwest Florida.
The following streams were studied by detailed methods: the Carrabelle River, the
Ochlockonee River, and the Apalachicola River.
For this revision to the countywide FIS, all coastal hazards affecting the county
have been revised. The existing detailed study for the Ochlockonee River has
been superseded with the revised coastal study. Additionally, the floodplain for
the Apalachicola River has been redelineated using updated topographic data.
Existing data for St. James Bay and the area in the vicinity of Eastpoint has also
been incorporated.
Limits of detailed study for riverine flooding sources are indicated on the Flood
Profiles (Exhibit 1) and on the FIRM (Exhibit 2). The areas studied by detailed
methods were selected with priority given to all known flood hazard areas, and
areas of projected development or proposed construction.
No Letters of Map Change (LOMCs) were incorporated as part of this revision to
the countywide FIS.
3
All or portions of numerous flooding sources within the county were studied by
approximate methods. Approximate analyses were used to study those areas having
a low development potential or minimal flood hazards. The scope and methods of
study were proposed to, and agreed upon by, FEMA and Franklin County.
2.2
Community Description
Franklin County is located in northwest Florida on the Gulf of Mexico
approximately 40 miles southwest of Tallahassee. It is bounded on the west by
Gulf County, on the north by Liberty County, and on the east by Wakulla County.
Major communities within the county are the City of Apalachicola, located at the
mouth of the Apalachicola River, and the City of Carrabelle which is located on St.
George Sound. The county includes St. Vincent, St. George and Dog Islands.
Chartered in 1832, Franklin County encompasses an area of approximately 1,037
square miles. The 2010 population of Franklin County was reported to be 11,549
(U.S. Department of Commerce, Bureau of the Census, 2010.)
The primary east-west artery serving the county is State Route 30 (U.S. Route 98)
which provides interconnection to most of the coastal counties in the area. State
Routes 65, 67 and 377 provide access to areas north of Franklin County. The
Apalachicola Northern Railroad runs north-south through the western portion of the
county, and provides service to the City of Apalachicola. The Apalachicola River
accommodates barge traffic and is a part of the extensive Flint-Chattahootchee
River System with navigable channels as far north as Columbus, Georgia. The
Intracoastal Waterway extends from the mouth of the Apalachicola River upstream
to the confluence of the Brothers River and then turns westward through Lake
Wimico.
Residential and commercial development within the county is centered around the
coastal cities of Apalachicola and Carrabelle with coastal areas along St. George
Sound and Apalachicola Bay also being populated. St. George Island is being
increasingly populated, primarily with second home development. Large portions
of the county are essentially undeveloped wilderness areas and the Apalachicola
National Forest occupies a large area in the northwest quadrant.
The climate in Franklin County is relatively mild with mean annual temperatures in
the upper sixties and average winter time temperatures about 48 to 50 degrees
Fahrenheit (°F). Temperatures in the summer months average in the low 80s °F,
being moderated by sea breezes and frequent thunderstorms. Rainfall averages
about 55 inches per year with the majority of the accumulation occurring in the
months of July through September. Winds are generally southerly in summer
months and northerly in winter months (U.S. Department of Commerce, 1978).
2.3
Principal Flood Problems
General flooding in Franklin County stems from two sources: periods of intense
rainfall causing ponding and sheet runoff in the low, poorly-drained areas and
coastal flooding associated with hurricanes and tropical storms. The floodplains
4
of the Apalachicola River, the New River, the Crooked River, the Carrabelle
River, and the Ochlockonee River are also subject to flooding during high river
stages.
The floodplains of the Apalachicola River are subject to riverine flooding during
periods of heavy rainfall. As mentioned previously, the Apalachicola River is
part of an extensive river system whose drainage area extends northward about
five hundred miles to a point near the northern Georgia border, and encompasses
an area over 19,000 square miles.
Other rivers in the county have smaller drainage areas and are therefore less
significant sources of flooding. These include the New and Crooked Rivers,
which flow through the central portion of the county and join to form the
Carrabelle River, which then discharges into St. George Sound at Carrabelle. The
Ochlockonee River forms a portion of the northeast county boundary and empties
into the Gulf of Mexico through Ochlockonee Bay. Low-lying, poorly drained
areas of the county are also subject to rainfall ponding.
Franklin County is subject to coastal flooding caused by extra tropical cyclones
and hurricanes. Extra tropical cyclones can occur at any time of the year but
are more prevalent in the winter. The prime hurricane season is from August
to October during which time 80 percent of all hurricanes occur. September is
the worst month for hurricanes during which 32 percent of the total occur.
Hurricanes are of shorter duration than northeasters and generally last through
only one tidal cycle.
In meteorological terms, a hurricane is defined as a tropical cyclone which has a
central barometric pressure of 29 inches or less of mercury, and wind velocities of
75 miles per hour or more. The low barometric pressures and high winds
combine to produce abnormally high tides and accompanying tidal flooding. The
high winds can generate large waves, provided there are no obstructions or barrier
beaches to dissipate wave momentum. The winds of a hurricane in the Northern
Hemisphere spiral inward in a counterclockwise direction towards the "eye" or
center of low pressure. The eye of the hurricane (where winds are subdued) can
vary in diameter. Normally, the "eye" can extend for 15 miles, although the eye
of a mature hurricane can reach diameters of 20 to 30 miles or even greater.
A hurricane develops as a tropical storm either near the Cape Verde Islands off
the African coast or in the western Caribbean Sea. Most hurricanes which reach
northwestern Florida approach from a southerly direction after crossing the
Florida peninsula, the island of Cuba, or the western Gulf of Mexico. These
hurricanes start their journey northward with a forward speed of about 10 miles
per hour.
The most destructive winds in a hurricane occur east of the eye, where the spiral
wind movement and forward motion of the storm combine. Several past
hurricanes have tracked over the Florida Panhandle; therefore, Franklin County is
prone to experience the full intensity of a major hurricane. In order for Franklin
5
County to experience the highest winds and accompanying highest tides of a
hurricane, the storm would need to track west of the county.
Historical data indicates that several hurricanes have had significant impact on
Franklin County, since 1972 – on June 19, 1972 (Agnes), on August 31, 1985
(Elena), on November 21, 1985 (Kate), on September 3, 1998 (Earl), and on July
10, 2005 (Dennis). Data provided by the Florida Department of Environmental
Protection, regarding these storms, is summarized below:
Hurricane Agnes, in 1972, made landfall west of Cape San Blas, in Gulf County,
with peak winds reaching 55 mph at Apalachicola. Despite being a Category One
hurricane, the storm surge affecting Franklin County is estimated to have been
approximately 8 feet at St. Marks. Beach and dune erosion was significant along
the entire open coast of Jefferson County, with breaches occurring on the Marsh
Islands.
Hurricane Elena, in 1985, made two passes offshore of Jefferson County before
making landfall in Mississippi. Wind damage associated with Hurricane Elena
was limited to shoreline areas of Jefferson County; however, the accompanying
storm surge, of approximately 8 to 9 feet at St. Marks, resulted in damage to
shorefront protection structures and buildings.
Hurricane Kate, in 1985, made landfall at Mexico Beach, in Gulf County, with
peak winds reaching 85 mph at Apalachicola, just 2 months after Hurricane Elena.
The storm surge affecting Jefferson County is estimated to have been
approximately 8.4 feet at Shell Point. Land falling wind and waves, associated
with Hurricane Kate, resulted in the destruction of 46 buildings and damage to 15
more.
Hurricane Earl, in 1998, made landfall in Panama City Beach in Bay County. In
Jefferson County, the storm surge was approximately 8 feet at St. Marks.
Shorefront erosion resulted in damage to the Marsh Islands.
Hurricane Dennis, in 2005, made landfall on Santa Rosa Island, between Navarre
Beach and Pensacola Beach, in Escambia County. Although well westward of
Jefferson County, this hurricane produced a storm surge of 6 to 9 feet in
Apalachee Bay and 7.5 feet at the mouth of the Aucilla River. High waves,
associated with Hurricane Dennis resulted in beach erosion to open coast areas of
both Franklin County and Jefferson County, with approximately 37 buildings
sustaining damage in Jefferson County.
Coastal flooding is not limited to hurricane activity; in fact, extra tropical
cyclones, have resulted in significant tidal flooding along the Florida panhandle.
Extra tropical cyclones can develop in the Gulf of Mexico and along strong
frontal boundaries and can potentially occur at any time of year, but most
frequently in the winter and spring months. Typically, these storms have centers
that are colder than the surrounding air, with strongest winds in the upper
atmosphere, and lower wind velocities and higher central pressures than a major
6
hurricane; however, wind velocities associated with an extra tropical cyclone can
easily reach tropical storm and Category 1 hurricane levels. In addition, the high
winds of an extra tropical cyclone can last for several days, causing repeated
flooding and excessive coastal erosion. The long exposure of property to high
water, high winds, and pounding wave action can result severe property damage.
2.4
Flood Protection Measures
Franklin County does not have any flood protection measures designed and
constructed specifically for flood protection. The U.S. Army Corps of Engineers
(USACE) designed and built the Jim Woodruff Lock and Dam, which is located
north of Franklin County on the Apalachicola River at the Florida/Georgia state line
and approximately 108 miles north of the mouth. Construction of this dam was
initiated in September 1947, and the impounding of water occurred in May 1954.
Although the Jim Woodruff Dam was primarily designed for navigation purposes, it
does offer a limited amount of flood regulation of the Apalachicola River. Because
of the dam’s geographical location, it provides minimal flood protection for
Franklin County. The Jackson Bluff Dam on Lake Talquin (Ochlockonee River) is
a hydroelectric installation operated by the Florida Power Corporation. This project
was completed in 1930, and offers no appreciable flood control for properties
located downstream.
The coastal areas of Franklin County are, for the most part, surrounded by barrier
islands. St. George Island and Little St. George Island, for example, offer some
protection to the coastal area along St. George Sound and Apalachicola Bay from
wave action. It is expected, however, that portions of the barrier islands would be
overtopped during the larger storm events.
In 1973, the state of Florida established a Coastal Construction Control Line that
now includes the coastal beaches of St. George Island, Dog Island, and Alligator
Point. The purpose of this line is to control coastal land use and building
construction methodology for areas susceptible to direct storm surge, erosion and
wave runup.
3.0
ENGINEERING METHODS
For the flooding sources studied in detail in the county, standard hydrologic and hydraulic
study methods were used to determine the flood hazard data required for this FIS. Flood
events of a magnitude which are expected to be equaled or exceeded once on the average
during any 10-, 50-, 100-, or 500-year period (recurrence interval) have been selected as
having special significance for floodplain management and for flood insurance rates.
These events, commonly termed the 10-, 50-, 100-, and 500-year floods, have a 10-, 2-, 1-,
and 0.2-percent chance, respectively, of being equaled or exceeded during any year.
Although the recurrence interval represents the long term average period between floods of
a specific magnitude, rare floods could occur at short intervals or even within the same
year. The risk of experiencing a rare flood increases when periods greater than 1 year are
considered. For example, the risk of having a flood which equals or exceeds the 100-year
flood (1-percent chance of annual exceedence) in any 50-year period is approximately 40
7
percent (4 in 10), and, for any 90-year period, the risk increases to approximately 60
percent (6 in 10). The analyses reported herein reflect flooding potentials based on
conditions existing in the county at the time of completion of this FIS. Maps and flood
elevations will be amended periodically to reflect future changes.
3.1
Riverine Hydrologic Analyses
Initial Countywide Analysis
Hydrologic analyses were carried out to establish the peak discharge-frequency
relationships for the flooding sources studied in detail in Franklin County.
The flows of the required frequencies for the Apalachicola River, in the City of
Apalachicola, were based on statistical analyses of discharge records covering the
twenty-year period taken from the Bloutstown, Florida gage (No. 02358700) on the
Apalachicola River. This statistical analysis is the Log-Pearson Type III Method
recommended by the Water Resources Council (Water Resources Council, 1976).
