Rebuilding post-Sandy: Whole greater than parts
President Barack Obama asked Congress for more than $60 billion to help repair and rebuild infrastructure damaged by Hurricane Sandy in the Northeast. The House of Representatives finally voted Friday on a small down payment, roughly 10 percent.
As in the past, engineering experts will likely seek to build in added protections for the specific pieces of the infrastructure that failed in the storm – for example, flooded subway lines or power substations. What they donâ€™t usually address, however, is how to protect networks as a whole.
Ignoring how everything works together is short-sighted. No matter how much money is spent, one part of the system can always go down again. As Sandy demonstrated, a failure at any point can have a cascading effect.
We must be aware of how these pieces fit together to form the larger transportation, energy or other networks that support our lives â€“ taking a â€śsystems engineering approach.â€ť Then, we must make sure that at least some recovery funds are spent to keep entire systems up and running â€“ even if one part fails.
Hurricane Sandy offered plenty of examples that show how vulnerable our infrastructure is. For example, the critical Port Authority Trans-Hudson (PATH) rail line from the damaged Hoboken, N.J. station to Manhattan was knocked out of service for seven weeks â€“ and is still on a limited schedule.
The problem, however, wasnâ€™t just with the storm damage to this one line. Many of the 28,000 commuters who had taken the PATH each weekday faced considerably longer bus and ferry rides into New York City. Other commuters had to vie for seats on already overcrowded trains on the other cross-Hudson rail lines, or opted to drive in, further clogging Â the Lincoln Tunnel Â and adding to everyoneâ€™s commute time.
So this one point of weakness â€“ the Hoboken line â€“ led to continuing dysfunction across a large part of the overall transportation network between New York and New Jersey. During and after Sandy, similar cascading failures in infrastructure resulted in massive and persistent power outages, disruptions in telephone and Internet service, and overflows in sewage treatment plants that contaminated waterways and low-lying neighborhoods.
Using systems engineering, we can think instead about how to keep the overall system operating when one part goes down. This starts with the overall objective â€“ making sure commuters can get from New Jersey to Manhattan every day, for example â€“ and looks at how the various elements of a system need to work together to make that happen.
When we look at the larger picture, we see that repairs or improvements to one part of the system â€“ though essential â€“ may not be enough. In the PATH example, officials are now considering flood-mitigation measures, such as giant balloons to block water in tunnels, to help the rail line withstand another Sandy.
But what happens if the next super storm shuts down, say, the George Washington Bridge instead â€“ creating a new set of cascading problems in the larger transportation network? We could be right back where we started â€“ with a single weak link leading to system-wide failure.
The solution is to strengthen not just the parts of the transportation, energy and other networks that broke down during Sandy, but to strengthen the systems as a whole. If one piece of a system fails in a disaster, the other parts must be ready to pick up the slack.
This can be accomplished through measures such as building in redundancies and adding capacity to the larger systems. Â In the New Jersey-Manhattan transportation network, for example, it might mean purchasing extra rail cars that would not be used on a regular basis, but could be pressed into service if a bridge or rail line is shut down and rider capacity needs to be increased suddenly.
It is possible to build in system redundancies that increase capacity without adding a great deal to the overall rebuilding cost. Typically, only modest investments are needed. Yet this extra step is often overlooked.
If the billions to rebuild after Hurricane Sandy are to be well spent, however, a portion must be dedicated to keeping the larger systems functioning. Even if some of the individual pieces break down.
PHOTO (Top): A flooded stairwell down to a submerged subway tunnel beneath street level at the South Ferry-Whitehall Subway Terminal in lower Manhattan after Hurricane Sandy October 31, 2012. REUTERS/Mike Segar
PHOTO (Insert Middle): Flood waters in the Hugh L. Carey Tunnel in New York October 30, 2012 REUTERS/Metropolitan Transit Authority/Patrick Cashin/Handout
PHOTO (Insert Bottom): A massive wooden beam blocks the entrance to the South Ferry-Whitehall Subway Terminal in lower Manhattan, after Hurricane Sandy October 31, 2012. REUTERS/Mike Segar