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Miami-Dade Back Bay Coastal Storm Risk Management Feasibility Study

Sewell ParkThe Miami-Dade Back Bay Coastal Storm Risk Management Feasibility Study examines the impacts of and potential responses to storm-surge damage in Miami-Dade County. The study area includes coastal and inland areas that are at risk from coastal-storm flooding and sea-level rise. This study does not address barrier-island beach projects (Miami Beach, for example) undergoing a separate and concurrent study by the U.S. Army Corps of Engineers. The study examines current and future strategies and measures to address these coastal risks. It evaluates current studies, scientific consensus, guidelines and design standards to recommend a project that increases resilience for infrastructure systems and the built environment. Draft analyses include assessments of engineering feasibility, costs, economic benefits, and impacts to the environment and local communities.
 
Supplemental funding allows the Corps of Engineers to complete a three-year feasibility study that evaluates measures for coastal-storm risk management, sea-level rise and chronic Back Bay flooding issues for Miami-Dade County.

The federal funding for this study is $3 million.

Miami-Dade Back Bay Coastal Storm Risk Management Study

Frequently Asked Questions

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A: The study investigates solutions to reduce risks within Miami-Dade County from future coastal storm events, especially from storm surge, specifically to reduce the economic damage, as well as risk to life and safety.

A: The study is planned for completion within 3 years (October 2018 – September 2021) and $3 million.  Due to the budget and schedule limitations, and widespread coastal flooding concerns in Miami-Dade County, the study will not provide a holistic solution to coastal storm risk in Miami-Dade County.  The study addresses seven refined focus areas most vulnerable to storm surge flooding to include Arch Creek, Aventura, Cutler Bay, Little River, Miami River, North Beach and South Beach.  The study also includes critical infrastructure vulnerable to storm surge flooding on a county-wide basis.

A: This study will develop and evaluate coastal storm risk management (CSRM) measures for Miami-Dade County. Miami-Dade County and its 34 municipalities, with a total of approximately 2.8 million people, lie in a relatively low-lying and flat coastal area. The region is well known for its risks of coastal flooding from hurricanes and tropical storms. Sea level rise (SLR) has increased these risks and will continue to do so in the future. Without plans to reduce coastal flood risk and increase resiliency, threats to life, property, and the economy will continue to increase. This study will develop and evaluate CSRM measures for Miami-Dade County residents, industries, and businesses, some of which are critical to the regional and national economy.

A: Currently estimated at $4.6 billion, the Tentatively Selected Plan (TSP) includes surge barriers at Little River, Biscayne Canal, and Miami River (including associated floodwalls and pump stations), nonstructural measures (which include home elevations or floodproofing) within the seven refined focus areas, floodproofing critical infrastructure countywide and one potential area for Natural and Nature Based Feature (a site in Cutler Bay). If the project is authorized and funds are appropriated by Congress as a result of the study, a non-Federal sponsor would cost share in 35% of the implementation costs of the Project and be responsible for all future operation and maintenance.

A: The draft report is available above in the "Study Documents" section of this web-page.

A: The public is encouraged to provide feedback on the draft report on our website through the “Public Comment Tool” or by sending an email to: MDBB-CSRMStudy@usace.army.mil.  If written correspondence is required, written comments can be submitted to our district office (Environmental Analysis Section, Norfolk District, 803 Front Street, Norfolk, Virginia 23510).  For any accessibility issues that prevent written comments, please call (757) 201-7728. The 45-day public comment period ends on July 20, 2020.

A: Following a series of hurricanes and severe storms, the U.S. Army Corps of Engineers (USACE) received $3 million of Federal Emergency Supplemental Funding to study the impact and potential solutions of coastal storm events in Miami-Dade County. The study does not involve a cost-share requirement from a non-Federal sponsor until the next phase of preliminary engineering designs (Preconstruction Engineering and Design (PED) Phase) is approved and funded by Congress, which would be in 2022-2023 at the earliest.

A: At this preliminary phase, the study discusses but hasn’t confirmed the need for eminent domain or acquisition as part of the Tentatively Selected Plan. 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.   Additionally, the alignment of structural measures will be further reviewed and revised during detailed design if the project moves into the Preconstruction Engineering and Design (PED) Phase.  Negotiation is required to acquire real estate. Fair market value as established by a real estate appraisal is the basis for the initial offers to the owner. If negotiation fails, eminent domain is an option that can be utilized. This does not replace the reasonable efforts to negotiate a purchase before initiating an eminent domain action. Again, while the non-Federal sponsor must generally possess the capability to exercise eminent domain, use of this process assumes that particular relocations or acquisitions are identified as necessary for the project.

