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2021 08 09 Consent 306 - Resolution 2021-22 Adoption of Seminole County Floodplain Management Plan
• CONSENT AGENDA ITEM 306 ,n m=ared CITY COMMISSION AGENDA I AUGUST 9, 2021 REGULAR MEETING 1959 TITLE Resolution 2021-22 Adoption of Seminole County Floodplain Management Plan SUMMARY The City of Winter Springs was accepted for participation in the National Flood Insurance Program (NFIP) on September 16, 1981. The City also participates in the Community Rating System, which awards credits to the City based on the adoption of higher standards for development in special flood hazard areas than those minimum standards required by federal law and allows City residents to benefit from discounted flood insurance premiums as a result of such participation. The adoption of a floodplain management plan allows the City to maintain its Community Rating System participation status, resulting in discounted flood insurance premiums for City residents. RECOMMENDATION Staff recommends that the City Commission approve the resolution as presented in the agenda. 135 RESOLUTION NO. 2021-22 A RESOLUTION OF THE CITY COMMISSION OF THE CITY OF WINTER SPRINGS, SEMINOLE COUNTY, FLORIDA; ADOPTING THE FLOODPLAIN MANAGEMENT PLAN FOR SEMINOLE COUNTY AND ITS MUNICIPALITIES; PROVIDING FOR REPEAL OF PRIOR INCONSISTENT RESOLUTIONS, SEVERABILITY, AND AN EFFECTIVE DATE. WHEREAS,the City is granted the authority,under Section 2(b),Article VIII,of the State Constitution, to exercise any power for municipal purposes, except when expressly prohibited by law; and WHEREAS, floodplain management is the operation of a community program of corrective and preventative measures for reducing flood damage; and WHEREAS, the City of Winter Springs was accepted for participation in the National Flood Insurance Program (NFIP) on September 16, 1981; and WHEREAS, the City also participates in the Community Rating System, which awards credits to the City based on the adoption of higher standards for development in special flood hazard areas than those minimum standards required by federal law and allows City residents to benefit from discounted flood insurance premiums as a result of such participation; and WHEREAS,the adoption of a floodplain management plan allows the City to maintain its Community Rating System participation status,resulting in discounted flood insurance premiums for City residents; and WHEREAS, further, the adoption of a floodplain management plan allows the City to become eligible to apply for both pre- and post-disaster mitigation funds as detailed in 44 C.F.R., Part 201; and WHEREAS,the Floodplain Management Plan for Seminole County and its Municipalities (the "Plan") was developed under the guidance of the Floodplain Management Planning Committee, which included staff representatives of Winter Springs; and WHEREAS, the City Commission adopts a substantial revision of Chapter 8, Flood Damage Prevention, of the City Code via Ordinance 2021-05 simultaneously with the adoption of this Resolution and determines that the Plan is consistent with Ordinance 2021-05; and WHEREAS, while certain aspects of the Plan focus on standards applicable to unincorporated Seminole County and not to the City,the Plan also contains a Hazard Assessment, City of Winter Springs Resolution No.2021-22 Page 1 of 4 136 Mitigation Measures, and floodplain management Goals specific to the City of Winter Springs; and WHEREAS,the City of Winter Springs has already adopted higher standards than some of the floodplain management standards referenced in the Plan, including adoption of a freeboard standard of 18 inches above base flood elevation and compensatory storage requirements; and WHEREAS,the City Commission fully supports Seminole County's floodplain mitigation efforts as described in the Plan, such as the creation of the Natural Lands Program to preserve natural areas and wetlands in Seminole County, which will benefit and reduce flood risks for all residents of the County; and WHEREAS,the City Commission of the City of Winter Springs finds that this Resolution is in the best interests of the public health, safety, and welfare of the citizens of Winter Springs. NOW THEREFORE, THE CITY COMMISSION OF THE CITY OF WINTER SPRINGS HEREBY RESOLVES,AS FOLLOWS: Section 1. Recitals. The foregoing recitals are deemed true and correct and are hereby fully incorporated by this reference. Section 2. Adoption of the Floodplain Management Plan for Seminole County and its Municipalities. The City Commission of the City of Winter Springs hereby adopts the Floodplain Management Plan for Seminole County and its Municipalities, attached hereto as "Exhibit A." Section 3. Repeal of Prior Inconsistent Resolutions. All prior inconsistent resolutions adopted by the City Commission, or parts of prior resolutions in conflict herewith, are hereby repealed to the extent of the conflict. Section 4. Severability. If any section, subsection, sentence, clause, phrase, word or provision of this Resolution is for any reason held invalid or unconstitutional by any court of competent jurisdiction,whether for substantive,procedural,or any other reason, such portion shall be deemed a separate, distinct and independent provision, and such holding shall not affect the validity of the remaining portions of this Resolution. Section 5. Effective Date. This Resolution shall become effective immediately upon adoption by the City Commission of the City of Winter Springs. ADOPTED by the City Commission of the City of Winter Springs, Florida, this day of 52021. City of Winter Springs Resolution No.2021-22 Page 2 of 4 137 Kevin McCann,Mayor ATTEST (City Seal): Christian Gowan, City Clerk Approved as to legal form and sufficiency for the City of Winter Springs only: ANTHONY A. GARGANESE, City Attorney City of Winter Springs Resolution No.2021-22 Page 3 of 4 138 EXHIBIT A City of Winter Springs Resolution No.2021-22 Page 4 of 4 139 EXHIBIT A Floodplain Management Plan for Seminole County And its Municipalities / SM SEA41NOtE COUNTY FLORIDA'S NATLIKAL CHOICE 2020-2025 140 1 Introduction Table of Contents 1 Introduction....................................................................................................................................................5 1.1 Planning Approach................................................................................................................................6 1.2 Topography and Land Use.....................................................................................................................8 1.3 Development,Redevelopment and Population Trends ..........................................................................10 1.4 The Community Rating System............................................................................................................12 1.5 References...........................................................................................................................................14 2 Planning Process........................................................................................................................................... 15 2.1 Planning Approach.............................................................................................................................. 15 3 Flood Risk Assessment.................................................................................................................................20 3.1 Precipitation in Seminole County.........................................................................................................20 3.2 Seminole County Water Resources and Watersheds .............................................................................22 3.3 Flood Risks .........................................................................................................................................23 3.4 Historical Flooding..............................................................................................................................26 3.5 Locally Identified Flood Areas.............................................................................................................28 3.6 The National Flood Insurance Program................................................................................................28 3.7 Future Flood Risk................................................................................................................................29 3.8 Flood Impacts......................................................................................................................................30 3.9 Flood Warning Systems.......................................................................................................................42 3.10 Natural and Beneficial Areas................................................................................................................43 3.11 References...........................................................................................................................................44 4 Goals and Objectives....................................................................................................................................45 4.1 Background.........................................................................................................................................45 4.2 Goals...................................................................................................................................................46 5 Preventive Measures.....................................................................................................................................48 5.1 Building Codes....................................................................................................................................48 5.2 Planning and Zoning............................................................................................................................50 5.3 Open Space Preservation......................................................................................................................52 5.4 Subdivision Regulations......................................................................................................................54 5.5 Floodplain Regulations........................................................................................................................54 5.6 Stormwater Management.....................................................................................................................57 5.7 Conclusions.........................................................................................................................................59 5.8 Recommendations ...............................................................................................................................59 5.9 References...........................................................................................................................................60 6 Property Protection Measures........................................................................................................................61 6.1 Keeping the Hazard Away...................................................................................................................61 6.2 Retrofitting..........................................................................................................................................64 6.3 Insurance.............................................................................................................................................65 6.4 The Government's Role.......................................................................................................................68 6.5 Repetitive Loss Properties and Analysis...............................................................................................70 6.6 Conclusions.........................................................................................................................................71 6.7 Recommendations...............................................................................................................................71 6.8 References...........................................................................................................................................72 7 Natural Resource Protection..........................................................................................................................73 7.1 Wetland Protection..............................................................................................................................73 7.2 Erosion and Sedimentation Control......................................................................................................75 7.3 Lake and Stream Restoration................................................................................................................76 7.4 Stormwater Best Management Practices...............................................................................................78 7.5 Pollution Regulations...........................................................................................................................80 7.6 Farmland Protection.............................................................................................................................81 7.7 Conclusions.........................................................................................................................................82 7.8 Recommendations...............................................................................................................................83 7.9 References...........................................................................................................................................83 8 Emergency Services Measures......................................................................................................................84 8.2 Warning..............................................................................................................................................86 2 141 1 Introduction 8.3 Response.............................................................................................................................................88 8.4 Evacuation and Shelter.........................................................................................................................90 8.5 Post-Disaster Recovery and Mitigation.................................................................................................91 8.6 Conclusions.........................................................................................................................................93 8.7 Recommendations...............................................................................................................................93 8.8 References...........................................................................................................................................93 9 Structural Project Measures...........................................................................................................................95 9.1 Flood Control Measures.......................................................................................................................95 9.2 Conclusions.........................................................................................................................................99 9.3 Recommendations............................................................................................................................. 100 9.4 References......................................................................................................................................... 100 10 Public Information Measures.................................................................................................................. 101 10.1 Outreach Projects............................................................................................................................... 101 10.2 Real Estate Disclosure....................................................................................................................... 102 10.3 Libraries and Websites....................................................................................................................... 103 10.4 Technical Assistance.......................................................................................................................... 104 10.5 Program for Public Infonnation.......................................................................................................... 105 10.6 Conclusions....................................................................................................................................... 106 10.7 Recommendations............................................................................................................................. 107 10.8 References......................................................................................................................................... 107 11 Revisions and Maintenance.................................................................................................................... 108 Table of Tables Table 1: Acres of Land by Land Use Category ...............................................................................................11 Table 2: Community Rating System Premium Reductions.............................................................................12 Table 3: Seminole County Policy Savings for CRS Participation...................................................................13 Table 4: FMPC— Floodplain Management Planning Committee................................................................... 