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Wake Up: It's Sandy!

Hurricane Sandy will not just be remembered as a “Frankenstorm” that wrecked the northeastern US, but will become a major milestone in infrastructure planning, engineering, and maintenance. With overall economic loss reaching $50 billion,1 millions of homes without power for more than a week, and very limited public transportation for several days within and around New York City, it is time to focus attention on the resiliency of our infrastructure under extreme weather events. Record-breaking storm surges and extreme winds brought up by Sandy have sparked a series of discussions ranging from impact of climate change on coastal communities to emergency planning and management to climate change adaptation. While most of the discussion has centered on whether or not climate change is to blame for Sandy’s damages, the dialogue has failed to focus on a more significant question:

What is next?

A study2 performed by Jacob et al. approximately 12 years ago indicates that “…even under current or recent climate conditions, many of the major transportation facilities’ operations [within the metropolitan New York area] will be flooded during worst-case track scenarios of hurricanes of Category 1 through 4.”

The combined effect of Sandy and high tide produced a record storm surge of 13.88 feet (4.2 meters) into New York’s Battery Park (at the southern tip of Manhattan). This storm surge exceeded the Federal Emergency Management Agency/US Army Corps of Engineers (USACE)/National Weather Service-estimated3 Category 1 storm surge height of 10.5 feet (3.2 meters) as well as the flooding threshold elevations for the South Ferry subway station4 and the Brooklyn Battery Tunnel2 located near the Battery Park by 2.9 feet (0.9 meters) and 5.28 feet (1.6 meters), respectively. In addition to the South Ferry subway station and Brooklyn Battery Tunnel, three roadway tunnels and several subway tunnels and stations within and around New York City were flooded during Hurricane Sandy.

Estimating hurricane storm surge requires complex analysis. Lin et al.5 performed several thousand synthetic storm simulations both under observed climate (1981 to 2000) and projected climate at the end of this century to assess the storm surge threat for New York City. The worst case simulations for observed climate resulted in a slightly greater surge (4.57 to 4.75 meters or 15 to 15.6 feet) than that which Sandy produced. Lin et al. also concluded that, under projected climate from four general circulation models and sea level rise, the current 100-year surge levels will be exceeded on an average of every three to 20 years by end of this century.

In addition to “Frankenstorms” like Sandy, experience with less extreme weather events in recent years have demonstrated the vulnerability of our aging infrastructure. In 2011, Tropical Storm Irene cost the Metropolitan Transportation Authority in New York (MTA) almost $110 million in operating costs and damage to its assets.6 The toll was close to $1 billion for all of New York State.7 In Vermont, more than 500 miles of state highway, 200 miles of state-owned rail, and six rail bridges were heavily damaged during Irene.8

Flooded roadways, landslides triggered by heavy precipitation, buckling rail lines and ruptured pipelines due to heat waves have all been associated with recent extreme weather. Recent experience has shown that our infrastructure is already suffering from extreme weather events, and so the potential for damage from future extreme events with increased frequency and/or intensity is a source of much concern. Even less-disruptive weather events can affect transportation infrastructure costs as a result of increased energy costs related to air-conditioning on hot days, additional snow plowing due to increased snow storms, or tunnel drainage (sump pumping) from above-normal levels of rainfall.

Because of the vulnerability of the infrastructure and other assets under current and future weather extremes, climate change
adaptation measures, including storm surge barriers, for the New York City area have been discussed over recent years.

During its 2009 seminar at Polytechnic Institute of New York University, the American Society of Civil Engineers discussed conceptual designs for storm surge barriers at three locations in the waterways surrounding New York City, including a hydraulically-operated flap gate for the East River presented by Michael Abrahams of Parsons Brinckerhoff.9 While these barriers are estimated to cost approximately $17 billion,4 the hydrodynamic storm surge simulations performed by Kim et al.9 indicate that the storm surge barriers would reduce the maximum water elevations as much as five feet (1.5 meters) at locations protected by the barriers. Along these same lines, development of artificial islands/wetlands to protect the flood-prone areas and use of inflatable plugs for the tunnel or underground structure portals as an emergency response have all been discussed in the recent years. However, these conceptual ideas have yet to be realized.

Coordination difficulties, budgetary constraints, and climate uncertainties reduce the speed of action needed to keep pace with the changing climate. In keeping with these concerns, Parsons Brinckerhoff has worked with clients—the Maryland Department of Transportation, the District Department of Transportation (Washington, DC), the National Cooperative Highway Research Program, and the Western Federal Lands Division of the US Federal Highway Administration—to provide guidance and tools to incorporate adaptation into planning, engineering, maintenance, and operations in the face of the uncertainties associated with climate projections and the knowledge gap between the field of climate science and civil engineering.

A few agencies and infrastructure owners throughout the world have proposed interim solutions. In the US, California Department of Transportation and USACE recently developed design criteria for sea level rise due to climate change. The Port Authority of New York and New Jersey, which owns, operates, and maintains critical New York metropolitan area infrastructure, developed relatively more comprehensive interim design guidelines that incorporate future climate projections for air temperature, precipitation, sea level rise, and flood elevations (Box 1). However, recent extreme events may necessitate revisions of these guidelines and criteria.

Given that infrastructure is already suffering from current extreme weather and the potential for increased damage from future extreme events, there is an urgent need for the development of comprehensive tools to predict potential damage due to changing climate, design and analysis procedures incorporating future climate and extreme event projections for both new and existing infrastructure, comprehensive adaptation measures, and stable financing systems for climate change adaptation projects.

 

Notes:

  1. New York Times
  2. Jacob, K.H., N. Edelblum, J. Arnold. Risk Increase to INfrastructure due to Sea Level Rise. Published in Climate Change and a Global City: An Assessment of the Metropolitan East Coast Region (2000)
  3. FEMA , USACE, NWS. Metro New York Hurricane Transporation Study, Interim Technical Data Report (1995)
  4. Bloomberg News
  5. Lin, N., Emanuel, K., Oppenheimer, M., Vanmarcke, E. Physically based assessment of hurricane surge threat under climate change. Published in Nature Climate Change, Vol. 2 (2012)
  6. Village Voice
  7. New York Daily News
  8. State of Vermont. Tropical Storm Irene, After Action Report/ Improvement Planm Fnial Draft (2012)
  9. ASCE. Against the Deluge: Storm Surge Barriers to Protect New York City. Seminar at Polytechnic Institute of NYU (2009)

 

Image Header Source: NASA Goddard Space Flight Center (Creative Commons)


Geographies: United States
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Topics: Policy, Funding & Finance, Other