st. lucie county, florida - north carolina · 2015. 10. 1. · st. lucie county, florida and...

ST. LUCIE COUNTY, FLORIDA AND INCORPORATED AREAS

Community Name Community

Number

FORT PIERCE, CITY OF 120286

PORT ST. LUCIE, CITY OF 120287

ST. LUCIE COUNTY (UNINCORPORATED AREAS) 120285

ST. LUCIE VILLAGE, TOWN OF 120288

REVISED February 16, 2012

Federal Emergency Management Agency FLOOD INSURANCE STUDY NUMBER

12111CV000A

St. Lucie County

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 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 Flood Insurance Study may be revised and republished at any time. In addition, part of this Flood Insurance Study may be revised by the Letter of Map Revision process, which does not involve republication or redistribution of the Flood Insurance Study. It is, therefore, the responsibility of the user to consult with community officials and to check the community repository to obtain the most current Flood Insurance Study components.

Initial Countywide FIS Effective Date: August 19, 1991

First Revised Countywide FIS Date: November 4, 1992

Second Revised Countywide FIS Date: June 30, 1999

Third Revised Countywide FIS Date: February 16, 2012

i

TABLE OF CONTENTS

Page

1.0 INTRODUCTION ......................................................................................................................... 1

1.1 Purpose of Study ............................................................................................................... 1 1.2 Authority and Acknowledgments ...................................................................................... 1 1.3 Coordination ...................................................................................................................... 4

2.0 AREA STUDIED ........................................................................................................................... 4

2.1 Scope of Study .................................................................................................................. 4 2.2 Community Description .................................................................................................... 6 2.3 Principal Flood Problems .................................................................................................. 7 2.4 Flood Protection Measures ................................................................................................ 8

3.0 ENGINEERING METHODS ....................................................................................................... 8

3.1 Hydrologic Analyses ......................................................................................................... 9 3.1.1 Methods for Flooding Sources with New or Revised Analyses in Current Study ............ 9 3.1.2 Methods for Flooding Sources Incorporated from Previous Studies .............................. 11 3.2 Hydraulic Analyses ......................................................................................................... 22 3.2.1 Methods for Flooding Sources with New or Revised Analyses in Current Study .......... 22 3.2.2 Methods for Flooding Sources Incorporated from Previous Studies .............................. 23 3.3 Vertical Datum ................................................................................................................ 27

4.0 FLOODPLAIN MANAGEMENT APPLICATIONS ............................................................... 28

4.1 Floodplain Boundaries .................................................................................................... 28 4.2 Floodways ....................................................................................................................... 28

5.0 INSURANCE APPLICATIONS ................................................................................................. 36

6.0 FLOOD INSURANCE RATE MAP .......................................................................................... 37

7.0 OTHER STUDIES ....................................................................................................................... 38

8.0 LOCATION OF DATA ............................................................................................................... 38

9.0 BIBLIOGRAPHY AND REFERENCES ................................................................................... 40

ii

TABLE OF CONTENTS (continued)

FIGURES

Page

Figure 1: Transect Location Map ................................................................................................................ 25 Figure 2: Transect Schematic ...................................................................................................................... 26 Figure 3: Floodway Schematic ................................................................................................................... 36

TABLES

Table 1: Summary of Flooding Sources Presented in Current Study ........................................................... 2 Table 2: Flooding Sources Studied by Detailed Methods ............................................................................. 5 Table 3: Flooding Sources Studied by Approximate Methods ..................................................................... 6 Table 4: Summary of Discharges .................................................................................................................. 9 Table 5: Parameter Values for Surge Elevations ........................................................................................ 12 Table 6: Coastal Data Table ........................................................................................................................ 13 Table 7: Summary of Roughness Coefficients ........................................................................................... 22 Table 8: Floodway Data Table .................................................................................................................... 30 Table 9: Community Map History .............................................................................................................. 39

EXHIBITS

Exhibit 1 – Flood Profiles

Blakeslee Creek Panel 01P Panel 02P Panels 03P-04P Panels 05P-06P Panels 07P-09P Panels 10P-11P Panel 12P Panel 13P Panel 14P Panel 15P Panels 16P-17P Panels 18P-20P Panel 21P

Blakeslee Creek Tributary Canal 8 Fivemile Creek Howard Creek Moores Creek North Fork St. Lucie River North Fork St. Lucie River/Tenmile Creek Tenmile Creek Platts Branch Taylor Creek Tenmile Creek Tributary Winters Creek

Exhibit 2 – Flood Insurance Rate Map Index (Published Separately) Flood Insurance Rate Maps (Published Separately)

FLOOD INSURANCE STUDY

ST. LUCIE COUNTY, FLORIDA AND INCORPORATED AREAS

1.0 INTRODUCTION

1.1 Purpose of Study

This Flood Insurance Study (FIS) revises the previous countywide FIS, dated August 19, 1991, and updates information on the existence and severity of flood hazards in the geographic area of St. Lucie County, including the Cities of Fort Pierce and Port St. Lucie, the Town of St. Lucie Village, and the unincorporated areas of St. Lucie County (referred to collectively herein as St. Lucie County), and aids in the administration of the National Flood Insurance Act of 1968 and the Flood Disaster Protection Act of 1973. This study has developed flood-risk data for various areas of the community that will be used to establish actuarial flood insurance rates and to assist the community in its efforts to promote sound floodplain management practices. Minimum floodplain management requirements for participation in the National Flood Insurance Program (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.

The Digital Flood Insurance Rate Map (DFIRM) and FIS Report for this countywide study have been produced in digital format. Flood hazard information was converted to meet the Federal Emergency Management Agency (FEMA) DFIRM database specifications and geographic information standards and is provided in a digital format so that it can be incorporated into a local Geographic Information System and be accessed more easily by the community.

1.2 Authority and Acknowledgments

The sources of authority for this FIS report are the National Flood Insurance Act of 1968 and the Flood Disaster Protection Act of 1973.

For this revision of the countywide FIS, new hydrologic and hydraulic analyses were prepared by AECOM (the study contractor) for FEMA, under Contract No. EMA-2002-CO-011A. These analyses were completed in June 2010.

The following streams were included in these analyses:

• Blakeslee Creek • North Fork St. Lucie River• Blakeslee Creek Tributary • Platts Branch • Canal 8 • Taylor Creek • Fivemile Creek • Tenmile Creek • Howard Creek • Tenmile Creek Tributary• Moores Creek • Winters Creek

The previous countywide FIS included a detailed coastal flooding analysis on the complete coastline of St. Lucie County, where the flooding source is the Atlantic Ocean. In addition, a detailed coastal flooding analysis was performed on the Indian River and North Fork St. Lucie River, where flooding propagates inland to affect St. Lucie County.

Table 1, “Summary of Flooding Sources Presented in Current Study”, contains a chronological summary of the most recent analyses of flooding sources studied by detailed methods within St. Lucie County, the contract number under which they were performed (if known), and the communities affected by each.

Table 1: Summary of Flooding Sources Presented in Current Study

Flooding Source

Completion Date Study Contractor(s)

Contract or Inter-

Agency Agreement

No.

Communities Affected

Atlantic Ocean February 1988

Engineering Methods & Applications, Inc.1

EMW-85-C-2062

City of Fort Pierce City of Port St. Lucie

St. Lucie County Town of St. Lucie

Village

Blakeslee Creek February 1988

Engineering Methods & Applications, Inc. 1

EMW-85-C-2062

City of Port St. Lucie St. Lucie County

Blakeslee Creek Tributary

February 1988


EMW-85-C-2062


Canal 8 June 2010 AECOM EMA-2002-CO-011A

City of Fort Pierce St. Lucie County

Fivemile Creek June 2010 AECOM EMA-2002-CO-011A


Howard Creek June 2010 AECOM EMA-2002-CO-011A


Indian River February 1988


EMW-85-C-2062


St. Lucie County Town of St. Lucie

Village

Moores Creek February 1988


EMW-85-C-2062


North Fork St. Lucie River

February 1988


EMW-85-C-2062


St. Lucie County

2

3

Table 1: Summary of Flooding Sources Presented in Current Study

Contract or Inter-Flooding Completion Communities Study Contractor(s) Agency Source Date Affected Agreement

No.

Platts Branch February 1988


EMW-85-C-2062


St. Lucie River February 1988


EMW-85-C-2062 St. Lucie County

Taylor Creek February 1988


EMW-85-C-2062 St. Lucie County

Tenmile Creek February 1988


EMW-85-C-2062


Tenmile Creek Tributary June 2010 AECOM EMA-2002-

CO-011A City of Port St. Lucie

St. Lucie County

Winters Creek February 1988


EMW-85-C-2062


Various Zone A Streams June 2010 AECOM EMA-2002-

CO-011A


St. Lucie County

Various Zone A Streams

February 1988


EMW-85-C-2062 Countywide

Various Zone AH Ponds

February 1988


EMW-85-C-2062


St. Lucie County

Various Zone AO Ponds

February 1988


EMW-85-C-2062 Barrier Island

1All analyses performed by Engineering Methods & Applications, Inc. reported in August 19, 1991, FIS report for St. Lucie County and Incorporated Areas (Reference 1)

Base map information shown on this Flood Insurance Rate Map (FIRM) was derived from multiple sources. Base map information was provided in digital format by St. Lucie County and the Florida Geographic Data Library.

The coordinate system used for producing this FIRM was Transverse Mercator State Plane Florida East FIPS 0901. The horizontal datum used was NAD83 HARN, GRS1980 spheroid. 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.

