The study investigates solutions to reduce risks within Collier County from future coastal storm events, especially storm surge, specifically to reduce economic damage, as well as risk to life and safety.

The study is planned for completion within three years (October 2018 to September 2021) and $3 million. The study will develop, analyze and evaluate coastal storm risk management alternatives for the North County (including Naples) and Marco Island study areas, covering both Gulf-facing shorelines and inland bay areas.

This study will result in the recommendation of a project authorized for construction. Collier County and its municipalities, with a total of about 320,000 people, lie in a relatively low-lying and flat coastal area. The region is well known for its coastal-flooding risk from hurricanes and tropical storms. Sea-level rise has increased these risks and will continue to do so in the future. Without plans to reduce coastal storm risk and increase resiliency, threats to life, property and the economy will continue to increase. This study will identify and evaluate coastal storm risk management measures for Collier County residents, industries and businesses.

Currently estimated at $4.8 billion, the Tentatively Selected Plan (TSP) includes structural and nonstructural measures. The structural measures include six surge-barrier systems (miter and/or sluice gates), three tide gates (sluice gates) and three floodwalls, as well as approximately 9.5 miles of beach and dune fill. The nonstructural measures include acquisition and elevation of residential structures and floodproofing of commercial structures and critical infrastructure. If the project is authorized and funds are appropriated by Congress as a study result, a nonfederal sponsor would cost-share 35% of project-implementation costs and be responsible for all future operation and maintenance.

The draft report is available above in the "Study documents" section of this webpage.

The public is encouraged to provide feedback on the draft report by sending an email to: Collier-CSRM@usace.army.mil. If written correspondence is required, comments can be submitted to our district office (Environmental Analysis Section, Norfolk District, 803 Front St., Norfolk, Virginia 23510). For any accessibility issues that prevent written comments, call 757-201-7728. The 45-day public comment period ends Sept. 14, 2020.

Following a series of hurricanes and severe storms, the U.S. Army Corps of Engineers received $3 million in Federal Emergency Supplemental Funding to study the impact and potential solutions of coastal storm events in Collier County. The study does not involve a cost-share requirement from a nonfederal sponsor until the next phase of preliminary engineering designs (Preconstruction Engineering and Design Phase) is approved and funded by Congress, which would be 2022 at the earliest.

The Tentatively Selected Plan includes acquisition as a nonstructural measure, which requires the use of eminent domain based on current USACE policy. U.S. Army Corps of Engineers sponsors must have the ability to use eminent domain if required. Further analysis will occur prior to the final report on the structures to be included in the nonstructural plan for acquisition. Negotiation is required to acquire real estate. Fair-market value as established by a real estate appraisal is the basis for initial offers to property owners. If negotiation fails, eminent domain is an option that can be utilized. This does not replace reasonable efforts to negotiate a purchase before initiating an eminent domain action.

The study is only about halfway complete and the plan identified in the draft report is a Tentatively Selected Plan. This means that while the plan’s basic components will likely remain the same between now and the plan ultimately recommended for construction at the end of the study, the number and location of structures recommended for each nonstructural measure may change as additional analysis is used to refine the TSP. Further analysis and adjustments will also occur during future phases such as Preconstruction Engineering and Design and Construction. Because the structures currently included in the plan may not be part of the final plan recommended at the end of the study, specific property information is not released at this point in the study.

Optimization is the next step in the study process and involves further refinement of the Tentatively Selected Plan. Collier County and the U.S. Army Corps of Engineers — with input from stakeholders and the public — will assess different storm frequencies to evaluate the implementation of renourished beach lengths and elevations of storm-surge barriers and floodwalls for alignment in the draft report. The optimization stage is July 2020 to October 2021.

The National Environmental Policy Act requires that federal agencies take a hard look at how their actions affect the human and natural environment (please see Chapter 8 Environmental Consequences and Appendix D Environment). To ensure NEPA compliance, the draft report was prepared as an integrated Environmental Impact Statement. Compliance with other applicable federal environmental laws and statutes is also addressed in the draft report (refer to Chapter 9 Environmental Compliance). Interagency coordination is ongoing for this study. 

This study’s purpose is to address storm-surge flooding, and high-tide flooding events between storms are not included in the scope. The proposed structural measures will not address flooding from sea-level rise because the surge barriers will only be closed during major storms.

Collier County is currently vulnerable to flooding from heavy rainfall events that could come with hurricanes. The purpose of this study is to address storm-surge flooding. The study’s scope does not include improvements to existing flood-control systems that manage rainwater. In addition, the U.S. Army Corps of Engineers is not authorized to address local stormwater flooding, found in streets and other areas, which is a local government’s responsibility. However, USACE will not recommend a plan that worsens any flood risk. A preliminary interior-drainage analysis has been completed for this study. If this project is carried forward, a more detailed drainage analysis would be completed in the Preconstruction Engineering and Design Phase to ensure that any new infrastructure, such as floodwalls, will not worsen stormwater flooding risks.

The number of projected closure events depends on the number of coastal storms reaching the system’s design level. The design level will be confirmed during the study’s optimization phase prior to the final report. At least one closure per year is anticipated for testing and maintenance. Closure events during a coastal storm could occur for several days at a time depending on each storm. The storm-surge barriers are not recommended to be closed for sea-level rise. The height of storm-surge barriers is designed to consider coastal storm impacts while accounting for sea-level rise during the 50-year analysis period. It is likely the barriers will close more frequently in future years, as sea levels rise, due to increased flooding potential from coastal storms exacerbated by the rising sea levels. The nonfederal sponsor would develop an operation and maintenance plan for the gate system in the project’s Preconstruction Engineering and Design Phase.

