Verrazano Narrows Storm Surge Barrier

ASCE Met Section Infrastructure Group Seminar 2009 Conference “Against the Deluge: Storm Surge Barriers to Protect New York City, March 31st 2009

Peter Jansen, Principal Engineer Hydraulic Structures, ARCADIS Piet Dircke, Program Director Water, ARCADIS Contents

• Introduction • Location• inhoudsopgave Verrazano Narrows • Passage of ships • Tide reduction and wet cross section • Conceptual design • Height and overtopping • Details • Reliability • Estimate of Costs • Concluding remarks

• Questions and discussion The Netherlands

1

2

3

5

4 Comparison of New York / New Jersey and the Netherlands

• Complex sea, tidal and river water systems • Urban area with high property values & densities • Large urban areas below or just above sea level vulnerable to floods • Environmental impact as a major issue • Large ports with intense shipping

New York Rotterdam Location Verrazano Narrows

New York Harbor Bay

North of Bridge Not too far Depth The Narrows

Alignment half a mile north of Verrazano Bridge Staten Island Long Island

Verrazano bridge Present Cross section Verrazano Narrows

Cross section

60 Cross section Cross section 40

20 Width: 6000 feet Width: 6000 feet Depth: 60 feet (max) 0 Depth: 60 feet (max) -20 Wet cross section: Wet surface: -40 310.000 ft2 310.000 ft2 -60

-80 Embankement above

0 Embankement above -330 330

660 50 feet within 990

1300 50 feet within 1650 1980 2310 2640

2970 300-600 feet 3300 R1 3630 3960 4290

4620 300-600 feet 4950 depth (ft) 5280 5610 5940

width (ft) 6270 6600 Impeding water only

tion ic op ealist No r Passing ships Tidal flow Passage of ships

Biggest ship afloat must be able to pass

Emma Maesk

Length: 1300 feet Beam: 185 feet Draft: 53 feet Heigth: 251 feet Cross section for biggest ships

Requirements for Requirements for passage of ships passage of ships Width: 860 feet Width: 860 feet Sill: - 66 feet Sill: - 66 feet Clearance: unlimited Clearance: unlimited = blue area Wet surface: Wet cross section: 57.000 ft2 19 % Additional cross section for smaller ships Additional cross section for smaller ships

2 gates 2 gates Width: 165 feet Width: 165 feet Sill: - 40 feet Sill: - 40 feet Clearance: 80 feet Clearance: 80 feet Total wet cross Total wet surface: Section 70.000 ft2 23 % Reduction tide in New York Harbor Bay (1)

Tides Limited wet cross section = limited tide Present tide NYHB

4,0

3,0

2,0

1,0

0,0 Waterlevel (ft) Waterlevel

20,0 30,0 40,0 50,0 60,0 70,0 80,0 90,0 -1,0

-2,0 Tide NYHB, limited cross section -3,0

-4,0 Reduction tide in New York Harbor Bay (2)

Limited wet cross section Tide in relation to wet cross section = limited tide

Reduction to 23% 100 = tide reduction to 85-90 % 90 Tide; basis model 80 ) with safety margin % ( 70 .. 60 Tide Tide 50

40

30

20

10

0

002 1030405060

Cross section (%) Reduction tide in New York Harbor Bay (3)

Limited wet cross section

8 = limited tide Maximum velocity 7 during mean tide Reduction to 70.000 sq ft2 6 = tide reduction to 85-90 % 5

4 .. and higher peak velocities Velocity (knots) 3 up to 6-8 knots 2

1 Additional wet cross 0 section for 0 102030405060• higher tidal range Cross section (%) • lower velocities Additional cross section tidal flow

16 gates

Width: 130 feet Sill: - 40 feet Clearance: 5 feet

Total wet cross section 155.000 ft2

= 50 % of present wet cross section Combination of three existing Dutch barriers …(1)

Maeslant storm surge barrier 1997 Combination of three existing Dutch barriers …(2)

Hartel Canal storm surge barrier 1997 Combination of three existing Dutch barriers …(1)

Easter Scheldt storm surge barrier 1986 … used in the right places (1)

Sector gate for large opening: Maeslant … used in the right places (2)

Sector gate for large opening: Maeslant Lifting gates, high clearance for smaller openings: Hartelkering … used in the right places (3)

Sector gate for large opening: Maeslant Lifting gates, high clearance for smaller openings: Hartelkering Lifting gates, fixed beam for extra wet cross section: Easter Scheldt Technical overview

Closed

Open Artist impression Requirements impeding water

- Structural reliability - Reliability closure - Limit overtopping and leakage Desig n sto Cate rm Water level outside gory Sur 3 hu 30,0 ge rri of 22 cane feet 25,0 Water level

20,0 Storm surge 15,0 Normal tide 10,0 Sea level rise

water level (ft) water 5,0

0,0 1 7 13 19 25 31 37 43 49 -5,0 time (hr) Height: allowing overtopping and some leakage

• Allowing overtopping is reducing height and reducing costs

30,0

25,0

20,0 Outside 15,0

10,0 water level (ft) level water 5,0 Inside

0,0 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 -5,0 Opentime (hr) Closed Open Allowing overtopping and some leakage

• Allowing overtopping is reducing height and reducing costs • Inside water level will rise - allowable below safe water level

8,0

7,0 Safe level

6,0 With overtopping 5,0

4,0 With river discharge 3,0

water levelwater (ft) 2,0

1,0 No river, no overtopping 0,020,0 25,0 30,0 35,0 40,0 45,0 50,0

-1,0 time (hr) Open Closed Open Details sector gate

Enormous gates 640 feet long Sliding over sill Height -66 to + 30 feet Detail sector gate

Large Foundation Locomobiel Details 130-feet lifting gate

Fixed beam between + 5 and + 36 feet Sill at -40 feet Gate between -40 and + 5 feet Gate hanging on cylinders Maintenance road Details 130-feet lifting gate

Some leakage between gate and fixed beam Operating mechanism 130-feet lifting gates

Cylinders able to lift heavy gates Fail-safe solution: If operating system fails automatic closure of gates by local system, battery controlled, using gravity Applicable up to lifts of 80 feet Reliable if used / tested monthly Details 165-feet lifting gate

No fixed beam Sill at -40 feet Clearance of 80 feet No cylinders but winches in towers Height up to + 28 feet

Large lifting gate 1,000 kips (= 1 meps?) Reliability

Reliability is a key issue; meassures taken include

• Use proven concepts • Operating mechanism above water • Fail save design • Simple movement (horizontal or vertical only) • Easy accessible for maintenance

Operations is vital

• Early warning system • Dicision making (who en when) • Stopping of ships Maintaining reliability is essential

How to keep a structure reliable when you use it only one every 10 years

• Maintenance driven design • Thoughtful construction • Risk based management • Learning and cooperating with other storm surge barrier managers • Strong organization with sufficient budget Costs

Rough estimate Sector gate US$ 2.5 bln 16 + 2 lifting gates US$ 3.5 bln Tie-in structures US$ 0.5 bln Total US$ 6.5 bln

O&M Budget estimated US$ 75mln annually

Much lower costs with less lifting gates

Many additional studies required Concluding remarks

Storm surge barrier possible

Reliability is key issue

Barrier includes all state of the art knowledge of barrier design and operation

Requirements and dimensions will determine costs => additional studies

An extra landmark for New York … Conclusion

bringing safety when required Questions Questions