Sarasota County

Vulnerability Assessment and

Adaptation Plan

Taylor Engineering, Inc.

January 2025

Sarasota County Government Vehicle at Casey Key Courtesy of Sarasota County

EXHIBIT F-1

DEP AGREEMENT NO. 22PLN98

SARASOTA COUNTY

VULNERABILITY ASSESSMENT

AND

ADAPTATION PLAN

Sarasota County January 2025

This work was funded in part through a grant agreement from the Florida Department of Environmental Protection, Resilient Florida Program, by a grant provided by the Office of Resilience and Coastal Protection. The views, statements, findings, conclusions, and recommendations expressed herein are those of the author(s) and do not necessarily reflect the views of the State of Florida or any of its subagencies. DEP Agreement Number: 22PLN98.

TABLE OF CONTENTS

EXECUTIVE SUMMARY ............................................................................................................ VI

1.0 BACKGROUND

2.0 INTRODUCTION

Legal Context for Resilience and Adaptation Planning

3.0 REVIEW OF VULNERABILITY ASSESSMENT AND FINDINGS

Critical & Regionally Significant Asset Inventory

Topographic Data

Flood Hazard Scenarios

3.3.1 High Tide Flooding

3.3.2 Storm Surge Flooding

3.3.3 Rainfall Induced Flooding

3.3.4 Sea Level Rise

Exposure and Sensitivity Analyses

3.4.1 Exposure Analysis

3.4.2 Sensitivity Analysis Criteria

3.4.3 Sensitivity Analysis Results

Focus Areas and Prioritized Assets

3.5.1 Focus Area 1 – Phillippi Creek Area

3.5.2 Focus Area 2 – Siesta Key

3.5.3 Focus Area 3 – Casey Key

3.5.4 Focus Area 4 – Nokomis and Nokomis Beach

3.5.5 Focus Area 5 – South Myakka River Area

3.5.6 Focus Area 6 – Manasota Beach Area

4.0 ASSESS ADAPTIVE CAPACITY AND IDENTIFY NEEDS

Adaptative Capacity

Identify Community Needs

4.2.1 County Department Survey

4.2.2 Public Workshop Survey Responses

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5.0 ADAPTATION RECOMMENDATIONS

Range of Adaptation Strategies

5.1.1 Accommodation

5.1.1 Protection

5.1.2 Managed Relocation/ Retreat

5.1.3 Avoidance and Procedural

Prioritized Adaptation Strategies

5.2.1 Wastewater Treatment Facilities

5.2.2 Parks, Wetlands, Shorelines and Natural Areas

5.2.3 Transportation Assets, Roadways, and Evacuation Routes

Prioritized Projects within Focus Areas

6.0 CONCLUSION AND NEXT STEPS

7.0 REFERENCES

APPENDIX A Exposure Analysis Flood Depth Maps and Tables APPENDIX B Sensitivity Analysis Maps and Tables APPENDIX C Focus Area Maps, Recommendation Tables, and Survey Responses APPENDIX D Adaptive Capacity Survey Responses APPENDIX E County Department’s Survey Responses APPENDIX F Project Prioritization Criteria Summary, Template, Presentation, Survey

Responses, and County Projects List

Table of Figures

Figure 1.1 Sarasota County Location Map

Figure 2.1 Vulnerability Assessment and Adaptation Planning Cycle

Figure 3.1 2000-2025 Annual Flood Days – Fort Myers, FL

Figure 3.2 2000-2025 Annual Flood Days – Port Manatee, FL

Figure 3.3 Storm Surge Flooding

Figure 3.4 Relative Sea Level Trend from St. Petersburg, FL

Figure 3.5 Relative Sea Level Trend from Fort Myers, FL

Figure 3.6 Sea Level Rise Projections for Sarasota County file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808095 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808096

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Figure 3.7 Example Inundation Depth Map for the 100-Year Event with combined Storm Surge and

Rainfall-Induced Flooding, south Sarasota County near the Venice Inlet

Figure 3.8 Percent of Critical Assets in Sarasota County Impacted by Current and Future Coastal-Induced

Flooding Scenarios

Figure 3.9 Percent of Critical Assets in Sarasota County Impacted by Current and Future Rainfall-Induced

Flooding Scenarios

Figure 3.10 Sarasota County Focus Area Map

Figure 4.1 Assess Adaptive Capacities: Regulatory Assessment

Figure 4.2. Public Workshop Survey Question and Answers: What public services and facilities are most critical to you after a flood event?

Figure 4.3 Public Workshop Survey Question and Answers: What Adaptation Strategies do you want to see the County do more of to address flood risks?