Storm-surge elevations outside the floodwalls and surge barriers are not expected to be significantly higher. Due to the nature of coastal flooding in this area, the floodwall impacts are expected to be minimal. This will be confirmed with further feasibility and detailed analysis during the Preconstruction Engineering and Design Phase, in accordance with U.S. Army Corps of Engineers policy.

The feasibility study’s first phase examined the recommended structural barriers at 1% annual chance event, including sea-level rise projections, to determine if the structures are economically justified (benefits should exceed costs in selecting the plan with the greatest net benefits). Prior to the final feasibility report, the structures will be examined at a range of storm frequencies to reach a design level with the greatest net benefits. This will determine the final wall heights for the recommended plan. Further adjustments in wall heights may also be made in the Preconstruction Engineering and Design Phase as detailed designs are developed with additional field data, subsurface information and modeling. The proposed height of floodwalls on land varies depending on the location; however, the general range being considered is 3 feet to 23 feet. The proposed height of floodwalls in the water also varies by location – the general range under consideration is 7 feet to 33 feet.

The study’s purpose is coastal storm risk management. If green infrastructure can be incorporated to provide a significant and measurable reduction in coastal-risk drivers such as storm surge, wave energy and erosion, then it can be included in the study as a Natural and Nature-Based Feature, or NNBF. Although the value of green infrastructure (NNBF) is recognized and acknowledged, it is often difficult to quantify the benefits of NNBFs in the context of reduced economic impacts such as damage to infrastructure. The project ultimately recommended at the completion of this Coastal Storm Risk Management study must have a benefit-to-cost ratio (BCR) of 1.0 or greater in order to be authorized into law and implemented. NNBF features can only be included in the recommended plan if the reduction in economic impacts they provide are greater than the cost to implement them. Unfortunately, it has been difficult to achieve a positive BCR for NNBF within the framework for economic evaluation used in the U.S. Army Corps of Engineers planning process. If they can be justified, offshore artificial reefs may be included as NNBFs in the Collier County Coastal Storm Risk Management Feasibility Study. Although not considered an NNBF because they are required mitigation, vegetative plantings are part of the dune-fill design and will be used for wave attenuation and as a storm-surge barrier.

The wall is positioned based on a combination of risk from flooding and engineering viability. The exact location of structural alignments currently recommended will continue to evolve through the Preconstruction Engineering and Design Phase, when additional field surveying and sampling can advise the detailed design. Please refer to the draft report for additional details on the scoping phase.

We cannot predict the project’s impact on future property values. Property values may be affected by project implementation, but there are too many factors to make a determination during this study. It is important to remember that property values will be impacted by future risk from coastal storm-based flooding, and this project strives to reduce risk from future coastal storms. 

It is possible FEMA flood insurance rates could be reduced for elevated or floodproofed structures; however, that is not this study’s primary goal and the final impact will be determined by FEMA.

The feasibility study includes 10% design (a conceptual level of design) and further details will be developed if the project enters the Preconstruction Engineering and Design Phase. Two public meetings have been held with open comment periods since study initiation in the fall of 2018.  The public is invited to participate in a virtual online public meeting to learn more about the study, its findings and ask questions. The sessions are set for Aug. 18 from 1-3:30 p.m. and Aug. 24 from 5:30 to 8 p.m. Comments may be provided in writing to Collier-CSRM@usace.army.mil  or by mail to: ATTN: Zachary Martin, Norfolk District, U.S. Army Corps of Engineers, 803 Front St., Norfolk, Virginia 23510. The public comment period begins on July 31, 2020, and concludes Sept. 14, 2020. 

The project will only be implemented if an eligible cost-sharing nonfederal sponsor participates in project implementation.

The feasibility study includes 10% design (conceptual level design) and further details will be developed if the project enters the Preconstruction Engineering and Design Phase. The U.S. Army Corps of Engineers actively works with Collier County, the study’s nonfederal sponsor, which serves as liaison to jurisdictions within the county. The project will only be implemented if an eligible cost-sharing nonfederal sponsor participates in project implementation. The nonfederal sponsor must have the capability to acquire the real estate necessary for the project.

During Preconstruction Engineering and Design, recommendations to historic structures will ensure they remain classified as historic. Neighborhood cohesiveness will be considered during the feasibility study’s next phase and documented in the final report. A draft Programmatic Agreement has been developed to address adverse effects and mitigation for those adverse effects on cultural resources, including historic structures. The Draft PA is found in the report’s Cultural Resources Appendix (i.e., Appendix H). If affected, historic structures would not be demolished but could be elevated or floodproofed.

Yes, roadway gates will need to be closed prior to a storm’s arrival for the system to work. The nonfederal sponsor must engage in public outreach as part of the Operations, Maintenance, Replacement, Repair and Rehabilitation manual prepared by the U.S. Army Corps of Engineers in the Preconstruction Engineering and Design Phase.

Existing waterfront assets may be impacted if they are required for project construction. Property owners may receive compensation if all or a portion of their property must be acquired to construct the project. The U.S. Army Corps of Engineers seeks to position structural-measure locations in a way that reduces impacts to property owners. Final alignment locations will not be determined until the Preconstruction Engineering and Design Phase.

In this study, U.S. Army Corps of Engineers only has the authority to address risk caused by coastal storm events, not the more broad effects of sea-level rise that may occur on a more frequent basis, such as “sunny-day flooding” and “king tides.” However, sea-level rise is included in the evaluation of impacts expected from future coastal storms. It is also important to note that many project features such as home elevation will also be effective in mitigating future sea-level rise impacts.