For locations where no discharge records are available, or where discharge records
are not of sufficient length to yield reliable results from statistical analysis, the gage
analyses were extrapolated based on increases in drainage area. The extrapolated
flows downstream of Gage No. 02358700 were adjusted to account for the Chipola
Cutoff and the Intracoastal Waterway-Lake Wimico-Jackson River System.
Revised Countywide Analysis
Existing data developed by the NFWMD for the area in the vicinity of Eastpoint
has been incorporated into this FIS. Hydrologic analysis was performed using the
Environmental Protection Agency’s Storm Water Management Model (SWMM)
version 5 (NFWMD, 2010).
Existing data developed by Engineering Methods & Applications, Inc. for St.
James Bay has also been incorporated into this FIS. Soil Conservation Service
(SCS) curve number-based hydrologic analysis was performed for this study
(Engineering Methods & Applications, Inc., 2001).
A summary of the drainage area-peak discharge relationships for all the streams
studied by detailed methods is shown in Table 1, "Summary of Discharges."
8
TABLE 1 - SUMMARY OF DISCHARGES
FLOODING SOURCE
AND LOCATION
APALACHICOLA RIVER
At Apalachicola Bay
At confluence of Brothers
River
OCHLOCKONEE RIVER1
At mouth
1
DRAINAGE
AREA
(sq. miles)
PEAK DISCHARGES (cfs)
10-YEAR
50-YEAR
100-YEAR
18,363
149,190
187,985
204,074
241,150
18,163
157,680
198,675
215,675
254,485
2,000
31,000
59,000
74,000
116,000
500-YEAR
This information has been superseded by the most recent coastal restudy.
3.2
Riverine Hydraulic Analyses
Analyses of the hydraulic characteristics of flooding from the source studied were
carried out to provide estimates of the elevations of floods of the selected recurrence
intervals. Users should be aware that flood elevations shown on the FIRM represent
rounded whole-foot elevations and may not exactly reflect the elevations shown on
the Flood Profiles or in the Floodway Data tables in the FIS report. For construction
and/or floodplain management purposes, users are encouraged to use the flood
elevation data presented in this FIS in conjunction with data shown on the FIRM.
Initial Countywide Analysis
Cross sections for the water-surface elevation analyses of the Apalachicola River
were obtained by aerial survey methods from photography flown in 1979 for upland
areas and by field measurement below the water surface. Bridges were field
checked to confirm elevation data and structural geometry.
Locations of selected cross sections used in the hydraulic analyses are shown on the
Flood Profiles (Exhibit 1). For stream segments for which a floodway was
computed (Section 4.2), selected cross section locations are also shown on the
FIRM (Exhibit 2). Flood profiles were drawn showing computed water-surface
elevations for floods of the selected recurrence intervals.
Channel roughness factors (the "n" factor for Manning's formula) used in the
hydraulic computations were chosen based on field observations of the streams and
floodplain areas. This measure of roughness for the main channel of the
Apalachicola River ranges from 0.040 to 0.065 with floodplain roughness values
ranging from 0.090 to 0.130.
The acceptability of the above hydraulic factors, cross sections, and hydraulic
structure data was checked using these computations and comparing the result of
known historic storms and the resulting flood elevations.
9
Water-surface elevations of floods of the selected recurrence intervals for the
Apalachicola River were computed using the USACE HEC-2 step backwater
computer program (USACE, 1976). Starting water-surface elevations at the mouth
of the Apalachicola River used in these calculations were determined using the
slope/area method.
Revised Countywide Analysis
The hydraulic analyses for this FIS were based on unobstructed flow. The flood
elevations shown on the profiles are thus considered valid only if hydraulic
structures remain unobstructed, operate properly, and do not fail.
Existing data developed by the NFWMD for the area in the vicinity of Eastpoint
has been incorporated into this FIS. One-percent annual chance base flood
elevations (BFEs) were established using the Environmental Protection Agency’s
Storm Water Management Model (SWMM) version 5 (NFWMD, 2010). The 1percent annual chance floodplain was delineated to be in agreement with the
results of the storm surge analysis in this area.
Existing data developed by Engineering Methods & Applications, Inc. for St.
James Bay has also been incorporated into this FIS. A hydraulic analysis was
performed using the ICPR model version 2.x (Engineering Methods &
Applications, Inc., 2001).
All qualifying bench marks within a given jurisdiction that are cataloged by the
National Geodetic Survey (NGS) and entered into the National Spatial Reference
System (NSRS) as First or Second Order Vertical and have a vertical stability
classification of A, B, or C are shown and labeled on the FIRM with their 6character NSRS Permanent Identifier.
Bench marks cataloged by the NGS and entered into the NSRS vary widely in
vertical stability classification. NSRS vertical stability classifications are as
follows:

Stability A: Monuments of the most reliable nature, expected to hold
position/elevation well (e.g., mounted in bedrock)

Stability B: Monuments which generally hold their position/elevation
well (e.g., concrete bridge abutment)

Stability C: Monuments which may be affected by surface ground
movements (e.g., concrete monument below frost line)

Stability D: Mark of questionable or unknown vertical stability (e.g.,
concrete monument above frost line, or steel witness post)
In addition to NSRS bench marks, the FIRM may also show vertical control
monuments established by a local jurisdiction; these monuments will be shown on
10
the FIRM with the appropriate designations. Local monuments will only be
placed on the FIRM if the community has requested that they be included, and if
the monuments meet the aforementioned NSRS inclusion criteria.
To obtain current elevation, description, and/or location information for bench
marks shown on the FIRM for this jurisdiction, please contact the Information
Services Branch of the NGS at (301) 713-3242, or visit their Web site at
www.ngs.noaa.gov.
It is important to note that temporary vertical monuments are often established
during the preparation of a flood hazard analysis for the purpose of establishing
local vertical control. Although these monuments are not shown on the FIRM,
they may be found in the Technical Support Data Notebook associated with this
FIS and FIRM. Interested individuals may contact FEMA to access this data.
3.3
Coastal Hydrologic Analyses
For areas subject to tidal inundation, the 10-, 2-, 1-, and 0.2-percent-annualchance stillwater elevations and delineations were taken directly from a detailed
storm surge study documented in the Technical Support Data Notebook (TSDN)
for the Northwest Florida Water Management District coastal flood hazard study
for Franklin, Wakulla, and Jefferson Counties.
The Advanced Circulation model for Coastal Ocean Hydrodynamics (ADCIRC),
(Luettich, 1992), developed by the USACE was selected to develop the stillwater
elevations or storm surge for northwest Florida’s Franklin, Wakulla, and Jefferson
Counties. ADCIRC uses an unstructured grid and is a finite-element long wave
model. ADCIRC has the capability to simulate tidal circulation and storm surge
propagation over large areas and is able to provide highly detailed resolution
along the shorelines and areas of interest along the open coast and inland bays. It
solves three dimensional equations of motion, including tidal potential, Coriolis,
and nonlinear terms of the governing equations. The model is formulated from the
depth averaged shallow water equations for conservation of mass and momentum
which results in the generalized wave continuity equation. The model has the
capability to simulate tidal circulation and storm surge propagation over large
domains and is able to provide highly detailed resolution along the shoreline and
other areas of interest.
The coastal wave model Simulating Waves Nearshore (SWAN) developed by
Delft University in the Netherlands is used to calculate the nearshore wave fields
required for the addition of wave setup effects. This numerical model is a thirdgeneration (phase-averaged) wave model for the simulation of waves in waters of
extreme, intermediate, and finite depths. Model characteristics include the
capping of the atmospheric drag coefficient, dynamic adjustment of bathymetry
for changing water levels, and specification of the required save points. Three
nested grids are used to obtain sufficient nearshore resolution to represent the
radiation stress gradients required as ADCIRC inputs. Radiation stress fields
output from the SWAN inner grids are used by ADCIRC to estimate the
11
contribution of breaking waves (wave setup effects) to the total storm surge water
level. In order to model storm surge and wave fields using ADCIRC and SWAN,
wind and pressure fields are required for input. A model called the Planetary
Boundary Layer model (PBL) (Cardone, 1992), uses the parameters from a
hurricane or storm to simulate the event and develop wind and pressure fields.
The PBL model simulates hurricane induced wind and pressure fields by applying
the vertically integrated equations of motion. Oceanweather Inc. provided support
to run the PBL model and provide wind and pressure fields for each of the
selected storms events.
The Joint Probability Method (JPM) was used to develop the stillwater frequency
curves for the 10-, 2-, 1-, and 0.2-percent-annual-chance stillwater elevations. The
JPM application was not originally named as such (Russell, 1968). The JPM
approach is a simulation methodology that relies on the development of statistical
distributions of key hurricane input variables such as central pressure, radius to
maximum wind speed, maximum wind speed, translation speed, track heading,
and sampling from these distributions to develop model hurricanes. The resulting
simulation results in a family of modeled storms that preserve the relationships
between the various input model components, but provides a means to model the
effects and probabilities of storms that historically have not occurred.
An ADCIRC finite element mesh was created to determine inundation extents and
depths due to hurricane storm surge in northwest Florida’s Franklin, Wakulla, and
Jefferson Counties. The offshore portion of the mesh covers the Atlantic Ocean,
Caribbean Sea, and Gulf of Mexico west of 60o West Longitude. This offshore
portion is adapted from a proven existing mesh (Hagen, 2006). The inland portion
of the mesh was extended to floodplain areas of Franklin, Wakulla, and Jefferson
Counties and refined with node spacing ranging from 40-50 meters to 250-300
meters. The inland bathymetry portion of the ADCIRC mesh was populated with
datasets taken from National Ocean Service (NOS) and USACE Surveys, HECRAS one-dimensional river cross-sections, NOAA nautical charts, and
NWFWMD field knowledge. Bathymetry for most of the bays and northeastern
Gulf of Mexico was constructed from the National Geophysical Data Center's
(NGDC) Coastal Relief Model and USACE channel surveys. A portion of the
northern Apalachee Bay was constructed from NOS Surveys, NOAA nautical
chart data, and USACE channel surveys. Further offshore, the mesh restrains its
original node elevations as detailed in Hagen, 2006.
The topographic portion of the ADCIRC mesh was populated with topographic
LiDAR (Light Detection and Ranging) data along with five non-LiDAR terrain
datasets. LiDAR data was available for most of the study area with the exception
of small portions on the western boundary of Franklin County and the eastern
boundary of Jefferson County. LiDAR data for Franklin County was collected
between May and August of 2007 as part of the Florida Department of
Emergency Management's mapping program. For all other areas, non-LiDAR
terrain datasets were downloaded from the USGS National Map Seamless Server,
National Elevation Dataset. A shoreline was manually digitized referencing the
12
LiDAR data and 2007 aerial photos to define change between water and land
elements.
The ADCIRC model mesh includes other features, such as floodplain boundaries,
rivers, roads, ridges and valleys. The final mesh includes approximately 2,250
square miles of floodplain area with 869,000 total computational nodes. The
horizontal datum for the mesh is North American Datum (NAD) 1983,
Geographic Coordinate System. The vertical datum is referenced to the North
American Vertical Datum 1988 (NAVD 88) in units of meters. A land cover
dataset assembled by the Florida Fish and Wildlife Commission (FWC)
specifically to describe the diversity and distribution of vegetation within the state
of Florida was used to define Manning’s n values for bottom roughness
coefficients input at each node in the mesh. Model validation, which tests the
model hydraulics and ability to reproduce events, was performed against
Hurricanes Agnes (1972), Kate (1985), Opal (1995) and Dennis (2005).
Simulated water levels for each event were compared to High Water Mark
(HWM) data supplied by FEMA and historic reports and hydrograph data
supplied by NWFWMD and NOAA.
The SWAN model, used to calculate the wave setup component, uses ocean
bathymetry and coastal topography taken from two sources, the National
Geophysical Data Center (NGDC – GEODAS data set) and the NWFWMD
ADCIRC Grid, which incorporated the high resolution LiDAR survey data
reported on elsewhere. The coastal bathymetry data merged both the NGDC and
ADCIRC Grid data to more accurately represent the topography over the land.