Figure 5.1 Range of Adaptation Strategies

Figure 5.2 Example Showing the Benefit of Elevating Structures

Figure 5.3 Examples of Permeable Surfaces

Figure 5.4 Example of Nature Based Solutions

Figure 5.5 Project Prioritization Criteria Categories

List of Photos Photo 1 The Sarasota County VA identified roadways vulnerable to flooding

Photo 2 SCFD Station 13

Photo 3 Historic Osprey Library

Photo 4 Carlton Water Treatment Plant

Photo 5 Old Stickney Point Road Flooded

Photo 6 Flooding on Bahia Vista Street due to Hurricane Debby, 2024

Photo 7. FDOT’s Use of WADs Along the Sunshine Skyway Bridge in Tampa Bay

Photo 8 Stormwater Check Valve for Backflow Prevention

Photo 9. South Siesta Beach Repair Project Progress

Photo 10. Successful Flood Barrier (AquaFence) at Tampa General Hospital during Hurricane Helene, 2024 (Source: AquaFence (2024))

Photo 11. Bee Ridge Wastewater Treatment Plant Expansion

Photo 13. Lift station being pumped post Hurricane Milton file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808108 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808112 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808114 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808115 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808116 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808117 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808118 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808120 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808124

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Photo 12. Flooded Wastewater Treatment Facility

Photo 14. Water Reclamation Facility in Venice Gardens

Photo 15. Public Utilities removing debris after Hurricane Helene

Photo 16. Elevated lift station, with proper safety railings and security fence

Photo 17. Red Bug Slough Preserve Informational Sign

Photo 18. Damages from Hurricanes Helene and Milton near R-Monument 152

Photo 19. Damages from Hurricanes Helene and Milton near R-Monumnet 172

Photo 20. Bioswale at the roundabout intersection of Ringling Blvd and Pineapple Avenue

Photo 21. Roadway under water from Hurricane Debby in August 2024

Photo 22. Example of a Floating Dock

Photo 23. Manasota Key Road Damages after Hurricane Milton

* All photos are sourced from Sarasota County unless otherwise noted.

List of Tables

Table 3-1 Critical Asset Totals

Table 3-2 Design Storm Rainfall Depths and Future Change Factors

Table 3-3 NOAA 2017 Sea Level Rise Projections

Table 3-4 Flood Scenario Matrix for Current Conditions and Four Sea-Level Rise Projections

Table 3-5 Critical Asset Group Ranking Criteria

Table 3-6 Flood Inundation Damage and Risk Assessment Percentages

Table 3-7 Prioritized Vulnerable Critical Assets within the Six Focus Areas

Table 5-1 Adaptation Strategies Matrix

Table 5-2 Elevate and Safeguard Wastewater Lift Station Recommendations

Table 5-3 Nature Based Solutions (NbS) Recommendation

Table 5-4 Coastal Road Recommendations

Table 5-5 Highest Ranked Projects in Multiple Focus Areas

Table 5-6 Highest Ranked Projects in Phillippi Creek Focus Area

Table 5-7 Highest Ranked Projects in Siesta Key Focus Area

Table 5-8 Highest Ranked Projects in Casey Key Focus Area

Table 5-9 Highest Ranked Projects in Nokomis and Nokomis Beach Focus Area

Table 5-10 Highest Ranked Projects in South Myakka River Focus Area

Table 5-11 Highest Ranked Projects in Manasota Beach Focus Area file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808125 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808126 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808127 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808128 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808132 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808133 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808134 file://192.168.1.12/PROJECTS/2023/C2023-006%20Sarasota%20Co%20VA%20&%20Resilience/Task%206%20(Grant%20task%209)%20Resilience%20and%20AP%20Report/_9.1%20Final%20Resiliency%20and%20AP%20Report/Draft%20VA-AP%20Report_Combined.docx#_Toc186808135

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ACRONYMS & ABBREVIATIONS

ADCIRC Advanced Circulation Model

AP Adaptation Plan

CCMP Comprehensive Conservation and Management Plan

DEO Department of Economic Opportunity

EPA Environmental Protection Agency

FDEP Florida Department of Environmental Protection

FDOT Florida Department of Transportation

FEMA Federal Emergency Management Agency

FFE Finished Floor Elevations

GIS Geographic Information System

LiDAR Light Detection and Ranging

MHHW Mean Higher High Water

NAVD88 North American Vertical Datum of 1988

NOAA National Oceanographic and Atmospheric Administration

SLR Sea Level Rise

SWEL Storm Surge Stillwater Elevations

USGS US Geological Survey

VA Vulnerability Assessment

WSEL Water Surface Elevations

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EXECUTIVE SUMMARY

Sarasota County, as a coastal community, relies on healthy ecosystems and resilient infrastructure to sustain its economic vitality and quality of life. However, its low-lying terrain, high water table, extensive water bodies, and barrier islands make it particularly vulnerable to flooding, storm surges, and sea-level rise. To address these challenges, the Sarasota County Vulnerability Assessment and Adaptation Plan provides a comprehensive approach to identifying at-risk infrastructure and enhancing the County's resilience to flood hazards.

The Vulnerability Assessment (VA) identifies and prioritizes critical infrastructure and community assets susceptible to current and future flood risks. Following statutory requirements outlined in Section 380.093 of the Florida Statutes (FS), the VA catalogs critical assets into key categories, including critical infrastructure, community and emergency facilities, natural, cultural, and historical resources, and transportation systems. Using criteria such as exposure and sensitivity, the assessment evaluates flood hazards and their potential impacts, focusing on areas with a high density of at-risk assets. These areas were identified through collaboration with county representatives, technical experts, and community stakeholders.