15 Table 5: Number of Permits for New Construction per Year in Seminole County........................................25 Table 6: Historical occurrences of floods in the County..................................................................................28 Table 7: Flood Recurrence Intervals................................................................................................................29 Table 8: Appraised Value of Buildings in Unincorporated Seminole County by Flood Zone.......................33 Table 9: Seminole County Major Employers...................................................................................................34 Table 10: Seminole County Taxable Value.....................................................................................................34 Table 11: Flood Insurance Policies in Seminole County................................................................................67 Table 12: Flood Insurance Policies by Occupancy in Seminole County.......................................................67 Table 13: Flood Insurance Policies by Flood Zone.........................................................................................67 Table 14: Number and Value of Losses by Flood Zone.................................................................................67 Table 15: Flood Insurance for Repetitive Loss Properties..............................................................................71 Table of Figures Figure 1: Seminole County Location Map..........................................................................................................8 Figure 3: Mitigation Planning Process..............................................................................................................16 Figure 5: Rainfall Distribution across Florida...................................................................................................21 Figure 6: Watersheds within Seminole County...............................................................................................22 Figure 7: Historical Storm Tracks near Seminole County (1852 to 2019).....................................................24 Figure 8: Location of Permits for New Construction from January 1, 2015- June 30, 2020........................25 Figure 9: Dams in Florida, based on the 2018 National Inventory of Dams..................................................26 Figure 10: FEMA Flood Zones in Seminole County........................................................................................30 Figure 11: Evacuation Routes for Seminole County.......................................................................................32 Figure 12: Seminole County Repetitive Loss Property Areas........................................................................36 Figure 21:Wilderness Area Open to the Public in Seminole County............................................................44 Figure22: Elevated Home................................................................................................................................48 Figure 23: Planned Unit Developments...........................................................................................................50 3 142 1 Introduction Figure 24: Preserved Lands in Seminole County............................................................................................53 Figure25: BFE Examples.................................................................................................................................56 Figure 26: Effect of Development on Stormwater...........................................................................................57 Figure 27: Flood Protection Barrier..................................................................................................................61 Figure28: Dry Floodproofing............................................................................................................................64 Figure 29: Example Flood Insurance Premiums.............................................................................................65 Figure30: Straw Bales......................................................................................................................................75 Figure 31: Aquatic and Ripairian Buffer Plant Zones......................................................................................77 Figure 32: BMPs and Stormwater....................................................................................................................80 Figure 33: Seminole County Evacuation Routes ............................................................................................91 Figure 34: Flood Safety Brochure Distributed to Residents during Outreach Events ................................ 102 Figure 34: Flood Safety Brochure Distributed to Residents during Outreach Events ................................ 102 Municipal Annexes AltamonteSprings................................................................................................................A Casselberry........................................................................................................................B LakeMary..........................................................................................................................0 Oviedo...............................................................................................................................D Sanford..............................................................................................................................E WinterSprings.....................................................................................................................F Action Plan 2020-2025............................................................................................................G 4 143 1 Introduction I Introduction The Problem: Seminole County, Florida, is subject to natural hazards ate. that threaten life and health and that have caused extensive property damage. Floods inundated the County following Hurricane Irma in 2017, _ Tropical Storm Fay in 2008, following i Hurricane Frances in 2004, and - Tropical Storm Gabrielle in 2001. - Extensive flooding occurred in 1960 after Hurricane Donna brought heavy rainfall. During the summer of 1953, rainfall over the St. Johns River basin was above normal, and when a tropical storm passed nearby, bringing additional heavy rainfall, Lake Monroe flooded lakefront areas. To better understand these hazards and their impacts on people and property, and to identify ways to reduce those impacts, the County's Office of Emergency Management undertook this Floodplain Management Plan as an appendix to the County's Local Mitigation Strategy(LMS). "Hazard mitigation" does not mean that all hazards are stopped or prevented. It does not suggest complete elimination of the damage or the disruption caused by such incidents. Natural forces are powerful and most natural hazards are well beyond our ability to control. Mitigation does not mean quick fixes. It is a long-term approach to reducing hazard vulnerability. As defined by the Federal Emergency Management Agency (FEMA), "hazard mitigation" means any sustained action taken to reduce or eliminate the long-term risk to life and property from a hazard event. Why Plan: Every community faces different hazards and every community has different resources to draw upon in combating problems and different interests that influence the solutions to those problems. Because there are many ways to deal with flood hazards and many agencies that can help, there is no one solution for managing or mitigating their effects. Planning is one of the best ways to develop a customized program that will mitigate the impacts of hazards while taking into account the unique character of a community. The plan provides a framework for all interested parties to work together and reach consensus on how to move forward. A well- prepared flood mitigation plan will ensure that all possible activities are reviewed and implemented so that the problem is addressed by the most appropriate and efficient solutions. It can also ensure that activities are coordinated with each other and with other goals and activities, preventing conflicts and reducing the costs of implementing each individual activity. This Floodplain Management Plan was developed under the guidance of a Floodplain Management Planning Committee (FMPC). The Committee's representatives included representatives of Seminole County departments, interested municipalities, federal and state agencies, citizens, and other stakeholders. All municipalities in the County were also invited to attend and participate in the planning process. Mitigation activities require funding. A mitigation plan is now a requirement for Federal mitigation funds. Section 104 of the Disaster Mitigation Act of 2000 (42 U.S.C. 5164) states that as of November 1, 2003, local governments applying for pre-disaster mitigation funds must have an approved local mitigation plan. Similarly, as of November 1, 2004, a plan is also needed for 5 144 1 Introduction post-disaster mitigation funds under the Hazard Mitigation Grant Program. These requirements are detailed in 44 Code of Federal Regulations Part 201. Thus a mitigation plan will both guide the best use of mitigation funding and meet the prerequisite for obtaining such funds from FEMA. FEMA also recognizes plans through its Community Rating System (CRS), a program that reduces flood insurance premiums in participating communities. This Plan: This Floodplain Management Plan identifies activities that can be undertaken by both the public and the private sectors to reduce safety hazards, health hazards, and property damage caused by floods. The Plan fulfills the federal mitigation planning requirements, qualifies for CRS credit, and provides the County with a blueprint for reducing the impacts of these flood hazards on people, property, and the environment. 1.1 Planning Approach This Floodplain Management Plan is the product of a rational thought process that reviews alternatives and selects and designs those that will work best for the situation. This process is an attempt to avoid the need to make quick decisions based on inadequate information. It provides carefully considered directions to the County government by studying the overall damage potential and ensuring that public funds are well spent. 1.1.1 Planning Committee This Floodplain Management Plan was developed under the guidance of the FMPC with oversight from the Office of Emergency Management. The Committee includes representatives from the County and other local, state and federal agencies that serve Seminole County and private citizens and other stakeholders. The member organizations and participants who were members of this FMPC are shown in Table 4 in section 2.1.1 of this plan. The FMPC met and developed the plan starting in March 2020, and then from July 2020 to October 2020. Meetings were paused from March to July due to response to the COVID-19 virus, and resumed in July with a virtual format. Sign-in sheets from these meetings are kept for records by the Office of Emergency Management. The plan development included identifying the unique flood risks that affect the County, assessing these flood risks, identifying mitigation actions for these risks, and involving the public in the development of the plan. Technical support for the development and implementation of the Floodplain Management Plan is provided by the Seminole County Office of Emergency Management and Development Services. 1.1.2 Planning Process The Floodplain Management Planning Committee followed the CRS 10-Step Planning Process, based on the guidance and requirements of FEMA and the 2017 CRS Coordinator's Manual. The process is explained in further detail in Chapter 2 —Planning Process. 6 145 1 Introduction 1.1.3 Public Involvement Step 2 of the planning process was to obtain input from the public, particularly residents and businesses that have been affected by natural hazards. The public was invited to participate in the process through the following ways: • Attending and participating in meetings of the FMPC. Five meetings were held in total. • Contact with committee members. • A public meeting at the end of the planning process to gain comments on the draft plan. 1.1.4 Coordination Existing plans and programs were reviewed during the planning process. During the planning process, contacts were made with a variety of regional, state and federal agencies and organizations. Many of these agencies were members of the FMPC and provided review of and support for this planning effort. Seminole County also coordinated with representatives from the municipalities in the County, who were invited to participate and attend the FMPC meetings. Citizens representing various areas of the County were members of the FMPC and provided valuable support. At the end of the planning process, these same agencies and organizations reviewed the draft plan and provided feedback. 1.1.5 Hazard Assessment and Problem Evaluation The Committee addressed Steps 4 and 5 of the planning process (Assess the Hazard and Evaluate the Problem) during meetings of the Committee. The Committee's assessment and evaluation of the flood hazard are covered in Chapter 3 of this plan. The FMPC evaluated flooding data, including localized drainage, repetitive loss, hurricanes and tropical storms. 1.1.6 Goals The Committee conducted goal setting exercises at one of its meetings. During the meeting, the previous plan's goals were reviewed and then the Committee agreed upon a final list of goals and objectives. These goals and objectives are discussed in Chapter 4 of this plan. 1.1.7 Mitigation Strategies The FMPC considered everything that could impact the flood hazards and reviewed a wide range of possible alternatives. They are organized under six general strategies for reaching the goals. These strategies are the subject of Chapters 5 — 10 of this plan. • Preventive Measures: zoning, building codes and other development regulations • Property Protection Measures: relocation out of harm's way, retrofitting buildings, etc. • Natural and Beneficial Functions: preserving natural areas to protect species and habitats or developing in ways that are more protective of species and habitats • Emergency Services: warning, response, evacuation • Structural Projects: levees, reservoirs, channel improvements • Public Information: outreach projects, technical assistance to property owners, and other 7 146 1 Introduction measures. 1.1.8 Action Plan After reviewing the various alternatives, the Committee drafted an action plan to identify recommended projects,parties responsible for each of the projects, and a schedule for project completion. The action plan is included as an appendix to this plan. It should be noted that this Plan only serves to recommend mitigation measures. Implementation of these recommendations depends on the adoption of this Plan by the Seminole County Board of County Commissioners. 1.2 Topography and Land Use Seminole County is located in the central part of Florida and is part of the Orlando-Kissimmee- Sanford Metropolitan Statistical Area. The City of Sanford is the county seat. Seminole County covers 345 square miles, 37 square miles of which is water. The floodplains of Seminole County consist of lowlands adjacent to streams and lakes. The topography of the County is relatively flat, with some gently rolling hills. Ground elevations in Seminole County range from less than five (5) feet North American Vertical Datum of 1988 (NAVD) to 130 feet NAVD. The City of Sanford,the county seat, is located on the southern shore of Lake Monroe in the northern part of the County. In the southwestern part of the County are the Cities of Longwood, Winter Springs, Casselberry and Seminole County, Florida Altamonte Springs. The City of Oviedo is ---_'--- "T- in the south central portion of the County. Figure 1: Seminole County Location Map The City of Lake Mary borders Sanford, in the western part of the County. Seminole County's climate is characterized by long, warm summers and mild, dry winters. The average annual rainfall is about 53 inches. The majority of the rain falls from June through September and is associated with tropical storms or depressions which means that County Boundaries precipitation for any given month can gp Seminole County vary greatly from year to year. Seminole County is bordered on the north and east by the St. Johns River and on the west primarily by the Wekiva River. The St. Johns River is brackish. There are many lakes in Seminole County, and more than 120 of these are larger than 3 five acres. Most occur in karst areas on the sand ridges. In addition to Lake 6 56 160 260 Miles - e Monroe which straddles the northern 8 147 1 Introduction border of the County, Lake Jesup bisects much of the northern half of the County and Lake Harney sits along the County's eastern border. Seminole County's physiography consists of alternating ridges and valleys with abundant lakes. According to the USDA's Soil Survey of Seminole County, Florida, "The Osceola Plain is a broad, flat area of low, local relief and is generally between 60 and 70 feet in elevation. Most of the western part of the county is made up of this plain. The Orlando Ridge is an area of higher elevation that is generally parallel to the other surrounding ridges outside of Seminole County, such as the Mount Dora Ridge to the west. It is possible that the Orlando Ridge once was part of a relic, `Cape Orlando,' which resulted from progressive progradation that formed Cape Canaveral and False Cape in Brevard County from marine processes. The northern tip of the Orlando Ridge extends a few miles into Seminole County in the area of Altamonte Springs. The Eastern Valley is generally 20 to 25 feet in elevation and is characterized by a broad, flat area through which the St. Johns River flows. Most of the eastern part of Seminole County is composed of this valley. The Wekiva Plain is a flat area in western Seminole County dominated by the Wekiva River. In eastern Seminole County, the Geneva Hill is a high area in the Eastern Valley in the vicinity of Geneva." In terms of geology, Seminole County is underlain by a thick sequence of limestone and dolomite rock upon which a relatively thin section of sand, silt, shell material and clay was deposited. According to the USDA's Soil Survey of Seminole County, Florida, there are 10 soil map units in Seminole County, described below. Mineral soils on the uplands: 1. Urban Land-Pomello-Paola. This unit is about 4% of Seminole County and consists of moderately well drained and excessively drained soils that are sandy. 2. Urban Land-Astatula Apopka. This unit is about 22% of Seminole County, and is more than half urban land. The rest is excessively drained soils that are sandy and well drained sand soils that have a loamy subsoil. 3. Urban Land-Tavares-Millhopper. The soils in this unit are moderately well drained and sandy or have a loamy subsoil. This unit covers 23% of the County. Mineral soils on the flatwoods and in sloughs and depressions between the upland ridges and the floodplains, depressions and swamps: 4. Myakka-EauGalle-Urban Land. These are poorly drained soils that are sandy or have a loamy subsoil. This unit covers 24% of the County. 5. St. Johns-Malabar-Wabasso. This unit makes up 8% of Seminole County. These soils in the central part of the County are poorly drained and sandy or have a loamy subsoil. 