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HomeMy WebLinkAboutBack-Up DocumentsMIAMI-DADE BACK BAY COASTAL STORM RISK MANAGEMENT FEASIBILITY STUDY ENCY DECISION MI ESTO Colonel Kinsman Commander, Norfolk District Faraz Ahmed Planning Lead, Norfolk District Date: 18 November 2020 "The views, opinions and findings contained in this report are those of the authors(s) and should not be construed as an official Department of the Army position, policy or decision, unless so designated by other official documentation." US Army Corps of Engineers R MIAMI.L PE MUMMY 111 US Army Carps. of EngFriaars. *; AGENDA Meeting Introductions (NAD) Purpose of Meeting and Opening Remarks (NAD) Opening Remarks Miami -Dade Back Bay Coastal Storm Risk Management Feasibility Study Presentation (COL Kinsman and Faraz Ahmed) — Agency Decision Milestone Presentation • Agency Decision Milestone Purpose • Recommended Plan • Overview: Authority, Problem/Opportunities, Objectives/Constraints • Plan Formulation Overview • Environmental Compliance • Risk & Uncertainty • ATR, PGM, and IEPR Reviews • Schedule Open Discussion — Panel Discussion — Miami -Dade County Discussion — Request Endorsement of Recommended Plan (COL Kinsman) 2 1181 US Army Carps. of EngFriaars. BOTTOM LINE UP FRONT TSP - Alternative 8 • Structural Measures (Surge Barriers with associated Floodwalls and Pump Stations) at Biscayne Canal, Little River, and Miami River • Nonstructural Measures for Residential and Commercial Structures • Critical Infrastructure throughout all of Miami -Dade County • Natural and Nature -Based Features at Cutler Bay Total Project Cost (including contingency) $4.6B FY20 Price Level Average Annual Net Benefit: $1.8B Average Annual Cost: $200M BCR @ 2.75% Discount Rate: 9.4 BCR ;AVIV..1.11k4 Recommended Plan - Alternative 8 Total Project Cost (including contingency) $6.1 B FY21 Price Level Contingency Surge Barriers, Floodwalls, and Closures: 42% Pumps: 88% Lands and Damages: 50% PED & CM: 30% Cost Sharing Initial Construction: 65% Federal Funding of Project = $3.9B 35% non -Federal Funding of Project = $2.1 B BCR @ 2.5% Discount Rate: 10.9 BCR BCR @ 7% Discount Rate: 2.9 BCR 3 1181 US Army Carp. of EngFnesrs ., SCOPING & PLANNING STRATEGY Execute Feasibility Agreement with non - Federal Sponsor: 9 Oct 2018 • Initiate Scoping • Invite Agencies to Participate • Examine Existing and Future Without Project Conditions • Identify Problems, Opportunities, Objectives and Constraints SMART Feasibility Study Process: Miami -Dade Back Bay Coastal Storm Risk Management Stud - ALTERNATIVE \ FORMULATION & ANALYSIS 9 Jan 2019 • Receive Stakeholder Input on Potential Measures • Develop Screening Criteria • Formulate Initial Array of Alternatives Draft Report Release: 5 June 2020 FEASIBLITY- LEVEL ANALYSIS TO TSP Tentatively Selected Plan (TSP) Alternative Evaluation and Comparison: • Environmental Considerations • Parametric Costs and Determine Preliminary Benefits (Future With Project Conditions) • Final Array of Alternatives • Detailed Benefit -to -Cost Ratio • Stakeholder Input • Determine the TSP • Develop Draft Report FEASIBILITY - LEVEL ANALYSIS TO ADM CHIEF'S REPORT District Engineer transmits Final Report package April 2021 Agency Decision Milestone (ADM): 18 Nov 2020 • Release Draft Report (Integrated Environmental Impact Statement) and Respond to Comments • Initiate Multiple Levels of Quality Review • Finalize Environmental Mitigation Plans • Agree upon path forward to Final Report --= Sept 2021 Release Final Report Complete National Environmental Policy Act (NEPA) Conclusions 1181 US Army Carps. of EngFriaars STUDY AREA AND AUTHORIZATIONS Existing Authorization for Miami -Dade Back Bay CSRM Public Law 84-71 June 15, 1955 Water Resources Development Act of 1986 Bipartisan Budget Act of 2018 Public Law 115-123 Title IV, Division B Authorized examination and survey of the coastal and tidal areas of the eastern and southern