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Oct 2016 public meeting presentation acoe reformulation plan

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Army Corps of Engineers Rockaway Reformulation study for Rockaway Beach and Jamaica Bay

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Oct 2016 public meeting presentation acoe reformulation plan

  1. 1. US Army Corps of Engineers BUILDING STRONG® Atlantic Coast of New York East Rockaway Inlet to Rockaway Inlet and Jamaica Bay, NY Draft Reformulation Public Information October 2016
  2. 2. BUILDING STRONG® • 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 2
  3. 3. BUILDING STRONG® 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 3
  4. 4. BUILDING STRONG® 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)
  5. 5. BUILDING STRONG® Study Area 5
  6. 6. BUILDING STRONG® 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 6
  7. 7. BUILDING STRONG® Risks  Flooding (inundation) along Atlantic Ocean Coast and Jamaica Bay  Wave Damage  Beach Erosion  Effects of Sea Level Change
  8. 8. BUILDING STRONG® 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 8
  9. 9. BUILDING STRONG® Scale of the Flooding Problem Blue 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 9
  10. 10. BUILDING STRONG® Sand Movement and Erosion Simulation +16 years
  11. 11. BUILDING STRONG® 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 11
  12. 12. BUILDING STRONG® 12 Original Authorized Project
  13. 13. BUILDING STRONG® 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 13
  14. 14. BUILDING STRONG® Original Authorized Project Cross-Section As a beach erosion control project – no dune feature or wall to offer protection against surge (flooding) 14
  15. 15. BUILDING STRONG® 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.
  16. 16. BUILDING STRONG® 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.
  17. 17. BUILDING STRONG® 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
  18. 18. BUILDING STRONG®
  19. 19. BUILDING STRONG® Tentatively Selected Plan
  20. 20. BUILDING STRONG® 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 20
  21. 21. BUILDING STRONG® 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 Construction 34th St new groin - 526 ft 37th St extend groin - 175 ft 40th St extend groin - 200 ft 43rd St extend groin - 75 ft 46th St extend groin - 150 ft 49th St extend groin - 200 ft 92nd St new groin - 326 ft 95th St new groin - 326 ft 98th St new groin - 326 ft 101st St new groin - 326 ft 104th St new groin - 326 ft 106th St new groin - 326 ft 108th St new groin - 326 ft 110th St new groin - 351 ft 113th St new groin - 376 ft 115th St new groin - 376 ft 118th St new groin - 376 ft 121st St new groin - 326 ft Typical groin section Typical groin layout
  22. 22. BUILDING STRONG® Shorefront Component includes Initial sand placement and renourishment 50 years Red line indicates previous Authorized project elevation
  23. 23. BUILDING STRONG® 23 Composite Seawall Cross-Section
  24. 24. BUILDING STRONG® 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
  25. 25. BUILDING STRONG® Surge Barrier Details Hurricane 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 25 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!)
  26. 26. BUILDING STRONG® 26 Lake Borgne, New Orleans Surge Barrier built by the USACE in 2011 (1.8 miles long)
  27. 27. BUILDING STRONG® 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 27
  28. 28. BUILDING STRONG® Typical Residual Risk Measures FLOOD SIDE LAND SIDE FLOOD SIDE LAND SIDE Generic 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
  29. 29. BUILDING STRONG® Generic Residual Risk Measures (cont’d) FLOOD SIDE LAND SIDE FLOOD SIDE LAND SIDE New I-WallBulkhead FLOOD SIDE LAND SIDE Revetment FLOOD SIDE LAND SIDE Berm
  30. 30. BUILDING STRONG® Edgemere Residual Risk Concept
  31. 31. BUILDING STRONG® Mott Basin Residual Risk Concept 31
  32. 32. BUILDING STRONG® 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 32 FY 2016, 50 year study period, 3.125 discount rate
  33. 33. BUILDING STRONG® 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 33 FY 2016, 50 year study period, 3.125 discount rate
  34. 34. 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 FY 2016, 50 year study period, 3.125 discount rate Project Costs and Economics The TSP is the NED Plan, identified as the plan that has highest net benefits
  35. 35. 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.
  36. 36. BUILDING STRONG® 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 36
  37. 37. BUILDING STRONG® 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
  38. 38. BUILDING STRONG® 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) 38
  39. 39. BUILDING STRONG® 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 39
  40. 40. BUILDING STRONG® 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 40
  41. 41. BUILDING STRONG® 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 41
  42. 42. BUILDING STRONG® Real Estate Required  Perpetual beach easements for all parcels where sand is placed  Fee acquisition required for structural components 42
  43. 43. BUILDING STRONG® 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
  44. 44. BUILDING STRONG® Questions

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