4

1.3 Coordination

An initial Consultation Coordination Officer (CCO) meeting (often referred to as the Scoping meeting) is held with representatives of the communities, FEMA, and the study contractors to explain the nature and purpose of the FIS and to identify the streams to be studied by detailed methods. A final CCO (often also referred to as the Preliminary DFIRM Community Coordination, or PDCC, meeting) is held with representatives of the communities, FEMA, and the study contractors to review the results of the study.

For this revision of the countywide FIS, the initial CCO meeting was held on December 11, 2008, and attended by representatives of FEMA, St. Lucie County, all local communities, South Florida Water Management District, a local engineering company, and AECOM.

The final CCO meeting was held on March 28, 2011 to review and accept the results of this FIS. Those who attended this meeting included representatives of AECOM, FEMA, and the communities. All problems raised at that meeting have been addressed in this study.

The initial CCO date for the 1991 FIS report for St. Lucie County and incorporated areas was June 19, 1985. The final CCO date was April 18, 1990.

2.0 AREA STUDIED

2.1 Scope of Study

This FIS report covers the geographic area of St. Lucie County, Florida, including the incorporated communities listed in Section 1.1.

For the previous countywide FIS, flooding caused by overflow was studied in detail. A detailed coastal flooding analysis was also performed on the complete coastline of St. Lucie County, where the flooding source is the Atlantic Ocean. In addition, a detailed coastal flooding analysis was performed on the Indian River and North Fork St. Lucie River, where flooding propagates inland to affect St. Lucie County.

For this countywide FIS revision, re-delineation was performed for the coastal flood zones based on updated topographic data. The Primary Frontal Dune was re-delineated using updated topographic information and recent R-monument beach profile surveys from the Florida Department of Environmental Protection (Reference 2).

For this countywide FIS revision, all or portions of the following flooding sources, listed in Table 2Table 2, “Flooding Sources Studied by Detailed Methods”, were restudied and/or newly studied by detailed methods. Newly studied flooding sources were selected with priority given to all known flood hazard areas, and areas of projected development and proposed construction. The scope and methods of this study were proposed to and agreed upon by FEMA and St. Lucie County.

Table 2: Flooding Sources Studied by Detailed Methods

Flooding Source Reach Length (miles)

Study Limits

Atlantic Ocean 21 Entire St. Lucie County shoreline of Atlantic Ocean.

Indian River (Intracoastal Waterway)

21 Entire St. Lucie County shoreline of Indian River.

Blakeslee Creek 1.4 From confluence with north Fork St. Lucie River to a point approximately 1.2 miles upstream of confluence with North Fork St. Lucie River.

Blakeslee Creek Tributary 1.0

From confluence with Blakeslee Creek to a point approximately 200 feet downstream of Southbend Boulevard.

Canal 8 1.9 From confluence with Fivemile Creek to Sunrise Boulevard.

Fivemile Creek 4.2 From confluence with North Fork St. Lucie River to State Highway 68.

Howard Creek 1.5 From confluence with North Fork St. Lucie River to U.S. Highway 1.

Moores Creek 2.0 From Indian River Drive to 29th Street.

North Fork St. Lucie River 12.9

From the St. Lucie/Martin County boundary to a point approximately 1,030 feet upstream of 25th Street.

Platts Branch 1.4 From confluence with North Fork St. Lucie to a point approximately 290 feet upstream of U.S. Highway 1.

Taylor Creek 2.4 From confluence with Canal C-1 to a point approximately 235 feet upstream of Fairwinds Drive.

Tenmile Creek 3.7 From confluence with North Fork St. Lucie River to McCarty Road.

Tenmile Creek Tributary 2.2

From confluence with Tenmile Creek to a point approximately 1,400 feet upstream of Newell Road.

Winters Creek 1.3 From confluence with North Fork St. Lucie River to a point approximately 8,500 feet upstream of confluence with North Fork St. Lucie River.

Various Zone AH Ponds 52.81 Countywide

Various Zone AO Ponds 16.51 East of Ocean Drive and SR A1A

1 Units are square miles

5

Selected streams were studied by approximate methods, as indicated in Table 3, “Flooding Sources Studied by Approximate Methods”. Approximate analyses were used to study those areas having a low development potential or minimal flood hazards.

Table 3: Flooding Sources Studied by Approximate Methods

Flooding Source Reach Length (miles)

Study Limits

Moores Creek 0.9 From 29th Street to a point approximately 5,000 feet upstream of 29th Street.

Platts Branch 0.7 From a point approximately 290 feet upstream of U.S. Highway 1 to a point approximately 3,000 feet upstream of U.S. Highway 1.

Taylor Creek 3.5 From a point approximately 235 feet upstream of Fairwinds Drive to State Highway 713.

Tenmile Creek 1.4 From McCarty Road to S Header Canal Road.

Winters Creek Tributary 0.6

From a point approximately 390 feet upstream of the confluence with Winters Creek to a point approximately 1,300 feet upstream of SE Via Tesoro.

For this countywide FIS revision, a total of 6.9 stream miles were newly studied using detailed methods, and a total of 7.1 stream miles were newly studied using approximate methods. Floodplain boundaries of streams and ponding areas that had been previously studied by detailed and approximate methods were re-delineated (restudied) based on more detailed and up-to-date topographic information.

This countywide FIS revision reflects a vertical datum conversion from the National Geodetic Vertical Datum of 1929 (NGVD29) to the North American Vertical Datum of 1988 (NAVD88).

2.2 Community Description

St. Lucie County is located on the south-central Atlantic coast of Florida, approximately 120 miles north of Miami. St. Lucie County is bordered on the north by Indian River County; on the east by the Atlantic Ocean; on the south by Martin County; and on the west by Okeechobee County. The county encompasses an area of 688 square miles which includes 116 square miles of water.

St. Lucie County has a mild, subtropical climate, with average temperatures in the City of Fort Pierce ranging from 62.6 degrees Fahrenheit (°F) in January to 81.7 °F in July and August for the period 1971–2000 (Reference 3). Average annual rainfall is approximately 54 inches with September as the wettest month, averaging 7.81 inches of rainfall. Most rain falls from June through October. Rainfall is primarily associated with summer thunderstorms and so is of short duration; however, rains of longer duration can be associated with the passage of tropical storms and hurricanes (Reference 3).

6

The county physiography is divided into three major regions (Reference 4). In the southwest is the Osceola Plain, with elevations ranging from approximately 30 to 60 feet NAVD88. The Atlantic Coastal Ridge is a narrow zone along the Indian River reaching elevations of 60 feet NAVD88. The bulk of the county lies in the Eastern Valley between these two zones, where elevations range from about 15 to 30 feet NAVD88. A barrier island system ranges from a few hundred feet to three-fourths mile wide with elevations ranging from sea level to about 16 feet NAVD88 at dune crests (Reference 4).

The 2008 population of St. Lucie County was estimated to be 265,108 (Reference 5). In the last three decades of the 1900s, the population of the county grew by 279.1%. In 2008, retail trade was the largest of 20 major economic sectors in St. Lucie County. Citrus production has historically been important in this region, but hurricanes, freezes, citrus diseases and pests, competition with Brazil, and population growth reduced the citrus acreage in St. Lucie County by 32% from 1990 to 1995 (Reference 6). St. Lucie County is served by Interstate 95, U.S. Route 1, the Sunshine State Parkway (also known as the Florida Turnpike), and Florida East Coast Railway.

The county seat of St. Lucie County is the City of Fort Pierce, which had a year 2000 population reported as 50,574 (including adjacent Census Designated Places). St. Lucie County also includes the City of Port St. Lucie (population 93,944 including the adjacent Census Designated Place) and the Town of St. Lucie Village (population 604) (Reference 5) .

Major natural drainage features include Tenmile and Fivemile Creeks which feed into North Fork St. Lucie River, draining areas of the Eastern Valley. Much of the region is also affected by extensive canal systems operated by three agencies: the South Florida Water Management District, the North St. Lucie River Water Management District, and the Fort Pierce Farms Water Management District. Three major canals, C-23, C-24, and C-25, divide the county into four general regions: north, west, south, and east-central. The latter portion, bounded by C-24 to the south and west and by C-25 to the north, includes the North St. Lucie Water Control District which is divided by a complex network of secondary canals. To the north is the Fort Pierce Farms District, also with a pervasive secondary system. These canals help retain needed water for agriculture during winter (low rainfall) months, and provide some degree of control over drainage at normal frequency levels; however, they are not designed for the control of area-wide flooding at the 1-percent-annual-chance level.

The area lying between U.S. Route 1 and the coastal ridge, and extending from Fort Pierce southward into Martin County is known as the Savannahs. This wetlands complex consists of a series of freshwater lakes, ponds, and marshes and is a recreational center for the county.

2.3 Principal Flood Problems

Flooding in St. Lucie County results from two major sources: rainfall runoff causing overflow of streams, ponding, and sheetflow; and hurricane storm surge causing extreme water levels in coastal and tidal regions. Wave action which accompanies northeasters can also cause coastal flooding and serious erosion, although extreme (1-percent-annual-chance flood) levels are not to be expected from such storms. Major rainfall events can occur with hurricanes, tropical storms, northeasters, or localized thunderstorms. Due to the flatness of

7

the terrain, many inland areas are characterized by shallow flooding and ponding after heavy rainfall (References 7 and 8).

The flood of September 20-22, 1985, affected large areas of St. Lucie County. Over a four-day period, 14 inches of rain were recorded in the City of Fort Pierce, with about half falling during a seven-hour period over the night of September 20, 1985. Flooding of streets and houses was widespread, especially in the central area around Fivemile and Tenmile Creeks, where large numbers of residents were evacuated from their homes. Flood elevations during this storm approximated 1-percent-annual-chance levels and greater in many areas (References 9 and 10).