6. Basinger-Smyrna-Delray. These soils, covering about 7% of the County, are poorly drained and very poorly drained soils that are sandy throughout or have a loamy subsoil. 9 148 1 Introduction Mineral and organic soils on the floodplains and in depressions and swamps: 7. Nittaw-Felda-Floridana. These are very poorly drained and poorly drained mineral soils; some with a clayey subsoil and some sandy with a loamy subsoil. They exist on floodplains and in depressions and make up about 4% of the County. 8. Nittaw-Okeelanta-Terra Cela. The soils in this unit, which covers about 4% of the County, are on the floodplains adjacent to Lake Monroe and Lake Jesup and subject to frequent flooding. They are very poorly drained mineral and organic soils, some are mucky with a clayey subsoil, some are mucky with a sandy layer, and some are mucky throughout. 9. Brighton-Samsula-Sanibel. These soils are south of Lake Jesup and are ponded. They are very poorly drained organic and mineral soils. They make up about 1% of the County. Some are mucky throughout, some are mucky and have a sandy layer beneath, and some are sandy throughout. They exist in depressions and swamps. 10.Pompano-Nittaw-Basinger. The soils in this map unit are in floodplains adjacent to the Wekiva, St. Johns and Econlockhatchee Rivers and Lake Jesup. They make up about 3% of the county, and are poorly drained and very poorly drained mineral soils, some are sandy throughout and some are mucky with a clayey subsoil. The Floridan Aquifer underlies all of Seminole County and supplies at least 95 percent of the County's freshwater. Most of the County's soils are sandy and low in natural fertility, but they support forests and wildlife. In addition, ornamental plants,vegetables and other plant products are grown in the County. 1.3 Development, Redevelopment and Population Trends Seminole County's convenient location between Volusia and Orange Counties has made it one of the fastest growing counties in Florida. The Seminole County 2018 Comprehensive Plan has certain goals for future development. The goals and objectives outlined in the Future Land Use Section are: • Protection and preservation of the environment, including water resources, air quality, regionally significant natural areas, open space and recreational areas; • Creation and support of diverse, globally competitive economic conditions favorable to higher wage jobs; • Provision of a range of affordable housing opportunities and choices; • Provision of adequate services and facilities, including a variety of transportation choices; • Maintenance of established residential neighborhoods, revitalization of declining neighborhoods and creation of new energy-efficient communities with educational, health care and cultural amenities; • Protection of rural and agricultural areas; and • Protection of private property rights. to 149 1 Introduction Chapter 3 provides information on the number and location of building permits issued in Seminole County between January of 2015 Table 1: Acres of Land by Land Use Category and August of 2020. During this time period Fxisfing Land Use Categoriesali2.877 Percent Residential 51 le Fanti 29% more than 3,300 building permits were r1culWre 16% Man ed EnHronmenial Land 14% issued for single-family, multi-family, Dedicated ccrnmon n 5 ace 7% Vacant Cher 7% commercial and government buildings. The Publlc 6% Public Other 2% table to the right from the Seminole County Residential Muttfarrily 4,462 1 2% PesComprehensive Plan indicates the various Commercial i l bile Rome 3 832 2% p Commercial 3 632 2% land use categories and the acreage for each. Vacant Goma rd 3,969 2% Vacant Commercial 2,942 2% The map in Figure 2 below identifies future Trans rtatlon 2,669 1% Industrial 2 538 1% lnstiwUtinal 253' 1% land use proposed for Seminole County. l 2r295 1% Education 1906 1% There has not been a significant amount of ctl 1,801 1% Vacant Industrial 1,172 1% re-development within Seminole County. Fl143 °% Vacant Inslituflonal 91 0% All development must follow the guidance of -MAL(Irj11*5 crry acres) 187.657 1CM the Comprehensive Plan and must comply Source: Seminole County Comprehensive Plan with all current floodplain management regulations. Figure 2: Seminole County Land Use Pattern Seminole County Future Land Use Pattern 2027 Legend . 1.R A. YvekNa 6Ymevlrn irca n PovteNun Nea .a • e ysw;m.e W" Amey Future Land Ire: uary AA enaal3 nut �� eli�QueatlAmtic r.,J T J inti •t4 d 19N Cmaily a Y _ efiNGWOQDI__ ' •- e 1 Y ------------ -Y __ � _,J � WiNTFR SGRINGS , lT gal ill 4. ,r k Source: Seminole County Comprehensive Plan—Future Land Use 1.3.1 Population Trends In 2019, the estimated population of Seminole County was 471,826 people, an 11.6% increase from the 2010 population. According to the University of Florida Bureau of Economic and Business Research Florida Population Studies, the population of Seminole County is expected to increase to 5 10,7 10 people by 2025, an 8.2% increase in the next five years. By 2030, the 11 150 1 Introduction population is expected to increase another 4.9%,to 535,588 people. These figures include both the incorporated and unincorporated areas of the County. 1.4 The Community Rating System FEMA's National Flood Insurance Program (NFIP) administers the CRS. Under the CRS, flood insurance premiums for properties in participating communities are reduced to reflect the flood protection activities that these communities are implementing. This program can have a major influence on NFIpIclas the design and implementation of flood mitigation activities, so a brief summary is provided here. A community receives a CRS classification based on the credit points it receives for activities. It can undertake any mix of activities that reduce flood losses, such as enhanced mapping, regulatory changes, public information programs, flood damage reduction, or flood warning and preparedness programs. There are 10 CRS classes: class 1 requires the most credit points and gives the largest premium reduction; class 10 receives no premium reduction (see Table 2). A community that does not apply for the CRS or that does not obtain the minimum number of credit points is a class 10 community. On May 1, 2011, the County was rated a Class 6 and policy holders within the SFHA enjoy a 20 percent reduction on the cost of flood insurance. This CRS rating was reaffirmed in 2017 cycle verification. Table 2: Community Rating System Premium Reductions Reduction Class Points Premium in Outside Floodplain Floodplain 1 4500+ 45% 10% 2 4,000-4,499 40% 10% 3 3,500-3,999 35% 10% 4 3,000-3,499 30% 10% 5 2,500-2,999 25% 10% 6 2,000-2,499 20% 10% 7 1,500-1,999 15% 5% 8 1,000-1,499 10% 5% 9 500-999 5% 5% 10 1 0-499 1 0% 1 0% 1.4.1 Program Incentive The CRS provides an incentive not just to start new mitigation programs, but to keep them going. There are two requirements that encourage a community to implement flood mitigation activities. First, the County will receive CRS credit for this plan, once it is adopted. To retain that credit, the County must submit an evaluation report on progress made towards implementing this plan to FEMA by October 1st of each year. That report must be made available to the media and to the public. Second, the County must annually recertify to FEMA that it is continuing to implement its CRS credited activities. Failure to maintain the same level of involvement in flood 12 151 I Introduction protection can result in a loss of CRS credit points and a resulting increase in flood insurance rates to residents. It is expected that this undesirable impact of loss of CRS credit for failure to report on the plan's progress or for failure to implement flood loss reduction projects will be a strong incentive for the County to continue implementing this plan in dry years when there is less interest in flooding. 1.4.2 Benefits of CRS Participation Table 3 below shows the direct dollar benefit to Seminole County and the County's policy holders for participation in the CRS. The savings per policy are for properties in the FEMA mapped 100-year floodplain ("Special Flood Hazard Area"). The savings are lower for policies outside the mapped floodplain. CRS discounts do not apply to Preferred Risk Policies (PRP), as shown in Table 3 below. The Preferred Risk Policy (PRP) is a Standard Flood Insurance Policy (SFIP)that offers low-cost coverage to owners and tenants of eligible buildings located in the moderate-risk B, C, and X Zones in the National Flood Insurance Program(NFIP) Regular Program communities. Table 3: Seminole County Policy Savings for CRS Participation Total Policies Policies in X-STD/AR/A99 PRP SFHA Number of Policies 4,109 1,259 50 2,800 Total Premiums $2,105,881 $936,511 $66,489 $1,102,881 Average individual annual premium $512 $744 $1,330 $394 Class 9 savings per floodplain policy 15 $46 $74 $0 Class 9 savings for community $62,226 $58,532 $3,694 $0 Class 8 savings per floodplain policy $29 $93 $74 0 Class 8 savings for community $120,757 $117,063 $3,694 $0 Class 7 savings per floodplain policy $44 139 74 $0 Class 7 savings for community $179,289 $175,595 $3,694 1 $0 Class 6 savings per floodplain policy $59 186 148 0 Class 6 savings for community $241,515 $234,127 $7,388 sol Source: Insurance Services Office(ISO) In addition to the direct financial reward for participation in the CRS, there are many other reasons to participate. The other benefits that are more difficult to measure in dollars include: 1. The activities credited by the CRS provide direct benefits to residents, including: • Enhanced public safety, • A reduction in damage to property and public infrastructure, • Avoidance of economic disruption and losses, • Reduction of human suffering, and • Protection of the environment. 13 152 1 Introduction 2. A community's flood programs will be better organized and more formal. Ad hoc activities, such as responding to drainage complaints rather than an inspection program, will be conducted on a sounder, more equitable basis. 3. A community can evaluate the effectiveness of its flood program against a nationally recognized benchmark. 4. Technical assistance in designing and implementing a number of activities is available at no charge from the Insurance Services Office. 5. The public information activities will build a knowledgeable constituency interested in supporting and improving flood protection measures. 6. A community will have an added incentive to maintain its flood programs over the coming years. The fact that the community's CRS status could be affected by the elimination of a flood-related activity or a weakening of the regulatory requirements for new developments will be taken into account by the governing board when considering such actions. 7. Every time residents pay their insurance premiums,they are reminded that the community is working to protect them from flood losses, even during dry years. More information on the Community Rating System can be found at hgps://www.fema.gov/national-flood-insurance-program-community-rating`ystem. 1.5 References 1. Community Rating System Coordinator's Manual, FEMA, 2017. 2. Example Plans, FEMA/Community Rating System, 2006. 3. Getting Started Building Support for Mitigation Planning, FEMA, FEMA-386-1, 2002. 4. Local Multi-Hazard Mitigation Planning Guidance, FEMA, 2008. 5. Soil Survey of Seminole County, Florida, USDA Soil Conservation Service, 1990. 6. State and Local Plan Interim Criteria under the Disaster Mitigation Act of 2000, FEMA, 2002. 7. Florida Population Studies, College of Liberal Arts and Sciences Bureau of Economic and Business Research, 2020 https://www.bebr.ufl.edu/sites/default/files/Research%20Reports/projections_2020_asrh.pdf 8. Seminole County Comprehensive Plan, Seminole County Planning and Development Department, 2018. 14 153 2 Planning Process 2 Planning Process 2.1 Planning Approach This Floodplain Management Plan is the product of a rational thought process that reviews alternatives and selects and designs those that will work best for the situation. This process is an attempt to avoid the need to make quick decisions based on inadequate information during an emergency. It provides carefully considered direction to the County government by studying the overall damage potential and ensuring that public funds are well spent. The development of this plan also followed FEMA's CRS 10-Step Planning Process. 2.1.1 Planning Committee This Floodplain Management Plan was developed under the guidance of a Floodplain Management Planning Committee (FMPC) with oversight from the Seminole County Office of Emergency Management. The Committee included representatives from various County departments, other local, state and federal agencies that serve the County, and citizens from throughout the County. Some of these citizen members of the FMPC had been flooded in the past. The County department representatives, citizens and stakeholders who make up the FMPC are shown in Table 4 below. Table 4: FMPC — Floodplain Management Planning Committee Name Agency Daniel O'Keefe Citizen Karen Heriot Citizen Michelle Bernstein Citizen Pam Sanders Citizen Shannon Webster Citizen Victoria Colangelo Citizen April Davis City of Altamonte Springs Danielle Marshall City of Altamonte Springs Jane Dai City of Casselberry Kelly Brock City of Casselberry Danielle Koury City of Lake Mar Dave Dovan City of Lake Mary Shad Smith City of Longwood Tom Smith City of Longwood Amanda Kortus City of Oviedo Jeff Buchanan City of Oviedo Mike Cash City of Sanford Russel Sheibenberger City of Sanford Christopher Schmidt City of Winter Springs Rachel Gironella City of Winter Springs Lucius Cushman Seminole County Resiliency Committee—Citizen Representative Rob Wolf Seminole County Resiliency Committee—Citizen Representative Tony Coleman Seminole County Building Division Bill White Seminole County Development Review Engineering Division Alan Harris Seminole County Emergency Management Kathryn Valentine Seminole County Emergency Management Jeff Sloman Seminole County Engineering Division Tuan Huynh Seminole County Engineering Division Mary Robinson Seminole County Planning and Development Owen Reagan Seminole County Roads and Stonnwater Marie Lackey Seminole County Watershed Management 15 154 2 Planning Process The plan development included identifying the unique flood risks Figure 3: Mitigation Planning Process that affect the County, identifying mitigation actions for these risks, Step 1 and discussing how to involve the AL Organize public in the development of the 1 Plan. The Seminole County Board of Step 2 County Commissioners passed a Involve the Public Resolution amending (This step continues throughout the entire process) Administrative Code Section 4.12, 1 which established the planning process and created the FMPC. Step 3 Coordinate with Agencies &Organizations 2.1.2 Planning Process (This step continues throughout the entire process) The FMPC followed a standard 10- 1 step process, based on the guidance Step 4 and requirements of FEMA. The Assess the Hazard process is summarized in the flow 1 chart in the figure on the right. The Committee assessed the flood Step 5 hazards affecting the County, set Evaluate the Problem goals, and reviewed a wide range 1 of activities that can mitigate the adverse effects of the hazards. The Step 6 FMPC met five times over the Set Goals course of the planning process in 1 development of this plan. Agendas and sign-in sheets for each of the Step 7 meetings are documented and Review Mitigation Strategies saved by the Office of Emergency 1 Management. Step 8 Draft Action Plan 1 Step 9 Adopt the Plan 1 Step 10 Implement, Evaluate, Revise 16 155 2 Planning Process 2.1.3 Public Involvement Step 2 of the planning process was to obtain input from the public, particularly residents and businesses that had been affected by flooding. The public was invited to participate through: • Attending and participating in meetings of the Floodplain Management Planning Committee. Five meetings were held in total. • Contacting committee members. • Attending a public meeting held on May 18, 2021 to receive comments on the draft plan. 2.1.3.1 Public Meetings A public meeting was held at the end of the planning process to solicit comments on the draft plan. This meeting was held on May 18, 2021 in a virtual format, due to the current conditions of the COVID-19 pandemic. The meeting was advertised through the local newspaper, in a County public building, on the Seminole County website, and on multiple social media platforms. Background on the plan and its findings and recommendations were explained, and attendees were given an opportunity to ask questions and submit comments for review, consideration, and potential modification of the plan. 2.1.3.2 Other Public Involvement Methods Seminole County promoted the floodplain management plan through its established Local Mitigation Strategy Committee, which includes members from a cross-section of the community and who represent a variety of local organizations. 2.1.4 Coordination Existing plans and programs were reviewed during the planning process. In order to effectively update all parts of the plan, a review was done of the Seminole County and municipal Comprehensive Plans, the Local Mitigation Strategy, the Seminole County Future Land Use plan, National Inventory of Dams, Area Basin Studies, and Geographic Information Systems map data. In addition, contacts were made with regional, state and federal agencies and organizations during the planning process. Requests for updated information were made of a variety of stakeholder agencies, including the National Weather Service, the Florida Division of Emergency Management, and the Insurance Services Office to obtain technical information needed for review and inclusion in the plan. 2.1.4.1 Solicitation of Comments Members of the FMPC included representatives from different areas of the community, including citizen representatives from all five (5) commission districts. These stakeholders provided valuable comments throughout the planning process. 2.1.4.2 Neighboring Communities All incorporated municipalities within Seminole County were made aware of the planning process via e-mail and calendar invitation. Each incorporated municipality was invited to attend 17 156 2 Planning Process the FMPC meetings. Participating municipal agencies were involved through the planning process and community profiles are included as appendices to this plan for each of the six participating communities. 2.1.4.3 Contacting Other Agencies and Meetings with Agencies Because Seminole County is not a coastal county, the Florida Department of Environmental Protection's Coastal Management Program was not contacted for this planning effort. 