The Adaptation Plan (AP) builds on the findings of the Vulnerability Assessment, recommending strategies to enhance resilience for critical assets and natural resources in flood-prone areas, such as Phillippi Creek and Siesta Key. The AP outlines key adaptation strategies, including accommodation, protection, and managed retreat, while promoting Low Impact Development (LID) practices, community engagement, and ongoing monitoring. Funded through Florida’s Resilient Florida Grant Program, this plan emphasizes long-term resilience for Sarasota’s communities, economy, and ecosystems.

Key Highlights

• Critical Assets at Risk: Water and wastewater infrastructure, stormwater management facilities, and select roadways are among the most vulnerable assets identified in the Vulnerability Assessment.

• Geographic Focus: The assessment and adaptation efforts specifically address unincorporated Sarasota County, while municipalities such as the City of Sarasota, Venice, North Port, and Longboat Key conduct their own assessments under the same statutory requirements. Overlap in asset data, such as parks, enhances the comprehensiveness of this assessment.

• Stakeholder Engagement: Input from county staff, local stakeholders, and technical experts has been vital in identifying vulnerabilities and shaping strategies.

• Adaptation Strategies: The plan prioritizes strategies tailored to local needs, focusing on critical infrastructure, transportation networks, and natural and cultural resources.

• Prioritized Projects: In collaboration with County staff, the Project Team developed a project prioritization template and applied it to its compiled inventory of county projects for targeted implementation within the focus areas.

The data collection and assessments for this plan, conducted from 2023 to mid-2024, preceded three significant storms in late 2024—Hurricanes Debby, Helene, and Milton. While these events are referenced, the timeframe did not allow for detailed analysis. As an initial step in Sarasota County’s resilience planning, this plan highlights the need for ongoing studies and mitigation efforts. By integrating findings from the Vulnerability Assessment with strategies in the Adaptation Plan, the County is proactively addressing flood risks, enhancing resilience, and protecting its infrastructure and ecosystems.

BACKGROUND 1

Ted Sperling Nature Park

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1.0 BACKGROUND

Sarasota County (County) is located in southwest Florida (Figure 1) and contains approximately 37 miles of shoreline along the Gulf of Mexico (Sarasota County Gov., 2024a). Due to its location, the County enjoys the economic benefits of a thriving tourism industry, and therefore relies upon the health of its coastal communities. However, the naturally low-lying coastal topography combined with a high-water table leaves the County vulnerable to coastal and rainfall-induced flooding, as well as the impacts of rising sea levels (SWFRPC, 2017). Data from the National Oceanic and Atmospheric Administration (NOAA) reveals that southwest Florida has experienced an average mean sea level (MSL) increase of 1.17 feet over the last 100 years, and the area could see a potential increase of an additional 1.0 to 2.8 feet by the year 2070 (NOAA, 2024b, 2024c). As such, Sarasota County has taken a proactive approach to mitigate the impacts of flooding and sea level rise (SLR) throughout its communities. The following paragraphs detail the County’s extensive efforts towards a more resilient and sustainable future.

Figure 1.1 Sarasota County Location Map

In 1999, Sarasota County developed its first Local Mitigation Strategy (LMS) in an effort to organize community resources and plan local mitigation for a variety of natural and man-made hazards. The LMS was updated in 2004 and a working group was established in 2007 with a goal of including newly recognized standards and local floodplain plans in the document. Additional updates to the LMS were completed in 2010 and 2016. As part of 2016 study, the working group participated in the Pennsylvania State University Sea Level Rise Study in Sarasota County and included a discussion of past and potential future storm-related flood impacts in the updated report (Sarasota County Gov., 2016). The most recent update to the LMS, published in 2021, expands on the previous updates to identify and assess vulnerabilities and determine mitigation strategies (Sarasota County Gov., 2021a).

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In addition to the LMS working group, the County administration formed the Sarasota County SLR working group in 2015. The goal of the working group was to develop strategies to make public facilities and infrastructure more resilient to SLR. The project team utilized a Geographic Information System (GIS) tool and United States Army Corps of Engineers (USACE) SLR projection data for the years 2030, 2050, and 2100 to conduct a vulnerability assessment on County-owned assets. According to the report of findings published in 2021, the County showed minimal vulnerabilities for the 2030 and 2050 low and high scenarios. However, the 2100 high scenario revealed a greater volume of potential impacts on County assets. Notably, the USACE SLR projection data utilized in this study varies significantly from the NOAA data, with a much more conservative estimate for future SLR values (Sarasota County Gov., 2021b).

In 2021, the County contracted Taylor Engineering to conduct a baseline coastal analysis and an additional vulnerability assessment on the County’s coastal areas. Taylor Engineering used a GIS-based bathtub model along with six flood inundation scenarios to conduct the assessment. The evaluated flood scenarios included current (2020) water levels combined with 1.5 feet or 3.0 feet of SLR and a 50-year (2% annual chance) flood scenario. The study revealed minimal inundation for the 1.5-foot and 3.0-foot scenarios in the County’s coastal areas but showed extensive flooding under the 50-year storm surge conditions (Sarasota County Gov., 2021c).