The topography data was interpolated from the LiDAR data used to form the
ADCIRC grid. At locations farther inland than ADCIRC grid, the NGDC dataset
was used. The SWAN model was implemented on a set of nested grids, with
resolutions ranging from 10 kilometers down to approximately 160 meters. The
model is forced with the same wind and pressure fields from Oceanweather Inc.
Hurricanes Kate (1986), Opal (1995), and Dennis (2005) were used to validate the
SWAN model. Modeled wave heights were compared to available historic wave
data from NOAA wave buoys.
Statistical Analyses
Due to the excessive number of simulations required for the traditional JPM
method, the Joint Probability Method-Optimum Sampling (JPM-OS) was utilized
to determine the stillwater elevations associated with tropical events. JPM-OS is a
modification of the JPM method developed cooperatively by FEMA and the
USACE for Mississippi and Louisiana coastal flood studies that were being
performed simultaneously, and is intended to minimize the number of synthetic
storms that are needed as input to the ADCIRC model. The methodology entails
sampling from a distribution of model storm parameters (e.g., central pressure,
radius to maximum wind speed, maximum wind speed, translation speed, and
track heading) whose statistical properties are consistent with historical storms
impacting the region, but whose detailed tracks differ.
13
Production runs were carried out with SWAN and ADCIRC on a set of
hypothetical storm tracks and storm parameters in order to obtain the maximum
water levels for input to the statistical analysis. A total of 159 individual storms
with different tracks and various combinations of the storm parameters were
chosen for the production run set of synthetic hurricane simulations. Each storm
was run for at least 4 days of simulation and did not include tidal forcing. Wind
and pressure fields obtained from the PBL model and wave radiation stress from
the SWAN model were input to the ADCIRC model for each production storm.
All stillwater results for this study include the effects of wave setup; stillwater.
Stillwater Elevations
The results of the ADCIRC model, as described above, provided stillwater
elevations, including wave setup effects that are statistically analyzed to produce
probability curves. The JPM-OS is applied to obtain the return periods associated
with tropical storm events. The approach involves assigning statistical weights to
each of the simulated storms and generating the flood hazard curves using these
statistical weights. The statistical weights are chosen so that the effective
probability distributions associated with the selected greater and lesser storm
populations reproduce the modeled statistical distributions derived from all
historical storms. All of the 869,000 ADCIRC nodes were used as JPM output
points. This provided the maximum resolution and provided detailed coverage in
Franklin County. At each JPM point, the surge elevations obtained from the
standard ADCIRC output files for each of the 159 storms and the annual
recurrence rates for each storm were used as input of JPM-OS method. The final
result was surge elevations at each JPM point for each recurrence rate.
The stillwater elevations have been determined for the 10-, 2-, 1-, and 0.2-percent
annual chance floods for the flooding sources studied by detailed methods and are
summarized in Table 2, "Summary of Stillwater Elevations."
14
TABLE 2 - SUMMARY OF STILLWATER ELEVATIONS
FLOODING SOURCE
AND LOCATION
GULF OF MEXICO
South shoreline of St. Vincent
Island
Shoreline from west end point
of St. George Island to Cape
St. George
Shoreline from Cape St.
George to Government Cut
South shoreline of St. George
Island from Government
Cut to St. George Island
State Park
South shoreline of St. George
Island from St. George
Island State Park to Dr.
Julian G. Bruce St. George
Island State Park
South shoreline of St. George
Island from Dr. Julian G.
Bruce St. George Island
State Park to east end point
of St. George Island
South shoreline of Dog Island
North shoreline of St. George
Island from east end point
of St. George Island to East
Cove
North shoreline of St. George
Island from East Cove to
State Co. Rd 300
Shoreline from Eastpoint to
Carrabelle Thompson
Airport
Shoreline from Ho Hum RV
Park to Florida State
University Coastal and
Marine Laboratory
End of Peninsula Point to the
shoreline adjacent to the end
of Alligator Drive
10-PERCENT
ELEVATION (feet1 NAVD88*)
2-PERCENT
1-PERCENT
0.2-PERCENT
4.6-4.7
8.3-8.8
9.6-10.3
12.5-13.1
4.7-4.8
8.4-8.7
9.7-10.0
12.5-12.7
5.5-5.8
9.9-10.1
11.4-11.6
14.4-14.8
5.7-6.0
10.2-10.5
11.7-12.1
15.0-15.3
6.1-6.2
10.6-10.9
12.2-12.5
15.4-15.7
6.2
10.9-11.1
12.5-12.8
15.7-16.3
6.2-6.3
5.9
11.0-11.4
10.5
12.7-13.2
12.2
16.1-16.5
15.7
5.5-5.7
9.4-9.9
10.9-11.4
14.4-14.9
6.2-6.7
10.7-12.3
12.4-14.2
16.4-18.1
6.9-7.1
12.8-13.1
14.6-15.0
18.2-18.7
6.7-6.5
11.9-12.3
13.6-14.1
17.0-17.6
*North American Vertical Datum of 1988
1
Includes wave setup
15
TABLE 2 - SUMMARY OF STILLWATER ELEVATIONS - continued
FLOODING SOURCE
AND LOCATION
GULF OF MEXICO, cont.
Shoreline adjacent to the
intersection of Alligator
Drive and Mardi Gras Lane
to the shoreline adjacent to
the intersection Alligator
Drive and Pelican Street
Shoreline adjacent to the
intersection of Alligator
Drive and Pelican Street to
the shoreline at the end of
Gulf Shore Boulevard
Shoreline at the end of Gulf
Shore Boulevard to the
shoreline at the end of
Tarpon Street
Shoreline at the end of Tarpon
Street to Bald Point Beach
(Ochlockonee Bay)
SAINT GEORGE SOUND
North shoreline of Dog Island
Shoreline from Carrabelle
Thompson Airport to Ho
Hum RV Park
St. Teresa shoreline from
Turkey Point (St. George
Sound) to 2.6 miles ENE of
Turkey Point (St. George
Sound)
St. Teresa shoreline from 2.6
miles ENE of Turkey Point
(St. George Sound) to
Alligator Harbor
APALACHICOLA BAY
North shoreline of St. George
Island from State Co. Rd
300 to Government Cut
10-PERCENT
ELEVATION (feet1 NAVD88*)
2-PERCENT
1-PERCENT
0.2-PERCENT
6.4-6.6
11.6-11.8
13.2-13.4
16.5-16.7
6.5-6.7
11.7-11.9
13.4-13.5
16.6-17.0
6.5-6.8
11.9-12.2
13.5-14.0
17.0-17.6
6.8-7.2
12.2-12.7
14.0-14.6
17.0-17.8
6.4
6.7-7.0
11.5
12.3-12.8
13.2
14.1-14.7
16.6
18.0-18.5
6.8-6.9
12.7-12.8
14.5-14.6
18.0-18.2
6.8
12.5-12.7
14.3-1.5
17.8-18.0
4.8-5.1
8.1-8.7
9.4-10.1
12.5-13.3
*North American Vertical Datum of 1988
1
Includes wave setup
16
TABLE 2 - SUMMARY OF STILLWATER ELEVATIONS - continued
FLOODING SOURCE
AND LOCATION
APALACHICOLA BAY, cont.
North shoreline of St. George
Island from Government
Cut to west end point of St.
George Island
Shoreline from Apalachicola
Municipal Airport to
entrance of Little Bay
Shoreline from east end of
John Corrie Memorial
Bridge to State Co. Rd 300
SAINT VINCENT SOUND
North shoreline of St. Vincent
Island
Shoreline from County
boundary to Apalachicola
Municipal Airport
EAST BAY
Shoreline from entrance of
Little Bay to east end of
John Corrie Memorial
Bridge
ALLIGATOR HARBOR
Entire WSW facing shoreline
on the Franklin County
mainland
Entire north facing shoreline
along the peninsula
OCKLOCKONEE BAY
Bald Point Beach (Gulf of
Mexico) to Ocklockonee
Bay Bridge
Shoreline from Ocklockonee
Bay Bridge to Wakulla
County Line
10-PERCENT
ELEVATION (feet1 NAVD88*)
2-PERCENT
1-PERCENT
0.2-PERCENT
4.7
7.6
8.8
12.0
5.4-5.5
9.2-9.3
10.8-10.9
14.2-14.4
5.6
9.8
11.3
14.7
5.4
9.2
10.6
13.9
5.6-5.9
9.7-10.4
11.3-11.9
14.8-15.4
5.7-6.0
9.8-10.7
11.4-12.3
14.8-15.5
6.1-6.8
11.4-12.5
13.0-14.3
16.3-17.8
6.2-6.7
11.3-12.3
13.0-14.1
16.2-17.6
7.2-7.5
12.7-13.2
14.6-15.2
18.4-19.3
7.4-7.7
13.2-13.4
15.2-15.4
19.3-19.9
*North American Vertical Datum of 1988
1
Includes wave setup
17
3.4
Coastal Hydraulic Analyses
Areas of coastline subject to significant wave attack are referred to as coastal high
hazard zones. The USACE has established the 3.0-foot breaking wave as the
criterion for identifying the limit of coastal high hazard zones (USACE, 1975). The
3.0-foot wave has been determined as the minimum size wave capable of causing
major damage to conventional wood frame and brick veneer structures.
Figure 1, “Transect Schematic,” illustrates a profile for a typical transect along with
the effects of energy dissipation and regeneration on a wave as it moves inland.
This figure shows the wave crest elevations being decreased by obstructions, such
as buildings, vegetation, and rising ground elevations, and being increased by open,
unobstructed wind fetches. The figure also illustrates the relationship between the
local still water elevation, the ground profile and the location of the V/A boundary.
This inland limit of the coastal high hazard area is delineated to ensure that
adequate insurance rates apply and appropriate construction standards are
imposed, should local agencies permit building in this coastal high hazard area.
Figure 1: Transect Schematic
For Franklin County the deepwater wave conditions associated with the 1-percent
annual chance storm were developed using the Simulating WAves Nearshore
(SWAN) model results. The outputs from the model production runs provided
wave heights and periods to determine the wave heights associated with the 1percent annual chance flood level. For each of the production runs, the maximum
wave heights achieved at each grid point were put into files, as well as the average
wave periods associated with the time when the maximum waves occurred. Then
the wave heights at each of 596,000 coastal wave grid points were rank ordered.
Using the probability of each storm, the 1-percent annual chance flood thresholds
were determined, so the wave periods associated with the wave heights were
determined afterwards. This technique gave a least squares best fit linear
relationship between the flood levels from each storm and the wave heights for each
storm.
18
FEMA guidelines for V Zone mapping define H s as the significant wave height or
the average over the highest one third of waves and T s as the significant wave
period associated with the significant wave height. Mean wave conditions are
described as:
H = H s  0.626
T = T s  0.85
where H is the average wave height of all waves and T is the average wave
period.
The transects were located with consideration given to the physical and cultural
characteristics of the land so that they would closely represent conditions in their
locality. Transects were spaced close together in areas of complex topography
and dense development. In areas having more uniform characteristics, transects
were spaced at larger intervals. It was also necessary to locate transects in areas
where unique flooding existed and in areas where computed wave heights varied
significantly between adjacent transects. Transects are shown on the FIRM
panels for Franklin County.
The transect profiles were obtained using bathymetric and topographic data from
various sources. The topographic dataset was comprised of LiDAR data provided
by the NWFWMD. LiDAR data was collected in July 2007 in leaf-off conditions,
and delivered in ESRI multipoint format in November 2008. Data, as delivered,
was in the North American Datum (NAD) of 1983, projected to Florida HARN
State Plane coordinates, North Zone, in units of feet. The vertical datum was
relative to North American Vertical Datum (NAVD) of 1988 in units of feet. The
LiDAR mass point dataset had a nominal point spacing of 0.7 meters (2.3 feet),
with a horizontal accuracy of 3.8-foot, and a vertical accuracy of 9.14 cm
RMSEz. This data fully meets and exceeds the accuracy standards of FEMA
specifications, and should meet the expectations for an accurate, high quality
digital terrain product.
