VKB Resilience General Obligation Bond Protecting the Village’s Beaches and Shoreline Town Hall #2 August 20, 2020
Upcoming GO Bond Town Halls: ✓ August 20, 2020 September 3, 2020 September 17, 2020
For Dial-in Instructions: https://keybiscayne.fl.gov/clientuploads/COVID19/Virtual_Public_Meeting_Instructions.pdf
(Source: Long Range Beach Nourishment Plan, CSI 1997)
Nearshore / Offshore Bathymetry, March 2017
Physical factors that drive erosion: • Depth of bedrock • Depth of water • Bottom characteristics 1. Hard, high relief (reefs) 2. Hard, low relief (rocky) 3. Soft, sandy 4. Soft, vegetated (seagrass) • Wind intensity/direction • Wave intensity/direction • Tidal currents intensity/direction
Bedrock Elevation
EVERYTHING IS CONNECTED
Shoreline Protection is about managing ENERGY/EROSION
Nearshore and Offshore Hardbottom Coverage Natural offshore reefs (hardbottom) are first line of defense for shoreline protection. Hardbottom habitat effective dissipator of wave energy. Seagrass beds provide stability to otherwise soft and shifting sediments
General direction of longshore sediment transport
As sea level rises and storms intensify, energy onto the beach increases and so does erosion
VKB Beach Management Feasibility Study, 2018
Directional wave rose along 2m contour (-6.56 ft)
Southeast
Northeast
(Source: Long Range Beach Nourishment Plan, CSI 1997) 1904 – Government Cut dredged through southern extent of barrier island (aka South Miami Beach) forming Fisher Island Changes to tidal currents through cuts have significant effects on sand movement
Influence of Government Cut on Historic Shorelines
5
Summary of Historical Beach Nourishment Events 1969 – USACE Beach Fill, offshore sand source 1987 – USACE Beach Fill, offshore sand source + reconstruction/extension of groin at lighthouse. Prior to 1998, projects were managed by the U.S. Army Corps of Engineers with MiamiDade County as the local sponsor. The Village has managed and implemented projects between 1998-2017. 2002, 2008, 2012, 2017 – Non-federal Beach Fill, offshore sand source
Future will Require Continual Nourishment Events (2021, 23, 26………)
St. Lucie County, FL FPL Reef/Breakwater Project
SUBMERGED STRUCTURES
Maiden Island, Antigua
Reduce beach erosion associated with cooling canal for nuclear power plant, in conjunction with dune restoration.
Colonized Reef Ball Reef Ball Foundation, Bradenton, FL
1,200 Reef Balls were used to create
the world’s largest fringing breakwater reef system
Considering Offshore Structure / Artificial Reef to Reduce Shoreline Erosion
Sunny Isles Beach, FL
Village of Key Biscayne
discontinuous submerged structure
Bahamar Beach, Bahamas
8
(VKB Beach Management Feasibility Study, 2018)
Challenges at a Glance
increased deposition
increased erosion
Impacts to sediment transport Impacts to water circulation Habitat impacts to seagrass Creating new hard bottom habitat Permitting (USACE, FDEP, DERM)9
Update on Inclusion of VKB into USACE Feasibility Study 1. USACE is proceeding with feasibility study for Miami-Dade County without Key Biscayne 2. A Waiver has been submitted and processed by the USACE Jaxs Office and forwarded to USACE Headquarters for approval and inclusion of VKB into feasibility study 3. Rep. Donna Shalala submitted letter of support to ASA requesting approval, co-signed by Reps. Diaz-Balart, Mucarsel-Powell, Wasserman Schultz 4. Waiver is due to be reviewed by Assistant Secretary of the Army (ASA) for approval
IF KEY BISCAYNE INCLUDED IN FEASIBILITY STUDY A. VKB will work with USACE JAXS to provide data to support a federal project (aka. Tentatively Selected Plan) B. Once TSP developed, it is submitted to USACE Headquarters for review and release to Chief of Engineers for further evaluation/refinement C. Once Chief of Engineers signs off on the TSP, USACE makes recommendation to Congress for project funding (2022 first opportunity to secure an authorization, funds in FY23)
What If……………….. What if Not ? either way it is a long multi-year process
✓ IF the project is authorized in Water Resources Development Act (WRDA) 2022, the first construction phase could be funded in FY 2023 assuming the Corps allows the new project to begin before the expiration of the current Dade County authorization at the end of 2024.
✓ IF included in this complex process, 65% federal funding, 35% other funds (local, state grants etc….)
Congressional authorization process and the congressional appropriations process will require continuous communication and work with the pertinent congressional committees of jurisdiction, the Village’s congressional delegation, and the USACE.
G.O. Bond at a Glance GOB Programs GOB Projects
Mitigating the Effects of Sea Level Rise and Flooding
Total Cost
GOB Program
$40,000,000
$40,000,000
Roadway Improvements/Complete Streets South
Series 1
Series 2
$14,000,000
Roadway Improvements/Complete Streets North
$13,000,000 $64,550,000
$23,300,000
2023 Beach Nourishment & Breakwater Analysis
$3,000,000
2026 Beach Nourishment & Breakwater Analysis Cont.+ Permitting
$4,500,000
Breakwater Construction
$7,900,000
Breakwater Mitigation
Hardening Infrastructure to the Effects of Hurricanes
Series 4
$13,000,000
Roadway Improvements/Complete Streets Central
Protecting the Village's Beaches and Shoreline
Series 3
$7,900,000
$49,200,000
$35,200,000
Hardening & Undergrounding Phase 1 (South)
$9,000,000 $11,500,000
Hardening & Undergrounding Phase 2 (Central)
$10,000,000
Hardening & Undergrounding Phase 3 (North)
$4,700,000
Hardening & Undergrounding Phase 4 (Mashta) $153,750,000
$98,500,000
$25,000,000
$30,000,000
$30,900,000
$12,600,000
Shoreline Protection Estimated Budget
Sub-Total =
$3.4 MM Truck-haul @50,000 Cubic Yards $10.3MM Offshore Breakwater hard cost $2.1MM soft cost $7.5 MM Seagrass Mitigation $23.3MM (GOB)
Over the next 50 years, assume 6 nourishment events $3.4MM = $21.25MM Over the next 50 years, assume 4 seagrass mitigation events $5MM = $20MM Sub-Total =
$41.25MM (other funding sources)
Grand Total =
$64.55MM
THANK YOU
QUESTIONS Email: VKBresilience@keybiscayne.fl.gov