On October 17, 1995, an estimated 13 inches of rain fell in the county, flooding 12 homes and most roadways in the southern part of the county. Total damage was estimated near $4 million (Reference 7). Hurricane Frances crossed Florida in September 2004, causing widespread flooding of roads, residences and businesses in coastal communities (Reference 11). When Tropical Storm Fay hit Florida on August 19, 2008, rainfall amounts from 10 to 15 inches fell over St. Lucie County as well as Martin, Okeechobee, and Indian River Counties. Property damage estimates were $67 million (Reference 11). In December 2009, a South Florida Water Management Rain Gage recorded a 24-hour total of nearly 13 inches, which caused extensive flooding to roadways, lowlands, and urban areas (Reference 11).

2.4 Flood Protection Measures

Extensive canal systems extend throughout St. Lucie County. Canals C-23, C-24, and C-25 constructed by the U.S. Army Corps of Engineers (USACE), and the drainage systems of the South Florida, Fort Pierce Farms, and North St. Lucie River Water Management Districts provide regulation of flows at the 10-percent-annual-chance flood level. They do not control floods of 1-percent-annual-chance severity, although the durations of such severe floods may be reduced by the enhanced drainage they offer.

3.0 ENGINEERING METHODS

For the flooding sources studied by detailed methods in the community, standard hydrologic and hydraulic study methods were used to determine the flood-hazard data required for this study. Flood events of a magnitude that is 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 that equals or exceeds the 1-percent-annual-chance flood in any 50-year period is approximately 40 percent (4 in 10); 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 community at the time of completion of this study. Maps and flood elevations will be amended periodically to reflect future changes.

8

3.1 Hydrologic Analyses

3.1.1 Methods for Flooding Sources with New or Revised Analyses in Current Study

For this countywide study, hydrologic analyses were carried out to establish peak discharge frequency relationships for each flooding source studied by detailed and approximate methods affecting the community. A summary of peak discharge-drainage area relationships for streams studied by detailed methods is shown in Table 4, “Summary of Discharges”.

Table 4: Summary of Discharges

Flooding Source and Location

Drainage Area

(Sq. Mi.)

Peak Discharges (CFS) 10-percent 2-percent 1-percent 0.2-percent

BLAKESLEE CREEK At confluence with North Fork St. Lucie River * 2,163 ** 3,405 ** About 5,500 feet upstream of confluence 0.8 232 ** 463 ** BLAKESLEE CREEK TRIBUTARY About 1,500 feet upstream of mouth * 306 ** 610 ** CANAL 8 At confluence with Fivemile Creek 0.7 136.5 197.7 217.4 264.7 At 35th Street 0.5 99.8 118.2 121.8 130.0 At 25th Street 0.3 80.6 90.6 97.1 115.0 At Admiral Street 0.1 52.4 78.3 81.9 91.7 FIVEMILE CREEK At confluence with North Fork St. Lucie River 11.4 1,325 2,178 2,634 3,808 At Edwards Road 9.5 1,182 1,944 2,350 3,391 At State Road 70 4.9 798 1,320 1,591 2,289 At Whiteway Dairy Road 3.4 636 1,054 1,268 1,823 At Peterson Road 1.8 401 670 805 1,160 HOWARD CREEK At confluence with North Fork St. Lucie River 2.3 1,491 2,137 2,356 3,034 At Ballantrae Boulevard 2.2 1,437 2,057 2,266 2,917 Just upstream of Westmoreland Boulevard 0.8 617 867 950 1,222 At U.S. Highway 1 0.5 380 536 588 750 MOORES CREEK At mouth 3.4 786 1,276 1,536 2,186 At 17th Street 2.4 522 858 1,034 1,497 At 25th Street 1.8 450 741 890 1,283 *Total drainage area for Blakeslee Creek, Blakeslee Creek Tributary, and Winters Creek is approximately 18.6 square miles. **Data not available

9

10

Table 4: Summary of Discharges

Flooding Source and Location

Drainage Peak Discharges (CFS) Area

(Sq. Mi.) 10-percent 2-percent 1-percent 0.2-percent

NORTH FORK ST. LUCIE RIVER At Kitching Cove 260.5 8,960 14,370 17,580 25,580 At Mud Cover (downstream Port St. Lucie Boulevard) 150.3 4,560 7,420 9,090

13,520

At Prima Vista Boulevard 117.0 4,620 7,490 9,150 13,490 PLATTS BRANCH At Sunrise Boulevard 1.6 324 537 645 925 At Oleander Boulevard 1.4 281 470 564 809 At U.S. Highway 1 0.8 174 292 350 507 TAYLOR CREEK At Canal C-1 (Ft. Pierce Farms) 4.3 510 848 1,024 1,489 At St. Lucie Boulevard 3.5 412 690 833 1,214 At Dirt Road 1.5 231 390 470 689 TENMILE CREEK At confluence of Fivemile Creek 87.8 3,940 6,410 7,820 11,560 At Sunshine State Parkway 61.4 3,070 5,010 6,110 9,010 At Eleven Mile Road 56.3 2,890 4,710 5,750 8,470 At McCarty Road 36.3 2,010 3,300 4,020 5,940 TENMILE CREEK TRIBUTARY At mouth 17.2 1,370 2,254 2,733 4,000 At McCarty Road 15.9 2,166 3,231 3,711 4,923 At Midway Road 3.3 584 874 1,009 1,331 About 1,400 feet upstream of Midway Road (at Dirt Road) 2.9 558 835 962 1,259 About 2,000 feet downstream of Newell Road 2.4 453 678 780 1,021 WINTERS CREEK At confluence with North Fork St. Lucie River * 1,185 ** 1,865 ** *Total drainage area for Blakeslee Creek, Blakeslee Creek Tributary, and Winters Creek is approximately 18.6 square miles. **Data not available

Hydrologic calculations for new detailed riverine studies in this countywide revision were performed using the HEC-HMS 3.3 computer program (Reference 12) except Canal 8 which was performed using the Inter-Connected Pond Routing Program (ICPR) (Reference 13). These new detailed hydrologic calculations for this countywide revision include Howard Creek, Tenmile Creek Tributary, and Canal 8. The respective flooding sources were subdivided into areas and routing sections of sufficient detail so that frequency flows of 10-, 2-, 1-, and 0.2-percent-annual-chance could be calculated. For all flooding sources in St. Lucie County, studied by this methodology, standard Soil Conservation Service (SCS) methods

were used, with the exception of using a peaking factor of 256 in lieu of the standard 484 peaking factor (References 14 and 15). This variation was adopted to account for the difference in terrain between the SCS default terrain and the terrain in St. Lucie County (gently rolling hills and flat areas with slight slopes, respectively). The rainfall parameters of the modeled events were based on guidance and documentation from the South Florida Water Management District (SFWMD) (Reference 16).

3.1.2 Methods for Flooding Sources Incorporated from Previous Studies

This section describes the methodology used in previous studies of flooding sources incorporated into this FIS that were not revised for this countywide revision. Hydrologic analyses were carried out to establish peak discharge-frequency relationships for each flooding source studied by detailed methods affecting the community. A summary of peak discharge-drainage area relationships for streams studied by detailed methods is shown in Table 4, “Summary of Discharges”.

The 10-, 2-, 1-, and 0.2-percent-annual-chance discharges for riverine flooding sources were determined using regional regression equations (Reference 17). Adjustments were made to discharges of basins more than 10-percent urbanized to account for faster runoff and lower infiltration rates (Reference 18). Basins containing extensive small-canal systems were treated in a similar fashion in order to account for enhanced runoff. This treatment produced results consistent with the C-25 Canal Basin Hydrologic Study (Reference 19).

Discharges for Blakeslee Creek, Blakeslee Creek Tributary, and Winters Creek were determined for the 10- and 1-percent-annual-chance floods only. The drainage basins for these streams are regulated by canals, weirs, detention ponds, and other control structures. The discharges were calculated by routing the 10- and 1-percent-annual-chance floods, determined previously for southwest Port St. Lucie on the west side of the Sunshine State Parkway, to the outfalls of the respective streams on the east side of the Parkway (Reference 20).

For the Savannahs, the 10-day, 1-percent-annual-chance storm, with adjustments for infiltration and evaporation, was determined to provide the total ponding volume (Reference 7). Ponding surface elevations were estimated using topographic maps (Reference 21).

Inundation from the Atlantic Ocean, the Indian River, and North Fork St. Lucie River caused by passage of storms (storm surge) was determined by the joint probability method (Reference 22). The storm populations were described by probability distributions of five parameters that influence surge heights. These parameters were central pressure depression, which measures the intensity of the storm; radius to maximum winds; forward speed of the storm; shoreline crossing point; and crossing angle. These characteristics were described statistically based on an analysis of observed storms in the vicinity of St. Lucie County. The primary source of data for this analysis was Hurricane Climatology for the Atlantic and Gulf Coasts of the United States (Reference 8). A summary of the parameters used for the area is presented in Table 5, “Parameter Values for Surge Elevations”.

11

12

Table 5: Parameter Values for Surge Elevations

Parameter Assigned Values Central pressure depression (millibars) 18.9 32.6 46.4 60.1 73.9 87.6 101.4 115.1

Probability1 0.274 0.358 0.181 0.092 0.047 0.024 0.012 0.012

Storm radius to maximum winds (nautical miles) 13 28

Probability 0.523 0.477

Forward speed (knots) 7.5 16.5

Probability2 0.617 0.383

Direction of storm path (degrees from true north)

111

ENTERING 174

238

Probability2 0.283 0.360 0.357

Frequency of storm occurrence (storm/nautical mile/year) 0.00455

1 Average of entering, alongshore, and exiting 2 Probabilities for entering data taken from Brevard County, Florida, FIS. All values not used in this study.

