COWI has over 7 000 employees COWI Worldwide

COWI has over 7, 000 employees COWI World-wide 2 OCTOBER 7, 2020 PANYNJ FLOOD BARRIER

Ben C. Gerwick, Inc. › Internationally renowned engineering consulting firm HQ in Oakland, CA › History of creative solutions that minimize risk, cost, and time › Focused on constructability, serviceability, maintenance, and durability of structures in waterways and marine sites › Conceptual design, cost estimates planning, permitting, final design and construction support › Documentation & quality control › Decades of experience with government design criteria to streamline the approval and permitting process › Work is exemplified by New Orleans IHNC Floodgates, Braddock Dam, Olmsted Dam, and Chickamauga Lock. IHNC Swing Gate Tow 3

Select projects Experience › IHNC Lake Borgne Barrier (Design/ Constr. Supt. ) › Montezuma Slough Salinity Barrier (Concept. Des. / Constr. Eng. ) › Braddock Dam (Design/ Constr. Supt. ) › Chickamauga Lock (Design/ Constr. Eng. ) › Olmsted Lock and Dam (Design/ Constr. Eng. ) › Venice Storm Surge Barrier (Conceptual Des. ) › Yeong-Am Lift Gate (Conceptual Des. ) 4

Venice Storm Surge Barrier Compressed air is used to raise gates during a storm. Gerwick performed detailed constructability review for this project. 5

Montezuma Slough Salinity Barrier Complex Radial gate structure for Salinity Barrier in the California Delta. Offsite prefabrication & float-in. 6

Chickamauga Lock Cofferdam, Chattanooga, TN 7

Olmsted Dam Construction Photos › Over 4, 000 -ton Elements have Been Placed with 1 -Inch Accuracy in Six Degrees of Freedom 8 OCTOBER 7, 2020 PANYNJ FLOOD BARRIER

Braddock Dam – Dam Segment Tow to Site Float-in of dam elements allows for minimal construction time, saving money and time 9

Braddock Dam, Pittsburgh, PA – Graving Site Two-Level Graving Dock for Float-in Shell 10

IHNC Hurricane Protection Project New Orleans, Louisiana • › › 11 Gerwick is the Lead Designer for the $1. 3 -billion design-build contract for the USACE Hurricane Protection Office. The barrier reduces the risk of damage from 100 -year and 500 -year storms. Gerwick designs: 150' Swing Gate, GIWW Sector Gate Monolith, Approach Walls, and the flood wall itself. Gerwick provided construction support, on-site staff for project duration, cost estimating assistance, management of mech. subs, QC, and documentation. Sector Gate (150') & Swing Gate (150') Flood Wall (9, 000 ft. ) Lift Gate (150 -ft. Channel) MRGO Closure

IHNC Hurricane Storm Damage Risk Reduction System Gerwick's concept allowed for in-the-wet methods to expedite construction 12

IHNC Flood Wall Construction – August 2009 36" Diameter Steel Piles Driven to EL -190 ft 18" Concrete Closure Piles 66" Diameter Concrete Piles Driven to EL -130 ft 13

IHNC Gate Structures at Gulf Intracoastal Waterway (GIWW) Swing Gate Sector Gates Approach Walls 14

IHNC Gate Structures at Gulf Intracoastal Waterway (GIWW) Swing Gate and Sector each close a 150 -ft. Navigation Channel Swing Gate Sector Gate 15

IHNC Swing Gate Tow to Site – January 2011 16

Cost of Existing Barriers vs CH 2 M-Hill's Concept Gerwick's Base Case Barrier as a Unit Cost of ~$0. 75 billion / mile 17

Gate Type Comparison, Including IHNC Gates

Double Swing Gate › Two barges together use less material than the single swing gate › Does not require stout piers › Adaptive foundations are feasible › Concrete barges are more durable than a steel gate › Cannot operate with a head difference › Not useful as a salinity barrier 19

Double Swing Gate (Open) Proposed for the Port of Houston Channel at Gate: 200 ft. wide 35 ft. deep Flood Wall Levee Approach Wall 20 Swing Gate: 103 ft. x 80 ft. broad x 60 ft. tall

Double Swing Gate (Closed) • Provides Protection to EL 20. 0 ft. + 3'-0" freeboard • In-the-wet construction • No channel closure during construction 21

Rising Sector Gate (Thames Barrier) › Can be used as a salinity barrier › Can open and close quickly › Can operate with a head difference › Requires stout piers for reactions 22

Rising Sector Gate 23

Concentrated Loads vs. Light Piers › Rising Sector Gates (Thames Barrier), Swing Gates (IHNC), and Sector Gates (IHNC) all concentrate gate reactions on a heavy pier acting as a thrust block. › Flap Gates and Gerwick's Double Swing Gate Concept put the load directly into the foundation and only require light piers to provide a sealing surface. 24

Swing Gate (Single Barge) › Concrete barge is more durable than a steel gate › Cannot operate with a head difference › Requires stout piers for reactions › Not useful as a salinity barrier 25

Swing Gate (Single Barge) 26

Sector Gate › Can operate with a head difference › Requires stout piers for reactions › Not useful as a salinity barrier 27

Sector Gate 28

Flap Gates › Some types can be used as a salinity barrier › Some types can open and close quickly › Some types can operate with a head difference › Can be steel or lightweight concrete › Do not require stout piers › Adaptive foundations are feasible 29

Flap Gate Sub-Types › Wicket Gate (Olmsted Dam) › Inflatable Flap Gate (Obermeyer) › Flap Gate with a Hydraulic Prop › Buoyant Gate (Venice) Options: › Flap with Air Chamber for Neutral Buoyancy 30