United States, with particular reference to areas where severe damages have occurred from hurricane winds and tides. Specifies the cost -sharing requirements generally applicable to feasibility studies. Authorizes the government to conduct the Study at full Federal expense to the extent that appropriations provided under the Investigations heading of the BBA 2018 are available and used for such purpose. Dept. of Defense (DoD) - Major Roads Site Boundaries O Miami -Dade County • Cities and Towns Federal Lands Florida Counties maw see. ❑ Miami -Dade County contains 34 different municipalities ❑ Complex H&H modeling for water quality and hydrodynamics limited due to budget Due to the limitations of the Corps' 3X3X3 policy, it is not possible to complete environmental and cultural surveys during the Feasibility Phase. These will be deferred to the Preconstruction Engineering and Design (PED) Phase when detailed mitigation plans will be finalized. 5 1 BACKGROUND US Army Corps of Engineers The non -Federal sponsor is Miami -Dade County The study is 100% federally funded Miami -Dade County has a population of -2.8 million people (76% in high social vulnerability, 17% over 65) with over 500k structures, of which 240k are in the effective FEMA 1% annual chance flood, making it the most populous county in Florida and the seventh most populous in the United States The Miami -Dade Back Bay CSRM Study will investigate solutions that will reduce damage and risks from impacts of coastal storms while considering sea level rise. The study will not address federally owned land (e.g. Everglades National Park), but will focus primarily on the urban and coastal areas of the county. Approval Authority is delegated to the MSC (NAD) Study will be completed in accordance with the National Environmental Policy Act (NEPA), a programmatic Environmental Impact Statement (EIS) is integrated with the feasibility report and further NEPA and environmental compliance is expected in Pre -construction Engineering and Design CountyBounds Flood Hazard Flood Hazard Type 0.2 %Annual Chance Flood Hazard Area of Minimal Flood Hazard Area of Undetermined Flood Hazard 1%Annual Chance Flood Hazard — — Urban_Development_Boundary 6 US Army Corps of Engineers PROBLEMS, OPPORTUNITIES, OBJECTIVES AND CONSTRAINTS PROBLEMS • The geographic location, low elevation, and high population of Miami -Dade County make it vulnerable to storm surge from hurricanes and tropical storms. • Increasing high tides and king tides resulting from sea level rise result in recurrent flooding to roads and properties. • Increasing groundwater elevations from sea level rise result in flood risks to inland areas. • Increasing flooding from rain events due to the higher groundwater elevations and higher tailwater elevations from sea level rise threaten properties and infrastructure and exacerbate coastal storm risk. OPPORTUNITIES • Reduce the risk to human life and health due to coastal flooding, high flooding events or infrastructure failure. • Reduce coastal storm -related economic damage and improve economic resiliency of the local economy and communities, particularly low- income communities and vulnerable populations. • Increase resiliency, structural integrity, and reliability of critical infrastructure. • Reduce transportation impacts due to high flooding events. • Utilize available natural areas and open spaces for improving wave attenuation, water retention, and/or water storage. OBJECTIVES • Increase the resiliency of Miami -Dade County to function effectively before, during, and after coastal storm events by decreasing the vulnerability of critical infrastructure to flooding damage from storm surge with consideration for sea level rise. • Reduce economic damage to structures in communities vulnerable to severe flooding damage from storm surge with consideration for sea level rise. • Incorporate natural and nature based features to reduce flood