A: Optimization is the next step in the study process and involves further refinement of the Tentatively Selected Plan (TSP).  Miami-Dade County and the U.S. Army Corps of Engineers — with input from stakeholders and the public — will assess different frequencies of storms to evaluate different storm surge barrier and wall elevations for the alignments in the draft report. The optimization stage begins June 2020 and ends October 2021

How will this study align with U.S. Army Corps of Engineers’ other efforts in Southeast Florida (including the South Atlantic Coastal Study and Miami-Dade County Coastal Storm Risk Management Study)?

The purpose of this study is address storm surge flooding and high tide flooding events between storms are not included in the scope of this study.  The proposed structural measures will not address flooding from sea level rise since the surge barriers will only be closed during major storms.

A: The Miami-Dade County area 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 scope of the study does not include improvements to the existing Central & Southern Flood control system that manages rainwater. Additionally, the U.S. Army Corps of Engineers (USACE) is not authorized to address local stormwater flooding, found in streets and other areas, which is the responsibility of the local government. However, the USACE will not recommend any plan that worsens any flooding risk. If this project is carried forward, a more detailed drainage analysis would be completed in the Planning Engineering and Design Phase to ensure that any new infrastructure, such as floodwalls, will not worsen any stormwater flooding risks.

A: The number of closure events projected depends on the number of coastal storms reaching the design level of the system.  The design level will be confirmed during the optimization phase of the study prior to the final report.  At least one closure per year is anticipated for testing and maintenance events.  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 the storm surge barriers are designed to consider the impacts from coastal storms while considering sea level rise during the 50-year period of analysis.  It is likely that the barriers will close more frequently in future years, as sea level rises, due to the increased flooding potential from coastal storms exacerbated by the rising sea levels.

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

A: The first phase of the feasibility study examined the recommended structural barriers at 1% annual chance event including sea level rise projections to determine if the structures are economically justified (the benefits exceed the costs and 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 determine the 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 PED phase as detailed designs are developed with additional field information, subsurface information and modeling.  The proposed height of the floodwalls on land varies depending on the location; however, the approximate general range of heights that is currently being considered is from 1 foot to 13 feet above ground.   The proposed height of the floodwalls in the water varies depending on the location; however, the approximate general range of heights that is currently being considered is from 10.5 feet to 36 feet.

A: The purpose of the study is coastal storm risk management.  If green infrastructure can be incorporated to provide benefits towards reducing coastal storm risk, then it is included in the study as a Natural and Nature-Based Features or “NNBF”.  Through scoping meetings, the potential to restore mangroves in the Cutler Bay area was identified.  This measure is included in the draft plan and is planned for further evaluation before the completion of the study for its ability to provide a storm surge reduction benefit.  Although the value of green infrastructure (or “NNBF”) is recognized and acknowledged, it is difficult to quantify the benefits of the NNBFs in the context of coastal storm risk.  This Coastal Storm Risk Management study must quantify how the NNBF will significantly reduce damage to the community.  These features have been difficult to justify within the U.S. Army Corps of Engineers Planning process.

A: The wall is located based on a combination of risk from flooding and engineering viability of a flood wall. The scoping phase of the study generated seven refined focus areas based upon risks from coastal flooding and social vulnerability.  Within these areas, structural measures are recommended where feasible based on the existing topography.  The exact location of the structural alignments currently recommended will continue to evolve through the Preconstruction Engineering and Design (PED) 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.

A: We cannot predict the project’s impact on future property values.   Property values may be affected by the implementation of the project, but there are too many factors that affect property values 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. 

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

The feasibility study includes 10% design (a conceptual level of design) and further design details will be developed if the project enters the Preconstruction Engineering and Design (PED) Phase. During the feasibility phase two public meetings have been held with open comment periods since the initiation of the study in the fall of 2018.  The public is invited to participate in a virtual online public meeting to learn more about the study and findings and ask questions.  Two identical virtual meetings will be held June 9, 2020 from 5-7 pm and June 11, 2020 from 1-3 pm.  Virtual office hours will be held June 10, 2020 from 1-2 pm and June 18, 2020 from 5-6 pm.  Comments may be provided in writing to: MDBB-CSRMStudy@usace.army.mil or http://arcg.is/fm0Xe or by mail to: Ms. Justine Woodward, U.S. Army Corps of Engineers, Norfolk District, 803 Front St., Norfolk, VA 23510. The public comment period begins on June 5, 2020 and concludes on July 20, 2020.

A: The project will only be implemented if an eligible cost sharing non-Federal sponsor participates in the implementation of the project.