The bathymetric dataset for Franklin County was processed and provided by the
University of Central Florida during April 2009. Bathymetry for most of the bays
and northeastern Gulf of Mexico consisted of NOAA National Ocean Service
(NOS) hydrographic surveys, NOAA National Geophysical Data Center (NGDC)
Coastal Relief Model, NOAA nautical chart data, and USACE navigation channel
surveys. Data, as delivered, were in grid format with various grid spacing, in the
NAD of 1983, projected to Florida State Plane coordinates, North Zone, in units
of feet. The vertical datum was relative to NAVD of 1988 in units of meters.
The inland bathymetry in the Apalachicola and Carabelle/Ochlockonee areas
consisted of NOS Surveys, USACE navigation channel surveys, HEC-RAS onedimensional river cross-sections, NOAA nautical charts, and NWFWMD field
knowledge. Data, as delivered, were in grid format with various grid spacing, in
the NAD of 1983, projected to Florida State Plane coordinates, North Zone, in
19
units of feet. The vertical datum was relative to NAVD of 1988 in units of meters.
The bathymetric dataset’s depths were converted from meters to feet using a
factor of 3.2808. Data were then reprojected to the NAD83 FL HARN State Plane
North zone coordinate system in units of feet, in agreement with the topographic
dataset. Where surveys overlapped, the older survey data were removed. To
facilitate use of the bathymetric data to build a seamless digital elevation model,
the ESRI shapefile-format point data were converted to three-dimensional feature
class, and then to ASCII format dataset. Finally, the bathymetric data were ready
to be merged with the topographic data-multipoint feature class.
To facilitate floodplain analysis, the provided datasets were processed into a
digital elevation model (DEM). The recently developed ESRI Terrain modeling
framework is considered to be the most efficient data format to create terrain, and
was utilized for this study. First, a file geodatabase was created to contain the
topographic and bathymetric dataset and allow generation of the terrain model. A
pre-determined coverage shapefile was loaded into the database to serve as the
study area boundary. Next, a shoreline vector was also loaded as a hard line
feature class with an assigned zero-elevation, in order to enforce the shoreline
feature in the terrain dataset. The terrain was then created by combining the
topographic and bathymetric multipoint files, zero-elevation shoreline vector and
study-area boundary. The completed terrain dataset was generated with an
average point spacing of 10 feet. The terrain was then converted directly to the
final seamless DEM in order to support the overland wave modeling and coastal
hazard mapping.
Storm-induced beach erosion is well documented along the Gulf of Mexico
coastlines of Franklin County. Review of the literature showed that the standard
FEMA (2003 and 2007) Guidelines and Specifications for Flood Hazard Mapping
Partners methodology were applicable for the Gulf coast of Franklin County.
Where dunes were identified and delineated, the VE Zone was mapped up to the
extent of the Primary Frontal Dune (PFD).
Nearshore wave-induced processes, such as wave setup and wave runup,
constitute a greater part of the combined wave envelope than storm surge due to
the coast exposure to ocean waves. For this study the wave setup was included in
the storm surge modeling results.
RUNUP 2.0 was used to predict wave runup value on natural shore and then
adjusted to follow the FEMA (2005) “Procedure Memorandum No. 37” that
recommends the use of the 2% wave runup for determining base flood elevations.
For wave run-up at the crest of a slope that transitions to a plateau or downslope,
run-up values were determined using the “Methodology for wave run-up on a
hypothetical slope” as described in the FEMA (2007) Guidelines and
Specifications for Flood Hazard Mapping Partners.
Wave height calculation used in this study follows the methodology described in
FEMA’s Guidelines and Specifications for Flood Hazard Mapping Partners
(2003 and 2007). The Wave Height Analysis for Flood Insurance Studies
20
(WHAFIS) was used to propagate wave heights over land and to define the base
flood elevations for mapping. The starting wave conditions were obtained just
offshore of the shoreline from the 2D wave model SWAN as described
previously. Local land use data and aerial photography was used to define the
overland wave obstruction coefficients for input to WHAFIS. The 1% stillwater
elevations were extracted from the storm surge modeling results to define a
stillwater profile along each transect.
Figure 2, “Transect Location Map,” illustrates the location of each transect. Along
each transect, wave envelopes were computed considering the combined effects
of changes in ground elevation, vegetation and physical features. Between
transects, elevations were interpolated using topographic maps, land-use and landcover data, and engineering judgment to determine the aerial extent of flooding.
The results of the calculations are accurate until local topography, vegetation, or
cultural development within the community undergo major changes. The transect
data for the county are presented in Table 3, “Transect Descriptions,” which
describes the location of each transect. In addition, Table 3, provides the 1percent annual chance stillwater with wave setup and the maximum wave crest
elevations for each transect along coastline. In Table 4, “Transect Data,” the
flood hazard zone and base flood elevations for each transect flooding source is
provided, along with the 10-, 2-, 1-, and 0.2-percent annual chance stillwater
elevations for the respective flooding source.
TRANSECT
1
2
3
TABLE 3 - TRANSECT DESCRIPTIONS
ELEVATION (ft NAVD 88*)
MAXIMUM
1-PERCENT
1-PERCENT
ANNUAL
ANNUAL
CHANCE
CHANCE
LOCATION
STILLWATER
WAVE CREST
St. Vincent Island on the south side of the
Island, on the Gulf of Mexico coastline,
approximately 1.9 miles southeast of Indian
Pass, at N 29.671208°,
W 85.200326°
St. Vincent Island on the south side of the
Island, on the Gulf of Mexico coastline,
approximately 1.9 miles southeast of Indian
Pass, at N 29.653275 °, W 85.161028 °
St. Vincent Island on the south side of the
Island, on the Gulf of Mexico coastline,
approximately 1.2 miles west of West Pass,
at N 29.637501°,
W 85.116546 °
*North American Vertical Datum of 1988
1
Includes wave setup
21
10.31
15.4
10.01
15.0
9.61
13.6
TABLE 3 - TRANSECT DESCRIPTIONS – continued
TRANSECT
4
5
6
7
8
9
10
11
12
13
ELEVATION (ft NAVD 88*)
MAXIMUM
1-PERCENT
1-PERCENT
ANNUAL CHANCE
ANNUAL CHANCE
STILLWATER
WAVE CREST
LOCATION
St. George Island on the south side of the Island,
on the Gulf of Mexico approximately 2.2 miles
northwest of Cape St. George, at N 29.614014 °,
W 85.080509 °
St. George Island on the south side of the Island,
on the Gulf of Mexico approximately 0.7 miles
east of Cape St. George, at N 29.588593°, W
85.052237°
St. George Island on the south side of the Island,
on the Gulf of Mexico approximately 2.7 miles
east of Cape St. George, at N 29.595566°, W
85.006371°
St. George Island on the south side of the Island,
on the Gulf of Mexico approximately 0.5 miles
west of Bob Sikes Cut, at N 29.608464°, W
84.963425°
St. George Island on the south side of the Island,
on the Gulf of Mexico approximately 0.9 miles
east of Bob Sikes Cut, at N 29.617896°, W
84.952573°
St. George Island on the south side of the Island,
on the Gulf of Mexico approximately 0.3 miles
east of Cedar Point, at N 29.627655°, W
84.931225°
St. George Island on the south side of the Island,
on the Gulf of Mexico approximately 3.8 miles
west of the intersection of Franklin Blvd and West
Gulf Beach Drive, at N 29.633436°, W
84.915479°
St. George Island on the south side of the Island,
on the Gulf of Mexico approximately 3.1 miles
west of the intersection of Franklin Blvd and West
Gulf Beach Drive, at N 29.641097°, W
84.908639°
St. George Island on the south side of the Island, on
the Gulf of Mexico, approximately 1.7 miles west of
the intersection of Franklin Boulevard and West Gulf
Beach Drive at N 29.651846°, W 84.886856°
St. George Island on the south side of the Island, on
the Gulf of Mexico, approximately 0.8 miles west of
the intersection of Franklin Blvd and West Gulf
Beach Drive/West Gorrie Drive at N 29.657052°, W
84.874321°
*North American Vertical Datum of 1988
1
Includes wave setup
22
9.71
14.5
10.01
15.1
11.41
16.9
11.61
17.4
11.71
17.6
11.81
17.7
11.71
17.6
11.81
17.7
11.81
17.7
11.81
17.7
TABLE 3 - TRANSECT DESCRIPTIONS – continued
TRANSECT
14
15
16
17
18
19
20
ELEVATION (ft NAVD 88*)
MAXIMUM
1-PERCENT
1-PERCENT
ANNUAL CHANCE
ANNUAL CHANCE
STILLWATER
WAVE CREST
LOCATION
St. George Island on the south side of the Island,
on the Gulf of Mexico, approximately 0.5 miles
east of St. George Island Bridge and
approximately 0.3 miles east of the intersection of
Franklin Blvd and West Gulf Beach Drive at N
29.664852 °,
W 84.857715 °
St. George Island on the south side of the Island,
on the Gulf of Mexico, approximately 3.0 miles
east of St. George Island Bridge and
approximately 1.3 miles east of the intersection of
Franklin Boulevard and West Gulf Beach Drive at
N 29.669990°,
W 84.842897°
St. George Island on the south side of the Island,
on the Gulf of Mexico, approximately 2.9 miles
east of the intersection of Franklin Boulevard and
West Gulf Beach Drive, at N 29.676773 °, W
84.815975°
St. George Island on the south side of the Island,
on the Gulf of Mexico, approximately 0.1 mile
east of the terminus of West Gulf Drive, at N
29.684678°, W 84.795601°
St. George Island on the south side of the Island,
on the Gulf of Mexico, approximately 0.7 miles
east of the terminus of West Gulf Drive, at
N 29.688365°, W 84.787013°
St. George Island on the south side of the Island,
on the Gulf of Mexico, approximately 2.3 miles
east of the terminus of West Gulf Drive, at
N 29.700710°, W 84.765334°
St. George Island on the south side of the Island,
on the Gulf of Mexico, approximately 0.5 miles
east of East Slough and approximately 3.8 miles
east of the terminus of West Gulf Drive, at N
29.715482°, W 84.745744°
*North American Vertical Datum of 1988
1
Includes wave setup
23
11.71
17.6
11.81
17.6
12.11
18.0
12.21
18.1
12.21
18.1
12.31
18.3
12.51
18.6
TABLE 3 - TRANSECT DESCRIPTIONS – continued
ELEVATION (ft NAVD 88*)
MAXIMUM
1-PERCENT
1-PERCENT
ANNUAL CHANCE
ANNUAL CHANCE
STILLWATER
WAVE CREST
TRANSECT
LOCATION
21
St. George Island on the south side of the Island,
on the Gulf of Mexico, approximately 3.5 miles
southwest of East Pass and approximately 5.8
miles east of the terminus of West Gulf Drive, at
N 29.734914°, W 84.722059°
St. George Island on the south side of the Island,
on the Gulf of Mexico, and approximately 5.8
miles east of the terminus of West Gulf Drive, at
N 29.759575°, W 84.694180°
Dog Island on the south side of the Island, on the
Gulf of Mexico, approximately 0.2 miles east of
East Pass at N 29.779608°, W 84.667669°
Dog Island on the south side of the Island, on the
Gulf of Mexico, approximately 2.0 miles east of
East Pass at N 29.783685°, W 84.640600°
Dog Island on the south side of the Island, on the
Gulf of Mexico, approximately 4.0 miles east of
East Pass at N 29.797287°, W 84.607556°
Dog Island on the south side of the Island, on the
Gulf of Mexico, approximately 4.9 miles east of
East Pass at N 29.801521°, W 84.595611°
Dog Island on the south side of the Island, on the
Gulf of Mexico, approximately at the eastern end
of Dog Island at N 29.818682°, W 84.572877°
Dog Island on the north side of the Island, on St.
