oct 2016 public meeting presentation acoe reformulation plan

US Army Corps of Engineers

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Atlantic Coast of New York

East Rockaway Inlet to Rockaway Inlet

and Jamaica Bay, NY

Draft Reformulation

Public Information

October 2016

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• Project Overview & History

• Problem Statement

• Plan Formulation Process

• Tentatively Selected Plan

• Shorefront features

• Inundation Features

• Tie-In features

• Residual Risk features

• Environmental Analysis

• Next steps

Presentation Outline

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Meeting Purpose

Public Information Session & NEPA Meeting

Provide an update on the Reformulation Study and

Tentatively Selected Plan (TSP)

Provide an opportunity for feedback on:

► Tentatively Selected Plan

► Alternatives considered in arriving at the TSP

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Project Partners

►NY State Department of Environmental

Conservation (NYSDEC)

►New York City • Mayor’s Office of Recovery and Resiliency

• Department of Parks and Recreation

• Department of Environmental Protection

►National Park Service, Gateway (Cooperating Agency)

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Study Area

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Reformulation Goals

Recommend long-term coastal storm risk reduction

for Rockaway and Jamaica Bay

Address multiple risks in a comprehensive system

for Rockaway and Jamaica Bay that is

► Engineeringly Feasible

► Economically Justified

► Environmentally Acceptable

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Risks

Flooding (inundation) along Atlantic Ocean

Coast and Jamaica Bay

Wave Damage

Beach Erosion

Effects of Sea Level Change

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Coastal Storm Risk Vulnerability► Structures exposed to inundation, waves and erosion

► Naturally low-lying topography – inundation occurs across broad areas

► Densely populated urban area

► Extensive low-lying infrastructure – Critical infrastructure within inundation impact areas

► Degraded coastal ecosystems undermine natural resiliency of the area

>41,000 structures at risk of inundation for 1% event

Problem Statement

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Scale of the Flooding ProblemBlue illustrates current 1% annual chance of flooding

Purple illustrates 1.3 feet of Relative Sea Level Change in 2070, (mid-range SLC) added to the 1% flooding

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Sand Movement and Erosion

Simulation

+16 years

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Original Project (1970s)

Project Authorized in 1965 as a Beach Erosion Control and

Hurricane Protection Project

Beach Erosion Control Features:

Beach Berm at +10 ft Mean Sea Level (MSL)

5M Cubic Yards of sand place for initial construction

Renourishment for a period of 10 years

Hurricane Protection Features:

Never Constructed and Subsequently De-authorized

Hurricane Barrier w/ Navigation gate across Rockaway Inlet

Floodwall at +18 ft MSL, for 7.7 miles along Rockaway

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Original Authorized Project

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Original Project (1970s)

1974 authorization – authorized separate construction of “beach erosion

control” portion plus 10 years of renourishment

The “Hurricane Protection Features” were de-authorized by Congress

Constructed in 1975-1977

Terminal groin added at Beach 149th Street in 1979

Project renourished regularly through 1987, and in 1996, 2000, and 2004

Due to lack of renourishment, the beach was below design size when

Sandy hit

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Original Authorized Project Cross-Section

As a beach erosion control project – no dune feature or

wall to offer protection against surge (flooding)

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Planning Process Overview

Rockaway Project Area formulated as a system,

considering shorefront and bay

- First Planning step is to evaluate and screen measures

- Second Planning Step is to compare alternatives and

identify the Tentatively Selected Plan

- Following the Draft Report and EIS additional

feasibility-level design is conducted on TSP.

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Storm Risk Management Measures

Coastal storm risk management can be achieved through a variety of engineered features, designed as appropriate for each project area.

Features can include

► hurricane storm surge barriers

► hurricane dunes and levees

► seawalls

► revetments

► groins

► breakwaters

► beaches and dunes (beach nourishment)

► bypassing and backpassing of sand

► non-structural measures such as house-raising,

road raising, relocations and buyouts.