2.1.5 Hazard Assessment and Problem Evaluation The Committee addressed Steps 4 and 5 of the planning process (Assess the Hazard and Evaluate the Problem) during the March and July meetings of the FMPC. The flood hazard data and vulnerability to critical facilities, buildings and infrastructure and the impact of the flood hazard on life, health and safety is covered in Chapter 3 of this document. The LMS also provided data and support for Hazard Assessment and Problem Evaluation sections of the plan. 2.1.6 Goals The Committee reviewed the Floodplain Management Plan Goals at the August FMPC meeting. During this meeting, the list of current goals was reviewed and discussed, and then the Committee agreed upon a final list of goals and objectives. These goals are discussed in Chapter 4 of this document. 2.1.7 Mitigation Strategies During the September meeting of the FMPC, the Committee reviewed and discussed various mitigation measures which could help to reduce or eliminate the flood hazards. The Committee went through a comprehensive list of potential mitigation options based on the following six general categories: • Preventive Measures • Property Protection Measures • Natural Resource Protection Measures • Emergency Services Measures • Structural Measures • Public Information Measures 2.1.8 Action Plan After reviewing the various alternatives, the Committee drafted an action plan to identify recommended projects,parties responsible for implementation, a schedule for project completion, and identification of funding sources. The action plan is included as an appendix to this document. This Floodplain Management Plan serves only to recommend mitigation measures. Implementation of these recommendations depends on adoption of this plan by the Seminole County Board of County Commissioners. 18 157 2 Planning Process 19 158 3 Flood Risk Assessment 3 Flood Risk Assessment Flooding is the deadliest and most costly storm-related natural hazard in the United States. Many deaths due to flooding can be avoided by not driving through flooded roads and paying attention to evacuation warnings. Types of Flooding: The most common and most damaging floods occur along rivers and streams. This type of flooding is called overbank flooding. Overbank flooding of rivers and streams can be caused for any of the following reasons: 1. There is more precipitation in the watershed than the waterways and the storm system can convey; 2. There are obstructions in a channel, such as a beaver dam, 3. There is a large release of water when a dam or other obstruction fails; or 4. A combination of these factors. Most floods are caused because of the first factor, a larger amount of precipitation than the watershed can manage. Another contributor to flooding is storm water runoff. This problem has recently become more critical because of development in areas subject to urban flooding. Causes of Flooding: For most of Seminole County, the primary causes of flooding are tropical systems and afternoon thunderstorms. These storms generally occur during the rainy season, from June through November. The rain associated with hurricanes and tropical storms can produce extreme amounts of rainfall in short periods of time, which can overwhelm the capacity of streams, channels, or drainage infrastructure. In addition, certain areas of Seminole County are low-lying, which makes them subject to flooding from rising water. Historical Floods: Since 1994, Seminole County has experienced eight major floods. These floods have disrupted life for community members by closing streets and causing property damage to homes and businesses, and one of these floods even caused the death of a Seminole County resident. To address flood control and protection issues, Seminole County continues to update and implement this floodplain management plan. 3.1 Precipitation in Seminole County Seminole County receives an average of 53 inches of rain each year. However, this rainfall is not spread out evenly from month to month or across all parts of the County. Most precipitation occurs during the rainy season, from June to October. 20 159 0 � _ 3 e 3 / 2 / § � u , 2 / LO � \ Ln � ƒ � 2 $ � ° © 2 7 § } \ . \ o / / \ ( \ 8 Co n \ f z & a / ■ X22 \ c 2 y \ _ § � z m . / 2 Ca on o u _ G = E 2 to. .. . g \ / = / @ E e § G \ \ Q / \ . D $ \ \_ k � c � � § .. o # o � \ � \ LM L $ 3 Flood Risk Assessment 3.2 Seminole County Water Resources and Watersheds Seminole County has an abundance of surface water resources. The St. Johns River and Econlockhatchee River as well as three large lakes —Lake Monroe, Lake Jesup and Lake Harney —fall at least partly within the County boundaries. There are also six watersheds that fall partly within Seminole County, as shown in Figure 5. Within these six major watersheds are smaller subwatersheds that drain into the tributaries. Each of these streams has adjacent floodplains that are inundated during a flood. The condition of the land in the watershed affects what happens when precipitation falls. For example, more rain will run off the land and into streams if the terrain is steep, if the ground is already saturated from previous rains, if the watershed is significantly covered with impervious pavement and parking lots, or if depressional storage areas (like swamps)have been filled in. Thus, urban development in the watershed can contribute to flooding. Each of the watersheds in Seminole County contains urban as well as rural areas, except for Deep Creek, which is mostly rural. Watersheds that are more urbanized tend to flood more quickly than rural watersheds. Figure 5: Watersheds within Seminole County Seminole County, Florida Watersheds S f_ 1 C3County Boundary Deep Creek Unit,Middle SJR Econlockhatchee River Lake Jesup N [ Lake M onroe Unit " � 0 2.5 5 10 Miles C-3Puzbe Lake Unit s1 1 1 1 1 [ VUekiva River Source: Seminole County GIS Division Seminole County Floodplain Management Plan 22 161 3 Flood Risk Assessment 3.3 Flood Risks 3.3.1 Tropical Cyclones Flooding in Seminole County is often the result of hurricanes, tropical storms, or tropical depressions, all of which are tropical cyclones. These storms bring heavy rainfalls and high winds to Seminole County, which can cause significant damage. These storms can last for several days, and therefore they have the potential to cause sustained flooding. Rain combined with high winds can also create wave action on the three lakes and can damage properties adjacent to these bodies of water. Historically, many hurricanes and tropical storms have passed near or through Seminole County, as shown in Table 7. Table 7: Major Storms near Seminole County, Florida (1990 to 2020) Date Storm Name Deaths(FL) Injuries(FL) Property Damage 9/11/2017 Hurricane Irma 7 Hundreds $50,000,000,000(US) (direct&indirect) 10/7/2016 Hurricane Matthew 2 0 $10,000,000,000(US) 8/24/2008 Tropical Storm Fay 5 0 $390,000,000(FL) 2/3/2007 Severe Storms and Tornadoes 0 0 $43,000,000(FL) 8/24/2006 Hurricane Ernesto 0 0 $500,000,000(US) 10/5/2005 Tropical Storm Tammy 0 0 <$25,000,000(US) 9/24/2004 Hurricane Jeanne 3 0 $6,900,000,000(US) 9/16/2004 Hurricane Ivan 14 0 $8,300,000,000(FL) 9/4/2004 Hurricane Frances 5 0 $8,000,000,000(FL) 8/13/2004 Hurricane Charley and TS 9 0 $14,000,000,000(FL) Bonnie 9/3/2003 Tropical Storm Henri 0 2 "minor" 9/2/2002 Tropical Storm Edouard 0 0 "minor" (roadway flooding in Seminole County) 9/13/2001 Tropical Storm Gabrielle 2(1 in Seminole) 0 $230,000,000(FL) 10/4/2000 Tropical Storm Leslie 3 0 $700,000,000(FL) 10/20/1999 Hurricane Irene 8 3 $8,000,000(FL) 10/22/1998 Hurricane Mitch 2 65 $20,000,000(FL) 9/15/1998 Hurricane Georges 0 0 $20,000,000(FL) 8/22/1995 Tropical Storm Jerry 0 0 $30,000,000(FL) 7/31/1995 Hurricane Erin 0 0 $700,000,000(FL) 11/8/1994 Tropical Storm Gordon 8 0 $400,000,000(FL) Sources: National Oceanic and Atmospheric Administration's National Hurricane Center and the Federal Emergency Management Agency Of particular importance to communities susceptible to hurricane damage is the track of an approaching storm. Proximity and direction of an approaching storm are important when determining impacts and subsequent damage from the storm. Figure 6 on the next page shows the historical tracks of storms that have passed through or near Seminole County. Seminole County Floodplain Management Plan 23 162 3 Flood Risk Assessment Figure 6: Historical Storm Tracks near Seminole County (1852 to 2019) 9 ID � � 4 aD ,/ vii G O .q4,f ax. 4 1t" y C1a ?6 .� 11 © � �d0 ABRIELLE 00 1 r1ando co :dc m fig180 Source:NOAA Historical Hurricane Tracks 3.3.2 Flash Floods A second source of flooding in Seminole County is flash flooding. Flash floods are generated by severe storms that drop a large amount of rainfall in a short period of time. Flash floods strike quickly and end quickly, with very little warning time. Areas with steep slopes and narrow stream valleys are particularly vulnerable to flash flooding, as are the banks of small tributary streams. In hilly areas, the high velocity flows and short warning times make flash floods hazardous and destructive. In urban areas, flash flooding can be triggered by increased stormwater runoff due to land development. When buildings are constructed on open spaces, hard surfaces like parking lots and rooftops replace forests, swamps, fields, and other natural land covers. When rainfall hits these impervious surfaces, it runs off of them rather than infiltrating into the soil that was once there. Along the way, stormwater runoff picks up sediment, debris and pollutants on the hard surfaces and carries them to streams or rivers. Thus, developed land absorbs less rainfall than Seminole County Floodplain Management Plan 24 163 3 Flood Risk Assessment undeveloped land, and also increases pollution in local waterways. As we develop land, the amount and speed of storm water runoff increases. As a result, flash floods often occur in urban areas where much of the watershed is covered in impervious surfaces. Development in the floodplain and watersheds of Seminole County could lead to increased flooding problems in the future, if not mitigated. Figure 7 shows the distribution of building permits issued from 2015 to mid-2020. New development such as this can trigger more flash floods. This data comes from the Seminole County Building Division. Table 5: Number of Permits for New Construction per Year in Seminole County January 2015- August 2020 2015 2016 2017 2018 2019 2020 Total Commercial 24 19 24 21 14 2 104 Single Family Res 454 298 381 466 675 506 2780 Multi-Family Res 48 85 90 171 69 0 463 Government 0 2 4 0 4 0 10 Total 526 404 499 658 762 508 3357 Figure 7: Location of Permits for New Construction from January 1, 2015-June 30, 2020 Seminole County, Florida • _ °°�'°� Building Permits o � Unincorporated Areas NmR January 1,2015-June 30,2020 I I - I D 1.25 2.5 5 Miles I I I Source: Seminole County GIS Seminole County Floodplain Management Plan 25 164 3 Flood Risk Assessment 3.3.3 Dam Failure Dams are designed to hold back large amounts of water. If they fail or are overtopped,they can produce a dangerous flood situation because of high velocities and large volumes of water released. A break in a dam can occur with little or no warning on clear days when people are not expecting rain or a flood. Breaching often occurs within hours after the first visible signs of dam failure, leaving little time for evacuation. Dam failures are usually caused either by structural problems with the dam or by hydrologic Figure 8: Dams in Florida, based on the 2018 National problems. Structural problems Inventory of Dams include seepage, erosion, _ cracking, sliding and overturning resulting from the age of the dam or a lack of maintenance. Hydrologic problems typically occur when there is excessive runoff due to heavy precipitation. For example, a dam failure can occur if the dam has to impound more water than it was designed to, or if the spillway capacity is inadequate for the amount of water that needs to pass downstream. A dam can suffer a partial failure or a complete failure, but the potential energy of the water stored behind even a small dam can cause loss of life and great property damage downstream. There are currently no dams located within Seminole County, but there are dams located to the north, west and south of the County. 3.3.4 Obstructions Obstructions can affect a channel, such as small bridge openings or log jams, or they can affect an entire floodplain, such as road embankments, fill and buildings. Channel obstructions will cause smaller, more frequent floods, while floodplain obstructions impact the larger, less frequent floods where most of the flow is overbank, outside the channel. Obstructions can be either natural or manmade, and will vary in depth based on the size and type of obstruction. Natural obstructions like log jams can be washed away during larger floods. Manmade obstructions pose a more serious problem, because they tend to be more permanent. 3.4 Historical Flooding Seminole County has experienced several flooding events in the past, caused by heavy rainfall or tropical events. In 1994, two storms brought heavy rain to most of the Florida peninsula during the last half of September. Rivers and streams overflowed, flooding streets and some urban areas. A flash flood Seminole County Floodplain Management Plan 26 165 3 Flood Risk Assessment on July 21, 2001 produced by heavy rain inundated the Tuskawilla area of Winter Springs, flooding three homes and causing $15,000 worth of property damage. There has been one recorded death caused by flooding which took place on September 15, 2001. This occurred in the City of Winter Springs during the aftermath of Tropical Storm Gabrielle, which brought wind gusts to around 45 miles per hour, causing minor damage across much of east central Florida. Following the storm, a 15-year-old boy drowned while playing with friends in Gee Creek near Winter Springs after he was pulled underwater by branches and other debris in the fast-moving water. Raising awareness about the danger of currents following heavy rains, as well as the potential for debris in floodwaters, can help prevent similar accidents in the future. On August 19, 2002,three inches of rapidly falling rain flooded streets and six homes in Sanford. This led to $60,000 of property damage. A thunderstorm brought rainfall and widespread flooding of major roadways in Seminole County on August 29, 2002. The roadway flooding occurred about three miles south of Oviedo. On September 5, 2004, Hurricane Frances brought eight to ten inches of rain across much of Seminole County, flooding homes and streets. Four days later, the rain from Hurricane Frances had caused water levels to reach flood stage in the middle St. Johns River Basin. Levels continued to rise and then fell slightly until Hurricane Jeanne followed the same track across Florida as Hurricane Frances. Significant flooding followed, and the Lake Harney gauge reached a record crest of 10.1 feet. Near Geneva, roads, nurseries and homes along Lake Harney were flooded. Water came over the seawall in Sanford and flooded numerous structures along the south shore of Lake Monroe. The total amount of property damages due to these events was $4.8 million. Flooding in Seminole County following Tropical Storm Fay in 2008(photos courtesy Gary Bg&,A&-antage Consulting LLC}. In 2008, Tropical Storm Fay made four landfalls in Florida. While crossing central Florida, Fay unexpectedly strengthened over land to just under hurricane intensity with 70 mph winds. The storm caused extensive flooding in east central Florida, including historic flooding on the St. Johns River. The rainfall during this period, from August 18th to August 23rd, at its highest reached 17.59 inches with the highest single day being 9.81 inches on August 21 st Approximately 500 homes and many roadways were damaged as the river's water level continued to climb after the storm had passed. Seminole County schools were closed due to impassable roads. The pictures in the box above show floods from Tropical Storm Fay in Seminole County. In October of 2016, Hurricane Matthew brought minor flooding to the Little Wekiva River and Altamonte Springs area. Although the storm only brought tropical storm force winds to Seminole County, $15,000,000 worth of damage occurred as a result. In September of 2017, Hurricane Irma brought major, near record flooding to the Little Wekiva River and St. John's River at Lake Harney. Moderate flooding also occurred in Sanford along Lake Monroe. Although Seminole Seminole County Floodplain Management Plan 27 166 3 Flood Risk Assessment County only experienced tropical storm force winds from Hurricane Irma, the flooding that resulted due to heavy rainfall and already saturated lakes and rivers was severe. Overall, property damages from Irma were approximately $543,200,000. Table 6: Historical occurrences of floods in the County Location Date Time Type Deaths Injuries Property Damages Florida 9/15/1994 NA Flooding 0 0 $500,000 Winter Springs 7/21/2001 5:00 PM Flash Flood 0 0 $15,000 Winter springs 9/15/2001 1:00 PM Urban/Small 1 0 $0 Stream Flood Sanford 8/19/2002 4:45 PM Flash Flood 0 0 $60,000 Oviedo 8/29/2002 4:38 PM Flash Flood 0 0 $0 Seminole County 9/5/2004 1:30 AM Flash Flood 0 0 $0 Geneva and Sanford 9/9/2004 7:00 AM Flooding 0 0 $4,800,000 Seminole County 9/23/2014 5:00 PM Heavy Rain 0 0 $0 Altamonte Springs 6/30/2016 5:30PM Flooding 0 0 $10,000 Seminole County 10/7/2016 3:OOAM Flooding 1 0 $15,000,000 Seminole County 9/10/2017 9:06PM Flooding 0 0 $543,200,000 Source:National Oceanic and Atmospheric Administration's National Environmental Satellite,Data,and Information Service 3.5 Locally Identified Flood Areas While many floodplain boundaries are mapped by NFIP, floods sometimes go beyond the mapped floodplains or change courses due to natural processes, such as erosion and sedimentation, or human development, such as Filling in floodplains to build houses, increased imperviousness within the watershed from new development, or debris. The County has approximately 8,400 single family residences and 150 commercial buildings that could be affected by flooding during a 100-year flood. These businesses and homeowners have been identified by address and GIS mapping. In many flood prone areas, the terrain is heavily wooded with vast areas of marshlands, which receive the overflows from Lake Monroe, Lake Harney, Lake Jesup and the St. Johns River. 