George Sound, approximately 4.2 miles east of
East Pass at N 29.805419°, W 84.608183°
St. George Island on the north side of the Island,
on St. George Sound, approximately 5.5 miles west
of East Pass, at N 29.716713°, W 84.761873°
St. George Island on the north side of the Island,
on St. George Sound, approximately 3.3 miles east
of the intersection of Franklin Boulevard and West
Gulf Drive, at N 29.680912°, W 84.811564°
22
23
24
25
26
27
28
29
30
*North American Vertical Datum of 1988
1
Includes wave setup
24
12.61
18.9
12.81
18.7
12.81
18.7
12.91
19.0
12.81
18.9
12.71
18.8
13.21
19.4
13.21
17.4
12.21
16.5
11.41
16.2
TABLE 3 - TRANSECT DESCRIPTIONS – continued
TRANSECT
ELEVATION (ft NAVD 88*)
MAXIMUM
1-PERCENT
1-PERCENT
ANNUAL CHANCE
ANNUAL CHANCE
STILLWATER
WAVE CREST
LOCATION
31
St. George Island on the north side of the Island,
on St. George Sound, approximately 0.25 miles
east of St. George Island Bridge/Franklin
Boulevard, at
N 29.668602°, W 84.861279°
32
St. George Island on the north side of the Island,
on St. George Sound, approximately 2.0 miles west
of St. George Island Bridge/Franklin Boulevard, at
N 29.655507°, W 84.895636°
33
St. George Island on the north side of the Island,
on St. George Sound, approximately 0.76 miles
east of Bob Sikes Cut, at N 29.623254 °,
W 84.948958°
36
Franklin County, approximately 1.4 miles east of
the Gulf/Franklin County Line along State Road 30
on St. Vincent Sound at N 29.695736 °,
W 85.189631°
37
Franklin County, approximately 3.5 miles east of
the Gulf/Franklin County Line along State Road 30
on St. Vincent Sound at N 29.704670°,
W 85.154186°
38
Franklin County, approximately 6.6 miles east of
the Gulf/Franklin County Line along State Road 30
at the intersection of Highway 98 on St. Vincent
Sound at N 29.715099°, W 85.109135°
39
Franklin County, approximately 8.8 miles east of
the Gulf/Franklin County Line approximately 0.5
miles past the intersection of Tilton Rd and
Highway 98 on St. Vincent Sound at N
29.715623°, W 85.074046°
40
Franklin County, approximately 1 mile west of
Green Point on Apalachicola Bay approximately
3.3 miles east of the intersection of State Road 30
and Highway 98 on St. Vincent Sound at
N 29.713534°, W 85.051057°
41
Franklin County, approximately 0.1 mile east of
the intersection of Highway 98 and Apalachee
Street, Apalachicola Bay at N 29.713597°, W
85.026952°
42
Franklin County, approximately 0.2 miles east of
the intersection of Highway 98 and Airport Road
and approximately 1.5 miles east of Green Point,
Apalachicola Bay at N 29.711766°, W 85.017986°
*North American Vertical Datum of 1988
1
Includes wave setup
25
10.91
15.0
10.11
13.5
9.41
13.5
11.91
14.1
11.91
14.2
11.91
13.9
11.51
14.4
11.31
14.1
10.91
14.7
10.81
14.6
TABLE 3 - TRANSECT DESCRIPTIONS – continued
ELEVATION (ft NAVD 88*)
MAXIMUM
1-PERCENT
1-PERCENT
ANNUAL CHANCE
ANNUAL CHANCE
STILLWATER
WAVE CREST
TRANSECT
LOCATION
43
Franklin County, at approximately the intersection
of Avenue East and 24th Avenue and just west of
the City of Apalachicola, on Apalachicola Bay at
N 29.713002°, W 85.002573°
Franklin County, at approximately the intersection
of Bay Avenue and 9th Street within the City of
Apalachicola, on Apalachicola Bay approximately
0.9 miles west of East Bay at N 29.720273°,
W 84.983227°
Franklin County, at approximately 0.3 miles north
of Highway 98 within the lower portion of the
Jackson River approximately 0.3 miles west of
East Bay within the City of Apalachicola, on
Apalachicola Bay at N 29.728406°,W 84.981528°
Franklin County, at approximately 2.7 miles
northeast of the City of Apalachicola within East
Bay near Alligator Bayou at N 29.754393°,
W 84.949170°
Franklin County, at approximately 1 mile east of
Shoal Bayou within East Bay at N 29.760914°,
W 84.912521°
Franklin County, at approximately 2.6 miles east of
Shoal Bayou within East Bay at N 29.826128°,
W 84.865078°
Franklin County, at approximately 1.9 miles
northeast of Highway 98/State Route 30 along
North Bayshore Drive on the eastern side of East
Bay at N 29.760454°, W 84.886629°
Franklin County, at approximately 4.7 miles
southeast of Highway 98/State Route 30 and 0.8
miles northwest of the St. George Island Bridge in
Apalachicola Bay at N 29.728717°,
W 84.899231°
Franklin County, at approximately 0.9 miles east of
the intersection with the St. George Island Bridge
along Highway 98/State Route 30 in St. George
Sound at N 29.738049°, W 84.873286°
44
45
46
47
48
49
50
51
*North American Vertical Datum of 1988
1
Includes wave setup
26
10.81
14.6
10.91
14.7
10.81
14.6
11.41
14.9
12.11
15.7
12.31
16.0
11.71
15.4
11.31
15.5
12.41
17.1
TABLE 3 - TRANSECT DESCRIPTIONS – continued
ELEVATION (ft NAVD 88*)
MAXIMUM
1-PERCENT
1-PERCENT
ANNUAL CHANCE
ANNUAL CHANCE
STILLWATER
WAVE CREST
TRANSECT
LOCATION
52
Franklin County, at approximately 2.0 miles east of
the intersection with the St. George Island Bridge
along Highway 98/State Route 30 in St. George
Sound at N 29.745265°, W 84.857669°
Franklin County, at approximately 3.3 miles east of
the intersection with the St. George Island Bridge
along Highway 98/State Route 30 and
approximately 0.6 miles west of Hwy 65 in St.
George Sound at N 29.751788°, W 84.841252°
Franklin County, at approximately 1.7 miles east of
the intersection with the State Road 65 along
Highway 98/State Route 30 and approximately 5.4
miles east of the intersection with the St. George
Island Bridge in St. George Sound at N
29.765065°, W 84.805307°
Franklin County, at approximately 5 miles east of
the intersection with the State Road 65 along
Highway 98/State Route 30 in St. George Sound at
N 29.793537°, W 84.759982°
Franklin County, at approximately 8.6 miles east of
the intersection with the State Road 65 along
Highway 98/State Route 30 and approximately1.9
miles west of the intersection with Northwest
Avenue A along Highway 98 in St. George Sound
at N 29.818033°, W 84.709063°
Franklin County, at approximately 2.7 miles west
of the Carrabelle River and approximately 0.4
miles west of the intersection with Northwest
Avenue A along Highway 98/State Route 30 in St.
George Sound at N 29.828544°, W 84.689726°
Franklin County, at approximately 1.4 miles west
of the Carrabelle River at Northwest Avenue A
along Highway 98/State Route 30 in St. George
Sound at N 29.829509°, W 84.681454°
Franklin County, at approximately 0.7 miles west
of the Carrabelle River at Timber Island Road
along Highway 98/State Route 30 in St. George
Sound at N 29.841774°, W 84.670859°
53
54
55
56
57
58
59
*North American Vertical Datum of 1988
1
Includes wave setup
27
12.51
17.2
12.81
17.5
13.21
18.4
13.71
19.5
14.21
20.2
14.21
20.1
14.11
19.8
14.31
20.1
TABLE 3 - TRANSECT DESCRIPTIONS – continued
Franklin County
TRANSECT
ELEVATION (ft NAVD 88*)
MAXIMUM
1-PERCENT
1-PERCENT
ANNUAL CHANCE
ANNUAL CHANCE
STILLWATER
WAVE CREST
LOCATION
60
Franklin County, approximately within the
Carrabelle City Limits at Gulf Avenue along
Highway 98/State Route 30 in St. George Sound at
N 29.844379°, W 84.656029°
61
Franklin County, approximately 1.0 miles east of
the eastern Carrabelle City Limits at the
intersection of Gulf Avenue and Highway 98/State
Route 30 in St. George Sound at N 29.847523°,
W 84.645104°
62
Franklin County, approximately 0.7 miles west of
the intersection of Lake Morality Road and
Highway 98/State Route 30 in St. George Sound at
N 29.860477°, W 84.623103°
65
Franklin County, approximately 0.5 miles west of
Anneewakee Road along Highway 98/State Route
30 and approximately 4 miles west of the
intersection with US 319/State Route 377 and
Highway 98/State Route 30 in St. George Sound at
N 29.886510°, W 84.579240°
66
Franklin County, approximately 1.7 miles west of
the intersection with US 319/SR 377 and US Hwy
98/SR 30 in St. George Sound at N 29.903950°,
W 84.544725°
67
Franklin County, approximately 1.4 miles west of
Turkey Point and at the intersection with US
319/SR 377 and Highway 98/State Route 30 in St.