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Final Array of Alternatives

A - No Action Alternative

B - Non-Structural Alternative

C - Rockaway Storm Surge Barrier (2 Possible

Alignments)

• Beachfill with reinforced dune

• Groins & Groin extensions

• Barrier with navigation and sector gates

• Tie In Features

D - Jamaica Bay Perimeter Plan

• Beachfill with reinforced dune

• Groins & groin extensions

• Living Shoreline and/or T-Wall where appropriate

• Smaller inlet closure gates to reduce wall length

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Tentatively Selected Plan

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Elements Common to All Alternatives

Atlantic Shorefront Features (Composite Seawall,

Beachfill, Groins)

Atlantic Shorefront East and West Tie-ins*

Rockaway Bayside Tie-in*

Coney Island Tie-in*

* Alternative tie-ins will be developed further during detailed design

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Tentatively Selected Plan(Shorefront Component)

• Composite Seawall, beach berm

• Construction of 12 new groins between Beach 90th to Beach 122nd

• Enhancement of existing groin field from Beach 36th to Beach 49th

(extending groins) and new groin at Beach 34th

Groin Construction34th St new groin - 526 ft

37th St extend groin - 175 ft


43rd St extend groin - 75 ft



92nd St new groin - 326 ft

95th St new groin - 326 ft


101st St new groin - 326 ft








121st St new groin - 326 ft

Typical groin section Typical groin layout

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Shorefront Component includes Initial sand placement and

renourishment 50 years

Red line indicates previous

Authorized project elevation


Composite Seawall Cross-Section

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Barrier Alignment Alternatives

Three alignments of the storm surge barrier originally considered

- Hydrodynamic modeling undertaken for design of openings

- Effects of scour on Gil Hodges Bridge eliminated C-1W

- Impacts to existing utilities considered

C-1E is the preferred alignment, C-2 is close in comparison

Preliminary Water Quality modeling undertaken to evaluate plans

Additional modeling to be undertaken for the final design

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Surge Barrier DetailsHurricane Barrier Alternative Alignment Gate Opening Aggregate Length

Alignment Total Opening (ft)

Number of 100-foot

Vertical Lift Gates

Number of 200-foot

Sector Gates

C-1E 1,100 7 2

C-2 1,700 11 3

Both Alignments• Maximum tidal amplitude change of 0.2 feet, Minimal change to flow speeds and direction

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Oosterscheldekering Storm Surge Barrier

with lift gates Source: (https://beeldbank.rws.nl Rijkswaterstaat / Harry van Reeken)

Spijkenisse - Hartelkering Storm Surge Barrier

with sector gates (credit: Quistnix!)

https://beeldbank.rws.nl/

http://www.flickr.com/people/33932522@N07


Lake Borgne, New Orleans Surge Barrier

built by the USACE in 2011 (1.8 miles long)

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Residual Risk Features

Areas vulnerable to SLC or high frequency

events will be protected in the short term prior to

construction of the barrier

NNBFs and some structures identified

Small scale Non-Structural solutions will be

explored in final design

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Typical Residual Risk Measures

FLOOD SIDE LAND SIDE

FLOOD SIDE LAND SIDEGeneric measures are assigned

considering:

► Shoreline Type and Condition

► Alignment

► Land Use

Generic measure is either:

► Retrofit Existing Structure

► New Construction

Cost developed for each project

based on measure and length

Retrofit L-Wall

Retrofit Crown Wall

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Generic Residual Risk Measures (cont’d)

FLOOD SIDE LAND SIDE FLOOD SIDE LAND SIDE

New I-WallBulkhead


Revetment


Berm

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Edgemere Residual Risk Concept

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Mott Basin Residual Risk Concept

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Cost Breakdown

Construction, Mitigation, and Real Estate Costs

Alternative C-1E Alternative C-2 Alternative D

Construction $3,328,135,000 $3,361,337,000 $4,467,352,000

Mitigation $90,833,000 $75,783,000 $123,383,000

Real Estate $29,436,000 $17,386,000 $179,955,000

First Cost Total $3,448,404,000 $3,454,506,000 $4,770,690,000

IDC $333,029,000 $336,274,000 $424,262,000

Total Construction

Cost

$3,781,433,000 $3,790,780,000 $5,194,952,000

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FY 2016, 50 year study period, 3.125 discount rate

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Annual Costs

Annual Costs

Alternative C-1E Alternative C-2 Alternative D

Construction $150,474,000 $150,846,000 $206,722,000

Renourishment $5,740,000 $5,740,000 $5,740,000

OMRR&R $7,424,000 $7,124,000 $14,954,000

Total AAEQ $163,638,000 $163,710,000 $227,416,000

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Alternative Plan – Benefit Cost Ratio