damage and complement the recommended nonstructural and structural measures. U.S RMY CONSTRAINTS • Avoid creating or exacerbating flooding within the project area, to other local municipalities, and to local military installations. • Avoid flooding solutions for the study area that would induce increased flooding issues in locations outside of the study area. • Avoid and/or minimize impacts to existing environmental and cultural/historic resources in the study area and nearby (e.g. Biscayne Bay National Park, Miami Circle National Historic Landmark). • Cannot exacerbate saltwater intrusion which will negatively impact fresh water for drinking and agriculture. 7 USArmy Corps HAZUS OUTPUTS FOR FEMA of Engineers ; 100 YEAR STORM + 3' SLR EXISTING CONDITIONS CAT 5 SLOSH MOM STORM SURGE INUNDATION Q Urban Development Boundary n Watershed Boundaries Damage (Total Loss) (S1000s) ▪ 0 - S2,500 ▪ S2,501 - S5,000 $5,001 - S10.000 S10,001 - $25,000 S25,001 - $50,000 ▪ S50,001 - $75,000 ▪ S75,001 - $400,000 6 12 Miles 0 Urban Development Boundary Less than 3 feet above ground Greater than 3 feet above ground Greater than 6 feet above ground Greater than 9 feet above ground 8 US Army Corps. of Engineers EXISTING CONDITIONS - STRUCTURES IN FLOOD ZONES Legend Urban Development Boundary QMiami -Dade County Boundary Flood Hazard Type A Zone AE Zone AH Zone VE Zone X, 0.2% Annual Chance Flood Hazard X, Area of Minimal Flood Hazard Effective FEMA Flood Zone # of structures 1 %annual chance flood A 1,391 AE 113,262 AH 129,036 VE 610 0.2% annual chance flood X 34,108 1181 US Army Carps. of EngFriaars. FUTURE WITHOUT PROJECT (FWOP) ❑ Miami -Dade County SLR impacts for up to a 3 foot increase in sea levels ❑ Documented Sea Level Rise ❑ Approximately 1 in 6 annual chance of a hurricane strike Value of structures in the county is approximately $311 billion within the urban development boundary - $5.66 in construction in the last year ❑ Federal government has an opportunity to reduce economic and life safety risks from storm surge through a variety of measures ❑ Miami -Dade County intervention would occur 6-1 it - 23 ft 10 1181 US Army Carps. of EngFriaars. ❑ SE Florida region recognizes the USACE intermediate and high curves, but not the low in their SLR guidance ❑ USACE sea level change curve calculator — NOAA gage 8723970, at Vaca Key, FL, is the nearest compliant gage ❑ Local preference is to formulate using the NOAA high curve. District formulated to USACE high curve with approval from Climate Community of Practice. Sea level tracker shows Mean Sea Level (MSL) trending above intermediate curve for 20 years. The PDT will also look at project performance at USACE low and intermediate curves. SEA LEVEL CHANGE Estimated Relative Se 14 ,2 2020 vel Change Projections - Gauge: 8723970, Vaca Key, FL Potential 50 Year Economic Period of Analysis 2040 2050 co co N 2080 Year — NOAA High Rate — USACE High Rate — NOAA Int High Rate — USACE Int, NOAA Int Low — USACE1NOAA Low Rate 2100 Sea Level Rise with USACE SLC Scenarios for vacs Key. FL (8723970) ubre arai 2120 IIW lw — PIMA I. -.. ,. 2140 Projected SLR Increase (ft) to 2084 using 2019 sea level trend of 0.01263 ft/yr USACE Low 0.83 USACE Intermediate 1.52 USACE High 3.72 NOAA High 4.82 — High SLC — Intermediate SLC — Low SLC — Linear Trend Value for MSL (entire period of record) - Linear Trend of MSL November, 1979 - November. 