For areas subject to flooding directly from the Atlantic Ocean, Indian River, and the North Fork St. Lucie River, the FEMA standard storm surge model was used to simulate the coastal surge generated by any chosen storm (that is, any combination of the five storm parameters defined previously). By performing such simulations for a large number of storms, each of known total probability, the frequency distribution of surge height can be established as a function of coastal location. These distributions incorporate the large-scale surge behavior, but do not include an analysis of the added effects associated with much finer scale wave phenomena, such as wave height or runup. As the final step in the calculations, the astronomic tide for the region is then statistically combined with the computed storm surge to yield recurrence intervals of total water level (References 23 and 24). The storm surge elevations for the 10-, 2-, 1-, and 0.2-percent-annual-chance floods have been determined for the Atlantic Ocean, the Indian River, and North Fork St. Lucie River. A listing of the transect location, stillwater starting elevations, and initial wave crest elevations are shown in Table 6, “Coastal Data Table”. The analyses reported herein reflect the stillwater elevations due to tidal and wind setup effects and include the contributions from wave action effects.

Wave setup was determined to significantly contribute to the total stillwater flood levels along the coastline of St. Lucie County. The amount of wave setup was calculated using methodology outlined in the Shore Protection Manual (Reference 25).

Table 6: Coastal Data TableTable 6: Coastal Data Table

Community Name

Description Latitude &

Longitude at Start of Transect

Starting Stillwater Elevations (feet NAVD 88)Range of Stillwater Elevations (feet NAVD88)

Zone Designation

and BFE (feet NAVD

88)1

Transect 10% Annual Chance

2% Annual Chance

1% Annual Chance

0.2% Annual Chance

Unincorporated St. Lucie County 1

From the Atlantic Coastline, about 1,100 feet south of the Indian River/St. Lucie County boundary, extending west

(27.5544, -80.3204)

2.5 4.5 7.62 7.5 VE 10-143

AE 8-10


From the Atlantic Coastline, about 1.8 miles south of the Indian River/St. Lucie County boundary, extending west

(27.5322, -80.3135)

2.5 4.5 7.62 7.5 VE 10-143

AE 8-10

Unincorporated St. Lucie County

3


(27.5145, -80.3067)

2.4 4.4 7.52 7.3 VE 10-143

AE 8-10



(27.5069, -80.3031)

2.4 4.4 7.52 7.3 VE 10-143

AE 8-10


From the Atlantic Coastline, about 1.7 miles north of the north jetty at Fort Pierce Inlet, extending west

(27.4969, -80.299) 2.4 4.4 7.52 7.3 VE 10-133

AE 8-10


From the Atlantic Coastline, about 0.8 mile north of the north jetty at Fort Pierce Inlet, extending west

(27.4835, -80.2947)

2.4 4.4 7.52 7.3 VE 10-133

AE 8-10

1 Rounded to nearest foot and may include effects of wave action; base flood elevations may represent average elevations for zones 2 Includes the effect of wave setup 3 Includes the effect of wave run up

Table 6: Coastal Data Table (Cont.)

1 Rounded to nearest foot and may include effects of wave action; base flood elevations may represent average elevations for zones 2 Includes the effect of wave setup 3 Includes the effect of wave run up

Community Name



Starting Stillwater Elevations (feet NAVD 88) Zone Range of Stillwater Elevations (feet NAVD88) Designation

and BFE (feet NAVD

88)1

Transect 10% 2% 1% 0.2% Annual Chance

Annual Chance

Annual Annual Chance Chance


From the Atlantic Coastline, just north of the north jetty at Fort Pierce Inlet, extending west

(27.4739, -80.2898) 2.4 4.4 7.52 7.2

VE 10-133

AE 8-10

Fort Pierce, City of 8

From the Atlantic Coastline, about 2,500 feet south of the south jetty at Fort Pierce Inlet, extending west

(27.4633, -80.2883)

2.4 1.7-2.4

4.4 3.1-4.4

7.52 3.7-7.5

7.2 5.1-7.2

VE 6-13 AE 5-10


From the Atlantic Coastline, about 1.3 miles south of the south jetty at Fort Pierce Inlet, extending west

(27.4531, -80.2844)

2.4 4.4 7.52 7.2 VE 10-133

AE 8-10

Fort Pierce, City of

10

From the Atlantic Coastline, about 2.2 miles south of the south jetty at Fort Pierce Inlet, extending west

(27.4401, -80.2795)

2.5 1.7-2.5

4.5 3.2-4.5

7.62 3.8-7.6

7.3 5.3-7.3

VE 10-13 AE 4-10


From the Atlantic Coastline, about 4,200 feet south of Pete Stones Creek, extending west

(27.4106, -80.2681)

2.5 1.7-2.5

4.5 3.1-4.5

7.72 4.1-7.7

7.4 5.7-7.4

VE 10-13 AE 5-10


From the Atlantic Coastline, east of the intersection of Middle Cove Access Road and State Road A1A, extending west

(27.3997, -80.2639)

2.5 1.7-2.5

4.5 3.4-4.5

7.72 4.1-7.7

7.4 5.7-7.4

VE 10-13 AE 5-10


1 Rounded to nearest foot and may include effects of wave action; base flood elevations may represent average elevations for zones 2 Includes the effect of wave setup

Community Name




and BFE (feet NAVD

88)1


Annual Chance



From the Atlantic Coastline, about 1,800 feet north of the State Road A1A bridge over Blind Creek, extending west

(27.3689, -80.248)

2.6 1.8-2.6

4.6 3.6-4.6

7.82 4.7-7.8

7.5 5.9-7.5

VE 10-13 AE 5-10


From the Atlantic Coastline, about 2,700 feet south of Big Mud Creek on State Road A1A, extending west

(27.3496, -80.238)

2.6 4.6

7.82 5.7-7.8

7.5 VE 8-13 AE 6-10


15 From the Atlantic Coastline, extending west across Herman Bay

(27.3407, -80.2338)

2.6 4.6

7.82 5.6-7.8

7.5 VE 10-13 AE 6-10


16 From the Atlantic Coastline, about 4.7 miles north of the St. Lucie/Martin County boundary, extending west

(27.3264, -80.2282)

2.7 4.6

7.92 5.7-7.9

7.6 VE 10-13 AE 7-10



(27.3032, -80.2182)

2.7 4.6 7.92 7.6 VE 10-13 AE 8-10



(27.2883, -80.2115)

2.7 4.6 7.92 7.6 VE 10-13 AE 8-10


1 Rounded to nearest foot and may include effects of wave action; base flood elevations may represent average elevations for zones 2 Includes the effect of wave setup

Community Name




and BFE (feet NAVD

88)1


Annual Chance



19 From the Atlantic Coastline, about 2,800 feet north of the St. Lucie/Martin County boundary, extending west

(27.2702, -80.203)

2.8 4.7

8.02 6.0-8.0

7.7 VE 8-14 AE 6-10


From the Indian River east bank at Big Starvation Cove, about 1,600 feet south of the Indian River/St. Lucie County boundary, extending east

(27.5526, -80.3278)

1.4 2.6 3.1 4.2 VE 6 AE 4-6


From the Indian River west bank, about 3,200 feet south of Indian River/St. Lucie County boundary, extending west

(27.549, -80.3533)

1.4 2.6 3.1 4.2 VE 6 AE 4-6


From the Indian River east bank, just south of the confluence of Blue Hole Creek, extending east

(27.5438, -80.337)

1.5 2.8 3.4 4.5 VE 6 AE 4-6


From the Indian River west bank, about 6,000 feet north of the northern corporate limits of the Town of St. Lucie Village, extending west

(27.529, -80.3481)

1.5 2.8 3.4 4.5 VE 6 AE 4-6

Unincorporated St. Lucie County 24 From the Indian River east bank

at Garfield Cut, extending east

(27.518, -80.3282)

1.6 3.0 3.6 4.9 VE 6-7 AE 4-6


1 Rounded to nearest foot and may include effects of wave action; base flood elevations may represent average elevations for zones

Community Name




and BFE (feet NAVD

88)1


Annual Chance


St. Lucie Village, Town of 25

From the Indian River west bank, about 1,200 feet south of the northern corporate limits, of the Town of St. Lucie Village, extending west

(27.5097, -80.343)

1.7 3.1 3.8 5.1 VE 6-7 AE 4-6


From the Indian River east bank, at Old Inlet, extending east

(27.5043, -80.3233)

1.7 3.1 3.8 5.1 VE 6-7 AE 4-6

St. Lucie Village, Town of 27

From the Indian River west bank, near Chamberlain Boulevard, extending west

(27.4898, -80.336)

1.8 3.3 4.1 5.6 VE 7-8 AE 5-7


From the Indian River east bank, about 1,200 feet north of the confluence of Snapper Cut, extending east

(27.4908, -80.322)

1.8 3.3 4.1 5.6 VE 7-8 AE 5-7

St. Lucie Village, Town of

29

From the Indian River west bank, about 200 feet north of Yacht View Lane, extending west

(27.484, -80.3342)

2.0 3.6 4.4 6.0 VE 7-8 AE 5-7


30 From the Indian River east bank, at the confluence of St. Lucie Cut, extending east

(27.4827, -80.3181)

2.0 3.6 4.4 6.0 VE 7-8 AE 5-7



Community Name




and BFE (feet NAVD

88)1


Annual Chance



31 From the Fort Pierce Inlet coastline, at Coon Island, extending east

(27.4703, -80.3063)

1.9 3.4 4.1 5.6 VE 7-8 AE 5-7


32 From the Indian River Coastline, on the north side of Causeway Island, extending south

(27.461, -80.3157)