3.6 The National Flood Insurance Program In 1968, Congress created the National Flood Insurance Program (NFIP), which enables property owners in participating communities to purchase insurance from the federal government against losses due to flooding. The program is designed as an alternative to disaster assistance. Participation in the NFIP is based on an agreement between local governments and the NFIP that the local government will adopt and enforce a floodplain management ordinance to reduce future flood risks to new construction in Special Flood Hazard Areas, while the federal government will make flood insurance available within the community. More properties are insured for flood damages under NFIP in Florida than in any other state. Seminole County participates in the NFIP, which means that NFIP flood insurance is available to residents living anywhere in the unincorporated area. According to the NFIP, in Seminole County there were 4,109 NFIP flood insurance policies in effect, for a total of$1,218,941,100 in insurance, as of October 2, 2020. Seminole County Floodplain Management Plan 28 167 3 Flood Risk Assessment 3.7 Future Flood Risk Flooding can occur along all waterways in Seminole County, including the St. Johns River, Lake Monroe, Lake Harney, and Lake Jesup. Because there are numerous surface water bodies throughout the County, many locations in the County may be subject to flooding. Areas identified as vulnerable to flooding are depicted on FEMA's Flood Insurance Rate Maps (FIRMS), which are developed through the NFIP and are the official floodplain maps for Seminole County. Many of the County's floodplain management regulations are based on the floodplain limits shown in these maps. It is important to realize that on an annual basis more than 30 percent of all flood losses occur outside any mapped floodplain. FEMA's flood zones represent the areas of risk for flooding. These zones are based on the statistical risk of future flooding, which is extrapolated from historical records to determine the statistical potential that storms and floods of a certain magnitude will recur. Such events are measured by their "recurrence interval," i.e., a 10-year storm or a 50-year flood. A 10-year storm means that there is a 1 in 10 chance, or 10% chance, of that storm occurring in any given year. A 50-year flood has a 1 in 50 chance, or 2% chance, of occurring in any given year. Because these identifiers are based on statistics, such a flood could occur twice in one year, or could not occur at all over the course of 100 years. Table 7: Flood Recurrence Intervals Time Period Chance of Flooding over a Period of Years Flood Size 1 Year 10% 4% 2% 1% 10 Years 65% 34% 18% 10% 20 Years 88% 56% 33% 18% 30 Years 96% 71% 45% 26% 50 Years 99% 87% 64% 39% The map below shows flood zone areas within Seminole County. Areas marked as Zone A have a 1% annual chance of flooding, which translates to a 26% chance of flooding over the life of a 30-year mortgage. This area is the base flood for Seminole County. Detailed analyses are not performed for Zone A, thus flooding depths and base flood elevations are not shown for Zone A areas. Zone AE areas have a 1% annual chance of flooding. These have been determined using detailed methods, thus base flood elevations —the level to which flood waters are expected to rise— are available in these areas. Zone AH are areas subject to 1% annual chance flooding, usually as ponding, with average depths between one and three feet. Areas in yellow have a moderate flood hazard. These are places susceptible to a 0.2% annual chance of flooding. Zone X shows areas where flood hazards are minimal, and have a less than 0.2% annual chance of flooding. Seminole County Floodplain Management Plan 29 168 3 Flood Risk Assessment Figure 10: FEMA Flood Zones in Seminole County Seminole County, Florida Flood Zones FEMA Flood Zones =AE AH F X500 ,-�' -- X —Major Roads LAKE MONROE 0 WaWr Bodies jd(MJ9HNBOHNS Eg[ID RfVER wsR afi r 116- w a ' � a W DIKE RY-SL E� _ LANE HARNEY LAKEJESUP µt1Ps' A. 3 11 &S'41 T -opt 43u- A yh Miles * 1ho LL Source: Seminole County GIS 3.8 Flood Impacts The impacts of floods affect people, buildings, and the economy. These impacts are discussed in this section. 3.8.1 Safety Floods can be extremely dangerous, and even six inches of moving water can knock over a person given a strong current. A car will float in less than two feet of moving water and can be swept downstream into deeper waters. This is one reason floods kill more people trapped in vehicles than anywhere else. During a flood, people can also suffer heart attacks or electrocution due to electrical equipment short outs. 3.8.2 Health While such problems are often not reported,three general types of health hazards accompany floods. The first comes from the water itself. Floodwaters carry anything that was on the ground that the upstream runoff picked up, including dirt, oil, animal waste, and lawn, farm and Seminole County Floodplain Management Plan 30 169 3 Flood Risk Assessment industrial chemicals. Pastures and areas where cattle and hogs are kept or their wastes are stored can contribute polluted waters to the receiving streams. Floodwaters also saturate the ground, which leads to infiltration into sanitary sewer lines. When wastewater treatment plants are flooded, there is nowhere for the sewage to flow. Infiltration and lack of treatment can lead to overloaded sewer lines that can back up into low-lying areas and homes. Even when it is diluted by flood waters, raw sewage can be a breeding ground for bacteria such as E.coli and other disease causing agents. If a water system loses pressure, a boil water order may be issued to protect people and animals from contaminated water. The second type of health problem arises after most of the water has gone. Stagnant pools can become breeding grounds for mosquitoes, and wet areas of a building that have not been properly cleaned breed mold and mildew. A building that is not thoroughly cleaned becomes a health hazard, especially for small children and elderly individuals. Another health hazard occurs when heating ducts in a forced air system are not properly cleaned after inundation. When the furnace or air conditioner is turned on, the sediments left in the ducts are circulated throughout the building and breathed in by the occupants. The third problem is the long-term psychological impact of having been through a flood and seeing one's home damaged and irreplaceable keepsakes destroyed. The cost and labor needed to repair a flood-damaged home puts a severe strain on people, especially the unprepared and uninsured. There is also a long-term problem for those who know that their homes can be flooded again. The resulting stress on floodplain residents takes its toll in the form of aggravated physical and mental health problems. 3.8.3 Evacuation of Residents and Visitors A key evacuation and safety concern is when roads and bridges go under water. Generally, the larger the road,the less likely it is to flood, but this is not always the case. In addition, a bridge does not have to be under water to be damaged or to cut off an evacuation route. In some cases the bridge is high, but the access road may be flooded. In other cases, the bridge or culvert can be washed out. This is especially dangerous if a person drives on a flooded road and assumes that the bridge is still there. Residents and visitors within Seminole County should be made aware of evacuation routes. It is important that the County work with both public and private entities to ensure that everyone knows which roads and thoroughfares are designated for evacuation. The Office of Emergency Management may use the Integrated Public Alert and Warning System (IPAWS) to alert residents and visitors to voluntary and mandatory evacuations. For local flood concerns, the opt- in Alert Seminole system will be used to notify residents who are at risk of flooding. Below is a map from the Florida Division of Emergency Management which indicates the designated evacuation routes for Seminole County. Seminole County Floodplain Management Plan 31 170 3 Flood Risk Assessment Figure 11: Evacuation Routes for Seminole County �owm.E 1! naul � �crtlie. erz-e� Si rt.:o eRa a�J� 93 �Ty . a E '4rsmw.,e � µ L� ■ P Legend s ewd.non RnuMa i.. - a � G � Gmatrtl 6Y:GA�S.cLon.re: °•°°! SEMINOLE R.qumtrd Sy:6trMaN M.y RivwcEVACUATION ROUTES 6.tr:Tl1LtB16 ROI�tl1YfHS]M Tim.:4:89:8ORM OF EL9Mi01SY F.M:S:11ho�.cenEv.cReutrBu.�Eme Mp42G18LLY.psWME:lv.doutr.WTM1Y Lnducay..m.d YRNA6EIIOYT Source: floridadisaster.org/knowyourzone 3.8.4 Critical Facilities Seminole County's FMPC identifies several types of critical facilities including some roads and bridges. The Seminole County Office of Emergency Management maintains a list of critical facilities within Seminole County. This critical infrastructure list is updated on an annual basis and is organized using the Department of Homeland Security's (DHS) Critical Infrastructure Sectors. 3.8.5 Building Damage Floods can cause severe damage to buildings, which can be costly to repair. Although flood insurance can help pay for repairs to buildings damaged by floods, not all property owners obtain insurance. Moreover, preventing damage to buildings is less costly, less disruptive, and less dangerous than sustaining damage. In a few situations, deep or fast moving waters will push a building off its foundation, but this is rare. More frequently, structural damage is caused by the weight of standing water, known as Seminole County Floodplain Management Plan 32 171 3 Flood Risk Assessment "hydrostatic pressure." Basement walls and floors are particularly susceptible to damage by hydrostatic pressure. Not only is the water acting on basement walls deeper, but a basement is also subject to the combined weight of water and saturated earth. In addition, water in the ground underneath a flooded building will seek its own level, resulting in uplift forces that can break a concrete basement floor. The most common type of property damage inflicted by a flood is soaking. When soaked, many materials change their composition or shape. Wet wood will swell and, if dried too quickly, will crack, split or warp. Plywood can fall apart. Drywall will fall apart if it is bumped before it dries. The longer these materials remain wet, the more moisture, sediment and pollutants they will absorb. Soaking can cause extensive damage to household goods. Wooden furniture may become so badly warped that it cannot be used. Other furnishings, such as upholstery, carpeting, mattresses, and books, are usually not worth drying out and restoring. Electrical appliances and gasoline engines will not work safely until they are professionally cleaned and dried. While a building may appear sound and unharmed after a flood, the water may have caused a lot of damage. To properly clean a flooded building, the walls and floors should be stripped, cleaned and allowed to dry before being recovered. This can take weeks and is a costly process. Flood insurance claims figures do not include those items that are not covered by a flood insurance policy, like cars and landscaping, or the value of family heirlooms. They also do not include damages to uninsured or underinsured properties. Table 8 below shows the appraised value of all buildings in unincorporated Seminole County by FEMA flood zone. All of the buildings in these zones are at risk of flood damage. Table 8: Appraised Value of Buildings in Unincorporated Seminole County by Flood Zone A AE AH XJ X500 Row Labels Bldg Value Bldg Count Bldg Value Bldg Count Bldg Value Bldg Count Bldg Value Bldg Count (Agriculture $403,141 7 $1,645,014 32 $18,639,783 277 Commercial $43,523,655 48 $40,122,134 105 $1,478,215,969 2,582 Government $883,135 2 $11,708,347 14 $115,598,910 258 Industrial $15,884,882 48 $18,260,407 126 $11,061,826 3 $941,423,779 2,313 Institutional $9,342,120 29 $74,242,683 48 $833,629 2 $797,744,168 1,303 Multi Family Residential $143,554,658 712 $297,041,819 1,392 $42,150,009 61 $6,344,964,245 32,387 Misc Residential $32,055 4 $383,017 16 $3,321,492 111 Open Space $0 6 $0 23 $0 188 Single Family Residential $632,784,946 2,8261$1,218,018,411 5,373 $40,334,385 203 $20,342,152,825 109,150 Grand Total $846,408,5921 3,6821$1,661,421,832 7,129 $94,379,8491 269 $30,042,061,171 148,569 Source: Seminole County GIS 3.8.6 Economic Impacts Although repairing structural flood damages can be costly, they can also have economic impacts beyond building repairs. Floods can close down businesses for days, weeks, or longer. Businesses can lose their inventories, customers are unable to reach them, and employees are often unable to work. Below is a table which indicates the largest employers in Seminole County which make up much of the tax base. Seminole County Floodplain Management Plan 33 172 3 Flood Risk Assessment Table 9: Seminole County Major Employers Employer Number Employed Seminole County Public Schools 7,868 Central Florida Regional Hospital 2,865 Concentrix Cvg Corporation(Convergys) 1,900 JP Morgan Chase/Chase Bankcard Services 1,900 Deloitte Consulting LLP 1,850 Seminole State College 1,588 Seminole County Government 1,340 Verizon Corporate Resources Group(VCRG) 1,300 Seminole County Sheriffs Office 1,250 Paylocity Holding Corporation 1,100 Liberty Mutual 1,070 Veritas Technologies,LLC(Formerly Symantec) 932 South Seminole Hospital 900 AAA 873 Waste Pro USA Inc. 820 Adventhealth System 800 Elite Technical Svc Inc 600 Tri-City Electrical Contractors Inc. 570 Adventhealth Information Svc 500 Centralsquare Technologies(Superiors LLC) 500 Collis Roofing Inc 500 Del-Air Inc 500 Fisery 500 Mid Fl Procuring&Distribution 500 D&A Window Cleaning Svc Inc 450 Fortress Insurance Partners 450 D&A Building Services Inc. 418 Insurance Office of America Inc. 409 JEUNESSE LLC 407 ABB Inc 400 Irby Construction Co 400 Ethnos(New Tribes Mission USA) 368 A.Duda&Sons Inc. 367 Aerosim Flight Academy-Sanford 350 David Maus Toyota 350 Hartford 350 Maronda Homes 350 Mercedes-Benz Club Of America 350 Source: Seminole County Economic Development According to the 2018 American Community Survey, there are approximately 245,000 workers in the labor force in Seminole County. The most common job groups, by number of people living in Seminole County are Office & Administrative Support Occupations (31,813 people), Management Occupations (29,466 people), and Sales & Related Occupations (28,857 people). Other notable job groups after these include Business and Financial Operations Occupations, Education Instruction& Library Occupations, and Food Preparation& Serving Related Occupations. The table below indicates the taxation value in Unincorporated Seminole County from 2015 through 2019 according to the County Property Appraiser. Table 10: Seminole County Taxable Value Year Value %Change 2015 $13,978,137,571 5.32% 2016 $14,752,369,807 5.54% 2017 $15,661,722,908 6.16% 2018 $16,646,459,602 6.29% Seminole County Floodplain Management Plan 34 173 3 Flood Risk Assessment 2019 $17,892,470,376 7.49% Source:https://www.scpafl.org/Portals/0/LinkFile/202OTaxRolINalueHistory.pdf?ver--2020-06-30-081233-733 3.8.7 Repetitive Loss Properties A repetitive loss property is a property that has experienced repeated flooding that caused financial losses. The National Flood Insurance Program (NFIP) is continually faced with the challenge of balancing the financial soundness of the program with the competing expectations of keeping premiums affordable. Repetitive loss properties are one of the largest obstacles to achieving financial soundness. A repetitive loss property is defined as any insurable building for which two or more claims of more than $1,000 were paid by the NFIP within any rolling 10-year period since 1978. Two of the claims paid must be more than 10 days apart but, within 10 years of each other. A repetitive loss property may or may not be currently insured by the NFIP. Severe Repetitive Loss properties consist of any NFIP-insured residential properties that have met at least 1 of the following paid flood loss criteria since 1978, regardless of ownership: four or more separate claim payments of more than $5,000 each, or two or more separate claim payments where the total of the payments exceeds the current value of the property. Repetitive loss properties are the biggest draw on the National Flood Insurance Fund. Repetitive loss properties are not only costly; they also disrupt and threaten residents' lives. These properties may be sponsored by state or local government programs that mitigate the flood losses or provide information on how to mitigate flood losses through such measures as elevating buildings above the level of the base flood, demolishing buildings, removing buildings from the Special Flood Hazard Area, or local drainage improvement projects. In unincorporated Seminole County, there are forty (40) repetitive loss properties. Three (3) properties were previously designated as repetitive losses, but have been removed from the list after being mitigated. $3,189,486 of building and contents damage has been incurred in total at these repetitive loss properties, with $3,134,014.11 of the damage having occurred on the unmitigated properties. A detailed analyses of each repetitive loss area is recommended to further assess the problem within each specific area of concern, and provide recommendations for solutions. The repetitive loss areas in Seminole County are shown in Figure 11 below. The repetitive loss areas may contain multiple repetitive loss properties, or a single repetitive loss property. Due to privacy restrictions,the individual properties that received the losses are not identified on the maps. Detailed areas of repetitive loss are shown in the following figures. Seminole County Floodplain Management Plan 35 174 3 Flood Risk Assessment Figure 12: Seminole County Repetitive Loss Property Areas Xepetitive LossAreas uT4M�+RF ERkINGS GICSEtOERRY ure wnr �••• —Ma1r5Re[sN6 .,..,��.,�� D cwnv ow.♦an • fl ra all yr t^n 04 1 - R 0 1.25 2-5 5 7.5 10 Mlles Figure 13: Repetitive Loss Area 1 Xepetitive Goss Areas Area 1 + Q Repetitive Loss Area Parcels Major Waterbodies Flood Zones A AE X500 x ❑ 375 0 1,500 Feet Seminole County Floodplain Management Plan 36 175 3 Flood Risk Assessment Figure 14: Repetitive Loss Areas 2 8, 3 Xepetitive Goss Areas Areas 2 d 3 Repetitive Loss Area 9 Parcels Maior Waterbodies Flood Zones A LS AE X500 V X Ji6— 5060 Feet \ II y _ w Figure 15: Repetitive Loss Areas 4, 5, 8, 6 Xepetitive Goss Areas Areas 4, 5, d 6 Q Repetitive Loss Area Parcels e 0 Major Waterbodies Flood Zones -A -AE X500 x 1.00a o a,aoo Feet O Seminole County Floodplain Management Plan 37 176 3 Flood Risk Assessment Figure 16: Repetitive Loss Area 7 Kepetitive Loss-Areas ■� Area 7 �\ Q Repetitive Loss Area Parcels 0 Maior Waterbcdies Flood Zones A —AF X300 i X aAW 0 4,000 Feet Figure 17: Repetitive Loss Area 8 r1t'epetitive GossAreas Area 8 Q Repetitive Loss Area Parcels 0 Maior Waterbodies Flood Zones -AE x 5 0 1,500 Feet e�woomflrm. O =n. Seminole County Floodplain Management Plan 38 177 3 Flood Risk Assessment Figure 18: Repetitive Loss Area 9 Kepetitive LossAreas s� Area 9 Q Repetitive Loss Area Parcels Q Maier Waterbodies Flood Zones AE X500 x 375 9 599 Feet O U i fl Figure 19: Repetitive Loss Area 10 Xepetitive Loss Areas Area 10 Q Repetftive Loss Area .. - Parcels Flood Zones A I AE x 375 0 LSP9 Feet Seminole County Floodplain Management Plan 39 178 3 Flood Risk Assessment Figure 20: Repetitive Loss Area 11 Kepetitive LossAreas ,Area 11 Repetitive LOSS Area (single property) OM Parcels r5o FTM Flood Zones A AE X500 x 375 0 1,500 OlK�Feet Figure 21: Repetitive Loss Areas 12, 13, & 14 Ak IMF Kepetitive Goss Areas -Areas 12, 13, c�14 Repetitive Loss Area (single property) A, Parcels Flood I d Zones A AE x 4 TI ,.'