2019 - S-Year MSL Moving Average — MSL MSL Moving Average 1181 US Army Carps. of EngFriaars. PLAN FORMULATION STRATEGY ❑ Refine focus areas due to the large size of Miami -Dade County which includes 34 municipalities by using overlay of social vulnerability index and Hazus (FEMA model) outputs ❑ Identify applicable risk management measures in refined focus areas for structural, nonstructural, and natural and nature -based features ❑ Identify and prioritize critical infrastructure to increase resiliency by ensuring they are functional before, during, and after a coastal storm event ❑ Critical infrastructure inventory: Fire stations, police stations, evacuation centers, emergency operation centers, hospitals, pump stations, treatment plants, etc. ❑ Criticality and vulnerability ranking from Miami -Dade County's Rapid Action Plan which identifies vulnerable critical infrastructure ❑ Develop alternatives ❑ Evaluate and compare alternatives using refined areas, screening measures, and G2CRM economics model ❑ Select Tentatively Selected Plan (TSP) ❑ Optimize TSP and select the Recommended Plan MIR 12 US Army Carps. of EngFrre$rs.., SCREENING TO REFINED ARRAY ❑ Hazus model outputs of potential damage was multiplied by the Centers for Disease Control and Prevention's (CDC) social vulnerability index (SVI) to obtain a composite risk map which showed seven socially vulnerable economic damage centers. ❑ Structural measures were screened based on seven focus areas identified, preliminary real estate and engineering concerns, and non -Federal sponsor (NFS) input. ❑ Nonstructural areas were narrowed down to the seven refined focus areas based on analysis how did it. ❑ Vulnerable critical infrastructure asset categories were determined through scoping meetings ❑ Natural and nature -based features (NNBF) were identified through coordination with local stakeholders. AN E. Legend Urban Development Boundary Miami -Dade County Boundary Refined Focus Areas n Arch Creek Aventura Cutler Bay I —I Little River n Miami River n North Beach n South Beach 0 2 4 8 Miles 13 FOCUSED ARRAY OF ALTERNATIVES Alternative Number Alternative Name Description ICI 1 No Action No Action 2 Critical Infrastructure Only Analyzing critical infrastructure throughout all of Miami -Dade County on priority asset categories. This includes wet and dry floodproofing structures. 3 4 5 Miami River Basin + Alternative 2 Nonstructural + Alternative 2 Inland Storm Surge Reduction (Structural) + Alternative 2 Surge barrier at Miami River (with associated floodwalls and pump stations) + Floodwall at Edgewater + Nonstructural outside of surge barrier. Acquiring, elevating, and wet and dry floodproofing of structures in seven socially vulnerable, economic damage centers defined by Hazus and the CDC SVI which include Miami River, Little River, Arch Creek River, Aventura, North Beach, South Beach, and Cutler Bay areas. Surge barriers (with associated floodwalls and pump stations) at the most socially vulnerable, economic damage centers which include Miami River, Little River, and Biscayne Canal. 6 Alternative 3 + 4 Miami River Basin + Nonstructural + Critical Infrastructure 7 Alternative 4 + 5 Nonstructural + Structural + Critical Infrastructure including Floodwall at , Edgewater 8 Alternative 4 + 5 Nonstructural + Structural + Critical Infrastructure including Nonstructural at Edgewater instead of Floodwall at Edgewater 14 STRUCTURAL DESIGN WATER SURFACE ELEVATION US Army car Structural Area Structural Breakdown Top of Wall Elevation (ft. NAVD88) Average ground elevation for floodwalls range from 5 to 8' NAVD88 2% AEP + USACE High Curve SLC 1 % AEP + USACE High Curve SLC 0.5% AEP + USACE High Curve SLC Miami River South Floodwall 12.1 13.6 15.6 South Wall in Water 15.8 17.8 19.3 — Surge Barrier 15.5 17.5 19 North Floodwall 11.9 14 16.1 Little River South Floodwall 9.1 9.7 10.7 Surge Barrier 11.1 12.6 14.6 North Floodwall 11.4 12.9 14.4 Biscayne Canal South Floodwall 10.1 8.6 11.6 Surge Barrier 10.5 11.5 13 North Floodwall 10 11.5 13 Note: Top of wall elevations were adjusted and determined based on wave overtopping rates. Stillwater levels were based on the 50% confidence levels which included storm surge, tides, and wave setup. 