1.9 3.4 4.1 5.6 VE 7-8 AE 5-7


33 From the Indian River east bank on Causeway Island, about 1,000 feet south of State Road A1A, extending east

(27.4584, -80.3111)

1.7 3.1 3.7 5.1 VE 6-7 AE 4-6


34 From the Indian River west bank, about 100 feet south of State Road A1A extending west

(27.4696, -80.3297)

1.7 3.1 3.7 5.1 VE 6-7 AE 4-6


35 From the Indian River east bank, about 200 feet north of Sunset Isles Road, extending east

(27.4505, -80.2896)

1.7 3.1 3.7 5.1 VE 6-7 AE 4-6


36 From the Indian River east bank, about 0.8 mile south of Jennings Cove, extending east

(27.4345, -80.2969)

1.7 3.2 3.8 5.3 VE 6-7 AE 4-6



Community Name




and BFE (feet NAVD

88)1


Annual Chance



37 From the Indian River west bank, about 4,500 feet north of the Fort Pierce/St. Lucie County boundary, extending west

(27.4219, -80.3136)

1.7 3.4 3.9 5.4 VE 6-7 AE 4-6


38 From the Indian River east bank, about 4,200 feet south of Pete Stones Creek, extending east

(27.4069, -80.2764)

1.8 3.4 4.1 5.7 VE 7-8 AE 5-7


From the Indian River west bank, about 1.0 mile north of the intersection of State Road 707 and State Road 712, extending west

(27.3943, -80.3011)

1.8 3.6 4.3 5.9 VE 7-8 AE 5-7


40

Fran the Indian River east bank, about 2,000 feet south of Middle Cove, extending east

(27.3953, -80.2636)

1.8 3.6 4.3 5.9 VE 7-8 AE 5-7


41

From the Indian River east bank, about 1.0 mile north of the confluence of Big Mud Creek, extending east

(27.3649, -80.2604)

1.8 3.9 4.7 6.3 VE 7-8 AE 5-7


42

From the Indian River west bank, about 2.2 miles north of the northern corporate limits of the City of Port St. Lucie, extending west

(27.3454, -80.2772)

1.8 4.0 4.9 6.6 VE 7-9 AE 5-7



Community Name




and BFE (feet NAVD

88)1


Annual Chance



From the Indian River east bank, about 3,000 feet south of Herman Bay Point, extending east

(27.3427, -80.2536)

1.8 4.0 4.9 6.6 VE 7-9 AE 5-7


44

From the Indian River east bank, at Herman Bay, extending east

(27.3402, -80.2377)

1.8 4.2 5.1 6.9 VE 8-9 AE 6-8


45

From the Indian River east bank, about 1.2 miles south of Herman Bay, extending east

(27.324, -80.2304)

1.8 4.4 5.4 7.2 VE 8-10 AE 6-8


46

From the Indian River east bank, about 1.5 miles north of Nettles Island, extending east

(27.3045, -80.2232)

1.8 4.4 5.4 7.2 VE 8-10 AE 6-8


47

From the Indian River east bank, at Nettles Island, extending east

(27.2858, -80.2275)

1.9 4.6 5.7 7.6 VE 8-10 AE 6-8


48

From the Indian River west bank, about 1.0 mile north of the St. Lucie/Martin County boundary, extending west

(27.276, -80.2422)

1.9 4.6 5.7 7.6 VE 8-10 AE 6-8



Community Name



Starting Stillwater Elevations (feet NAVD 88)Range of Stillwater Elevations (feet NAVD88)

Zone Designation

and BFE (feet NAVD

88)1

Transect 10% Annual Chance

2% Annual Chance

1% Annual Chance

0.2% Annual Chance


49

From the Indian River east bank, about 0.47 mile north of the St. Lucie/Martin County Boundary, extending east

(27.2695, -80.2092)

1.9 4.9 6.0 8.0 VE 9-10 AE 6-9


50

From the Indian River west bank, about 1,000 feet north of the St. Lucie/Martin County boundary, extending west

(27.2654, -80.2352)

1.9 4.9 6.0 8.0 VE 9-10 AE 6-8

22

3.2 Hydraulic Analyses

Analyses of the hydraulic characteristics of flooding from the sources 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. Flood elevations shown on the FIRM are primarily intended for flood insurance rating purposes. For construction and/or floodplain management purposes, users are cautioned to use the flood elevation data presented in this FIS in conjunction with the data shown on the FIRM.

Flood profiles were drawn showing the computed water-surface elevations for floods of the selected recurrence intervals. 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).

Roughness coefficients (Manning's “n” values) used in the hydraulic copmutations were chosen by engineering judgment and based on field observation of the channel and floodplain areas (References 26 - 28). Table 7, “Summary of Roughness Coefficients”, contains the channel and overbank "n" values for the streams studied by detailed methods.

Table 7: Summary of Roughness Coefficients

Flooding Source Channel Overbanks

Non-revised streams 0.015 – 0.06 0.06 – 0.19

Canal 8 0.028 – 0.05 0.05 – 0.125

Fivemile Creek 0.04 0.08

Howard Creek 0.028 – 0.07 0.10 – 0.15

Tenmile Creek Tributary 0.028 – 0.05 0.11 – 0.125

The hydraulic analyses for this study were based on unobstructed flow. The flood elevations shown on the Flood Profiles (Exhibit 1) are thus considered valid only if hydraulic structures remain unobstructed, operate properly, and do not fail.

3.2.1 Methods for Flooding Sources with New or Revised Analyses in Current Study

Cross sections for the backwater analyses were obtained from field surveys and U.S. Geological Survey (USGS) topographic maps. All bridges and culverts were field checked to obtain elevation data and structural geometry of waterway crossings.

For the streams studied in detail, Fivemile Creek, Howard Creek and Tenmile Creek Tributary, water surface elevations for floods of the selected recurrence

23

intervals were developed using the HEC-RAS computer program (Reference 29). Downstream boundary conditions for the hydraulic models were set to normal depth using a starting slope calculated from values taken from topographic data, or where applicable, derived from the water surface elevation of existing effective flood elevations. The dynamic hydraulic routing for Canal 8 water surface elevation calculations was performed using the ICPR program, version 3.10 (Reference 13).

3.2.2 Methods for Flooding Sources Incorporated from Previous Studies

For areas subject to stream overflow flooding, water-surface elevations were computed using the HEC-2 water-surface profile computer program (Reference 30). Starting water-surface elevation for most streams and tributaries was normal depth.

Cross sections for the backwater analysis of all streams studied in detail were obtained from field surveys and topographic maps (Reference 21). All bridges, dams, and culverts were surveyed to obtain elevation and structural geometry data.

A gated control structure on North Fork St. Lucie River at Gordy Road was modeled to reflect the actual conditions encountered during the flood of September 1985.

Hydraulic analyses considering storm characteristics and the shoreline and bathymetric characteristics of the flooding sources studied were also carried out to provide estimates of the elevations of floods of the selected recurrence intervals along each of the shorelines.

The FEMA storm surge model was utilized to simulate the hydrodynamic behavior of the surge generated by the various synthetic storms (References 23 and 24). This model utilizes a grid pattern approximating the geographical features of the study area and the adjoining areas. Surges were computed utilizing grids of 5 x 5 nautical miles and 0.5 x 1 nautical miles, depending on the resolution required. Estimates of land cover type and density for flow resistance calculations were made with the aid of aerial photos and site inspection.

Using the FEMA storm surge model, storms representative of those capable of producing 1-percent-annual-chance levels at the mouth of Fort Pierce Inlet were simulated. For each storm, the surge height outside the inlet was compared with the known 1-percent-annual-chance surge level (5.5 feet) without tide. Since the peak surge is linearly proportional to the central pressure depression, the central pressures for those storms were then scaled to obtain the storm central pressure capable of producing the 1-percent-annual-chance surge levels (5.5 feet outside the inlet). Using these central pressures, the corresponding probabilities were obtained subsequently from the pressure density frequency curve. For each simulated storm, ratios of surge height at selected points within the inlet to surge height outside the inlet were computed. These ratios were then weighted according to the relative probabilities of the corresponding storms obtained,

24

given the 1-percent-annual-chance surge transfer function between the open coast and the interior points in the vicinity of the inlet. Surge along the Indian River north of Fort Pierce Inlet was then determined by simple interpolation between values at the inlet and values obtained from the FIS for Indian River County, Florida (Reference 31). Similarly, surge along the Indian River south of the inlet was obtained by interpolation using the data obtained from the FIS for Martin County, Florida (Reference 32). Values on North Fork St. Lucie River at the St. Lucie-Martin County boundary were obtained from the FIS for Martin County, Florida, and used for this study since no appreciable gradient of elevation is to be expected in that area. On the open coast, values obtained from the FIS for Indian River County, Florida, were adopted between Fort Pierce Inlet and the northern boundary; values obtained from the FIS for Martin County, Florida, were interpolated from the inlet south to the boundary values.

Underwater depths and land heights for the model grid systems were obtained from topographic maps, nautical charts, and surveyed transects (References 21, 33, and 34).

The methodology for analyzing the effects of wave heights associated with coastal storm surge flooding is described in a report prepared by the National Academy of Sciences (NAS) (Reference 35). This method is based on the following major concepts. First, depth-limited waves in shallow water reach a maximum breaking height that is equal to 0.78 times the stillwater depth. The wave crest is 70 percent of the total wave height above the stillwater level. The second major concept is that wave height may be diminished by dissipation of energy due to the presence of obstructions, such as sand dunes, dikes and seawalls, buildings, and vegetation. The amount of energy dissipation is a function of the physical characteristics of the obstruction and is determined by procedures prescribed in the NAS report. The third major concept is that wave height can be regenerated in open fetch areas due to the transfer of wind energy to the water. This added energy is related to fetch length and depth.