. 1.0n0 0 4,000 Feet I f ."s k M Seminole County Floodplain Management Plan 40 179 3 Flood Risk Assessment Figure 22: Repetitive Loss Areas 15 & 16 Xepetitive GossAreas r Areas 15 a 16 is low O Repetitive Loss Area (single propeRy) Parcels Flood Zones .,.... A AE x 750 0 'x,000 Feel 'rte Ir Vp Figure 23: Repetitive Loss Areas 17 & 18 w Kepetitive Goss Areas Areas 17 c 18 ` 0 Repetitive Loss Area (single property) Parcels Flood Zones A f� AE X500 x500 x I 7s0 0 5.000 Feet E> Seminole County Floodplain Management Plan 41 180 3 Flood Risk Assessment Figure 24: Repetitive Loss Area 19 Repetitive.Goss Areas ' Area 19 O Repetitive Loss Area _ - (single property) Parcels - Flood Zones A X '37i 0 1,50 Feet 3.9 Flood Warning Systems Seminole County residents can sign up for the Alert Seminole Emergency Notification System, which will contact those registered in the event of an emergency that may require evacuation. Residents can register for this emergency notification system by visiting the County's preparedness website at www.prepareseminole.org or by calling the Seminole County Office of Emergency Management at 407-665-5102. Residents can also stay prepared by listening to a NOAA weather radio, particularly during hurricane season, or by calling the citizen's information hotline at (407) 665-0000. Seminole County Floodplain Management Plan 42 181 3 Flood Risk Assessment MONatural and Beneficial Areas In their natural, undeveloped state, floodplains play an important role in flooding. They allow flood waters to spread over a large area, reducing flood velocities and providing flood storage to reduce peak flows downstream. Natural floodplains reduce wind and wave impacts and w their vegetation stabilizes soils. Natural cover acts as a filter for runoff and overbank flows, improving water ' quality and minimizing the amount of sediment transported downstream and the impurities in that sediment. Wetlands at the Lake Jesup Wilderness Area in Seminole Floodplains can be recharge areas for County groundwater and reduce the frequency and duration of low flows of surface water. They provide habitat for diverse species of plants and animals, some of which cannot live in other habitats. Floodplains are particularly important as breeding and feeding grounds. Natural floodplains also moderate water temperature, reducing potential harm to aquatic plants and animals. Seminole County preserves and manages several wilderness areas to protect biodiversity of species, wildlife corridors, and water resources while offering passive recreation areas for Seminole County residents. Through a voter approved referendum in 1990, a $20 million bond was established, creating the Seminole County Natural Lands Program. The primary purpose of this program is to systematically assess, rank and purchase environmentally significant lands throughout the County. These lands are purchased to preserve or restore their important ecological functions as well as to provide sites for passive, resource-based recreational activities. Since the program's inception, Seminole County has purchased just over 6,600 acres. Many of the natural land areas are located within the Special Flood Hazard Area(SFHA), and provide natural and beneficial functions of a natural floodplain. Several of these sites have been opened for public access, as shown in Figure 24 on the next page. Seminole County Floodplain Management Plan 43 182 3 Flood Risk Assessment Figure 25: Wilderness Area Open to the Public in Seminole County BLACK BEAR % LDERNESS AREA I iw arwiru LAXE HARKEY WfLDERNESREA ° LAKE PROCTOR'wm'r LAKE 1ESUP WI LDERN ESS AREA WILDERNESSAREA RLACKHAMMOCK NIILDERN AREA jq rur SPRING HAMMOCK WILDERNESS AREA aaa ra@1EYA WILDERNESS AREA w w CHULUOT'A ECON RIVER WILDERS AREA 4" WILDEAREA 3.11 References 1. Local Mitigation Strategy for Seminole County and its Municipalities, 2020-2025 2. Seminole County Comprehensive Plan, Seminole County, 2018. 3. American Community Survey 2018 4. floridadisaster.org/knowyourzone 5. Seminole County Property Appraiser's Office 2020 Tax Roll 6. Flood insurance claims records for Seminole County, FEMA. 7. National Oceanic and Atmospheric Administration's National Environmental Satellite, Data, and Information Service 8. National Oceanic and Atmospheric Administration's National Hurricane Center Seminole County Floodplain Management Plan 44 183 5 Preventive Measures 4 Goals and Objectives Chapter 3 documents the flood risk that threatens the unincorporated areas of Seminole County, the vulnerability of structures, infrastructure, and critical facilities to floods, and the capacity the County has to reduce the flood hazard. The intent of Goal Setting is to identify areas where the County's existing capabilities (in terms of policies and programs) can be enhanced so that the community's overall vulnerability to flood hazards is reduced. Goals are also necessary to guide the review of possible mitigation measures. At the same time, this plan needs to ensure that recommended actions are consistent with what is appropriate for Seminole County. Mitigation goals need to reflect community priorities and be consistent with other plans for the County. 4.1 Background 4.1.1 Seminole County Local Mitigation Strategy The goals of this plan need to be consistent with and complement the goals of other planning efforts. The primary planning document that this Floodplain Management Plan must complement and be consistent with is the Seminole County Local Mitigation Strategy. This plan will be adopted as an appendix to Seminole County Local Mitigation Strategy; therefore the goals in both planning documents should align and not conflict. The six goals of the Seminole County Local Mitigation Strategy are: • Goal 1: Local government shall make every reasonable effort to identify, develop, implement, and reduce hazard vulnerability through effective mitigation programs. • Goal 2: All sectors of the community will work together to create a disaster resistant community. • Goal 3: Reduce the vulnerability of critical infrastructures and public facilities from the effects of all hazards. • Goal 4: Strengthen continuity planning for local government, businesses and community partners to avoid significant disruptions of services. • Goal 5: Develop policies and regulation to support effective hazard mitigation programming throughout the community. • Goal 6: Encourage economic vitality of the community by providing business continuity education, disaster planning, and diversifying employment opportunities. Seminole County Floodplain Management Plan 45 184 5 Preventive Measures 4.2 Goals Following the exercises, the FMPC agreed upon five general goals for this planning effort. The goals were refined and objectives in support of the goals were also added. Goal 1: Reduce vulnerability and exposure to flood hazards in order to protect the lives, health, safety and welfare of Seminole County citizens and guests. Objective 1.1: Focus mitigation efforts on flooding resulting from heavy rainfall which causes runoff, overbank, backwater, and stormwater issues to keep the problem from getting worse Objective 1.2: Implement regulatory measures to discourage new development in areas that are more likely to be exposed to the effects of flood damage Objective 1.3: Preserve open space in hazardous areas, especially where there are sensitive natural areas and agricultural lands Objective 1.4: Protect the environmental integrity of the natural water systems in Seminole County by focusing on water quality and best management practices Objectives 1.5: Continue to protect aquifers and environmentally sensitive lands from encroachment of development by requiring buffers and other setbacks mechanisms Objective 1.6: Reduce stormwater runoff through adequate stormwater management, flood control, on-site retention and best management practices to mitigate impacts associated with incremental construction and redevelopment projects Goal 2: Promote emergency management and warning system measures to provide better protection to the citizens and guests of Seminole County. Objective 2.1: Leverage state and federal emergency management funding for planning, training and equipment Objective 2.2: Seek funding for the installation of stream and river gages to help provide increased flood warning capability Objective 2.3: Monitor technological advancements and implement new technologies where applicable to ensure reliable communications with residents and guests Goal 3: Encourage property owners through education and outreach measures to protect their homes and businesses from flood damage. Seminole County Floodplain Management Plan 46 185 5 Preventive Measures Objective 3:1: Encourage residents to assume an appropriate level of responsibility for their own protection Objective 3.2: Promote flood insurance as a property protection measure against flood damage through multiple methods, including enhancements to the county website to provide information on comprehensive flood preparedness/protection and flood insurance Objective 3.3: Educate property owners, including repetitive loss properties, on FEMA grant programs and other methods in order to mitigate possible flood damage Goal 4: Protect critical and cultural facilities, public infrastructure, and businesses from the effects of flood hazards and reduce the vulnerability of flood damage to these facilities. Objective 4.1: Seek County, State and Federal support for projects Objective 4.2: Identify and implement flood mitigation measures or strategies as necessary to protect critical infrastructure and facilities from flood damage Goal 5: Identify properties susceptible to flood damage and implement cost-effective and affordable improvements, including those which reduce the number of repetitively damaged structures. Objective 5.1: Leverage state and federal grant funding to facilitate buyouts, elevations and other mitigation efforts Objective 5.2: Target repetitive loss properties for implementation of mitigation projects Objective 5.3: Allow continued opportunities for members of the public to be part of the planning process, including identifying areas susceptible to flooding Seminole County Floodplain Management Plan 47 186 5 Preventive Measures 5 Preventive Measures Preventive measures are designed to keep a problem such as flooding from occurring or from getting worse. The objective of preventive measures is to ensure that future development is not exposed to damage and does not cause an increase in damages to other properties. Building, zoning, planning and code enforcement offices usually administer preventive measures. Some examples of types of preventive measures include: • Building codes • Planning and zoning • Open space preservation • Floodplain regulations • Stormwater management 5.1 Building Codes Building codes provide one of the best methods of addressing flood hazards. When properly designed and Figure 26: Elevated Home constructed according to code,the average building can withstand many of the impacts of natural hazards. Hazard protection standards for all new and improved or repaired buildings can be incorporated into the local building code. Building codes can ensure that the first Local floors of new buildings are constructed to be higher ,00v �irement than the elevation of the 100-year flood (the flood thatis expected to have a one percent chance of occurring in any given year). Building codes in Seminole County also require that driveways are sloped so as to prevent flood waters from draining into a building. Just as important as having code standards is the enforcement of the code. Adequate inspections are needed during the course of construction to ensure the builder understands the requirements and is following them. Making sure a structure is properly anchored requires site inspections at each step. Seminole County's Code of Ordinances adopts the Florida Building Code by reference, and the State of Florida has some of the most stringent building codes in the nation. Nonetheless, during planning meetings where the mitigation strategies were evaluated, the FMPC discussed possible ways to strengthen Seminole County's building codes. There is relatively no cost involved in strengthening codes, but since the County adopts the Florida Building Code, the possibility of exceeding current code requirements is extremely slim. Another possibility discussed was to increase the freeboard requirement for buildings to be built higher than the current 1 ft. above the base flood elevation. Seminole County Floodplain Management Plan 48 187 5 Preventive Measures 5.1.1 Manufactured Homes - Manufactured or mobile homes are usually not regulated by local building codes. They are built in a factory and out of state, and they are shipped to a site. They do have to meet construction standards set by the U.S. Department of Housing `y;a and Urban Development. All mobile homes constructed after 1976 must comply with HUD's - National Manufactured Home Construction and Safety Standards. These standards apply uniformly across the country and it is illegal for a local unit of government to require additional construction requirements. Local jurisdictions may regulate the location of these structures and their on-site installation. The NFIP allows communities to exempt mobile homes in existing mobile home parks from some of the flood protection requirements. The CRS provides up to 50 points if the community does not use this exemption. Seminole County does not use this exemption. 5.1.2 Local Implementation Seminole County uses the 2017 Florida Building Code. The County's floodplain management ordinance requires development in areas of special flood hazard to be reasonably safe from flooding. This means that new construction and substantial improvements shall be designed or modified and adequately anchored to prevent flotation, collapse or lateral movement of the structure resulting from flooding. New construction and substantial improvements must also be constructed using methods that minimize flood damage.New construction or substantial improvement of any residential structure, including manufactured homes, must have the lowest floor, including the basement, elevated to no lower than one foot above the base flood elevation. In addition, manufactured homes must be anchored to prevent flotation, collapse, or lateral movement. For commercial properties, the first floor must be elevated to one foot above the base flood or they must be flood-proofed in lieu of being elevated. 5.1.3 CRS Credit The CRS encourages strong building codes. It provides credit in two ways: points are awarded based on the community's BCEGS (Building Code Effectiveness Grading Schedule) classification and points are awarded for adopting the International Code series. Seminole County's BCEGS rating is a Class 4 for residential and Class 3 for commercial. Seminole County uses the 2017 Florida Building Code, and will be adopting the 2020 FBC on 12/31/2020. The CRS also has a prerequisite for a community to attain a CRS Class 8 or better: the community must have a BCEGS class of 6 or better. To attain a CRS Class 4 or better,the community must have a BCEGS class of 5 or better. Seminole County Floodplain Management Plan 49 188 5 Preventive Measures 5.2 Planning and Zoning Building codes provide guidance on how to build in hazardous areas. Planning and zoning activities direct development away from these areas, especially floodplains and wetlands. They do this by designating land uses that are compatible with the natural conditions of lands prone to flooding, such as open space or recreation. Planning and zoning activities can also provide benefits simply by allowing developers more flexibility in arranging improvements on a parcel of land through the planned development approach. 5.2.1 Comprehensive Plans These plans are the primary tools used by communities to address future development. They can reduce future flood-related damages by indicating open space or low density development within floodplains and other hazardous areas. Unfortunately, natural hazards are not always emphasized or considered in the specific land use recommendations. Generally, a plan has limited authority. It reflects what the community would like to see happen. Its utility is that it guides other local measures, such as capital improvement programs, zoning ordinances, and subdivision regulations. 5.2.2 Zoning Regulations A zoning ordinance regulates development by dividing a community into zones and setting development criteria for each zone. Zoning codes are considered the primary tool to implement a comprehensive plan's guidelines for how land should be developed. Zoning ordinances can limit development in hazardous areas, such as reserving floodplain zones for agricultural uses. Often, developers will produce a standard grid layout. The ordinance and the community can allow flexibility in lot sizes and location so Figure 27: Planned Unit Developments developers can avoid hazardous areas. One way to encourage such flexibility is to use a planned unit >} development (PUD) approach. This , approach allows 1� developers to incorporate flood hazard mitigation measures into projects. Open PUD: In the standard zoning approach (left), the developer considers six equally-sized space or floodplain lots without regard for the flood hazard. Two properties are subject to flooding and the natural stream is disrupted.An alternative,flexible,PUD approach is shown on the right. preservation can be The floodplain is dedicated as public open space.There are seven smaller lots,but those facilitated as site design abutting the floodplain have the advantage of being adjacent to a larger open area_Four lots have nverfront views instead of two_These amenities compensate for the smaller lot standards and land use sizes, so the parcels are valued the same. The developer makes the same or more densities can be income and the future residents are safer adjusted to fit the property's specific characteristics, as shown in Figure 26. Seminole County Floodplain Management Plan 50 189 5 Preventive Measures 5.2.3 Capital Improvement Plans A capital improvement plan will guide a community's major public expenditures for a five- to 20-year period. Capital expenditures may include acquisition of open space within the hazardous areas, extension of public services into hazardous areas, or retrofitting existing public structures to withstand a hazard. 