15 US Army Carps of EngFoams NONSTRUCTURAL DESIGN WATER SURFACE ELEVATION Feet NAVD88, SLC USACE High curve to 2084, 50% confidence level Modeled Areas 2%AEP Water Levels* 1 % AEP Water Levels* 0.5% AEP Water Levels* Average Ground Elevation (ft. NAVD88) Arch Creek East 8.21 - 9.23 9.00 - 10.15 9.81 - 11.08 4.5 Arch Creek West 7.98 8.89 10.25 6.2 Aventura East 7.79 - 9.24 8.48 - 10.07 9.29 - 11.0 4.1 Aventura Center 7.91 - 9.19 8.61 - 10.03 9.44 - 11.0 5.0 Aventura West 7.55 8.33 9.28 6.5 Cutler Bay 10.57 - 15.08 11.86 - 16.75 13.22 - 18.49 7.3 Edgewater 8.05 - 8.81 8.91 - 9.76 10.01 - 10.94 5.8 Little River 7.96 - 8.61 8.74 - 9.52 9.53 - 10.46 6.7 Miami River 8.86 - 10.12 9.9 - 11.26 11.05 - 12.5 8.2 North Beach 7.69 - 7.74 8.36 - 8.45 9.07 - 9.26 3.4 South Beach 8.22 9.03 9.74 3.3 *Includes astronomical tides, storm surge, wave setup and significant wave height (SWH) where data was available and applicable. These levels were used as the Design Water Surface Elevation. 16 TENTATIVELY SELECTED PLAN US Army Carps. of EngFriaars Alternative Number & Name 1 — No Action 2 — Critical Infrastructure Only Total Average Annual Benefits Total Average Annualized Cost $o $o $9,000,000 $4,000,000 3 — Miami River Basin + Alternative 2 4 — Nonstructural + Alternative 2 5 — Inland Storm Surge Reduction (Structural) + Alternative 2 6 — Alternative 3 + 4 7 — Alternative 4 + 5 (includes Floodwall at Edgewater) 8 — Alternative 4 + 5 (includes Nonstructural at Edgewater instead of Floodwall at Edgewater) Project First Cost So $95,000,000 $1,345,000,000 $91,000,000 $422,000,000 $123,000,000 $1,589,000,000 $1,614,000,000 $1,836,000,000 $1,836,000,000 $144,000,000 $187,000,000 $229,000,000 $196,000,000 $1,944,000,000 $3,140,000,000 $3,067,000,000 $4,390,000,000 $5,214,000,000 $4,586,000,000 BCR 11.0 8.6 8.0 9.4 Net Remaining Benefits 0 $6,000,000 $1,255,000,000 $299,000,000 $1,444,000,000 $1,428,000,000 $1,607,000,000 $1,640,000,000 US Army Carps. of EngFriaars. *; NATIONAL ECONOMIC DEVELOPMENT (NED) PLAN Optimization Total Average Total Average Annual Benefits Annualized Cost Alternative 8 — TSP (1% AEP) $1,836,000,000 $196,000,000 Alternative 8 — 2% AEP $1,721,000,000 $246,000,000 Alternative 8 — 1% AEP $2,313,000,000 $265,000,000 Project First Cost BCR Net NED Benefits $4,586,000,000 9.4 $1,640,000,000 $5,163,000,000 $5,792,000,000 7.0 8.7 $1,474,000,000 $2,048,000,000 Alternative 8 — 0.5% AEP $3,079,000,000 $282,000,000 $6,058,000,000 10.9 $2,798,000,000 1181 US Army Carps of EngFne$rs. RECOMMENDED PLAN ❑ Critical infrastructure risk management on priority asset categories outside of structural measures such as fire stations, police stations, hospitals, evacuation centers, emergency operation centers, pump stations, etc. (not shown on map). ❑ Surge barriers at Biscayne Canal, Little River, and Miami River all of which include associated pump stations, floodwalls, and tide gates. ❑ Nonstructural risk management at refined focus areas outside of structural measures ❑ Elevations: 5,800 ❑ Floodproofing: 4,600 ❑ Natural and nature -based features are being considered at the Cutler Bay site. Total Project First Cost : $6,058,000,000 BCR: 10.9 Annual Net benefits: $2,798,000,000 0 2.5 5 7.5 10 Miles l l 1 1 1 1 1 1 1 1 1 1 1 1 1 i 1 0 Coral Springs 0Mia mi Everglades ational Park Structural Measures (Storm Surge Barriers, Pump Stations & Floodwalls)* — Biscayne Canal — Coral Gables — Little River — Miami River i 522 Risk Management Areas F' l C-8 (Biscayne Canal) Coral Gables Little River Miami River �-, S22 Refined Nonstructural Focus Areas Arch Creek Aventura Cutler Bay Little River Miami River North Beach South Beach Edgewater A *Estimates of locations and footprints of the structural measures have been initially determined at a mean confidence level based on the USACE derived 2084 0.5% annual exceedance probability stillwater elevation level from the FEMA South Florida Storm Surge Study (includes astronomical tide, storm surge, wave overtopping, and USACE high curve sea level rise) and will be finalized during the Preconstruction, Engineering, and Design Phase of the project when more detailed surveys and data are available. 