Army Corps of Engineers Reformulation study for Jamaica Bay

1. US Army Corps of Engineers
BUILDING STRONG®
Atlantic Coast of New York
East Rockaway Inlet to Rockaway
Inlet and Jamaica Bay, NY
Reformulation
Jamaica Bay Overview

2. BUILDING STRONG®
Authorized Study Area
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3. BUILDING STRONG®
Scale of the Problem
Blue illustrates current 1% annual chance of flooding
Purple illustrates 1.3 feet of RSLC in 2070, (mid-range SLC) added to the 1% Annual chance of flooding
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1965 Authorized Project Features

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June 21, 1965
“…the Chief of Engineers has recommended
that field studies and hydraulic model
investigations are to be conducted in
connection with the final design of the
project to determine the specific effects of
the proposed hurricane barrier on water
quality, fish, and wildlife, and currents in
Jamaica Bay…”
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7. BUILDING STRONG®
Reformulation Study
Recommendation of the Federal Project
is based on benefit/cost ratio
Primary purpose for P.L. 113-2 is the
reduction in future coastal flooding
damages
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8. BUILDING STRONG®
Reduce vulnerability to storm surge impacts
Reduce future flood risk in ways that will support the long-
term sustainability of the coastal ecosystem and communities
Reduce the economic costs and risks associated with large-
scale flood and storm events
Improve community resiliency, including infrastructure and
service recovery from storm effects
Enhance natural storm surge buffers and improve ecosystem
resiliency
Other Opportunities
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9. BUILDING STRONG®
Constraints
 Do not negatively impact ongoing recovery, ecosystem restoration, and risk
management efforts by others
 Do not negatively impact navigation access through Rockaway Inlet
 Do not induce flooding in areas not currently vulnerable to flooding and do
not induce additional flooding in flood-prone areas
 Do not reduce community access and egress during emergencies
 Do not impact operations at John F. Kennedy International Airport
 Do not negatively affect plants, animals, or critical habitat of species that are
listed under the Federal on NYS Endangered Species Act

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11. BUILDING STRONG®
Jamaica Bay Measures
Nonstructural
Acquisition
Managed Retreat
Floodplain zoning
Floodproofing/raising
Flood warning system
Structural
Hurricane barrier
Local Tide Gates
Levee
Floodwall
Bulkhead/Seawall
Breakwater
Natural or Nature Based
Living shoreline
Coastal wetland
Maritime and coastal forest
Reef
Dune and Beach
Swale/Channel
Other
Bay shallowing
Stormwater improvement
Wastewater treatment
Park access and recreation
Evacuation routes
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12. BUILDING STRONG®
Measure Screening
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Blue=Effective Green=Effective only for high frequency events

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Table 27: Percentage of Existing Tidal Amplitude
Opening Width Plan C-1 Plan C-2 Plan C-3
1,000 feet 58% 73% 58%
2,000 feet 91% 90% 70%
3,000 feet N/A 93% 79%
4,000 feet N/A 95% 81%
5,000 feet N/A N/A 90%
Note: N/A indicates that the opening width is not feasible for this alignment

19. BUILDING STRONG®
Structural Alternative Plan
Evaluation
Jamaica Bay Alternatives Preliminary Average Annual Net Benefits
(AAEQ)
Plan Name Total Annual
Cost
Benefits Net Benefits BCR
Barrier C-1b $148,012,000 $265,833,000 $117,821,000 1.80
Barrier C-2b $118,669,000 $265,833,000 $147,164,000 2.24
Barrier C-2c $141,900,000 $265,833,000 $123,933,000 1.87
Barrier C-2d $165,131,000 $265,833,000 $100,702,000 1.61
Barrier C-3e $214,430,000 $265,833,000 $51,403,000 1.24
Head of Bay $36,550,000 $71,036,000 $34,486,000 1.94
Rock Back Bay $18,809,000 $67,896,000 $49,087,000 3.61
BC Breakwater $45,124,000 $13,390,000 ($31,734,000) 0.30
Jam Bay NW $101,986,000 $113,511,000 $11,545,000 1.11
Note: EADs and AAEQ costs calculated at FY14 price levels, 3.5% discount rate, and 50-year period of analysis

20. BUILDING STRONG®
Jamaica Bay Alternatives
 No Action Alternative
 Non-Structural Alternative (can be mixed with other Alts)
 Rockaway Inlet Hurricane Barrier
► Provides Benefits to all Economic Reaches
 Jamaica Bay Perimeter Walls w/ Living Shorelines where
appropriate (Perimeter Plan)
► Individual Plan Developed for each Economic Reach
► Negative BCR for Broad Channel, and not applicable
for JFK area
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Preliminary Focused Array
Comparison
(without Real Estate or Mitigation costs)
Plan Name Total Costs Annualized
Costs
Annualized
Benefits
BCR
“Best” Inlet
Barrier
$2,743,300,000 $118,669,000 $265,833,000 2.24
Head of
Bay
$834,250,000 $36,550,000 $71,036,000 1.94
Rockaway
Back Bay
$313,168,000 $18,809,000 $67,896,000 3.61
NW Jam
Bay
$2,300,156,500 $101,966,087 $113,511,000 1.11
Perimeter
Total
$3,447,574,500 $157,325,087 $252,443,000 1.60
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23. BUILDING STRONG®
Choosing A Path Forward
 Further develop Jamaica Bay alternatives, including operational
considerations (O&M can be expensive)
 Estimate real estate and hazardous waste costs
 Integrate ocean and bay alternatives
 Define tie in features
 Refine hydrodynamic modeling of Jamaica Bay
 Improve quantification of environmental effects (WQ & habitats)
 Collaboration with regulatory agencies to inform environmental
thresholds, prioritize analysis
 Detail and broaden analysis of plan benefits
 Emphasize natural and nature based features and resiliency
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