5.2.4 Local Implementation The Seminole County Comprehensive Plan includes conservation goals to address the long-range implementation of programs aimed at meeting environmental regulations and preserving the County's natural amenities. Seminole County uses a multi-faceted system to direct incompatible land uses away from wetlands. To date, this system has managed to preserve most of the wetland acreage in the urban area. There are three primary methods by which the County directs incompatible land uses away from wetlands, and several secondary methods. The primary methods are: 1. Identification of environmentally sensitive lands. These lands are to be preserved during the development process. 2. Land acquisition. Seminole County also protects wetlands through land acquisition via the County's Natural Lands Program. In combination with the efforts of the U.S. Army Corps of Engineers, the Florida Department of Environmental Protection and the St. Johns River Water Management District, over 18,000 acres of the County's 41,000 acres of wetlands are in public ownership. This is roughly 44% of County lands. 3. Special areas. The County and the State have designated areas for special consideration to protect wetlands, including the Wekiva River Protection Area, the Econlockhatchee River Protection Zone, and the East Rural Area. These three areas make up roughly 75 percent of the County's unincorporated area. Development within these areas is managed and regulated to protect natural resources and maintain their rural character. The secondary methods of directing incompatible uses away from wetlands are through the implementation and execution of the Comprehensive Plan's Future Land Use designations and Seminole County's Land Development Code. 1. Special Techniques. For example, allowing clustering of development, or planned development, in exchange for preserving open areas which protects natural resources from development. 2. Environmentally Sensitive Land Overlay. Seminole County maintains an Environmentally Sensitive Lands Overlay Area, as defined in the Comprehensive Plan. The Environmentally Sensitive Lands Overlay Area includes any areas flooded during a 100-year flood event or identified by NFIP as Zone A or Zone V, as well as wetlands as defined by the St. Johns River Water Management District. This designation is used to limit permitted uses on wetland properties and direct development away from environmentally sensitive lands. 3. The Urban/Rural Boundary. This boundary forms the foundation for both wetland regulation and for the land uses that are assigned throughout the County. Having established that the East Rural Area contains a high quality mosaic of valuable wetland and upland systems, the County has adopted a limited number of land use designations of Seminole County Floodplain Management Plan 51 190 5 Preventive Measures very low density in the Rural Area to protect these resources. 5.2.5 CRS Credit The CRS provides flood insurance discounts to those communities that implement various floodplain management activities that meet certain criteria. Comparing local activities to those national criteria helps determine if local activities should be improved. Up to 100 points are provided for regulations that encourage developers to preserve floodplains or other hazardous areas from development. There is no credit for a plan, only for the enforceable regulations that are adopted pursuant to a plan. Up to 600 points are provided for setting aside floodplains for low density zoning, such as five acre lots or conservation. 5.3 Open Space Preservation Keeping the floodplain and other hazardous areas open and free from development is the best approach to preventing damage to new developments. Open space can be maintained in agricultural use or can serve as parks, greenway corridors and golf courses. Comprehensive and capital improvement plans should identify areas to be preserved by acquisition and other means, such as purchasing an easement. With an easement, the owner is free to develop and use private property, but property taxes are reduced or a payment is made to the owner if the owner agrees to not build on the part set aside in the easement. Although there are some federal programs that can help acquire or preserve open lands, open space lands and easements do not always have to be purchased. Developers can be encouraged to dedicate park land and required to dedicate easements for drainage and maintenance purposes. These are usually linear areas along property lines or channels. Maintenance easements also can be donated by streamside property owners in return for a community maintenance program. 5.3.1 Local Implementation In 1990, the voters of Seminole County approved a$20 million bond which created the Seminole County Natural Lands Program (NLP). The NLP established a system to access, rank and purchase environmentally significant lands throughout the County. In 2000, a voter-approved referendum provided for $25 million dollars with $20 million dollars of support of the County trails program and $5 million dollars for natural lands. The County used these funds to purchase land to preserve or restore their important ecological functions, as well as provide sites for passive resource-based recreational activities. Since the inception of the program, Seminole County has purchased and currently manages just over 6,600 acres of land through the NLP. The County's adoption of flood prone and wetland ordinances were critical steps in providing countywide protection of wetlands. The County's wetlands protection program has established an extensive network of wetlands under conservation easements. Conservation easements are used to protect post-development flood prone and wetland areas. Conservation easements are blanket easements over the area of concern and are granted to Seminole County, state or Federal Seminole County Floodplain Management Plan 52 191 5 Preventive Measures agencies or some combination thereof. Conservation easements act to limit any future encroachment or development and thus provide protection of flood prone and wetland areas. Conservation easements are required of all developments except for single family residences that contain post-development flood prone or wetland areas within their site boundaries and may be granted as specified in Section 35.101(a) (c) of the Land Development Code. Land acquisition efforts by Seminole County and the State of Florida have led to the conservation of major wetland systems in the Econlockhatchee, Wekiva, St. Johns, and Lake Jesup Basins. An ongoing focus on the conservation of intact wetland systems in the rural portion of the County supplements these acquisition programs. Preserved lands in Seminole County are shown in the figure below. Figure 28: Preserved Lands in Seminole County JAKE 3IO_NR.OI 1 # SP-46A STJOH.Z 1 RIVER SR-447 - SM46 L4KE ,V _'IiAxl.IFSUP IF SR 43 FO13-.Md=ATa crvs,R.n.Ex _ � ST3OFL�:S Legend MVER -6.1sjp Roads ' Wtein Wt.9dies C*Seminole Cointy Preserved Lands Florida Audition Sudety V4 County 3 C-3 ate fl 25 5 10 Miles a E Fedaal I I I I I I I 5 Wilderness areas and trails created from these referendums include the Black Bear, Black Hammock, Geneva, Chuluota, Lake Proctor, Econ River, Lake Jesup, and Spring Hammock Preserve. These environmental assets are open to the public for environmental education and passive recreation. The County designated these lands as "Preservation/Managed Lands" on the Future Land Use Plan Map in 2008. The County will continue to manage the more than 6,600 acres of Natural Lands acquired through these bond referendum for the preservation of significant natural habitats, open space areas and greenways. Seminole County Floodplain Management Plan 53 192 5 Preventive Measures In addition, the Comprehensive Plan states that the County shall include in its Land Development Code neighborhood performance standards for"common, liked and usable open space for active and/or passive recreation, including interconnected walkways,bikeways, trails and greenways" as well as "Preservation of onsite natural lands." The County's Land Development Code requires that all new development, unless otherwise specified within the Code, include a minimum amount of urban, suburban or rural open space and that open space areas within a development be connected to each other. The amount and type of required open space varies with the character of the proposed development and surrounding land uses. For commercial developments, the open space ratio is a minimum of 25% of the parcel. 5.3.2 CRS Credit Preserving flood prone areas as open space is one of the highest priorities of the Community Rating System. Up to 1,450 points can be given for keeping land vacant through ownership or regulations (Activity 420 — Open Space Preservation). 5.4 Subdivision Regulations Subdivision regulations govern how land will be subdivided and set construction standards. These standards generally address roads, sidewalks, utilities, storm sewers, and drainageways. They can include the following flood protection standards: • Requiring that the final plat show all hazardous areas • Requiring that each lot be provided with a building site above the flood level • Requiring that all roadways be no more than one foot below the flood elevation 5.4.1 Local Implementation Seminole County's subdivision regulations require: • Final subdivision plats require the 100-year floodplain boundary to be identified. 5.5 Floodplain Regulations Most communities with a flood problem participate in the National Flood Insurance Program (NFIP). The NFIP sets minimum requirements for the participating communities' standards for development, subdivision of land, construction of buildings, installation of mobile homes, and improvements and repairs to buildings. These are usually spelled out in a separate ordinance. The NFIP minimum requirements are summarized on the next page. It should be stressed that these are minimum requirements. To gain credit in the CRS, communities must adopt and implement floodplain regulations that go above and beyond the minimum requirements of the NFIP. 5.5.1 Enforcement To ensure that communities are meeting the NFIP standards, FEMA periodically conducts a Community Assessment Visit. During this visit, the maps and ordinances are reviewed, permits Seminole County Floodplain Management Plan 54 193 5 Preventive Measures are checked, and issues are discussed with staff. Failure to meet all of the requirements can result in one or more consequences: • Reclassification under the Community Rating System to a higher class • Probation, which entails a$50 surcharge on every flood insurance policy in the community, or • Suspension from the NFIP. If a community is suspended, the following sanctions are imposed: o Flood insurance will not be available. No resident will be able to purchase a flood insurance policy. o Existing flood insurance policies will not be renewed. o No direct federal grants or loans for development may be made in identified flood hazard areas under programs administered by federal agencies, such as HUD, EPA, and the Small Business Administration. o Federal disaster assistance will not be provided to repair insurable buildings located in identified flood hazard areas for damage caused by a flood. o No federal mortgage insurance or loan guarantees may be provided in identified flood hazard areas. This includes policies written by FHA (Federal Housing Administration), VA (Veterans Affairs), and others. o Federally insured or regulated lending institutions, such as banks and credit unions, must notify applicants seeking loans for insurable buildings in flood hazard areas that there is a flood hazard and the property is not eligible for federal disaster relief. These sanctions can be severe for any community with a substantial number of buildings in the floodplain. Most communities with a flood problem have joined the NFIP and are in full compliance with their regulatory obligations. One way to assure good administration and enforcement is to have Certified Floodplain Managers on staff. The Association of State Floodplain Managers administers the national Certified Floodplain Manager (CFM®)program. Certification involves a three hour exam and a requirement for continuing education each year. The exam covers the regulatory standards of the National Flood Insurance Program as well as mapping, administration, enforcement and flood hazard mitigation. 5.5.2 Minimum NFIP Regulatory Requirements The NFIP is administered by FEMA. As a condition of making flood insurance available for their residents, communities that participate in the NFIP agree to regulate new construction in the area subject to inundation by the 100-year (base) flood. The floodplain subject to these requirements is shown as an A or V Zone on the Flood Insurance Rate Map (FIRM). There are five major floodplain regulatory requirements. Additional floodplain regulatory requirements may be set by state and local laws. 1. Continue to enforce their adopted Floodplain Management Ordinance requirements, which include regulating all new development and substantial improvements in Special Flood Hazard Areas (SFHA). 2. Continue to maintain all records pertaining to floodplain development, which shall be available for public inspection. Seminole County Floodplain Management Plan 55 194 5 Preventive Measures 3. Continue to notify the public when there are proposed changes to the floodplain ordinance or Flood Insurance Rate Maps. 4. Maintain the map and Letter of Map Change repositories. 5. Continue to promote Flood Insurance for all properties. Communities are encouraged to adopt local ordinances that are more comprehensive or provide more protection than the federal criteria. The NFIP's Community Rating System provides insurance premium credits to recognize the additional flood protection benefit of higher regulatory standards. 5.5.3 Local Implementation Seminole County's Floodplain Ordinance meets all of the NFIP's floodplain BFB regulatory requirements. The County's _ Floodplain Ordinance exceeds minimum NFIP standards for a number of elements that are credited in the CRS. 5.5.4 CRS Credit There are many higher regulatory BFE standards that warrant CRS credit. These standards include: ~ • Delineating a floodway, the area of higher hazard near the channel. This would allow development outside the floodway(called the FE "floodplain fringe") without B . engineering studies to determine their impact on others. • Requiring all new construction to be elevated one or two feet above the base flood elevation to provide an extra level of protection from waves and higher floods. This extra protection is reflected in a distinct reduction in flood insurance rates. • Having all developers (not just the larger ones) provide flood data where none are available. • Specifications to protect foundations from erosion, scour and settling. • Prohibiting critical facilities from all or parts of the floodplain. • Prohibiting hazardous materials. • Requiring buffers adjacent to streams or natural areas. • Restrictions on use of enclosures below elevated buildings. • Flood storage lost due to filling and construction must be compensated for by removal of an equal volume of storage. • The CRS also provides credit for having trained staff and a higher credit if the staff members are Certified Floodplain Managers. Seminole County Floodplain Management Plan 56 195 5 Preventive Measures It should be noted that one of the prerequisites for participation in the CRS is that the community be in full compliance with the minimum requirements of the NFIR A community with a number of"potential violations" risks being removed from the CRS entirely. Seminole County's Floodplain Ordinance requires that residential construction is built with the lowest floor no lower than one foot above the base flood elevation, which is an extra requirement beyond NFIP's minimum requirements. An additional requirement beyond the minimum for Seminole County is that the ordinance sets specific restrictions on the use of enclosures below elevated buildings. The County has a total of seven Certified Floodplain Managers on staff, three of whom are in the Development Services Department. Buffers are required within wetlands to protect the natural and beneficial functions of the floodplain. Seminole County has a floodplain storage capacity requirement that requires that if fill is brought into a development, an equal amount of fill must be removed somewhere in the floodplain to maintain the floodplain storage capacity. 5.6 Stormwater Management Development in floodplains is development in harm's way. New construction in the floodplain Figure 30: Effect of Development on increases the amount of development exposed to Stormwater damage and can aggravate flooding on neighboring properties. Development outside a 401,6 evaporation floodplain can also contribute to flooding problems. Stormwater runoff is increased when natural ground cover is replaced by urban development (see graphic). Development in the w watershed that drains to a river can aggravate 10.E runoo ff downstream flooding, overload the community's 25%Shallow drainage system, cause erosion, and impair water infiltration quality. There are three ways to prevent flooding 25", deep infiltration problems caused by stormwater runoff. I. Regulating development in the floodplain to ensure that it will be protected from 30%evaporation flooding and that it won't divert floodwaters onto other properties. 