19 1181 US Army Carps of Engineers *; RECOMMENDED PLAN INUNDATION BOUNDARIES Legend Urban Development Boundary Q Miami -Dade County Boundary USACE 2084 0.5% AEP Without Project Condition FUTURE WITHOUT PROJECT Legend Urban Development Boundary Miami -Dade Q County Boundary USAGE 2084 0.5% AEP With Project Condition Structural Measures (Storm Surge Barriers, Floodwalls, and Pump Stations) — Biscayne Canal Coral Gables Way - Little River — Miami River S22 FUTURE WITH PROJECT Note: The inundation layers are based on the USACE 0.5% AEP mean value confidence level for the year 2084. The 2084 value is the total water level which includes astronomical tides, storm surge, and USAGE high curve SLR for a particular storm event. 20 US Army Carps of EngFrresrs ., IMPLEMENTATION OF RECOMMENDED PLAN Measure Approximate Duration (Years) FY Start FY End Critical Infrastructure 10 2026 2035 Nonstructural Measures 10 2026 2035 NNBF - Cutler Bay 5 2026 2030 Miami River Surge Barrier and associated features 10 2026 2035 Little River Surge Barrier and associated features 3 2028 2030 Biscayne Canal Surge Barrier and associated features 5 2031 2035 Mitigation (prior to construction of respective feature) 11 2025 2035 Priority 1 2 3 4 5 5 ❑ Implementation strategy discussed and agreed upon with Miami -Dade County ❑ Critical infrastructure and nonstructural measures are first due to less design and construction time ❑ Larger structural measures could still be in PED, obtaining permits, etc. i 21 US Army Carps of EngFnears. *, ENVIRONMENTAL COORDINATION ❑ Notice of Intent to prepare an Environmental Impact Statement (EIS) published 18 July 2019; Notice of Availability of draft Integrated Feasibility Report and Programmatic EIS published 5 June 2020 ❑ Interagency meetings held approximately bi-monthly ❑ Participating/Cooperating Agencies: ❑ Florida Department of Environmental Protection ❑ Biscayne Bay Aquatic Preserve ❑ Florida Department of Transportation* ❑ U.S. Fish and Wildlife Service ❑ National Park Service ❑ Federal Emergency Management Agency ❑ National Marine Fisheries Service * ❑ U.S. Environmental Protection Agency* ❑ U.S. Coast Guard ❑ South Florida Water Management District * = Cooperating Agencies i 22 US Army Carps of EngFrresrs ENVIRONMENTAL COMPLIANCE Feasibility Study/Planning Phase Notes Coastal Zone Management Act Conditional Federal Consistency Concurrence provided by Florida DEP on 08/04/20 Clean Water Act, Section 404 National Historic Preservation Act Fish and Wildlife Coordination Act (FWCA) Clean Water Act, Section 401 Water Quality Certification Endangered Species Act (ESA) Magnuson -Stevens Fishery Conservation and Management Act (MSA) Marine Mammal Protection Act (MMPA) 404B1 Guidelines analysis included in Environmental Appendix of draft report Regional Coastal Programmatic Agreement, coordination ongoing by SAJ; anticipated completion date of 1/31/2021 Memorandum of Agreement between USACE and USFWS signed 2/26/20. The USFWS will use ESA consultation process to complete coordination responsibilities under FWCA. Policy Waiver Request Package in Development Policy Waiver Request Package in Development Policy Waiver Request Package in Development; Formal Consultations anticipated Policy Waiver Request Package in Development; Formal Consultation anticipated Policy Waiver Request Package in Development 23 1181 US Army Carps of EngFnears ., ENVIRONMENTAL COMPLIANCE AND NEPA IMPLEMENTATION ❑ The final design and siting of project features would not occur until the PED Phase at which time resource surveys, including environmental surveys and a wetland jurisdictional determination, would be conducted. ❑ The structural components would have the potential to result in adverse effects to federally protected threatened and endangered species, critical habitats, and essential fish habitats. At this time, the information required to complete consultation requirements, including detailed design information, an operations and management plan, and survey data, is not available. The USFWS and NMFS have provided support for completing consultations during the PED Phase in their comments received on the draft EIS. ❑ A policy waiver request will be submitted for approval for environmental compliance requirements that cannot be achieved during the feasibility study/planning phase. ❑ Future, tiered NEPA documentation would also be prepared for site -specific project phases and coordinated with resource agencies as designs advance and more detailed resource data becomes available during the PED Phase. 