George Sound at N 29.912668°, W 84.519416°
68
Franklin County, approximately 0.2 miles west of
Turkey Point and approximately 1.5 miles east of
the intersection with US 319/SR 377 and Highway
98/State Route 30 in St. George Sound at N
29.916345°, W 84.494260°
69
St. Teresa on the Gulf of Mexico coastline,
approximately 1.51 miles northeast of Turkey
Point (St. George Sound), at N 29.922999°, W
84.472955°
70
St. Teresa on the Gulf of Mexico coastline,
approximately 2.83 miles east-northeast of Turkey
Point (St. George Sound), at N 29.928797°, W
84.450676°
*North American Vertical Datum of 1988
1
Includes wave setup
28
14.61
20.5
14.61
20.4
14.71
20.6
15.01
20.9
15.01
21.0
14.91
20.7
14.61
20.3
14.61
21.8
14.51
21.6
TABLE 3 - TRANSECT DESCRIPTIONS – continued
ELEVATION (ft NAVD 88*)
MAXIMUM
1-PERCENT
1-PERCENT
ANNUAL CHANCE
ANNUAL CHANCE
STILLWATER
WAVE CREST
TRANSECT
LOCATION
71
Alligator Point Peninsula on Alligator Harbor
coastline, approximately 3.18 miles east-southeast
of Peninsula Point, at N 29.899134°, W84.392229°
Alligator Point Peninsula on the Gulf of Mexico
coastline, approximately 0.55 miles southeast of
Peninsula Point, at N 29.910641°, W 84.436185°
Alligator Point Peninsula on the Gulf of Mexico
coastline, approximately 2.30 miles southeast of
Peninsula Point, at N 29.901674°, W 84.40.7885°
Alligator Point Peninsula on the Gulf of Mexico
coastline, adjacent to the east of Chip Morrison
Drive, at N 29.893616°, W -84.376108°
Franklin County adjacent the the northeast end of
Gulfshore Boulevard, on the Gulf of Mexico, at N
29.898893°, W 84.344861°
Franklin County 0.09 miles north of the shoreline
adjacent to the intersection of Sunrise Pointe Estate
Road and Bald Point Road on the Gulf of Mexico,
at N 29.915618°, W 84.335457°
Franklin County 0.18 miles north of the shoreline
at the end of Marlin Street on the Gulf of Mexico,
at N 29.932799°, W 84.334725°
Franklin County shoreline on Ocklockonee Bay
approximately 0.58 miles southeast of the
Ocklockonee Bay Bridge, at N 29.956715°, W
84.376856°
Franklin County shoreline on Ocklockonee Bay
approximately 1.71 miles west of the Ocklockonee
Bay Bridge, at N 29.963803°, W 84.413091°
Franklin County shoreline on Ocklockonee Bay
approximately 0.77 miles southeast of Shell
Hammock, at N 29.959298°, W 84.431750°
72
73
74
75
76
77
78
79
80
*North American Vertical Datum of 1988
1
Includes wave setup
29
13.31
17.6
13.91
19.5
13.51
18.5
13.41
19.1
13.51
19.2
13.81
19.1
14.21
19.3
15.11
19.6
15.31
19.4
15.31
18.2
TABLE 4 - TRANSECT DATA
FLOODING
SOURCE
Gulf of Mexico
Gulf of Mexico
Gulf of Mexico
BASE FLOOD
STILLWATER ELEVATION (feet1 NAVD88*)
ELEVATION
TRANSECT 10-PERCENT 2-PERCENT 1-PERCENT 0.2-PERCENT ZONE (feet NAVD88*)
1
2
3
4.7
8.8
10.3
13.1
4.6
5.6
8.9
9.4
9.4
11.0
13.6
14.1
4.6
8.5
10.0
12.8
4.6
5.4
7.3
8.9
9.3
11.0
13.0
14.2
4.7
8.3
9.6
12.5
1.5
6.8
8.9
12.5
5.5
8.9
10.3
13.6
VE
AE
AE
AE
12-15
10-12
9-10
11-12
VE
AE
AE
AE
12-15
10-12
9-10
11-12
VE
AE
AE
VE
AE
VE
12-14
10-12
9-11
11
10-13
13-14
Gulf of Mexico
4
4.7
8.4
9.7
12.5
VE
AE
12-15
10-12
Gulf of Mexico
5
4.8
8.7
10.0
12.7
4.8
7.6
9.0
12.2
VE
AE
AE
12-15
10-12
9
5.5
9.9
11.4
14.4
4.8
7.7
8.9
12.0
VE
AE
AE
13-17
12-13
10-11
5.8
10.1
11.6
14.8
4.6
8.8
9.8
12.8
VE
AE
AE
13-17
13
11-12
Gulf of Mexico
Gulf of Mexico
6
7
Gulf of Mexico
8
5.8
4.8
10.2
8.4
11.7
9.7
15.0
12.8
VE
VE
AE
14-18
11-13
11
Gulf of Mexico
9
5.8
10.2
11.8
15.1
8.3
9.7
12.9
VE
AE
VE
AE
14-18
13-14
12-14
10-12
4.8
*North American Vertical Datum of 1988
1
Includes wave setup
30
TABLE 4 - TRANSECT DATA - continued
FLOODING
SOURCE
Gulf of Mexico
Gulf of Mexico
Gulf of Mexico
Gulf of Mexico
Gulf of Mexico
Gulf of Mexico
Gulf of Mexico
BASE FLOOD
STILLWATER ELEVATION (feet1 NAVD88*)
ELEVATION
TRANSECT 10-PERCENT 2-PERCENT 1-PERCENT 0.2-PERCENT ZONE (feet NAVD88*)
10
11
12
13
14
15
16
5.8
10.2
11.7
15.1
5.3
9.1
10.6
14.1
4.9
8.4
9.7
12.9
5.8
10.2
11.8
15.2
4.8
8.3
9.7
13.0
5.8
10.3
11.8
15.2
5.0
8.4
10.0
13.3
5.8
10.2
11.8
15.2
5.1
9.4
10.3
13.9
5.7
10.2
11.7
15.1
5.5
9.6
10.8
14.4
5.7
10.2
11.8
15.0
5.5
10.0
11.2
14.6
6.0
10.5
12.1
15.3
5.5
9.5
11.2
14.8
VE
AE
VE
AE
AE
14-18
11-14
12-13
11-12
10-11
VE
AE
AE
14-18
10-14
9-12
VE
AE
AE
14-18
11-14
10-11
VE
AE
AE
13-18
11-13
10-11
VE
AE
AE
VE
14-18
11-14
11-13
13
VE
AE
AE
14-18
13-14
11-12
VE
AE
AE
14-18
11-14
11-12
Gulf of Mexico
17
6.1
10.6
12.2
15.4
VE
AE
14-18
13-14
Gulf of Mexico
18
6.1
10.6
12.2
15.4
5.8
10.1
11.7
15.2
VE
AE
AE
VE
14-18
13-14
14
14-15
*North American Vertical Datum of 1988
1
Includes wave setup
31
TABLE 4 - TRANSECT DATA - continued
FLOODING
SOURCE
Gulf of Mexico
BASE FLOOD
STILLWATER ELEVATION (feet1 NAVD88*)
ELEVATION
TRANSECT 10-PERCENT 2-PERCENT 1-PERCENT 0.2-PERCENT ZONE (feet NAVD88*)
19
6.1
10.7
12.3
15.5
5.8
10.2
11.8
15.3
VE
AE
VE
AE
VE
AE
14-18
14
14
13-14
14-15
11-14
Gulf of Mexico
20
6.2
10.9
12.5
15.7
VE
AE
15-19
12-15
Gulf of Mexico
21
6.2
11.0
12.6
16.0
VE
15-19
Gulf of Mexico
22
6.2
11.1
12.8
16.3
VE
AE
VE
AE
15-19
15
15
14-15
Gulf of Mexico
23
6.2
11.1
12.8
16.3
VE
AE
VE
15-19
15
15
Gulf of Mexico
24
6.3
11.2
12.9
16.3
VE
15-19
Gulf of Mexico
25
6.2
11.1
12.8
16.2
VE
AE
15-19
13-15
Gulf of Mexico
26
6.2
11.0
12.7
16.1
VE
AE
15-19
13-15
Gulf of Mexico
27
6.3
11.4
13.2
16.5
VE
15-19
Saint George
Sound
28
6.4
11.5
13.2
16.6
VE
AE
15-16
15
Gulf of Mexico
29
5.9
10.5
12.2
15.7
VE
15-16
Gulf of Mexico
30
5.7
9.9
11.4
14.9
VE
AE
13-16
13
*North American Vertical Datum of 1988
1
Includes wave setup
32
TABLE 4 - TRANSECT DATA - continued
FLOODING
SOURCE
BASE FLOOD
STILLWATER ELEVATION (feet1 NAVD88*)
ELEVATION
TRANSECT 10-PERCENT 2-PERCENT 1-PERCENT 0.2-PERCENT ZONE (feet NAVD88*)
Gulf of Mexico
31
5.5
9.4
10.9
14.4
VE
AE
13-15
11-13
Apalachicola Bay
32
5.1
8.7
10.1
13.3
VE
AE
12-14
10-12
Apalachicola Bay
33
4.8
8.1
9.4
12.5
VE
12-14
Apalachicola Bay
34
4.7
7.6
8.8
12.0
4.7
9.3
10.5
13.0
VE
AE
AE
11-12
9-11
10-11
Saint Vincent
Sound
35
5.4
9.2
10.6
13.9
VE
12-13
Saint Vincent
Sound
36
5.9
10.3
11.9
15.1
VE
AE
14
12-14
Saint Vincent
Sound
37
5.9
10.4
11.9
15.4
2.7
2.8
4.3
5.8
VE
AE
AE
14
11-14
4
Saint Vincent
Sound
38
5.9
5.9
2.5
10.3
8.6
5.7
11.9
10.6
6.0
15.4
11.7
10.4
AE
AE
AE
12-14
10-11
5-8
Saint Vincent
Sound
39
5.8
10.0
11.5
15.1
3.7
5.4
7.4
12.7
VE
AE
AE
13-14
10-13
6-9
5.6
9.7
11.3
14.8
3.7
5.2
6.1
7.7
7.2
9.1
10.2
12.0
VE
AE
AE
AE
VE
AE
13-14
11-13
7-8
9-12
11
11
5.5
9.3
10.9
14.4
VE
AE
13-15
11-13
Saint Vincent
Sound
Apalachicola Bay
40
41
*North American Vertical Datum of 1988
1
Includes wave setup
33
TABLE 4 - TRANSECT DATA - continued
FLOODING
SOURCE
BASE FLOOD
STILLWATER ELEVATION (feet1 NAVD88*)
ELEVATION
TRANSECT 10-PERCENT 2-PERCENT 1-PERCENT 0.2-PERCENT ZONE (feet NAVD88*)
Apalachicola Bay
42
5.4
9.2
10.8
14.3
VE
AE
13-15
10-13
Apalachicola Bay
43
5.4
9.3
10.8
14.3
5.2
9.0
10.5
13.8
VE
AE
AE
VE
13-15
10-13
10-13
13-14
Apalachicola Bay
44
5.5
9.3
10.9
14.4
VE
AE
13-15
10-13
Apalachicola Bay
45
5.4
9.2
10.8
14.2
5.0
8.8
9.0
13.7
VE
AE
AE
13-15
10-13
9
5.7
9.8
11.4
14.8
3.5
5.7
7.3
10.3
2.9
5.4
6.1
7.7
VE
AE
AE
VE
AE
VE
AE
14-15
10-14
7-9
9-10
6-11
8
8
5.9
10.5
12.1
15.5
5.8
9.7
10.5
14.1
VE
AE
AE
14-16
12-14
10-11
6.0
10.7
12.3
15.5
5.2
9.8
11.2
13.8
VE
AE
AE
14-16
12-14
11
East Bay
East Bay
East Bay
46
47
48
East Bay
49
5.8
10.2
11.7
15.0
VE
AE
14-15
11-14
Apalachicola Bay
50
5.6
9.8
11.3
14.7
VE
AE
13-15
11-13
Gulf of Mexico
51
6.2
10.7
12.4
16.4
VE
AE
15-17
12-15
*North American Vertical Datum of 1988
1
Includes wave setup
34
TABLE 4 - TRANSECT DATA - continued
FLOODING
SOURCE
BASE FLOOD
STILLWATER ELEVATION (feet1 NAVD88*)
ELEVATION
TRANSECT 10-PERCENT 2-PERCENT 1-PERCENT 0.2-PERCENT ZONE (feet NAVD88*)
Gulf of Mexico
52
6.2
10.8
12.5
16.6
VE
AE
15-17
12-15
Gulf of Mexico
53
6.3
11.0
12.8
16.9
VE
AE
15-18
13-15
Gulf of Mexico
54
6.4
11.3
13.2
17.4
VE
AE
15-18
13-15
Gulf of Mexico
55
6.5
11.8
13.7
17.7
VE
AE
16-19
14-16
Gulf of Mexico
56
6.7
12.3
14.2
18.1
VE
AE
16-20
14-16
Saint George
Sound
57
6.7
12.3
14.2
18.1
5.6
9.4
10.9
13.5
5.0
7.6
8.7
10.7
VE
AE
AE
VE
AE
AE
16-20
13-16
10-13
13
10-13
8-11
6.7
12.3
14.1
18.0
6.5
11.5
13.3
16.8
5.8
9.9
11.3
14.3
VE
AE
VE
AE
VE
AE
17-20
13-17
15-16
12-15
13
11-13
6.8
12.4
14.3
18.2
6.2
8.8
11.6
15.2
VE
AE
AE
16-20
14-16
11-12
Saint George
Sound
Saint George
Sound
58
59
Saint George
Sound
60
7.0
12.7
14.6
18.5
VE
AE
17-20
15-17
Saint George
Sound
61
6.9
12.7
14.6
18.4
VE
AE
17-20
14-17
*North American Vertical Datum of 1988
1
Includes wave setup
35
TABLE 4 - TRANSECT DATA - continued
FLOODING
SOURCE
BASE FLOOD
STILLWATER ELEVATION (feet1 NAVD88*)
ELEVATION
TRANSECT 10-PERCENT 2-PERCENT 1-PERCENT 0.2-PERCENT ZONE (feet NAVD88*)
Saint George
Sound
62
7.0
12.8
14.7
18.5
VE
AE
17-21
14-17
Gulf of Mexico
63
7.0
13.0
14.9
18.6
VE
AE
17-21
15-17
Gulf of Mexico
64
7.1
13.0
14.9
18.7
VE
AE
17-21
15-17
Gulf of Mexico
65
7.1
13.1
15.0
18.7
VE
AE
17-21
15-17
Gulf of Mexico
66
7.1
13.1
15.0
18.7
VE
AE
17-21
15-17
Gulf of Mexico
67
7.0
13.0
14.9
18.6
VE
AE
17-21
15-17
Gulf of Mexico
68
6.9
12.8
14.6
18.2
VE
AE
17-20
15-17
Gulf of Mexico
69
6.9
6.9
12.5
12.2
14.61
14.61
20.5
19.7
VE
AE
17-22
15-17
Gulf of Mexico
70
6.8
6.8
12.2
10.8
14.51
14.61
18.0
18.3
VE
AE
17-22
15-17
Gulf of Mexico
71
6.4
6.4
11.6
11.7
13.31
13.31
16.5
16.6
VE
AE
15-18
13-15
Gulf of Mexico
72
6.6
6.8
12.2
11.9
13.91
14.81
17.3
18.4
VE
AE
17-21
15-16
Gulf of Mexico
73
6.8
6.6
6.6
11.8
12.1
12.2
13.51
14.01
14.01
16.8
17.4
17.4
VE
VE
AE
17-19
16-19
14-16
*North American Vertical Datum of 1988
1
Includes wave setup
36
TABLE 4 - TRANSECT DATA- continued
FLOODING
SOURCE
BASE FLOOD
STILLWATER ELEVATION (feet1 NAVD88*)
ELEVATION
TRANSECT 10-PERCENT 2-PERCENT 1-PERCENT 0.2-PERCENT ZONE (feet NAVD88*)
Gulf of Mexico
74
6.6
6.3
6.4
6.4
11.7
11.4
11.9
11.9
13.41
13.11
13.61
13.71
16.6
16.3
16.9
17.0
VE
AE
VE
AE
15-19
15
16-18
14-16
Gulf of Mexico
75
6.4
5.8
11.9
11.9
13.51
13.61
16.9
17.8
VE
AE
16-19
15-16
Gulf of Mexico
76
6.3
6.4
6.4
6.4
12.1
12.2
12.2
11.8
13.91
14.01
14.11
13.91
17.6
18.0
18.2
16.6
VE
AE
VE
AE
16-19
15-16
16-17
14-16
Gulf of Mexico
77
6.8
7.0
7.0
6.5
12.3
12.6
12.6
12.6
14.21
14.41
14.51
14.41
17.9
18.5
18.5
18.8
VE
AE
VE
AE
16-19
16-17
17
14-17
Gulf of Mexico
78
7.4
6.4
13.1
12.7
15.11
14.51
19.1
19.1
VE
AE
17-20
14-17
Gulf of Mexico
79
7.6
7.5
13.2
12.3
15.21
14.71
19.6
19.5
VE
AE
17-19
15-17
Gulf of Mexico
80
7.5
7.5
7.5
13.3
12.8
12.9
15.21
15.01
14.31
19.8
19.8
18.6
VE
AE
AE
17-18
16-17
14-15
*North American Vertical Datum of 1988
1
Includes wave setup
Users of the FIRM should also be aware that coastal flood elevations are provided
in the Summary of Stillwater Elevations (Table 2) in this report. If the elevation
on the FIRM is higher than the elevation shown in this table, a wave height, wave
runup, and/or wave setup component likely exists, in which case, the higher
elevation should be used for construction and/or floodplain management
purposes.