Wave heights were computed along transects (cross-section lines) that were located along the coastal areas, as illustrated in Figure 1, “Transect Location Map”. 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, they were spaced at large 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 (References 34 and 36)

Each transect was taken perpendicular to the shoreline and extended inland to a point where wave action ceased. Along each transect, wave heights and elevations were computed considering the combined effects of changes in ground

26

elevation, vegetation, and physical features. The stillwater elevations for the 1-percent-annual-chance flood were used as the starting elevations for these computations. Wave heights were calculated to the nearest 0.1 foot, and wave elevations were determined at whole-foot increments along the transects. The location of the 3-foot breaking wave for determining the terminus of the V zone (area with velocity wave action) was computed at each transect.

Also, along the open coast, the V zone designation applies to all areas seaward of the heel of the primary dune system. Table 6, “Coastal Data Table”, provides a listing of the transect locations and stillwater starting elevations, as well as initial wave crest elevations.

Dune erosion was taken into account along the Atlantic Coastline. The amount of dune erosion was calculated using methodology established by FEMA (Reference 36).

In addition to the wave height analysis, wave runup was examined along the Atlantic Coastline and computed using the FEMA runup model (Reference 37).

Figure 2, “Transect Schematic”, represents a sample transect that illustrates the relationship between the stillwater elevation, the wave crest elevation, the ground elevation profile, and the location of the V/A zone boundary.

Figure 2: Transect Schematic

After analyzing wave heights along each transect, wave elevations were interpolated between transects. Various source data were used in the interpolation, including topographic maps, beach profiles, aerial photographs, and engineering judgment (References 21, 38, and 39). Controlling features affecting the elevations were identified and considered in relation to their positions at a particular transect and their variation between transects.

27

3.3 Vertical Datum

All FIS reports 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 used for newly created or revised FIS reports and FIRMs was the NGVD29. With the completion of the NAVD88, many FIS reports and FIRMs are now prepared using NAVD88 as the referenced vertical datum.

Flood elevations shown in this FIS report and on the FIRM are referenced to the NAVD88. These flood elevations must be compared to structure and ground elevations referenced to the same vertical datum. It is important to note that adjacent counties may be referenced to NGVD29, which may result in differences in base flood elevations across county lines.

Some of the data used in this revision were taken from the prior effective FIS reports and FIRMs and adjusted to NAVD88. The datum conversion factor from NGVD29 to NAVD88 in St. Lucie County is -1.44 feet.

Ground, structure, and flood elevations may be compared and/or referenced to NGVD29 by adding 1.44 feet to the NAVD88 elevation. The -1.44 foot value is an average for the entire county. The BFEs shown on the FIRM represent whole-foot rounded values. For example, a BFE of 12.4 feet will appear as 12 feet on the FIRM and 12.6 feet as 13 feet. Users who wish to convert the elevations in this FIS report to NGVD29 should apply the stated conversion factor 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 regarding conversion between the NGVD29 and NAVD88, see the FEMA publication entitled Converting the National Flood Insurance Program to the North American Vertical Datum of 1988 (Reference 40), visit the National Geodetic Survey website at www.ngs.noaa.gov, or contact the National Geodetic Survey at the following address:

NGS Information Services NOAA, N/NGS12 National Geodetic Survey SSMC-3, #9202 1315 East-West Highway Silver Spring, Maryland 20910-3282 (301) 713-3242

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 the FIS report and FIRM for this community. Interested individuals may contact FEMA to access these data.

28

To obtain current elevation, description, and/or location information for benchmarks shown on this map, please contact the Information Services Branch of the NGS at (301) 713-3242, or visit their website at www.ngs.noaa.gov.

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 report 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 a 1-percent-annual-chance floodway. This information is presented on the FIRM and in many components of the FIS report, including Flood Profiles, Floodway Data tables, and Summary of Stillwater Elevation tables. Users should reference the data presented in the FIS report 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 community. For each stream studied by detailed methods, the 1- and 0.2-percent-annual-chance floodplain boundaries have been delineated using the flood elevations determined at each cross section. Between cross sections, the boundaries were interpolated using contours with 1 foot intervals, derived from LiDAR data (Reference 41). For streams studied by approximate methods, the 1-percent-annual-chance floodplain boundaries were interpolated using contours with 1 foot intervals, derived from LiDAR data (Reference 41).

The 1- and 0.2-percent-annual-chance floodplain boundaries for streams studied by detailed methods 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, AE, AO, AH and VE), 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 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 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

29

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 base flood can be carried without substantial increases in flood heights. Minimum Federal standards limit such increases to 1 foot, provided that hazardous velocities are not produced. The floodways in this study 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 floodways presented in this study were computed for certain stream segments on the basis of equal-conveyance reduction from each side of the floodplain. 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 and provided in Table 8, “Floodway Data.” The computed floodway is 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 on the FIRM.

For Canal 8, it was decided that no floodway would be determined due to flood water flow rates in the canal being affected by storage areas located away from the canal.

Near the confluence of streams studied in detail, floodway computations were made without regard to flood elevations on the receiving water body. Therefore, “Without Floodway” elevations for several cross sections presented in Table 8, "Floodway Data” are shown as having lower elevations than the regulatory flood elevations for that area, which must take into account the 1-percent-annual-chance flooding due to backwater from other sources. Considering the Atlantic Ocean storm surge effect, the Howard Creek profile was developed using a joint probability method (Reference 42).

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. To reduce the risk of property damage in areas where the stream velocities are high, the community may wish to restrict development in areas outside the floodway.

FLOODING SOURCE FLOODWAY BASE FLOOD WATER SURFACE ELEVATION

CROSS SECTION DISTANCE WIDTH (FEET)

SECTION AREA

(SQUARE FEET)

MEAN VELOCITY (FEET PER SECOND)

REGULATORY(FEET NAVD)

WITHOUT FLOODWAY (FEET NAVD)

WITH FLOODWAY (FEET NAVD)

INCREASE (FEET)

BLAKESLEE CREEK

A 2,1501 284 1,586 2.1 6.0 2.13 3.1 1.0 B 5,5401 34 112 4.1 6.0 0.83 1.3 0.5

BLAKESLEE CREEK

TRIBUTARY

A 1,4902 173 1,002 3.4 6.0 4.03 5.0 1.0 B 3,9102 108 692 4.9 7.7 7.63 8.5 0.9

FIVEMILE CREEK

A 2,9001 334 1,861 1.4 9.0 7.73 8.7 1.0 B 5,9541 76 632 3.7 9.0 8.73 9.7 1.0 C 9,5601 71 524 3.8 10.7 10.7 11.2 0.5 D 11,7861 48 449 4.4 11.8 11.8 12.1 0.3 E 13,7861 68 473 3.4 12.9 12.9 13.1 0.2 F 17,5631 237 839 1.5 15.8 15.8 16.5 0.7 G 20,3591 197 1,115 0.7 16.0 16.0 17.0 1.0 H 20,6471 182 1,474 0.6 16.0 16.0 16.9 0.9 I 22,0751 179 1,542 0.5 16.0 16.0 17.0 1.0

1 FEET ABOVE CONFLUENCE WITH NORTH FORK ST. LUCIE RIVER 2 FEET ABOVE CONFLUENCE WITH BLAKESLEE CREEK 3 ELEVATIONS WITHOUT CONSIDERING STORM SURGE EFFECTS FROM ATLANTIC OCEAN

TAB

LE 8

FLOODWAY DATA

BLAKESLEE CREEK – BLAKESLEE CREEK TRIBUTARY – FIVEMILE CREEK

FEDERAL EMERGENCY MANAGEMENT AGENCY

ST. LUCIE COUNTY, FL AND INCORPORATED AREAS



SECTION AREA

(SQUARE FEET)





INCREASE (FEET)

HOWARD CREEK

A 2,8891 191 1,261 1.9 6.0 2.23 2.3 0.1 B 6,5051 95 549 4.1 6.1 4.83 5.3 0.5 C 8,2961 153 883 2.4 6.7 6.63 7.4 0.8 D 10,5461 81 553 2.7 9.0 9.0 9.9 0.9 E 11,3571 190 2,370 0.6 9.3 9.3 10.1 0.8 F 12,8701 51 169 5.6 10.2 10.2 10.8 0.6 G 14,0441 46 244 3.9 12.0 12.0 12.2 0.2

MOORES CREEK

A 2102 60 207 7.4 3.7 -1.54 -0.5 1.0 B 3792 41 178 8.6 3.7 0.84 0.8 0.0 C 4892 34 197 7.8 3.7 1.34 1.3 0.0 D 6262 36 167 9.2 3.7 1.44 1.4 0.0 E 7622 32 132 11.6 3.7 1.34 1.3 0.0 F 1,0492 36 201 7.6 4.7 4.24 4.2 0.0 G 1,3282 48 234 6.6 5.4 5.34 5.4 0.1 H 1,9532 173 1,133 1.4 7.9 7.9 8.5 0.6 I 2,1032 169 807 1.9 7.9 7.9 8.5 0.6 J 3,0722 150 470 2.9 8.1 8.1 9.1 1.0 K 3,4222 100 201 6.8 8.6 8.6 9.2 0.6

1 FEET ABOVE CONFLUENCE WITH NORTH FORK ST. LUCIE RIVER 2 FEET ABOVE CONFLUENCE WITH INDIAN RIVER 3 ELEVATIONS WITHOUT CONSIDERING STORM SURGE EFFECTS FROM ATLANTIC OCEAN 4 ELEVATIONS WITHOUT CONSIDERING STORM SURGE EFFECTS FROM INDIAN RIVER