A: The feasibility study includes 10% design (conceptual level design) and further design details will be developed if the project enters the Preconstruction Engineering and Design (PED) Phase.  U.S. Army Corps of Engineers actively works with Miami-Dade County, the non-Federal sponsor for the study, and Miami-Dade County serves as the liaison to jurisdictions within the County.  Additionally webinars and inclusion of local government staff beyond Miami-Dade County on site visits has been implemented as time and budget allows.   The project will only be implemented if an eligible cost sharing non-Federal sponsor participates in the implementation of the project.  The non-Federal sponsor must have the capability to acquire the real estate necessary for the project.

The construction of walls included in the Tentatively Selected Plan (TSP) of this study does not preclude the implementation of a Baywalk.  Baywalk implementation can be added to the project as a betterment at 100% non-Federal expense. 

A: During Preconstruction Engineering and Design (PED), if any historic homes identified in the recommended plan are determined not eligible to be elevated due to structural constraints then they will not be elevated. Recommendations to historic structures will ensure they remain classified as historic. Neighborhood cohesiveness will be considered during the next phase of the feasibility study and documented in the final report.

A: Yes, roadway gates will need to be closed prior to a storms arrival for the system to work. Public outreach will be a key part of the Operations, Maintenance, Replacement, Repair and Rehabilitation (OMRR&R) manual prepared by U.S. Army Corps of Engineers in the Preconstruction Engineering and Design (PED) Phase for the non-Federal sponsor to adhere to.

A: Existing waterfront assets may be impacted if they are required for the construction of the project.  Property owners may be compensated if all or a portion of their property is required to be acquired to construct the project.  U.S. Army Corps of Engineers seeks to site the final location of the structural measures to reduce impacts to property owners. The final location of the alignments will not be determined until the Preconstruction Engineering and Design (PED) Phase.

A: U.S. Army Corps of Engineers only has the authority to address coastal storm risk management while considering sea level rise exacerbation of coastal storms under this study.  However, many of the project features such as non-structural elevation will also be effective in mitigating impacts from future sea level rise.

Presentations & posters

2020 Virtual Public Meeting Presentation
June 2020 Virtual Public Meeting Presentation June 2020 Virtual Public Meeting Presentation
2020 Virtual Public Meeting Presentation 2020 Virtual Public Meeting Presentation - With associated notes page
Spanish Translation Creole Translation

 

2020 Virtual Meeting Displays
   
     
2020 Virtual Public Meeting Display Maps
 
     
2020 Virtual Public Meeting Fact Sheet
 

Miami-Dade Back Bay Coastal Storm Risk Management Feasibility Study public meeting posters (2019)
Note: Due to large file size, it may take several minutes to download files.

2019 Public Meeting Displays
Public input during scoping Feasibility Study Process  

Miami-Dade Back Bay Coastal Storm Risk Management Feasibility Study fact sheet (September 2019)
Miami-Dade Back Bay CSRM public scoping meeting presentation (2018)

Bipartisan Budget Act of 2018

The U.S. Army Corps of Engineers received disaster funds provided in Public Law 115-123, the Bipartisan Budget Act of 2018. The act provides nearly $17.4 billion to the Corps for disaster recovery. Jacksonville District received $3.35 billion for long-term recovery investments in its area of responsibility, which includes Florida, Puerto Rico and the U.S. Virgin Islands. This funding goes toward 13 studies and 22 projects that will reduce risk to communities damaged by storm events. So far, the total federal funding allocation for Jacksonville District recovery efforts exceeds $4 billion.

Announcements

USACE extends comment period for CSRM draft report

NORFOLK, Va. – At the request of Miami-Dade County, its nonfederal sponsor, the U.S. Army Corps of Engineers has extended the comment period for the Miami-Dade Back Bay Coastal Storm Risk Management Feasibility Study, due to the unprecedented amount of attention and resources needed to deal with the area's COVID-19 outbreak.

Originally set to close July 20, the comment period will now end Aug. 19. To submit comments on the Miami-Dade Back Bay Coastal Storm Risk Management Feasibility Study, send an email to MDBB-CSRMStudy@usace.army.mil or visit http://arcg.is/fm0Xe. They can also be sent by mail to: Ms. Justine Woodward, U.S. Army Corps of Engineers, Norfolk District, 803 Front St., Norfolk, VA 23510.

The Draft IFR and Programmatic EIS, prepared pursuant to the National Environmental Policy Act, identifies coastal storm flood risks to residents, industries and businesses; develops risk-management measures, and evaluates their impacts to public and natural environments.

Study details and documents are available on this webpage.

For more information about the study, contact Justine Woodward of USACE Norfolk District at 757-201-7728.