2. Regulating all development to ensure that the post-development peak runoff will not161� s5°'t runaff be greater than it was under pre- Pr, n"gyshallow development conditions. infiltration 3. Set construction standards so buildings 5,, deep infiltration are protected from shallow water. eve�oped Land Seminole County Floodplain Management Plan 57 196 5 Preventive Measures Many communities participate in the NFIP, which sets minimum requirements for regulating development in the floodplain. The State of Florida has more stringent requirements than the NFIP, including a requirement that all new buildings must be elevated to no lower than one foot above the base flood elevation. Stormwater runoff regulations require developers to build retention or detention basins to minimize the increases in the runoff rate caused by impervious surfaces and new drainage systems. Generally, each development must not let stormwater leave at a rate higher than what existed under pre-development conditions. Standards for drainage requirements are typical in subdivision regulations. Standards for storm sewers, ditches, culverts, etc., are best set when an area is laid out and developed. Traditionally, the national standard is to require that the local drainage system carry the 10-year storm. Recently, communities are finding that older estimates of the 10-year storm understated the true hazard, so they are addressing larger storms. One problem with requiring the drainage system to carry water away is that runoff increases with urban development. The runoff equivalent of a 10-year storm occurs more frequently, and from smaller storms. The problem is just sent downstream onto someone else's property. Accordingly, modern subdivision regulations require new developments to ensure that the post- development peak runoff will not be greater than it was under pre-development conditions. This is usually done by constructing retention or detention basins to hold the runoff for a few hours or days, until flows in the system have subsided and the downstream channels can accept the water without flooding. If the storm sewers or roadside ditches cannot handle a heavy rain, the standard subdivision design uses the streets to carry excess runoff If the flows exceed the streets' capacity, adjacent properties will flood. Therefore, the third approach to protecting from stormwater flooding is to make sure new buildings are elevated one or two feet above the street or above adjacent grade. 5.6.1 Local Implementation The County's surface water management standards, within the Public Works Engineering Manual, set requirements for managing runoff from new developments. The standards require the storage and controlled release or retention on-site and infiltration into the ground of excess stormwater runoff from any commercial, industrial, and residential developments such that runoff from the site and peak attenuation rates will not be greater post-development than they were prior to development. The procedure for disposing of excess stormwater runoff varies depending on the Hydrologic Soil Classification of the soils within the proposed development. For pervious soils (types A and B), the required overall stormwater management strategy is on-site retention and infiltration into the ground. For impervious soils (types C and D) or high ground water table areas (types A/D, B/D and C/D) the required overall stormwater management system is providing detention basins to attenuate the peak from the contributory drainage area and to settle solids washed off or eroded. The Public Works Engineering Manual also encourages the use of natural vegetative cover in controlling erosion. The Seminole County Land Development Code provides for two overlay districts that protect the Wekiva River and the Econlockhatchee River by requiring design standards that establish high Seminole County Floodplain Management Plan 58 197 5 Preventive Measures quality development that is rural, maintains existing vegetation, protects wetlands, and minimizes disturbance to certain species and their habitats. Within the Wekiva River zoning overlay, development activity and the placement or depositing of fill is prohibited within wetlands and the 100-year floodplain. Within the Econlockhatchee zoning overlay, native plants must be used and removal of vegetation minimized in landscaping to the greatest extent practical and peak discharge rates for stormwater BMPs shall not exceed the pre-development rate for the mean annual storm event (24 hour, 2.3 year return period) and the 25-year storm. In some parts of the Econlockhatchee zoning overlay, development is prohibited within 550 feet of the stream's edge of channels of the Big Econlockhatchee River and the Little Econlockhatchee River except for the creation of wetlands and passive recreational uses. 5.6.2 CRS Credit CRS credit is provided for both higher regulatory standards in the floodplain and stormwater management standards for new developments. Credit is based on how those standards exceed the minimum NFIP requirements. The Public Works Engineering Manual has the following provisions that would be recognized by the CRS (in addition to provisions discussed in previous sections): • Standards for retention and detention basis • Requirements for erosion and sedimentation control 5.7 Conclusions 1. Installation of new mobile homes appears to be adequately administered to ensure proper tie downs and flood protection. 2. The majority of the comprehensive and land use plans address floodplains and the need to preserve these hazardous areas from intensive development. However, most zoning ordinances do not designate floodprone areas for any special type of land use. 3. Standards in subdivision regulations for public facilities should account for the hazards present at the site. New building sites, streets, and water systems should facilitate access and use by fire and emergency equipment. 4. A percentage of the county's floodplain is open space in public ownership. Because some of the floodplain is still undeveloped and not preserved as open space preventive measures can have a great impact on future flood damages. There are more opportunities to preserve more open space, especially when new developments are proposed. 5. The County's floodplain development and stormwater management regulations exceed minimum national and state standards in many areas and will be helpful in preventing flood problems from increasing. 5.8 Recommendations 1. The County planning and engineering staff should develop example subdivision ordinance language that requires new infrastructure to have hazard mitigation provisions, such as: a. Buried utility lines and Seminole County Floodplain Management Plan 59 198 5 Preventive Measures b. Storm shelters in new mobile home parks. 2. The County should use every opportunity to preserve floodplain areas as open space or other uses compatible with the flooding hazard. 3. The County should consider increasing the freeboard requirement by six (6) inches, from one (1) foot above the base flood elevation (BFE) to 1.5 ft. above BFE. 4. The County should continue to enforce its existing regulations for development and mobile homes and consider other higher standards to further protect the residents of Seminole County. 5.9 References 1. CRS Coordinator's Manual, FEMA, 2017. 2. Design and Construction Guidance for Community Shelters, FEMA, 2000. 3. Manufactured Home Installation in Flood Hazard Areas, FEMA, 1985. 4. Multi-Hazard Identification and Risk Assessment, FEMA, 1997. 5. Seminole County Code of Ordinances and Land Development Code, Seminole County. 6. Subdivision Design in Flood Hazard Areas, American Planning Association and FEMA, PAS Report 473, 1997. 7. Floodplain Management in Florida Quick Guide, FDEM Bureau of Mitigation, 2017. Seminole County Floodplain Management Plan 60 199 6 Property Protection Measures 6 Property Protection Measures Property protection measures are used to modify buildings or property subject to damage. Property protection measures fall under three approaches: • Modify the site to keep the hazard from reaching the building, • Modify the building so it can withstand the impacts of the hazard, and • Insure the property to provide financial relief after the damage occurs. Property protection measures are normally implemented by the property owner, although in many cases technical and financial assistance can be provided by a government agency. These are discussed later in this chapter. 6.1 Keeping the Hazard Away Generally, natural hazards do not damage vacant areas. As noted earlier, the major impact of hazards is to people and improved property. In some cases, properties can be modified so the hazard does not reach the damage-prone improvements. For example, a berm can be built to prevent floodwaters from reaching a house. 6.1.1 Flooding There are five common methods to keep a flood from reaching and damaging a building: I. Erect a barrier between the building and the source of the flooding. 2. Move the building out of the floodprone area. 3. Elevate the building above the flood level. 4. Demolish the building. 5. Replace the building with a new one that is elevated above the flood level. 6.1.2 Barriers A flood protection barrier can be built Figure 31: Flood Protection Barrier of dirt or soil (a"berm") or concrete or steel (a"floodwall"). Careful design is needed so as not to create flooding or drainage problems on neighboring properties. Depending on how porous the ground is, if sf iki) and pur1n11 ii iridle floodwaters will staya for more than underseepage and p internal drainage an hour or two,the design needs to Berrn account for leaks, seepage of water underneath, and rainwater that will fall Small barriers can be effective against shallow flooding. inside the perimeter. This is usually done with a sump or drain to collect the internal groundwater and surface water and a pump and pipe to pump the internal drainage over the barrier. Seminole County Floodplain Management Plan 61 200 6 Property Protection Measures Barriers can only be built so high. They can be overtopped by a flood higher than expected. Barriers made of earth are susceptible to erosion from rain and floodwaters if not properly sloped, covered with grass, and properly maintained. A berm can also settle over time, lowering its protection level. A floodwall can crack, weaken, and lose its watertight seal. Therefore, barriers need careful design and maintenance (and insurance on the building, in case of failure). 6.1.3 Relocation Moving a building to higher ground is the surest and safest way to protect it from flooding. While almost any building can be moved, the cost increases for heavier structures, such as those with exterior brick and stone walls, and for large or irregularly shaped buildings. However, experienced building movers can handle any job. In areas subject to flash flooding, deep waters, or other high hazard, relocation is often the only safe approach. Relocation is also preferred for large lots that include buildable areas outside the floodplain or where the owner has a new flood-free lot (or portion of the existing lot) available. 6.1.4 Building Elevation Raising a building above the flood level can be almost as effective as moving it out of the _ floodplain. Water flows under the building, causing little or no damage to the structure or its contents. Raising a building above the flood level is cheaper than moving it and can be less disruptive to a neighborhood. Elevation has proven to be an acceptable and reasonable means of complying with floodplain regulations that require new, - substantially improved, and substantially damaged buildings to be elevated above the base flood elevation. One concern with elevation is that it may expose the structure to greater impacts from other hazards. If not braced and anchored properly, an elevated building may have less resistance to the shaking of an earthquake and the pressures of high winds. Seminole County Floodplain Management Plan 62 201 6 Property Protection Measures 6.1.5 Demolition Some buildings, especially heavily damaged or repetitively flooded ones, are not worth the expense to protect them from future damages. It is cheaper to demolish them and either replace them with new, flood protected structures, or relocate the occupants to a safer site. Demolition is also appropriate for buildings that are difficult to move — such as larger, slab foundation or masonry structures— and for dilapidated structures that are not worth protecting. Generally, demolition projects are undertaken by a government agency, so the cost is not borne by the property owner, and the land is converted to public open space use, like a park. One problem that sometimes results from an acquisition and demolition project is a "checkerboard" pattern in which nonadjacent properties are acquired. This can occur when some owners, especially those who have and prefer a waterfront location, are reluctant to leave their homes. Creating such an acquisition pattern in a community simply adds to the maintenance costs that taxpayers must support. 6.1.6 Pilot Reconstruction If a building is not in good shape, elevating it may not be worthwhile or it may even be dangerous. An alternative is to demolish the structure and build a new one on the site that meets or exceeds all flood and wind protection codes. This was formerly known as "demo/rebuild." FEMA funding programs refer to this approach as "pilot reconstruction." It is still a pilot program, and is not always funded. Certain rules must be followed to qualify for federal funds for pilot reconstruction: • Pilot reconstruction is only possible after it has been shown that acquisition or elevation are not feasible, based on the program's criteria. • Funds are only available to people who owned the property at the time of the event for which funding is authorized. • It must be demonstrated that the benefits exceed the costs. • The new building must be elevated to the advisory base flood elevation. • The new building must not exceed more than 10% of the old building's square footage. • The new building must meet all flood and wind protection codes. • There must be a deed restriction that states the owner will buy and keep a flood insurance policy. • The maximum federal grant is 75% of the cost, up to $150,000. FEMA is developing a detailed list of eligible costs to ensure that disaster funds are not used to upgrade homes. Seminole County Floodplain Management Plan 63 202 6 Property Protection Measures 6.1.7 Local Implementation Seminole County has had experience with acquisition, demolition, or elevation to protect buildings from flooding. The County has received grants from FEMA to manage these programs. The County is currently in the process of removing structures from the floodplain. 6.1.8 CRS Credit The CRS provides the most credit points for acquisition and relocation, because this measure permanently removes insurable buildings from the floodplain. The CRS credits barriers and elevating existing buildings (Activity 530 —Flood Protection). Elevating a building above the flood level will also reduce the flood insurance premiums on that individual building. Because barriers are less secure than elevation, not as many points are provided. Higher scores are possible, but they are based on the number of buildings removed compared to the number remaining in the floodplain. 6.2 Retrofitting An alternative to keeping the hazard away from a building is to modify or retrofit the site or building to minimize or prevent damage. There are a variety of techniques to do this, as described below. 6.2.1 Dry Floodprooring Dry floodproofing entails making all areas below the flood protection level watertight. Walls are coated with waterproofing compounds or plastic sheeting. Openings, such as doors,windows and vents, are closed, either permanently, with removable shields, or with sandbags. Dry floodproofing of new and existing nonresidential buildings in the Figure 32: Dry Floodproofing regulatory floodplain is permitted under state, FEMA and local MAXIMUM PROTECTION LEVEL IS 3 FEET(INCLUDING FREEBOARD) regulations. Dry floodproofing of existing residential buildings in the floodplain is also permitted as long as the building is not substantially damaged or being substantially SHIELDS FOR pPEMIINt}$ improved. Owners of buildings BACKFLOW VALVE PREV=NTS EXTERNAL OWMING OR located outside the regulatory s wLIa ANDUIiA1N"AFU�OOD WATER IMPERVIOUS TE7 floodplain can always use dry Dry floodproofed house floodproofing techniques. Dry floodproofing is only effective for shallow flooding, such as repetitive drainage problems. It does not protect from the deep flooding along lakes and larger rivers caused by hurricanes or other storms. Seminole County Floodplain Management Plan 64 203 6 Property Protection Measures 6.2.2 Wet Floodproofing The alternative to dry floodproofing is wet floodproofing: water is let in and everything that could be damaged by a flood is removed or elevated above the flood level. Structural components below the flood level are replaced with materials that are not subject to water damage. This is the approach used for the first floor of the elevated homes described in the previous section. For example, concrete block walls are used instead of wooden studs and gypsum wallboard. The furnace, water heater and laundry facilities are permanently relocated to a higher floor. Where the flooding is not deep,these appliances can be raised on blocks or platforms. This practice is not generally used in central and southern Florida where most structures are slab on grade. 6.2.3 Local Implementation It is likely that some properties in Seminole County have been retrofitted to protect them from flooding. However, because these projects are often so small, they generally do not require a building permit and there are no records of them. 6.2.4 CRS Credit Credit for dry and wet floodproofing is provided under Activity 530 —Retrofitting. Because these property protection measures are less secure than barriers and elevation, not as many points are provided. 6.3 Insurance Technically, insurance does not mitigate damage caused by a natural hazard. However, it Figure 33: Example Flood Insurance does help the owner repair, rebuild, and Premiums hopefully afford to incorporate some of the other property protection measures in the Building Exposure Premium process. Insurance offers the advantage of In the Special Flood Hazard Area (AE Zone) $1,689 Pre-FIRM("subsidized") rate protecting the property, as long as the policy is Post-FIRM (actuarial) rates in force, without human intervention for the 2 feet above the base flood elevation $440 measure to work. 1 foot above the base flood elevation $643 At the base flood elevation $1,167 6.3.1 Private Property 1 foot below the base flood elevation $4,379 Although most homeowner's insurance policies Outside the Special Flood Hazard Area $1,029 do not cover a property for flood damage, an Premiums are for$150,000 in building coverage and owner can insure a building for damage by $75,000 in contents coverage for a one-story house with surface flooding through the NFIP. Flood no basement and a $500 deductible, using the October insurance coverage is provided for buildings and 2008 Flood Insurance Manual. Premiums include the 5% their contents damaged by a "general condition Community Rating System discount. Premiums are higher for local governments that do not participate in the CRS. of surface flooding" in the area. Most people purchase flood insurance because it is required by the bank when they get a mortgage or home improvement loan. Usually these policies just cover the building's structure and not the contents. Renters can buy contents coverage, even if the owner does not buy structural coverage on the building. The 2018 Insurance Information Institute Pulse survey found Seminole County Floodplain Management Plan 65 204