COWI has over 7,000 employees COWI World-wide

JANUARY 17, 2013 2 PANYNJ 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 , 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

JANUARY 17, 2013 8 PANYNJ 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

Sector Gate (150') & • Gerwick is the Lead Designer Swing Gate (150') for the $1.3-billion design-build contract for the USACE Hurricane Protection Office. The barrier reduces the risk of damage from Flood Wall 100-year and 500-year storms. (9,000 ft.)

› Gerwick designs: 150' Swing Gate, GIWW Sector Gate Monolith, Approach Walls, and the flood wall itself. Lift Gate › Gerwick provided construction (150-ft. support, on-site staff for project Channel) duration, cost estimating assitistance, management of MRGO mech. subs, QC, and Closure documentation.

11 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" Diamet er 36" Diamet er Steel Piles Steel Piles Driven to EL -190 ft

18" Concrete Closure Piles

66" Diameter CtConcrete Piles Driven to EL -130 ft

13 IHNC Gate Structures at Gulf Intracoastal Waterway (GIWW)

Swing Gate

StSector GGtates

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 CH2M-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

Swing Gate: 103 ft. x 80 ft. broad Approach x 60 ft. tall Wall

20 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 hhdead 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 Secto r Gate s (IHNC) all conc entra te 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

› RiRequires stttout piers for reacti ons

› 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 saliliitnity bbiarrier

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 operat e with a hhdead 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 Gat e with a Hyd rauli c Prop

› Buoyant Gate (Venice)

Options:

› Flap with Air Chamber for Neutral Buoyancy

30 Mechanically Operated Wicket Gate Option

JANUARY 25, 2012 31 PORT OF WEST SACRAMENTO PRESENTATION Steel Wicket Gate (Raised)

32 Wicket Gate (Raised)

Protected Side Flood Side

Flap Gate: Steel or Steel 55 ft Ltwt. Conc. 35 ft Prop

o 60 Channel Bed Seal Bag

Sheet Pile Float-In Piles Driven Wall Driven Foundation "in-the-wet" "in-the-wet"

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

JANUARY 25, 2012 36 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 c ha nnel › 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 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' NAVD88 › Tidal Range (MHHW: 5.2', MSL: 1.5' NAVD88) › 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 contribfbution of astronomical component

JANUARY 25, 2012 43 Los Angeles, CA SLR and Monthly Extremes

› Some interaction exists between extreme water levels and a rise in base sea- level. › 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.

JANUARY 25, 2012 44 Design considerations: SLR Summary of the California State Lands Commission's Global SLR Projections

The indi cat ed val ues are based on a 2009 report by V&R to the NAS, wh ere A1FI, A2 and B1 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 reppport 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 NAVD88 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 ove rhe ad obst ruction s › Required freeboard: 1'-0" for Future Case

Present Future Req'd top of Gate EL. 14.0 14.0feet Flood Side Water EL. 909.0 13.0 feet Protected Side Water EL. 6.0 6.0feet Channel Bottom EL. -14.0 -14.0feet Top of Foundation EL. -18.0 -18.0feet

50 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

PdProposed Cross-Secti ona l 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

OAKLAND, CA SEATTLE, WA 1300 Clay St., 7th Floor 220 West Mercer St. Suit e W100 Oakland, CA 94612 Seattle, WA 98119 Tel. (510) 839-8972 Tel. (206) 588-2735 DlDale Berner, PhD, PE Paul Guenther, PE, SE [email protected] [email protected]

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 [email protected] [email protected]

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