Plan Total Cost Benefits Net Benefits BCR

C-1E $163,638,000 $509,233,000 $345,595,000 3.1

C-2 $163,710,000 $509,233,000 $345,523,000 3.1

D $227,416,000 $497,582,000 $270,166,000 2.2


Project Costs and Economics

The TSP is the NED Plan, identified as the plan that has highest net benefits

Consideration of Environmental Impacts

Unavoidable, Minimal &Temporary

Recreational and Environmental Impacts

Beach Access:

Temporary disruption to beach access via walkovers over the

Aesthetics:

Potential impacts to view of beach from north side of the dune

Surfing and Fishing:

Will be temporary and will dissipate as the beach returns to equilibrium

Beach Usage:

Impacts end as construction moves along Beach

Groins/Jetties:

Impact local shoreline sand supply, disrupt benthic habitat,

provide vertical and structural habitat for many marine organisms; Potential

adverse effect to buried cultural resources

Seawalls:

Reduce aquatic-terrestrial connectivity. Reduce spawning habitat for forage

fish. Potential loss of upper beach and backshore altered sediment

transport (loss of beach shoreward of the structure); Potential adverse

effects to buried cultural resources

Storm Surge Barrier Impacts:

Potential to affect tidal hydraulics and water quality parameters such as

temperature, dissolved oxygen, nutrient concentrations, etc. Impacts to bay

bottom, potentially limiting wetland areas along the shoreline area

Adverse effects to Gateway National Recreation Area historic districts

Impacts Avoided or Minimized

Benthic:Short term, recovery expected within 2 - 6.5 months nearshore and 1.5 to 2.5 years offshore following construction

Fisheries:No long-term impacts expected, will generally avoid construction area

Shorebirds/Endangered Species:No construction during breeding season Avoidance and enhancement of existing foraging/nesting habitats

Water Quality:Short term turbidity (including impacts to dissolved oxygen), ends as soon as each element is constructed

Air Quality and Noise: Temporary impacts, during 24-7 construction only

Aesthetics:New sand similar to the existing beach.

Impacts Considered: Benthic Communities, Fisheries, Shorebirds, Water Quality, Air Quality

and Noise, Cultural Resources, Aesthetics, Surfing, Fishing, Beach Usage.

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Hydrodynamic modeling to date:

1) Tidal Amplitude impacts► Identified reductions in tidal amplitude of less than 0.2 feet

► Results consistent

• over full 35-day simulation period, and

• for all hurricane barrier alignments and configurations

evaluated for the TSP

2) Jamaica Bay Eutrophication Model

Bay specific model to assess impacts in greater detail.

Barrier Analysis

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Next Steps

Public and agency input on features, locations and

scales

Refine design and evaluation of specific plans

► Detailed, coordinated Water Quality Modeling

► Refine design

► Identify scale of barrier and tie ins

Department of Interior (Gateway) agreement with plan

Final Report and Environmental Impact Statement

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Implementation

The Selected Plan will be built incrementally,

Atlantic Shoreline will be in the first phase

Significant Federal funding is available for

construction (Sandy Funding to USACE for

projects like this totals $3.5B)

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Schedule

Draft General Reevaluation Report available for public

and agency review: November 17, 2016

Final Report (June 2017) must be reviewed and

approved both internally within the USACE and

externally, including local, state, and other Federal

oversight

Construction start of first phase (Targeted for 2019) will

depend on length of reviews and approvals, and relative

complexity of design

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Local Sponsor

Responsibilities

Local Sponsor

►Must cost-share construction and renourishment

►Must commit to doing O&M

►Must indemnify State and Federal Governments

►Must obtain all necessary real estate

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Operation and Maintenance

Local Sponsor must maintain project once built► Maintain public access

► Prohibit excavation and alterations

► Grade and reshape beach to original elevations to repair erosion

► Operate and Maintain the Storm Surge Barriers

► Conduct quarterly inspections and take beach width

measurements

► Send quarterly inspection reports to State and Corps

► Conduct pre-storm & post-storm inspections

► Participate in yearly inspection with State and Corps

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Real Estate Required

Perpetual beach easements for all parcels

where sand is placed

Fee acquisition required for structural

components

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Public Access Overview

Federal funding requires public access open to all

Public accessways to beaches must be within ¼ of a mile in each direction

Local Sponsor responsible for developing a Public Access Plan

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Questions