Following Hurricane Ian in 2022, the County received Community Development Block Grant - Disaster Recovery (CDBG-DR) funding from the U.S. Department of Housing and Urban Development (HUD) to assist County recovery efforts in areas remaining after all other assistance efforts had been exhausted. As a result of this funding allocation, the County created the Sarasota County SRQ Program and conducted an extensive analysis to determine these unmet needs following Hurricane Ian. The County published its Public Action Plan in November of 2023, which outlines the methodology of the unmet needs assessment and discusses proposed uses of the funding (Sarasota County Gov., 2023).

Additionally, the County participated in the Sarasota/Manatee Metropolitan Planning Organization (MPO) Resiliency Vulnerability Assessment study published in 2023. The MPO is a regional planning entity whose board consists of elected officials from Sarasota and Manatee counties, nine cities, and a representative of the Sarasota Manatee Airport Authority (Sarasota/Manatee MPO, 2023). The goal of the study was to build on previously established local planning efforts to create a regionally focused vulnerability and mitigation analysis. The project team analyzed regional, natural, and transportation assets gathered from a variety of local, state, and federal sources against several flood scenarios to determine vulnerability. The study also considered each asset’s adaptive capacity, or its ability to cope with the hazard, how critical the asset is based on stakeholder input, the economic impact of each asset if it were to flood, and the probability of each flood scenario occurring. Following the vulnerability analysis, the project team determined several mitigation strategies and provided recommendations on project prioritization (Sarasota/Manatee MPO, 2023).

Outside of County conducted efforts, Sarasota County was the focus of a VA completed by the Southwest Florida Regional Planning Council (SWFRPC) and Central Florida Regional Planning Council (CFRPC) in 2017.

This study used NOAA SLR projections to analyze vulnerability of critical assets and natural areas. The study also examined socioeconomic factors such as poverty and elderly population percentages based on census block data (SWFRPC, 2017).

Road hazard warning sign, 2024 Courtesy of Taylor Engineering

INTRODUCTION

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2.0 INTRODUCTION

The County received funding from the Florida Department of Environmental Protection’s (FDEP) Resilient Florida Grant Program in 2022 to develop a Vulnerability Assessment (VA) and Adaptation Plan (AP), pursuant to the requirements in Section 380.093 of the Florida Statutes (FS) and FDEP’s Standardized Vulnerability Assessment: Scope of Work Guidance (FDEP, 2022). This report summarizes the process and findings of the Vulnerability Assessment and the Adaptation Plan. This combined VA and AP report may be referred to as the Sarasota County Vulnerability Assessment and Adaptation Plan (VA-AP). The VA-AP, developed by the Sarasota County UF/IFAS Extension and Sustainability Department in collaboration with Taylor Engineering, Inc. (Project Team), was shaped by coastal engineering expertise and valuable input from local stakeholders. The assessment process involved comprehensive community engagement including local government representatives and community members through in-person and virtual workshops, and interactive digital surveys. The VA-AP builds on the foundation of years of local knowledge and prior efforts, enhancing Sarasota County's resilience to current and future flood risks.

The County’s Sea Level Rise Working Group’s 2021 VA evaluated SLR and its potential impacts on various aspects of the county and its infrastructure. In the same year, the Resilient Florida Program was established under 380.093, FS, overseen by the FDEP, which provides planning and implementation grants for communities for a variety of flood resiliency planning and mitigation efforts. Sarasota County received the Resilient Florida funding to further investigate the flood impacts, including SLR, using the updated requirements and flood scenarios outlined in the statutory requirements. Section 380.093, FS, provides guidance for the VA methodology, critical asset criteria, and the use of SLR scenarios for planning horizons of 2040 and 2070 based on the 2017 National Oceanic and Atmospheric Administration (NOAA) Intermediate Low and Intermediate High projections. This VA-AP serves as a continuation of previous efforts with updated standards, methods, and data sources to be in compliance with the state requirements.

Following the requirements set forth in Section 380.093, FS, this VA-AP evaluates the impacts of 30 current and future flood hazard scenarios on public infrastructure, focusing on their exposure and sensitivity. The VA-AP summarizes the specific risks posed by flooding and rising sea levels to critical infrastructure, public facilities, and natural resources. Subsequently, feedback and recommendations were sought from County representatives, which have been incorporated into this final report. Beyond the technical components of this project, which rely heavily on Geographic Information Systems (GIS) and coastal engineering expertise, the VA-AP is informed by local input and feedback from staff and community members through public engagement workshops. The scope of the project is explicitly limited to utilizing publicly available data for both critical and regionally significant assets. The Project Team utilized local, regional, and statewide data resources to develop the inventory of critical assets and applied flood hazard data for current and future conditions from national government partners like the Federal Emergency Management Agency (FEMA) and NOAA, and from Sarasota County’s own stormwater model. It should be noted that this study relies on desktop evaluations and analyses; field evaluations are not employed.

This VA-AP builds upon the insights gained from previous efforts to identify potential adaptation projects.

The combined process applies a systematic process (Figure 2.1) to evaluate countywide vulnerabilities, conduct the vulnerability assessment, and identify adaptation strategies. The last and most important step in the process is to monitor, assess, and adjust strategies once they are implemented to ensure their success. The steps used to conduct the VA-AP are:

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1. Establish the Context by gathering local topographic and flood hazard data, develop a critical and regionally significant asset database, and facilitate public meetings to ensure input from county staff, local stakeholders, and the community.