TAB

LE 8

FLOODWAY DATA

HOWARD CREEK – MOORES CREEK





SECTION AREA

(SQUARE FEET)





INCREASE (FEET)

MOORES CREEK

L 3,7111 52 305 4.5 9.5 9.5 10.5 1.0 M 3,8721 44 229 6.0 10.0 10.0 10.8 0.8 N 5,2751 35 191 6.3 12.8 12.8 13.2 0.4 O 5,6251 40 217 5.5 13.9 13.9 14.1 0.2 P 5,9751 35 207 5.8 15.1 15.1 15.2 0.1 Q 6,6751 35 212 4.9 16.7 16.7 16.7 0.0 R 8,7001 37 243 3.7 19.6 19.6 20.1 0.5 S 9,3421 139 413 2.2 20.5 20.5 21.4 0.9 T 10,6921 101 406 2.2 21.0 21.0 22.0 1.0

NORTH FORK ST. LUCIE RIVER

A 3.002 1,641 9,523 1.8 6.0 -3.63 -2.6 1.0 B 3.862 2,342 4,839 3.6 6.0 -2.73 -1.9 0.8 C 4.812 1,961 6,369 1.4 6.0 -1.63 -1.0 0.6 D 5.442 1,006 4,745 1.9 6.0 -1.43 -1.0 0.4 E 5.912 1,218 3,717 2.4 6.0 -1.13 -0.7 0.4 F 6.412 1,139 3,496 2.6 6.0 -0.73 -0.3 0.4 G 7.342 1,376 4,385 2.1 6.0 -0.23 0.1 0.3 H 8.102 2,454 5,660 1.6 6.0 0.23 0.5 0.3 I 9.422 1,373 3,165 2.9 6.0 0.83 1.1 0.3

1 FEET ABOVE CONFLUENCE WITH INDIAN RIVER 2 MILES ABOVE COUNTY BOUNDARY 3 ELEVATIONS WITHOUT CONSIDERING STORM SURGE EFFECTS FROM ATLANTIC OCEAN

TAB

LE 8

FLOODWAY DATA

MOORES CREEK – NORTH FORK ST. LUCIE RIVER





SECTION AREA

(SQUARE FEET)





INCREASE (FEET)

NORTH FORK ST.

LUCIE RIVER

J 10.911 776 3,737 2.4 6.1 2.23 2.6 0.4 K 11.381 440 4,882 1.9 6.1 2.63 3.0 0.4 L 12.261 1,988 9,527 1.0 6.1 3.03 3.4 0.4 M 13.071 900 5,187 1.8 6.2 3.23 3.6 0.4 N 13.831 222 2,048 4.5 6.2 3.63 4.1 0.5 O 14.321 1,293 6,680 1.4 6.4 4.73 5.1 0.4 P 15.011 699 2,793 3.3 6.6 5.33 5.8 0.5 Q 15.571 473 2,565 3.6 7.1 6.43 7.2 0.8 R 15.941 874 6,475 1.4 7.8 7.43 8.1 0.7 S 16.741 752 5,040 1.6 8.3 8.13 9.0 0.9 T 17.281 776 4,453 1.8 8.8 8.73 9.6 0.9

PLATTS BRANCH

A 2,2002 30 158 4.1 8.2 2.03 3.0 1.0 B 3,4152 39 259 2.2 8.2 6.33 7.2 0.9 C 6,4032 31 128 2.7 9.7 9.7 10.3 0.6

1 MILES ABOVE COUNTY BOUNDARY 2 FEET ABOVE CONFLUENCE WITH NORTH FORK ST. LUCIE RIVER 3 ELEVATIONS WITHOUT CONSIDERING STORM SURGE EFFECTS FROM ATLANTIC OCEAN

TAB

LE 8

FLOODWAY DATA

NORTH FORK ST. LUCIE RIVER – PLATTS BRANCH





SECTION AREA

(SQUARE FEET)





INCREASE (FEET)

TAYLOR CREEK

A 5001 47 256 4.0 9.4 9.4 9.5 0.1 B 2,7801 57 332 3.1 10.9 10.9 10.9 0.0 C 3,7901 50 249 3.3 11.3 11.3 11.3 0.0 D 8,0061 164 852 1.0 14.8 14.8 15.4 0.6 E 10,0061 170 671 1.2 15.1 15.1 15.7 0.6 F 12,9061 195 697 0.7 16.3 16.3 17.3 1.0

TENMILE CREEK

U 18.062 705 5,840 1.3 9.7 9.7 10.6 0.9 V 18.542 497 2,538 3.1 10.3 10.3 11.1 0.8 W 19.402 403 2,761 2.8 12.6 12.6 13.4 0.8 X 20.152 499 4,517 1.7 13.9 13.9 14.8 0.9 Y 20.702 536 3,339 1.8 14.6 14.6 15.5 0.9 Z 20.782 330 3,968 1.5 14.8 14.8 15.8 1.0

AA 20.842 373 3,358 1.8 16.1 16.1 16.8 0.7 AB 21.732 423 3,797 1.6 16.5 16.5 17.2 0.7 AC 22.502 510 2,077 2.9 16.8 16.8 17.6 0.8 AD 23.012 694 4,169 1.5 17.7 17.7 18.4 0.7 AE 23.532 710 4,536 1.3 18.0 18.0 18.8 0.8 AF 24.152 702 3,399 1.7 18.3 18.3 19.3 1.0 AG 24.812 425 1,861 2.2 18.8 18.8 19.8 1.0 AH 25.492 424 1,614 2.5 19.5 19.5 20.5 1.0

1 FEET ABOVE MOUTH

2 MILES ABOVE COUNTY BOUNDARY

TAB

LE 8

FLOODWAY DATA

TAYLOR CREEK – TENMILE CREEK





SECTION AREA

(SQUARE FEET)





INCREASE (FEET)

TENMILE CREEK

TRIBUTARY

A 1,7001 130 795 3.4 18.6 17.23 18.2 1.0 B 4,2001 135 1,165 2.3 18.6 17.93 18.9 1.0 C 5,2411 450 1,757 2.1 18.6 18.2 19.2 1.0 D 6,4111 750 3,020 1.2 19.2 19.2 20.0 0.8 E 7,9301 780 2,554 0.4 20.5 20.5 21.1 0.6 F 10,2221 450 1,767 0.4 20.6 20.6 21.3 0.7 G 11,5001 690 2,446 0.3 20.7 20.7 21.4 0.7 H 12,1231 666 2,052 0.1 20.7 20.7 21.5 0.8 I 12,7731 632 1,543 0.1 20.7 20.7 21.5 0.8

WINTERS CREEK

A 2,1502 102 715 2.6 6.0 1.54 2.5 1.0 B 6,2102 83 504 3.7 6.0 4.64 5.6 1.0

1 FEET ABOVE MOUTH 2 FEET ABOVE CONFLUENCE WITH NORTH FORK ST. LUCIE RIVER 3 ELEVATIONS WITHOUT CONSIDERING BACKWATER EFFECTS FROM TENMILE CREEK 4 ELEVATIONS WITHOUT CONSIDERING STORM SURGE EFFECTS FROM ATLANTIC OCEAN

TAB

LE 8

FLOODWAY DATA

TENMILE CREEK TRIBUTARY – WINTERS CREEK



36

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 (WSEL) of the base flood more than 1 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”.

Figure 3: Floodway Schematic

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. These 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 report by approximate methods. Because detailed hydraulic analyses are not performed for such areas, no base (1-percent-annual-chance) flood elevations (BFEs) 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 report by detailed methods. Whole-foot BFEs derived from the detailed hydraulic analyses are shown at selected intervals within this zone.

37

Zone AH

Zone AH is the flood insurance rate zone that corresponds to areas of 1-percent-annual-chance shallow flooding (usually areas of ponding) where average depths are between 1 and 3 feet. Whole-foot BFEs derived from the detailed hydraulic analysis are shown at selected intervals within this zone.

Zone AO

Zone AO is the flood insurance rate zone that corresponds to 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 base flood depths derived from the detailed hydraulic analysis 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 that have additional hazards associated with storm waves. Whole-foot BFEs 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 0.2-percent-annual-chance floodplain, areas within the 0.2-percent-annual-chance floodplain, 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 (sq. mi.), and areas protected from the base flood by levees. No BFEs or depths are shown within this zone.

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 BFEs or average depths. Insurance agents use zones and BFEs 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.

The current FIRM presents flooding information for the entire geographic area of St. Lucie County. Previously, FIRMs were prepared for each incorporated community and the unincorporated areas of the County identified as flood-prone. This countywide FIRM also includes flood-hazard information that was presented separately on Flood Boundary and

38

Floodway Maps (FBFMs), where applicable. Historical data relating to the maps prepared for each community are presented in Table 9, “Community Map History”.

7.0 OTHER STUDIES

An FIS report was previously prepared for St. Lucie County and incorporated areas (Reference 1). Prior to that countywide study, FIS reports were prepared for the Cities of Fort Pierce and Port St. Lucie, for the Town of St. Lucie Village, and for the unincorporated areas of St. Lucie County (References 43 - 46).

FIS reports were previously prepared for the unincorporated and incorporated areas of Indian River County and Martin County, and for the unincorporated areas of Okeechobee County (31, 47, and 48).

This FIS report supersedes or is compatible with all previous studies published on streams studied in this report and should be considered authoritative for the purposes of the NFIP.