Mechanically Operated Wicket Gate Option 31 JANUARY 25, 2012 PORT OF WEST SACRAMENTO PRESENTATION

Steel Wicket Gate (Raised) 32

Wicket Gate (Raised) Protected Side Flood Side Flap Gate: Steel or Ltwt. Conc. Steel Prop 35 ft o 55 ft 60 Channel Bed Piles Driven "in-the-wet" Sheet Pile Wall Driven "in-the-wet" Seal Bag Float-In Foundation 33

Wicket Gate (Lowered) 35 ft Channel Bed Steel Props rest within Hurter Troughs 34

Inflatable Flap Gate (Obermeyer Type) 35

Schematic Obermeyer Bottom Hinge Gate 36 JANUARY 25, 2012 PORT OF WEST SACRAMENTO PRESENTATION

Flap Gate with Hydraulic Prop 37

Buoyant Flap Gate (Venice) 38

Advantages of In-the-Wet Construction › Limited or no channel closure during construction › Modular, floating elements lend themselves to design of the closure as an adaptive structure › 50 -foot wide units can be designed to built on grounded barges 39

Representative Construction Site for Grounded Barges 40

Salinity Control Advantages of Flap & Rising Sector Gates › Rising Sector Gates and Flap Gates rise from the bottom of the channel › They can be partially raised during a rising tide to form a salinity barrier against the intrusion of the dense, salt water 41

Site Characteristics Newport Harbor Floodgate Concept › Primary goal and key advantages › Comprehensive defense system against high tide events and other hazards › Cost-effective › Low footprint › Design considerations › Area Map (see following slides) › Current 1% Inundation EL 9' NAVD 88 › Tidal Range (MHHW: 5. 2', MSL: 1. 5' NAVD 88) › Sea Level Rise (Mean/Medium Guidance: 47" by 2100) › Local Settlement & Regional Subsidence (limited) › Soil Properties (use driven friction piles for foundation) 42

Impact of rising tides Flooding and Inundations › Major flooding events caused by interaction between: › Very high astronomical tides ("King tides"; see pictures) – Annual events › Storm surge (storm tide) – Fairly limited on West Coast › Wave set-up (mostly on exposed areas) › Rainfall and run-off › Sea-level rise › Influence of change in sea-level on total water levels may not be neutral because of large contribution of astronomical component 43 JANUARY 25, 2012

Los Angeles, CA SLR and Monthly Extremes › Some interaction exists between extreme water levels and a rise in base sealevel. › Historical volatility of tidal signal has increased over the past 90 years. › A rise in the magnitude of these extreme events may add to the linear contribution of sea-level change. › Historical data assessment highlights the need to establish solid design basis. 44 JANUARY 25, 2012

Design considerations: SLR Summary of the California State Lands Commission's Global SLR Projections The indicated values are based on a 2009 report by V&R to the NAS, where A 1 FI, A 2 and B 1 scenario-based GCM SLR projections, are input for the High, Medium and Low Classes, respectively; and these are provisional at least until the NRC 2012 report is adopted.

NRC 2012 RSLR Guidance for the West Coast for 2030, 2050, and 2100. from NRC 2012

FEMA "Flood Insurance Rate Map" for Newport Harbor 47 Vertical Datum NAVD 88

Pacific Institute's Estimate of Current 1% Inundation (light blue) & Inundation with 55" of SLR (dark blue) 48

FEMA Risk Areas and Jurisdiction Line 49

Preliminary Design Values › Nav. Channel: ~900 ft. wide, 14' to 20' ft. deep, no overhead obstructions › Required freeboard: 1'-0" for Future Case Req'd top of Gate Flood Side Water Protected Side Water Channel Bottom Top of Foundation 50 Present Future EL. 14. 0 feet EL. 9. 0 13. 0 feet EL. 6. 0 feet EL. -14. 0 feet EL. -18. 0 feet

Conceptual 600 -ft Pass Bottom Hinge Gate Barrier

Comparison of 600 -ft Pass & Proposed Tidal Water-Exchange Cross-Sectional Areas Original Cross-Sectional Area @ MHHW ~ 7, 200 sq ft Proposed Cross-Sectional Area @ MHHW ~ 11, 500 sq ft 52

Conceptual 400 -ft Pass Bottom Hinge Gate Barrier

Next Steps A. Initiate Comparative Feasibility Study › "King tides", SLR, run-up and others › Hydrodynamics (tidal exchange, flushing, water quality) › Groundwater infiltration › Benefits of rock armoring and other coastal works B. Identify Preferred Concept C. Work with Authorities to Finalize Concept D. Complete Final Design E. Bid and Construction 54

Gerwick Office Locations 55 OAKLAND, CA SEATTLE, WA 1300 Clay St. , 7 th Floor 220 West Mercer St. Suite W 100 Oakland, CA 94612 Seattle, WA 98119 Tel. (510) 839 -8972 Tel. (206) 588 -2735 Dale Berner, Ph. D, PE Paul Guenther, PE, SE deb@gerwick. com page@gerwick. com NEW ORLEANS, LA LONG BEACH, CA 400 Poydras Street, #1160 3780 Kilroy Airport Way, #200 New Orleans, LA 70130 Long Beach, CA 90806 Tel. (504) 528 -2004 Tel. (562) 598 -9888 Mike Bonin, PE Warren Stewart, PE, SE mclb@gerwick. com wnst@gerwick. com