2. Conduct the Vulnerability Assessment, which includes exposure and sensitivity analyses to assess which critical assets are most impacted by flood hazard scenarios for inland and coastal flooding and determine flood depths across the asset database.

3. Once the asset vulnerabilities are identified, the County can prioritize its needs and adaptive capacity to develop an array of Adaptation Strategies to integrate into existing plans and to guide the Resilience Plan.

4. Implementing the Strategies into projects and plans involves understanding the current infrastructure and fiscal capabilities, creating a schedule, seeking federal and state funding, and monitoring, evaluating, and adjusting the activities.

Figure 2.1 Vulnerability Assessment and Adaptation Planning Cycle

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Legal Context for Resilience and Adaptation Planning

Climate adaptation planning continuously evolves in response to the growing understanding of the need to address the impacts of climate change and SLR. Established in 1988, the Intergovernmental Panel on Climate Change (IPCC) plays a pivotal role in evaluating scientific information concerning climate change worldwide. Its inaugural Assessment Report (AR) was issued in 1990, and subsequent updates have followed every 5 to 8 years, with the most recent updates being the AR6 released in 2021 and the AR7 anticipated in 2029 (IPCC, 2024). There is ongoing advocacy by scientists, professionals, and governmental bodies, nationally and internationally, to promote education and implementation of adaptation planning across all governmental and geographical levels.

In accordance with Florida Statutes, all counties and municipalities in Florida are required to uphold a Comprehensive Plan, which serves as a blueprint for the community’s growth and development. These plans consist of land use policies that dictate patterns of development. Over time, additional statutes have been enacted to elaborate on coastal hazard mitigation and adaptation strategies. In 2011, the Community Planning Act provided the opportunity for communities to designate Adaptation Action Areas (AAAs). This is an optional but highly recommended comprehensive planning tool for designating areas that “experience coastal flooding due to extreme high tides and storm surge, and that are vulnerable to the related impacts of rising sea levels, for the purpose of prioritizing funding for infrastructure needs and Adaptation Planning” (Section 163.3164(1), FS). By integrating AAAs into the Comprehensive Plan, communities can better manage areas prone to natural hazards and flooding. The Conservation and Coastal Management Element became a mandatory addition to comprehensive planning in 2015 under Section 163.3177(6)(g), FS. This element requires local governments to include policies and strategies addressing the conservation, protection, and sustainable utilization of natural resources within their jurisdiction, with an emphasis on coastal regions.

Senate Bill 1094, signed into law in 2015, aims to address the threat of flood peril as “an Act relating to the peril of flood.” In accordance with SB 1094, Section 163.3178(2)(f), FS, or the Peril of Flood Florida Statute, now includes SLR as one of the causes of flood risk that must be addressed in the “redevelopment principles, strategies, and engineering solutions” to reduce flood risk. The statute also outlines components that must be included in the coastal management element of local Comprehensive Plans, emphasizing the removal of inappropriate and unsafe development in coastal areas when opportunities arise.

The FDEP and the Florida Department of Economic Opportunity (FDEO), now called Florida Commerce, collaborated and directed the development of the Florida Adaptation Planning Guidebook, which was published in 2018. The guidebook provides scalable steps to create effective APs for Florida communities, including processes for conducting a VA; assessing, prioritizing, and identifying adaptation strategies; and creating methods for implementation (FDEP, 2018).

In 2021, the Resilient Florida Program was established under Section 380.093, FS, to facilitate localized comprehensive assessments of flood vulnerability and SLR. This program offers financial support to local governments, regional entities, and non-profit organizations to undertake projects addressing various resilience aspects, such as coastal resilience, flood mitigation, green infrastructure, community resilience planning, and ecosystem restoration. In light of advancing insights into the impacts of climate change and corresponding legal obligations, several federal agencies have issued guidance on adaptation planning.

For instance, in 2010, NOAA’s Office of Ocean and Coastal Resource Management released the resource guide titled Adapting to Climate Change Planning Guide for State Coastal Managers (NOAA, 2010). This guide, among the earliest of its kind, aims to assist coastal managers in formulating and executing climate adaptation strategies. It covers crucial elements and concepts, such as climate change impacts, VAs, PAGE | 14 stakeholder engagement, integration with existing programs, decision support tools, funding sources, and policy assistance.

As more information became readily available and communities began to conduct VAs across the State of Florida, the FDEP published the Standardized Vulnerability Assessment: Scope of Work Guidance in May 2022 (FDEP, 2022). The purpose of this resource is to assist local communities in assessing vulnerability through the Resilient Florida Program’s planning grants; the document is designed to provide technical guidance in the preparation of a VA and to ensure that state-funded VAs are standardized to meet the requirements set forth by Section 380.093, FS. The statutory language references requirements applicable to critical and regionally significant asset definitions; flood hazard scenarios and planning assumptions;

data sources; and data standards. Section 380.093, FS first requires local governments to evaluate current and future tidal flooding, storm surge flooding, rainfall-induced flooding, and compound flooding, if applicable, when conducting a VA. The following standards must be followed for each flood scenario:

• Tidal flooding analyses must include future high tide flooding caused by SLR, and to the extent practicable, should geographically display the number of tidal flood days expected for each scenario and planning horizon.