8.0 LOCATION OF DATA

Information concerning the pertinent data used in the preparation of this study can be obtained by contacting Federal Insurance and Mitigation Division, FEMA Region IV, Koger-Center — Rutgers Building, 3003 Chamblee Tucker Road, Atlanta, GA 30341.

COMMUNITY NAME

INITIAL IDENTIFICATION

FLOOD HAZARD BOUNDARY MAP REVISIONS DATE

FIRM EFFECTIVE DATE

FIRM REVISIONS DATE

Fort Pierce, City of May 24, 1974 August 27, 1976 December 1, 1977 October 1, 1983 January 5, 1984

Port St. Lucie, City of December 13, 1974 April 9, 1976 March 15, 1982 None

St. Lucie County (Unincorporated Areas) January 24, 1975 None August 17, 1981 October 1, 1983

January 5, 1984

St. Lucie Village, Town of November 29, 1974 June 11, 1976 April 1, 1980 None

TAB

LE 9



COMMUNITY MAP HISTORY

40

9.0 BIBLIOGRAPHY AND REFERENCES

1. Federal Emergency Management Agency. Flood Insurance Study, St. Lucie County, Florida, And Incorporated Areas. Washington, D.C., August 19, 1991.

2. Florida Department of Environmental Protection, Bureau of Beaches and Coastal Systems. Geographic Information Systems Data. Florida Department of Environmental Protection. [Online] 2009. www.dep.state.fl.us/beaches/data/gis-data.htm.

3. Southeast Regional Climate Center. Historical Climate Summaries for Florida: City of Fort Pierce. [Online] [Cited: March 26, 2010.] http://www.sercc.com/climateinfo/historical/historical_fl.html.

4. U.S. Department of Agriculture, Soil Conservation Service. Soil Survey of St. Lucie County, Florida. March 1980.

5. U.S. Department of Commerce, Bureau of the Census. "State & County Quickfacts, Florida Quicklinks". [Online] [Cited: March 1, 2010.] Available http://quickfacts.census.gov/qfd.

6. Blokland, Jackie K. White and P.J. Van. Trends in Florida Citrus with Emphasis on Indian River, St. Lucie, Martin, and Palm Beach Counties. EDIS, Publication #FE636. [Online] University of Florida, IFAS Extension, June 2006. [Cited: March 26, 2010.] http://edis.ifas.ufl.edu/fe636.

7. U.S. Department of the Army, Corps of Engineers, Jacksonville District. Survey Report: Analysis of Hurricane Problems in Coastal Areas of Florida. Unpublished.

8. U.S. Department of Commerce, National Oceanic and Atmospheric Administration. Technical Report NWS 38: Hurricane Climatology for the Atlantic and Gulf Coasts of the United States. April 1987.

9. Lindahl, Browning & Hellstrom, Inc. September 21, 1985 Flood Profile. September 1985.

10. The News Tribune. Residents couldn't believe it was happening. The News Tribune. September 22, 1985.

11. U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Climate Data Center. "Storm Events". [Online] [Cited: March 26, 2010.] http://www4.ncdc.noaa.gov.

12. U.S. Department of the Army, Corps of Engineers, Hydrologic Engineering Center. HEC-HMS Hydrologic Modeling System 3.30. Davis, CA, October 9, 2008.

13. Singhofen, Peter J., P.E. Inter-Connected Pond Routing Progam, version 3.10. 2002.

14. U.S. Department of Agriculture, Natural Resources Conservation Service. Technical Release 55 - Urban Hydrology for Small Watersheds. June 1986.

41

15. U.S. Department of Commerce, National Oceanic and Atmospheric Administration. Unit Hydrograph Technical Manual. National Weather Service - National Operational Hydrologic Remote Sensing Center. [Online] October 12, 2008. [Cited: June 1, 2009.] http://www.nohrsc.noaa.gov/technology/gis/uhg_manual.html.

16. South Florida Water Management District, Water Resource Divison. Frequency Analysis of One and Three-Day Rainfall Maxima for Central and Southern Florida. October, 1990.

17. U.S. Department of the Interior, Geological Survey, in cooperation with the Florida Department of Transportation. Water Resources Investigations 82-4012: Technique for Estimating Magnitude and Frequency of Floods on Natural-Flow Streams in Florida. 1982.

18. U.S. Department of the Interior, Geological Survey. Water Supply Paper 2207: Flood Characteristics of Urban Wateshed in the United States. Washington, D.C., 1984.

19. Camp, Dresser & McKee, Inc. C-25 Canal Basin Hydrologic Study. Fort Lauderdale, Florida, 1985.

20. Reynolds, Smith and Hills, Inc. Southwest Port St. Lucie Water Management Plan. s.l., March 1979.

21. U.S. Department of the Interior, Geological Survey. 7.5 Minute Series Topographic Maps, Scale 1:24000, Contour Interval 5 feet. : Palm City, FL (1948, photorevised 1970); Indiantown NW, FL (1953, photorevised 1970); Okeechobee 4 NE, FL (1953, photorevised 1970); Okeechobee 4 NW, FL (1953, photorevised 1970); Eden, FL (1948, photorevised 1970); Ankona, FL (1948, photorevised 1983); Fort Pierce SW, FL (1953, photorevised 1970); Okeechobee 1 SE, FL (1953, photorevised 1970); Okeechobee 1 SW, FL (1953, photorevised 1970); Fort Pierce, FL (1949, photorevised 1970); Fort Pierce NW, FL (1950, photorevised 1970); Okeechobee 1 NE, FL (1953, photorevised 1970); Okeechobee 1 NW, FL (1953, photorevised 1970); Indrio, FL (1948, photorevised 1970); Oslo, FL (1949, photorevised 1970); Fellsmere 4 SE, FL (1953, photorevised 1970); Fellsmere 4 SW, FL (1953, photorevised 1970).

22. U.S. Department of Commerce, Environmental Science Services Administration. Technical Memorandums WBTM Hydro II: Joint Probability Method of Tide Frequency Analysis Applied to Atlantic City and Long Beach Island, New Jersey. : Vance A. Myers, April 1970.

23. Federal Emergency Management Agency. Coastal Flooding - Hurricane Storm Surge Model: Methodology Volume 1. Washington, D.C., August 1988.

24. —. Coastal Flooding Hurricane Storm Surge Model: User's Manual Volume 2. Washington, D.C., August 1988.

25. U.S. Department of the Army, Corps of Engineers. Shore Protection Manual. 1984.

26. Chow, Ven Te. Open Channel Hydraulics. New York : McGraw-Hill, 1959.

42

27. U.S. Department of Agriculture, Soil Conservation Service. Guide for Selecting Roughness Coefficient "n" Values for Channels. December 1963.

28. U.S. Department of Transportation, Federal Highway Administration. Guide for Selecting Manning's Roughness Coefficients for Natural Channels and Flood Plains. April 1984.

29. U.S. Department of the Army, Corps of Engineers, Hydrologic Engineering Center. HEC-RAS 3.1.3. Davis, CA, May 2005.

30. —. HEC-2 Water Surface Profiles, Generalized Computer Program 723-X6-L202A. Davis, California, April 1984.

31. Federal Emergency Management Agency. Flood Insurance Study, Indian River County, Florida, and Incorporated Areas. Washington, D.C., May 4, 1989.

32. —. Flood Insurance Study, Martin County, Florida, Unincorporated Areas. Washington, D.C., January 1984.

33. U.S. Department of Commerce, National Oceanic and Atmospheric Administration. Nautical Charts. No. 11474 (March 1980); No. 11472 (October 1984).

34. Federal Emergency Management Agency. Wave Height Analysis for Flood Insurance Studies. Washington, D.C., September 1988.

35. National Academy of Sciences. Methodology for Calculating Wave Action Effects Associated with Storm Surges. Washington, D.C., 1977.

36. Federal Emergency Management Agency. Guidelines and Specifications for Wave Elevation Determination and V Zone Mapping. Washington, D.C., October 1987.

37. —. User's Manual for Wave Runup Analysis, Coastal Flood Insurance Studies. Washington, D.C., November 1981.

38. Mark Hurd Corporation. St. Lucie County Aerial Photographs, Scale 1:24000. 1984.

39. Florida Department of Natural Resources, Bureau of Beaches and Shores. St. Lucie County Beach Profiles. 1984.

40. Federal Emergency Management Agency. Converting the National Flood Insurance Program to the North American Vertical Datum of 1988 - Guidelines for Community Officals, Engineers, and Surveyors. 6/1/1992. 3-0170.

41. Florida Division of Emergency Management. One Foot Contours derived from acquired LiDAR. Tallahassee, Florida, 2008.

42. David Divoky, Robert Battalio, Bob Dean, Lan Collins, Darryl Hatheway and Norm Scheffner. FEMA Coastal Flood Hazard Analysis and Mapping Guidelines Focused Study Report, Storm Meteorology. February, 2005.

43

43. Federal Emergency Management Agency. Flood Insurance Study, City of Fort Pierce, St. Lucie County, Florida. Washington, D.C., January 1984.

44. —. Flood Insurance Study,City of Port St. Lucie, St. Lucie County, Florida. Washington, D.C., March 1982.

45. —. Flood Insurance Study, Town of St. Lucie Village, St. Lucie County, Florida. Washington, D.C., April 1980.

46. —. Flood Insurance Study, St. Lucie County, Florida, Unincorporated Areas. Washington, D.C., January 1984.

47. —. Flood Insurance Study, Martin County, Florida, and Incorporated Areas. Washington, D.C., October 4, 2002.

48. —. Flood Insurance Study, Okeechobee County, Florida, Unincorporated Areas. Washington, D.C., August 4, 1980.

st. lucie county, florida - north carolina · 2015. 10. 1. · st. lucie county, florida and...

Documents