24 US Army Carps. of EngFriaars. RISK AND UNCERTAINTY Engineering/Geospatial ❑ Existing data quality and availability - Medium Risk ❑ Geotechnical Data known - substrate is limestone - Low Risk ❑ Uncertainty in time for data analysis - Medium Risk Economics ❑ Structure and content values - Low Risk ❑ First floor elevations - Medium risk ❑ Forecasted Stillwater elevation - Low Risk ❑ Using data from ERDC on updated ADCIRC model Environmental/Cultural Resources ❑ Methodology to assess any damage reduced by using natural and nature -based features - Low Risk ❑ Completion of environmental and cultural resource surveys during PED Phase - Medium Risk ❑ Water Quality Impacts/Modeling - Medium Risk ❑ Environmental permitting - Medium to High Risk • Or - Real Estate ❑ Property owner cooperation during the acquisition phase - Medium Risk ❑ Acquisition of property rights for in - water structures - Low Risk ❑ Utility Relocations - Low Risk Plan Formulation ❑ 3 x 3 budget and schedule goals will reduce comprehensive nature of the study and increase potential residual risk - Medium Risk ❑ Potential project intersection with Comprehensive Everglades Restoration Plan (CERP) and Central & Southern Florida (C&SF) Project may impact other projects (coordinating with SAJ) - Medium Risk 25 US Army Carps of Ent REVIEW FINDINGS ❑ Agency Technical Review (ATR) ❑ 198 comments All comments resolved and closed out. ❑ 1 critical H&H comment ❑ Legal and Policy Review The PDT and blended review team have agreed on the path forward to reach resolution on all comments. ❑ 37 comments ❑ 11 high, 5 medium/high ir❑ Independent External Peer Review (IEPR) All comments resolved and closed out. ❑ 16 comments ❑ 3 medium/high comments ❑ Public and Agency Comments - In Progress Under Review. r6, ❑ 539 comments (184 unique comments) UMW 26 1181 US Army Carps of EngEneers *, AGENCY TECHNICAL REVIEW COMMENTS H&H — 1 Critical Comment • Comment: Using 90% Confidence Limit for economic analysis is non -compliant with ER 100 and ER 101 • Response: The team has adjusted the model to use mean values per guidance for economic analysis. • ,•I I :•J i US Army Corps of Engineers:' POLICY REVIEW COMMENTS FROM PGM UrS.IIRNY • Comment: Ensure all USACE SLC curves were used to determine NED Plan. Provide additional description of residual risk and expected performance of the features. • Response: Mean values were used to determine NED plan. USACE low and intermediate curves as well as 90% CL will be looked at to determine project performance and determine residual risk. • Comment: Provide additional details regarding concurrent studies and multiple lines of defense. • Response: Additional details will be added to elaborate on the FWOP conditions and studies being conducted at SAJ • Comment: Justify NNBF at Cutler Bay and why additional NNBF could not be paired with structural features. • Response: Further investigation of NNBF is being conducted at Cutler Bay. • Comment: It appears unlikely that the project will achieve full environmental compliance by the final report and a policy waiver will be needed. • Response: A discussion with the Vertical Team will be coordinated to discuss the waiver requirements. The draft waiver request is currently in development. • Comment: The REP needs additional data regarding real estate requirements and all estates that may be required, potential costs and schedule impacts to the project if acquisition is part of nonstructural plan, and additional details on facility or utility relocations. • Response: Additional details have been refined since Draft Report release and will continue to be adjusted accordingly. 