37
As identified in FEMA’s Guidelines and Specifications for Flood Hazard
Mapping Partners (FEMA 2003 and 2007), the coastal high hazard area (Zone
VE) is the area where wave action and/or high velocity water can cause structural
damage. It is designated on the FIRM as the most landward of the following three
points:
1)
2)
3)
The point where the 3.0 feet or greater wave height could occur;
The point where the eroded ground profile is 3.0 feet or more below the
maximum runup elevation; and
The primary frontal dune as defined in the NFIP regulations.
These three points are used to locate the inland limit of the coastal high hazard
area to ensure that adequate insurance rates apply and appropriate construction
standards are imposed, should local agencies permit building in this area.
Along each transect, wave heights and wave crest elevations were
computed considering the combined effects of changes in ground elevation,
vegetation, and physical features. Wave heights were calculated to the nearest 0.1
foot, and wave crest elevations were determined at whole-foot increments along
the transects. The calculations were carried inland along the transect until the
wave crest elevation was permanently less than 0.5 foot above the stillwater-surge
elevation or the coastal flooding met another flooding source (i.e., riverine) with
an equal water-surface elevation. The results of the calculations are accurate until
local topography, vegetation, or cultural development of the community undergo
any major changes.
It has been shown in laboratory tests and observed in field investigations that
wave heights as little as 1.5 feet can cause damage to and failure of typical Zone
AE construction. Therefore, for advisory purposes only, a Limit of Moderate
Wave Action (LiMWA) boundary has been added in coastal areas subject to wave
action. The LiMWA represents the approximate landward limit of the 1.5-foot
breaking wave.
The effects of wave hazards in the Zone AE flood zone between the Zone VE
boundary (or shoreline in areas where VE Zones are not identified) and the limit
of the LiMWA boundary are similar to, but less severe than, those in Zone VE
where 3-foot breaking waves are projected during a 1-percent annual chance
flooding event.
In areas where wave runup elevations dominate over wave heights, such as areas
with steeply sloped beaches, bluffs, and/or shore-parallel flood protection
structures, there is no evidence to date of significant damage to residential
structures by runup depths less than 3 feet. However, to simplify representation,
the LiMWA is continued immediately landward of the VE/AE boundary in areas
where wave runup elevations dominate. Similarly, in areas where the Zone VE
designation is based on the presence of a primary frontal dune or wave
overtopping, the LiMWA is also delineated immediately landward of the Zone
VE/AE boundary.
38
39
AND INCORPORATED AREAS
3.5
Vertical Datum
All FISs and FIRMs are referenced to a specific vertical datum. The vertical
datum provides a starting point against which flood, ground, and structure
elevations can be referenced and compared. Until recently, the standard vertical
datum in use for newly created or revised FISs and FIRMs was the National
Geodetic Vertical Datum of 1929 (NGVD 29). With the finalization of the North
American Vertical Datum of 1988 (NAVD 88), many FIS reports and FIRMs are
being prepared using NAVD 88 as the referenced vertical datum.
All flood elevations shown in this FIS report and on the FIRM are referenced to
NAVD 88. Structure and ground elevations in the community must, therefore, be
referenced to NAVD 88. It is important to note that adjacent communities may be
referenced to NGVD 29. This may result in differences in base flood elevations
across the corporate limits between the communities.
Prior versions of the FIS report and FIRM were referenced to NGVD 29. When a
datum conversion is effected for an FIS report and FIRM, the Flood Profiles, and
base flood elevations (BFEs) reflect the new datum values. To compare structure
and ground elevations to 1-percent annual chance flood elevations shown in the
FIS and on the FIRM, the subject structure and ground elevations must be
referenced to the new datum values.
As noted above, the elevations shown in the FIS report and on the FIRM for
Franklin County are referenced to NAVD 88. Ground, structure, and flood
elevations may be compared and/or referenced to NGVD 29 by applying a
standard conversion factor. The conversion factor to NGVD 29 is + 0.57. The
conversion between the datums may be expressed as an equation:
NGVD 29 = NAVD 88 + 0.57 feet
The BFEs shown on the FIRM represent whole-foot rounded values. For
example, a BFE of 102.4 will appear as 102 on the FIRM and 102.6 will appear as
103. Therefore, users that wish to convert the elevations in the FIS to NGVD 29
should apply the stated conversion factor(s) to elevations shown on the Flood
Profiles and supporting data tables in the FIS report, which are shown at a
minimum to the nearest 0.1 foot.
For more information on NAVD 88, see Converting the National Flood Insurance
Program to the North American Vertical Datum of 1988, FEMA Publication FIA20/June 1992, or contact the Vertical Network Branch, National Geodetic Survey,
Coast and Geodetic Survey, National Oceanic and Atmospheric Administration,
Rockville, Maryland 20910 (Internet address http://www.ngs.noaa.gov).
40
4.0
FLOODPLAIN MANAGEMENT APPLICATIONS
The NFIP encourages State and local governments to adopt sound floodplain management
programs. To assist in this endeavor, each FIS provides 1-percent annual chance floodplain
data, which may include a combination of the following: 10-, 2-, 1-, and 0.2-percent
annual chance flood elevations; delineations of the 1- and 0.2-percent annual chance
floodplains; and 1-percent annual chance floodway. This information is presented on the
FIRM and in many components of the FIS, including Flood Profiles, Floodway Data tables,
and Summary of Stillwater Elevation tables. Users should reference the data presented in
the FIS as well as additional information that may be available at the local community map
repository before making flood elevation and/or floodplain boundary determinations.
4.1
Floodplain Boundaries
To provide a national standard without regional discrimination, the 1-percent
annual chance flood has been adopted by FEMA as the base flood for floodplain
management purposes. The 0.2-percent annual chance flood is employed to
indicate additional areas of flood risk in the county. For the streams studied in
detail, the 1- and 0.2-percent annual chance floodplain boundaries have been
delineated using the flood elevations determined at each cross section.
LiDAR data is remotely sensed high resolution elevation data collected by an
airborne collection platform. The LiDAR data used to delineate coastal floodplain
boundaries for the countywide analysis was collected from May 4, 2007 to August
16, 2007. The average point spacing for this data is 0.7 m and vertical accuracy is
9.14 cm RMSEz. Floodplain boundaries for coastal areas and the Apalachicola
and Ochlockonee Rivers were delineated using these data.
For the area in the vicinity of Eastpoint, floodplain boundaries were delineated
using topographic data obtained from the Eastpoint Stormwater Management
Master Plan (NFWMD, 2010).
Floodplain delineations for approximate 1% annual chance floodplains were taken
from the existing countywide FIRM for Franklin County (FEMA, 2002).
In areas where a wave height analysis was performed, the A and V zones were
divided into whole-foot elevation zones based on the average wave crest elevation
in that zone. Where the map scale did not permit delineating zones at 1 foot
intervals, larger increments were used.
The 1- and 0.2-percent annual chance floodplain boundaries are shown on the
FIRM (Exhibit 2). On this map, the 1-percent annual chance floodplain boundary
corresponds to the boundary of the areas of special flood hazards (Zones A and
AE), and the 0.2-percent annual chance floodplain boundary corresponds to the
boundary of areas of moderate flood hazards. In cases where the 1- and 0.2-percent
annual chance floodplain boundaries are close together, only the 1-percent annual
chance floodplain boundary has been shown. Small areas within the floodplain
41
boundaries may lie above the flood elevations but cannot be shown due to
limitations of the map scale and/or lack of detailed topographic data.
For the streams studied by approximate methods, only the 1-percent annual chance
floodplain boundary is shown on the FIRM (Exhibit 2).
4.2
Floodways
Encroachment on floodplains, such as structures and fill, reduces flood-carrying
capacity, increases flood heights and velocities, and increases flood hazards in areas
beyond the encroachment itself. One aspect of floodplain management involves
balancing the economic gain from floodplain development against the resulting
increase in flood hazard. For purposes of the NFIP, a floodway is used as a tool to
assist local communities in this aspect of floodplain management. Under this
concept, the area of the 1-percent annual chance floodplain is divided into a
floodway and a floodway fringe. The floodway is the channel of a stream, plus any
adjacent floodplain areas, that must be kept free of encroachment so that the
1-percent annual chance flood can be carried without substantial increases in flood
heights. Minimum federal standards limit such increases to 1.0 foot, provided that
hazardous velocities are not produced. The floodways in this FIS are presented to
local agencies as minimum standards that can be adopted directly or that can be
used as a basis for additional floodway studies.
The floodway presented in this FIS for the Ochlockonee River was obtained from
the Wakulla County FIS (FEMA, 1986), and was computed on the basis of equal
conveyance reduction, whenever possible, from each side of the floodplain. The
results of these computations were tabulated at selected cross sections for each
stream segment for which a floodway was computed and portions applicable to this
study are shown in Table 5, “Floodway Data”.
Floodway widths were computed at cross sections. Between cross sections, the
floodway boundaries were interpolated. The results of the floodway computations
are tabulated for selected cross sections (Table 5). The computed floodways are
shown on the FIRM (Exhibit 2). In cases where the floodway and 1-percent annual
chance floodplain boundaries are either close together or collinear, only the
floodway boundary is shown.
Portions of the floodway for the Ochlockonee River extend beyond the county
boundary. The portion of the Ochlockonee River downstream of the floodway
indicated is subject to coastal storm surge. A floodway is generally not appropriate
for coastal areas flooded by coastal storm surge and therefore, are not included in
this FIS.