• Storm surge analyses must use publicly available storm surge data published by NOAA or FEMA, and the initial storm surge event used must equal or exceed the current 100-year flood event.

• Rainfall-induced flooding, to the extent practicable, should be evaluated using spatiotemporal analysis or existing hydrological and hydraulic modeling results.

• Compound flooding, to the extent practicable, should be evaluated by analyzing a combination of tidal, storm surge, and rainfall-induced flooding.

Photo 1 The Sarasota County VA identified roadways vulnerable to flooding.

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Once all climate datasets are obtained, the next requirement is to obtain and develop a comprehensive inventory of critical and regionally significant assets that are publicly owned or managed by the County.

Critical and regionally significant assets are defined based on the following asset classes and examples are provided in Photos 2-5:

Critical community and emergency facilities, including schools, colleges, universities, community centers, correctional facilities, disaster recovery centers, emergency medical service facilities, emergency operation centers, fire stations, health care facilities, hospitals, law enforcement facilities, local government facilities, logistical staging areas, affordable public housing, risk shelter inventory, and state government facilities.

Natural, cultural, and historical resources, including conservation lands, parks, shorelines, surface waters, wetlands, and historical and cultural assets.

Critical infrastructure, including wastewater treatment facilities and lift stations, stormwater treatment facilities and pump stations, drinking water facilities, water utility conveyance systems, electric production and supply facilities, solid and hazardous waste facilities, military installations, communications facilities, and disaster debris management sites.

Transportation assets and evacuation routes, including airports, bridges, bus terminals, ports, major roadways and marinas.

Photo 2 SCFD Station 13

Photo 3 Historic Osprey Library

Photo 4 Carlton Water Treatment Plant

Photo 5 Old Stickney Point Road Flooded

REVIEW OF

VULNERABILITY

ASSESSMENT AND

FINDINGS

Hurricane Debby flooding at water reclamation facility, 2024

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3.0 REVIEW OF VULNERABILITY ASSESSMENT AND FINDINGS

The key components of the Vulnerability Assessment (VA) include the exposure analysis and sensitivity analysis. To conduct either analysis, critical and regionally significant asset information, topographic data, and flood hazard data must be compiled. Sections 3.1 through 3.3 provide a summary of the background data collected prior to the analyses, and Section 3.4 discusses the criteria and results of the analyses and vulnerability assessment. The identified focus areas for adaptation and the vulnerable assets within, are discussed in Section 3.5.

Critical & Regionally Significant Asset Inventory

During the initial phase of the County’s VA, the Project Team gathered and examined available data concerning critical and regionally significant assets within the study area. The team compiled an inventory of critical assets owned or managed by the County, as well as regionally significant assets as defined by Section 380.093(2)(a)1-4, FS, and consolidated them into a GIS geodatabase. Input from the County’s Project Team and departments was incorporated regarding additional critical assets important to the community that were not specified in the Florida Statutes. Following the guidelines outlined in the Standardized Vulnerability Assessment: Scope of Work Guidance (FDEP, 2022), the team collected asset information within the following asset groups: 1) Critical Community and Emergency Facilities; 2) Critical Infrastructure; 3) Natural, Cultural, and Historical Resources; and 4) Transportation Assets and Evacuation Routes. Sites were separated into their own category for the analyses to account for the land area projected to be inundated from the modeled flood scenarios. The total numbers of critical assets analyzed as part of this assessment are outlined in Table 3-1 by asset group.

Table 3-1 Critical Asset Totals

Asset Group Asset Total Critical Community and Emergency Facilities 522 Critical Infrastructure 3,610 Natural, Cultural, and Historical Resources 180 Transportation and Evacuation Routes 595 Site Analysis* 150

*Assets impacted determined using the percent land inundated and included assets from Asset Types: Airport Sites, Cemeteries, City-Owned Parcels, Disaster Debris Management Sites, Historic Sites/Districts, and Natural Areas and Parks.

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Topographic Data

Topographic data is critical for understanding flood risks, as it helps identify the elevations of key assets like buildings, infrastructure, and natural features, which are essential for accurate flood modeling. This data enables the assessment of vulnerability to flooding and helps determine appropriate adaptation measures. The quality of terrain data significantly affects the accuracy of flood inundation models, with more precise terrain maps improving the reliability of flood predictions (Horritt and Bates, 2002).

According to Section 380.093, FS, VAs in Florida must use the most recent publicly available digital elevation model (DEM). The DEM is essential for modeling and mapping flood inundation and is used to assign elevations to critical and regionally significant assets. In Sarasota County, the DEM used for assessments is derived from the latest Light Detection and Ranging (LiDAR) data provided by the United States Geological Survey (USGS).

To evaluate the elevation of assets relative to potential flood depths, topographic data and FEMA flood elevation certificates were obtained. The elevation certificates for available structures were sourced from the County and the Florida Department of Emergency Management (FDEM), while the LiDAR data for the county was provided by the USGS (FL Peninsular 2018 D19 DRRA).