1181 IEPR COMMENTS US Army Carps of EngFrresrs ., ❑ 3 Medium/High Comments: • Requesting confidence intervals on EAD and BCR estimates, exceedance probability ratings, long-term risk and assurance tables as required by ER 1105-2- 101 • Interior flood analysis and rainfall analysis has not been completed. Use multiple SLR curves to determine performance of TSP. Clarify potential effects of subsidence. Describe H&H modeling activities that will occur in PED. Evaluate how uncertainty from assumptions translate into confidence limits on EADs and BCRs • Identify critical infrastructure inventory and their role in protecting or improving resiliency of Miami -Dade County. Describe how critical infrastructure is expected to perform under FWOP conditions. 29 i 1181 US Army Carps of EngFrresr ., PUBLIC COMMENTS ❑ Public preferred seeing more natural and nature -based solutions like living shorelines and coral restoration and green infrastructure and less grey infrastructure ❑ Concerns that the solutions do not provide risk reduction to rainfall, nuisance/chronic flooding, and/or sea level rise on its own; water quality impact concerns associated with proposed structural measures ❑ Using property values to identify benefits rewards wealthy investors who continue to build along the coast and can afford to elevate their homes on their own. ❑ High value properties would benefit more from protection features compared to historically vulnerable communities ❑ Floodwalls will bisect communities and could lower property values of houses on the seaward side of the floodwall 30 US Army Carps. of EngFriaars. NON-FEDERAL SPONSOR EXEMPTION REQUEST / PATH FORWARD ❑ Sponsor submitted a letter requesting that Norfolk District submit a 3x3 exemption for additional time ❑ NAO and Sponsor reviewing exemption request schedule and budget ❑ Team continues to move forward towards Chief's Report ❑ If exemption sought, it will be for additional details on the Recommended Plan and not scope expansion ❑ Team to continue to work with Sponsor to address study comments ❑ Develop high level briefings for Sponsor and municipalities ❑ Develop additional outreach opportunities for the community ❑ Develop visual concept art for engineering features ❑ Provide details on integrating project into Central and Southern Florida Flood Control Project ❑ Provide details on incorporation and limits of natural and nature -based lamifeatures 31 US Army Carps of EngFriaars. *; CURRENT FEASIBILITY STUDY MILESTONE SCHEDULE Signing of Feasibility Cost Share Agreement (CW130) Alternatives Milestone (CW261) In -Progress Review Tentatively Selected Plan Milestone (CW262) Release of Draft Study for Concurrent Reviews (CW250) Agency Decision Milestone (CW263) Submit Final Report Package to MSC / Policy and Legal Compliance Review Team (CW160) State and Agency Review 11 June 2021 (S) Signed Chief's Report (CW270) 124 Sep 2021 (S) 09 Oct 2018 (A) 09 Jan 2019 (A) 07 May 2019 (A) 17 Jan 2020 (A) 5 June 2020 (A) 18 Nov 2020 (S) 23 April 2021 (S) 32 1181 US Army Carps of EngFriaars PANEL DISCUSSION L - ,T1I1-111111 _ _ _ I I 1 Pi •Et.- .6.174V 1181 US Army Carps of EngFriaars SPONSOR'S COMMENTS 1181 US Army Carps of EngFrresrs ., WAIN AGENCY DECISION REQUESTED ❑ The Recommended Plan ❑ Project First Cost: $ $6,058,000,000 ❑ Average Annual Net Benefit: $3,079,000,000 ❑ BCR at 2.5% Discount Rate: 10.9 ❑ BCR at 7% Discount Rate: 2.9 ❑ Life Risk is expected to be reduced compared to future without project condition ❑ Review findings did not result in comments that would change the Recommended Plan ❑ The team is still on track to complete the study within three years and for $3M • ` C1