Encroachment into areas subject to inundation by floodwaters having hazardous
velocities aggravates the risk of flood damage, and heightens potential flood
hazards by further increasing velocities. A listing of stream velocities at selected
cross sections is provided in Table 5, "Floodway Data." In order to reduce the risk
42
of property damage in areas where the stream velocities are high, the community
may wish to restrict development in areas outside the floodway.
43
FLOODING SOURCE
CROSS
SECTION
DISTANCE
BASE FLOOD WATER SURFACE
ELEVATION
FLOODWAY
1
WIDTH2
(FEET)
SECTION
AREA
(SQUARE
FEET)
MEAN
VELOCITY
(FEET PER
SECOND)
REGULATORY
(NAVD)
WITHOUT
FLOODWAY
(NAVD)
WITH
FLOODWAY
(NAVD)
INCREASE
28,570
2.6
17
10.43
11.13
0.7
25,110
3.0
15
10.83
11.43
0.6
28,480
2.6
13
12.13
12.83
0.7
17,480
4.2
11
13.93
14.73
0.8
OCHLOCKONEE
RIVER
A
-1,970
B
630
C
10,230
D
21,630
2,000/
1,150
2,000/
700
2,000/
480
1,000/
500
1
Feet above U.S. Route 319
Total width/width within county limits
3
Elevations computed without consideration of storm surge effects from Gulf of Mexico
2
TABLE 5
FEDERAL EMERGENCY MANAGEMENT AGENCY
FRANKLIN COUNTY, FL
AND INCORPORATED AREAS
FLOODWAY DATA
OCHLOCKONEE RIVER
The area between the floodway and 1-percent annual chance floodplain boundaries
is termed the floodway fringe. The floodway fringe encompasses the portion of the
floodplain that could be completely obstructed without increasing the water-surface
elevation of the 1-percent annual chance flood by more than 1.0 foot at any point.
Typical relationships between the floodway and the floodway fringe and their
significance to floodplain development are shown in Figure 3.
FLOODWAY SCHEMATIC
45
Figure 3
5.0
INSURANCE APPLICATIONS
For flood insurance rating purposes, flood insurance zone designations are assigned to a
community based on the results of the engineering analyses. The zones are as follows:
Zone A
Zone A is the flood insurance rate zone that corresponds to the 1-percent annual
chance floodplains that are determined in the FIS by approximate methods.
Because detailed hydraulic analyses are not performed for such areas, no base flood
elevations or depths are shown within this zone.
Zone AE
Zone AE is the flood insurance rate zone that corresponds to the 1-percent annual
chance floodplains that are determined in the FIS by detailed methods. In most
instances, whole-foot base flood elevations derived from the detailed hydraulic
analyses are shown at selected intervals within this zone.
Zone AH
Zone AH is the flood insurance rate zone that corresponds to the areas of 1-percent
annual chance shallow flooding (usually areas of ponding) where average depths
are between 1 and 3 feet. Whole-foot base flood elevations derived from the
detailed hydraulic analyses are shown at selected intervals within this zone.
Zone AO
Zone AO is the flood insurance rate zone that corresponds to the areas of 1-percent
annual chance shallow flooding (usually sheet flow on sloping terrain) where
average depths are between 1 and 3 feet. Average whole-foot depths derived from
the detailed hydraulic analyses are shown within this zone.
Zone AR
Area of special flood hazard formerly protected from the 1-percent annual chance
flood event by a flood control system that was subsequently decertified. Zone AR
indicates that the former flood control system is being restored to provide
protection from the 1-percent annual chance or greater flood event.
Zone A99
Zone A99 is the flood insurance rate zone that corresponds to areas of the 1-percent
annual chance floodplain that will be protected by a Federal flood protection
system where construction has reached specified statutory milestones. No base
flood elevations or depths are shown within this zone.
46
Zone V
Zone V is the flood insurance rate zone that corresponds to the 1-percent annual
chance coastal floodplains that have additional hazards associated with storm
waves. Because approximate hydraulic analyses are performed for such areas, no
base flood elevations are shown within this zone.
Zone VE
Zone VE is the flood insurance rate zone that corresponds to the 1-percent annual
chance coastal floodplains that have additional hazards associated with storm
waves. Whole-foot base flood elevations derived from the detailed hydraulic
analyses are shown at selected intervals within this zone.
Zone X
Zone X is the flood insurance rate zone that corresponds to areas outside the 0.2percent annual chance floodplain, areas within the 0.2-percent annual chance
floodplain, and to areas of 1-percent annual chance flooding where average depths
are less than 1 foot, areas of 1-percent annual chance flooding where the
contributing drainage area is less than 1 square mile, and areas protected from the
1-percent annual chance flood by levees. No base flood elevations or depths are
shown within this zone.
Zone D
Zone D is the flood insurance rate zone that corresponds to unstudied areas where
flood hazards are undetermined, but possible.
6.0
FLOOD INSURANCE RATE MAP
The FIRM is designed for flood insurance and floodplain management applications.
For flood insurance applications, the map designates flood insurance rate zones as
described in Section 5.0 and, in the 1-percent annual chance floodplains that were studied
by detailed methods, shows selected whole-foot base flood elevations or average depths.
Insurance agents use the zones and base flood elevations in conjunction with information
on structures and their contents to assign premium rates for flood insurance policies.
For floodplain management applications, the map shows by tints, screens, and symbols, the
1- and 0.2-percent annual chance floodplains. Floodways and the locations of selected
cross sections used in the hydraulic analyses and floodway computations are shown where
applicable.
The current FIRM presents flooding information for the entire geographic area of Franklin
County. Previously, separate FIRMs were prepared for each identified flood-prone
incorporated community and the unincorporated areas of the county. Historical data
47
relating to the maps prepared for each community are presented in Table 6, "Community
Map History."
7.0
OTHER STUDIES
Information pertaining to revised and unrevised flood hazards for the unincorporated and
incorporated areas of Franklin County has been compiled into this FIS. Therefore, this FIS
supersedes all previously printed FISs and FIRMs for the unincorporated and incorporated
areas of Franklin County.
48
COMMUNITY
NAME
INITIAL
IDENTIFICATION
FLOOD HAZARD
BOUNDARY MAP
REVISIONS DATE
FIRM
EFFECTIVE DATE
Apalachicola, City of
March 30, 1973
January 30, 1976
July 18, 1983
Carabelle,
City of
Monticello
January 18, 1974
January 30, 1976
July 18, 1983
Franklin County
(Unincorporated Areas)
Monticello
Mm
January 3, 1975
April 23, 1976
July 18, 1983
FIRM
REVISIONS DATE
October 1, 1983
August 3, 1992
July 20, 1998
Mm
FEDERAL EMERGENCY MANAGEMENT AGENCY
TABLE 6
COMMUNITY MAP HISTORY
FRANKLIN COUNTY, FL
AND INCORPORATED AREAS
49
8.0
LOCATION OF DATA
Information concerning the pertinent data used in preparation of this FIS can be obtained
by contacting FEMA, Mitigation Division, Koger Center – Rutgers Building, 3003
Chamblee Tucker Road, Atlanta, Georgia 30341.
9.0
BIBLIOGRAPHY AND REFERENCES
Cardone, V. J., Greenwood, C. V., and Greenwood, J. A. (1992). “Unified Program for
the Specification of Hurricane Boundary Layer Winds Over Surfaces of Specified
Roughness,” Contract Report CERC-92-1, U. S. Army Engineer Waterways Experiment
Station, Vicksburg, MS.
Engineering Methods & Applications, Inc. (April 2001). Base Flood Elevation Analysis,
St. James Bay, Franklin County, Florida. Jacksonville, Florida.
Federal Emergency Management Agency. (1990). RUNUP 2.0. Wave Runup Assessment
Tool. Washington, D.C.
Federal Emergency Management Agency. (April 2003). Guidelines and Specifications
for Flood Hazard Mapping Partners. Appendix D: Guidance for Coastal Flooding
Analysis and Mapping. Washington, D.C.
Federal Emergency Management Agency. (August 2005). Procedure Memorandum #37,
Protocol for Atlantic and Gulf Coast Coastal Flood Insurance Studies in FY05.
Washington, D.C.
Federal Emergency Management Agency. (February 2007). Atlantic Ocean and Gulf of
Mexico Coastal Guidelines update, Final Draft. Washington, D.C.
Federal Emergency Management Agency. (July 20, 1998, Flood Insurance Rate Map;
January 18, 1983, Flood Insurance Study report). Flood Insurance Study, Franklin
County, Florida (Unincorporated Areas). Washington, D.C.
Federal Emergency Management Agency. (July 18, 1983, FIRM; January 18, 1983, FIS
Report). Flood Insurance Study, City of Apalachicola, Franklin County, Florida
(Unincorporated Areas). Washington, D.C.
Federal Emergency Management Agency. (July 18, 1983, FIRM; January 18, 1983, FIS
Report). Flood Insurance Study, City of Carrabelle, Franklin County, Florida
(Unincorporated Areas). Washington, D.C.
Federal Emergency Management Agency. (June17, 2002, Flood Insurance Rate Map;
and Flood Insurance Study report). Flood Insurance Study, Franklin County, Florida and
Incorporated Areas. Washington, D.C.
Federal Emergency Management Agency. (June 2, 1992, FIRM; June 17, 1986, FIS
Report). Flood Insurance Study, Wakulla County, Florida (Unincorporated Areas).
Washington, D.C.
50
Federal Emergency Management Agency. (Revised February 1981). Users Manual for
Wave Height Analysis. Washington, D.C.
Federal Emergency Management Agency. (Revised January 1981). Computer Model for
Determining Wave Height Elevations for Flood Insurance Studies. Washington, D.C.
Florida Department of Environmental Protection. (1998). Digital topographic files, Scale
1”=100’, Contour Interval 2 feet.
Hagen, S.C., A. Zundel, and S. Kojima. (2006). “Automatic, Unstructured Mesh
Generation for Tidal Calculations in a Large Domain”, International Journal of
Computational Fluid Dynamics, 20 (8), 593-608.
Luettich, R.A., J.J. Westerink, and N.W. Scheffner. (1992). “ADCIRC: An Advanced
Three-dimensional Circulation Model for Shelves, Coasts and Estuaries, Report 1:
Theory and Methodology of ADCIRC-2DDI and ADCIRC-3DL.” Tech. Rep. DRP-92-6,
U.S. Army Corps of Engineers. Available at: ERDC Vicksburg (WES), U.S. Army
Engineer Waterways Experiment Station (WES), ATTN: ERDC-ITL-K, 3909 Halls Ferry
Road, Vicksburg, Mississippi, 39180-6199.
Northwest Florida Water Management District. (November 2010). Eastpoint Hydrologic
– Hydraulic Analysis. Havana, Florida.
Russell, L. R. (1968). Probability Distribution for Texas Gulf Coast Hurricane Effects of
Engineering Interest. Ph.D. Thesis, Stanford University.
U.S. Army Corps of Engineers, Galveston District.
Identifying Coastal Hazard Areas. Galveston, Texas.
(June 1975).
Guidelines for
U.S. Army Corps of Engineers, Hydrologic Engineering Center. (November 1976).
HEC-2 Water Surface Profiles, Computer Program. Davis, California.
U.S. Department of Commerce, Bureau of the Census.
Population. Washington, D.C.
(2010).
2010 Census of
U.S. Department of Commerce, National Oceanic and Atmospheric Administration,
Environmental Data Service, National Climatic Center. (1978). Climate of Florida, 1978.
Asheville, North Carolina.
U.S. Department of Interior, Geological Survey, Office of Water Data Collection,
Interagency Advisory Committee on Water Data. (March 1982). Bulletin 17B,
“Guidelines for Determining Flood Flow Frequency.” Reston, Virginia.
Water Resources Council. (March 1976). Bulletin 17A, “Guideline for Determining
Flood Flow Frequency.”
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STORM SURGE COMPLETELY OVERTAKES FLOOD PROFILES
STORM SURGE COMPLETELY OVERTAKES FLOOD PROFILES