Flood Hazard Scenarios

The flood hazard scenarios evaluated as part of the County’s VA assesses inland and coastal flooding with and without SLR for tidal flooding, storm surge, and extreme rainfall events. Future conditions were evaluated using SLR scenarios for planning horizons 2040 and 2070, based on the 2017 NOAA projections.

These projections are consistent with the state requirements at the time the project began. It is important to note that the flood hazard modeling was conducted prior to Hurricanes Helene and Milton which impacted the county significantly in October 2024.

• Tidal Flooding - Tidal flooding frequently occurs in low-lying coastal areas and is expected to increase with the effects of SLR.

• Storm Surge - Hurricanes and coastal storms impact coastal properties with storm surge, high waves, and high winds.

• Extreme Rainfall Flooding - Extreme rainfall events and heavy rainstorms can overwhelm stormwater systems, leading to flooding of streets, sidewalks, and low-lying areas.

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Figure 3.1 2000-2025 Annual Flood Days – Fort Myers, FL

3.3.1 High Tide Flooding

Tidal flooding, often referred to as high tide flooding or "sunny-day" flooding, may become an increasingly common issue in Sarasota County due to rising sea levels, the proximity to the Gulf of Mexico, and low-lying topography. This type of flooding occurs during regular high tides and king tides and does not require storms or heavy rainfall to cause disruptions.

Tidal flooding impacts areas differently as the sea levels don’t rise as the same rate everywhere (NOAA, 2023). NOAA’s 2023 Annual High Tide Flooding Outlook documents record breaking high tide days in 2023 across the US. Though there is not a station within Sarasota County, the historical flood days are recorded at nearby stations in Fort Myers (Figure 3.1) and Port Manatee (Figure 3.2). It is important to note that the annual flood days are not recorded based on the calendar year but are recorded from May to April of the following year.

• Fort Myers (Station ID: 8725520) o In 2023 (from May 2023-April 2024), there was a historic record of 7 high tide flood days.

o For 2024 (from May 2024-April 2025), which at the time of this report is not complete, there are 6 high tide flood days recorded.

• Port Manatee (Station ID: 8726384) o In 2023 (from May 2023-April 2024), there was a historic record of 7 high tide flood days.

o For 2024 (from May 2024-April 2025), which at the time of this report is not complete, there are 4 high tide flood days recorded.

Figure 3.2 2000-2025 Annual Flood Days – Port Manatee, FL https://tidesandcurrents.noaa.gov/high-tide-flooding/annual-outlook.html

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As sea levels continue to rise, this type of flooding will more frequently impact everyday life in coastal communities, leading to disruptions in transportation, damages to infrastructure, and overall inconveniences (NOAA, 2024a). The frequency and severity of these floods can also be compounded by natural factors like tidal cycles and onshore winds, which may push more water onto land. Understanding the growing impacts of tidal flooding in Sarasota County is crucial for planning appropriate adaptation measures to protect communities, infrastructure, and natural resources in the face of rising seas. Installing additional monitoring stations within the county may provide more specific measurements to the community. This assessment used the Mean Higher High Water (MHHW) scenario, which is defined as the average of the higher of the two daily high tides observed over the National Tidal Datum Epoch (NOAA, 2024a). MHHW elevations were calculated for Sarasota County by interpolating data from the two nearest NOAA sea level trend stations: St. Petersburg (Station ID: 8726520) and Fort Myers (Station ID: 8725520).

These stations provide valuable data on long-term sea level trends, which directly affect tidal flooding projections.

3.3.2 Storm Surge Flooding

Storm surge flooding, primarily caused by tropical storms and hurricanes, is a significant source of major flood damage in Florida’s coastal communities. These extreme weather events bring together storm surge, high winds, and heavy rainfall, which can have catastrophic effects when combined. NOAA defines storm surge as the abnormal rise in water level above the predicted astronomical tide, driven by storms pushing water onshore. The surge can inundate coastal areas, leading to severe flooding and damage to property and infrastructure. The impacts of storm surge coinciding with other flooding factors including high tide, rainfall, wind waves, and sea level rise is shown below in Figure 3.3, from NOAA’s Understanding Stormwater Inundation educational resource.

Figure 3.3 Storm Surge Flooding (Source: NOAA – Understanding Stormwater Inundation) https://coast.noaa.gov/stormwater-floods/understand/

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The storm surge scenarios evaluated are based on the Storm Surge Stillwater Elevations (SWEL) data from FEMA’s Southwest Florida coastal surge dataset, created as part of a Flood Insurance Study (FIS). The study analyzed the 25-year (4% annual chance) and the 100-year (1% annual chance) SWEL scenarios, with and without the influence of SLR. As sea levels rise and storm events become more frequent and severe, the risk and extent of storm surge flooding is expected to increase, making it critical for Sarasota County to plan for and implement flood mitigation strategies. By understanding how storm surge may evolve with changing environmental conditions, the County can better prepare for future events and reduce potential impacts on the community and infrastructure.

Given the devastating potential of storm surge flooding, this analysis highlights the need for proactive planning, infrastructure reinforcement, and coastal adaptation measures to ensure long-term resilience and sustainability in the face of rising seas and intensifying storms.

