Verrazano Narrows Storm Surge Barrier

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 Verrazano Narrows • inhoudsopgave 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 Alignment half a mile north of Verrazano Bridge

The Narrows

Staten Island

Long Island

Verrazano bridge

Present Cross section Verrazano Narrows Cross section

60

Cross section Cross section

40

Width: 6000 feet Width: 6000 feet Depth: 60 feet (max) Depth: 60 feet (max)

20 0 -20

Wet cross section: Wet surface: 310.000 ft2 310.000 ft2

-40 -60

6600

R1 6270

5940

5610

5280

4950

4620

4290

3960

3300

3630

width (ft)

2970

2640

2310

1980

1650

1300

990

660

330

0

-330

-80

depth (ft)

Embankement above Embankement above 50 feet within 50 feet within 300-600 feet 300-600 feet

Impeding water only

n o i t p o c i t s i l a e r o N

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: 2 57.000 ft 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)

Limited wet cross section = limited tide

Tides

Present tide NYHB

4,0

3,0

2,0

W aterlevel (ft)

1,0

0,0 20,0

30,0

40,0

50,0

60,0

70,0

80,0

-1,0

-2,0

-3,0

-4,0

Tide NYHB, limited cross section

90,0

Reduction tide in New York Harbor Bay (2)

Limited wet cross section = limited tide

Tide in relation to wet cross section 100 90

Reduction to 23% = tide reduction to 85-90 %

80

T i d e (% )

70

Tide; basis model with safety margin

60

..

50 40 30 20 10 0 0

10

20

30 Cross section (%)

40

50

60

Reduction tide in New York Harbor Bay (3) Limited wet cross section = limited tide

8

Maximum velocity during mean tide

7

Velocity (knots)

6

Reduction to 70.000 sq ft2 = tide reduction to 85-90 %

5 4

.. and higher peak velocities up to 6-8 knots

3 2 1 0 0

10

20

30 Cross section (%)

40

50

60

Additional wet cross section for • higher tidal range • 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


Hartel Canal storm surge barrier 1997


Easter Scheldt storm surge barrier 1986

… used in the right places (1)

Sector gate for large opening:

Maeslant


Sector gate for large opening: Lifting gates, high clearance for smaller openings:

Maeslant Hartelkering


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 Water level outside 30,0

Water level

water level (ft)

25,0

Desig n Cate storm gory 3 hur Surg rican e of 2 e 2 fe e t

20,0

Storm surge 15,0

Normal tide

10,0

Sea level rise

5,0 0,0 -5,0

1

7

13

19

25 time (hr)

31

37

43

49

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

Inside

5,0

49

46

43

40

37

34

31

28

25

22

19

16

13

10

7

4

0,0 1

water level (ft)

•

-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

Safe level

7,0

With overtopping

6,0 5,0

water level (ft)

• •

4,0

With river discharge

3,0 2,0 1,0

No river, no overtopping 0,0 20,0

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 16 + 2 lifting gates Tie-in structures Total O&M Budget estimated US$ 75mln annually Much lower costs with less lifting gates Many additional studies required

US$ 2.5 bln US$ 3.5 bln US$ 0.5 bln US$ 6.5 bln

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