3.3.3 Rainfall Induced Flooding

Areas across Sarasota County, and the country, are feeling the impacts of increased flood events. A record daily rainfall of 11.06 inches was set in Sarasota in August 2024 from the impacts of Hurricane Debby (NWS, 2024), with greater amounts reported in areas across the region (Photo 6). One month prior, the Sarasota-Bradenton Airport reported an all-time record of

3.93 inches for a one-hour event from a summer rainstorm (Bachmeier, 2024). As record breaking events continue to occur, urbanization, a high ground water table, and at-capacity drainage systems further exacerbate flooding by reducing the land's natural ability to absorb water, increasing runoff, and causing significant flooding in populated areas.

Rainfall-induced flooding in Sarasota County is assessed using the countywide hydrologic and hydraulic (H&H) model, which evaluates stormwater management systems and their response to various rainfall scenarios. The model specifically analyzes flooding for 25-year (4% annual chance), 100-year (1% annual chance), and 500-year (0.2% annual chance) return periods, based on 24-hour storm event durations. This approach aligns with both local (Sarasota County) and regional (Water Management District) standards for stormwater infrastructure evaluation.

The H&H model simulates how rainfall-runoff, or stormwater, is conveyed through the county's drainage systems under different storm scenarios. By doing so, it assesses the ability of existing stormwater systems to handle heavy rainfall events and identifies potential vulnerabilities. However, it's important to note that these models often assume stormwater systems are fully functional and well-maintained. As a result, the model may underestimate flooding risks if there are issues like clogged drains, insufficient maintenance, or damage during extreme storms, which could reduce the system's capacity.

Photo 6 Flooding on Bahia Vista Street due to Hurricane Debby, 2024

(Source: Thomas Bender/ Sarasota Herald Tribune)

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The stormwater model uses the SCS Type-II Florida-Modified for its rainfall distribution. Rainfall depths for the various storm events were obtained from the NOAA Atlas 14 Point Precipitation Frequency Estimates published at the time the model was run in August 2023. These rainfall depths were used as the current baseline condition. The values used in this assessment were obtained near the center of the county, taken at the coordinates: 27.1893, -82.3886. The values obtained from NOAA Atlas 14 vary based on location. The estimate totals were multiplied by future rainfall change factors to estimate future rainfall for 2040 and 2070, which were obtained from Florida International University’s (FIU) Sea-Level Solutions Center study (FIU, 2022). Change Factors were selected from the downscaled dataset that produced the highest values in the County’s region, the Multivariate Adaptive Constructed Analogs, statistically downscaled (MACA) dataset to be conservative. Values were also selected based on the 50th percentile from the downscaled dataset. This was done to keep change factors within reasonable thresholds as the range between the very high (factor of 2.12 for the 100-yr) or very low (factor of 1.06 for the 100-yr) percentiles was quite large.

Tailwater conditions were revised to account for the effects of the projected intermediate-low and intermediate-high SLR in 2040 and 2070. Table 3-2 shows the rainfall depths from the Atlas 14 data, the selected future change factors taken from the FIU study, and the calculated future rainfall depth estimates. The rainfall depth values in Table 3-2 were used within the ICPR4 stormwater model simulations to assess the rainfall-induced flood impacts.

Table 3-2 Design Storm Rainfall Depths and Future Change Factors

Return Frequency

(years)

Current Rainfall Depths (inches)

Future Change Factor for

2040 Rainfall Depths (inches)

Future Change Factors for

2070 Rainfall Depths (inches)

25 8.5 1.3 11.05 1.35 11.48

100 11.6 1.41 16.36 1.5 17.40

500 16.1 1.48 23.83 1.59 25.60

When using H&H models to simulate rainfall-induced flooding and assess stormwater infrastructure, it's important to note that these models often assume the infrastructure is properly maintained and fully operational. This can lead to underestimating the risks and impacts of flooding, as models often do not account for reduced capacity or damage during extreme events.

It is important to note that the data used in this assessment is the best available data at the time. The critical asset inventory including stormwater infrastructure, flood hazard data and topographic data were obtained and thoroughly reviewed as of June 2023. As additional data becomes available and future development infrastructure gets constructed, the datasets should be updated to reflect those improvements.

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3.3.4 Sea Level Rise

Sea level projections are also reported at the NOAA sea level trend stations throughout the US. The County lies between the NOAA sea level trends stations at St. Petersburg (Station ID: 8726520) and Fort Myers (Station ID: 8725520), and their respective relative sea level trends are shown in Figure 3.4 and Figure 3.5.

The NOAA 2017 projection values for the County are determined by interpolating the projection values between the two stations and weighting the station values by the distance from the center of the County to the stations. Applying a weighted distance average to the St. Petersburg and Fort Myers stations yields the interpolation Equation 1. Using the interpolation, the projections for Sarasota County indicate that sea levels could be between 0.4 to 0.8 feet higher by 2040 and 1.0 to 2.8 feet higher by 2070, when considering the NOAA Intermediate Low and NOAA Intermediate High scenarios (Table 3-3 and Figure 3.6).

Figure…