Asymmetrical Information - Megan McArdle

11.05.12

Should We Build Massive Flood Gates in New York Harbor?

There are calls to protect New York from storms like Sandy with massive technological fixes. Is that a good use of a lot of money?

The post-Sandy ‘ we told you so’ stories are starting to appear, often coupled with warnings about global warming and the frequency of record breaking storms. There are dire warnings everywhere and calls for enhanced protections for the New York mtropolitan area, of the kind found in New Orleans and in London.

But should we make the effort?  I asked my Dad, who got to experience New York disaster recovery first hand as an assistant to the mayor during the New York City blackouts of 1977, when he barely slept for four days.  He was also involved in disaster recovery planning as EPA commissioner, and again as a government liason from the heavy construction industry.  As EPA commissioner, he was actually one of the people in charge of reviewing previous similar proposals. Here's what he sent back:

There are some basic facts that should guide our thinking in this regard. The first has to do with the notion of the ‘100 year event’. The concept does not mean that there will only be one occurrence in one  hundred years and that once an event has taken place there is no need to worry for another 99 years; it's just a probability distribution. It may well be that we have a new pattern emerging. But we need more than two storms in close proximity ( Sandy and Irene) to decide that. After all the Philadelphia paper was reporting that no hurricane had made landfall in New Jersey since 1903, and while there have been close misses there is no recent record of a hurricane coming ashore in New York harbor. We simply do not know yet the meaning of the weather changes we perceive. While Nicholas Kristof reports that we have had three of the top ften flood events in the last three years, others are noting that we are well overdue for Category 3 hurricanes, which have been far fewer than expected. Who should we listen to at this point?

The second set of facts to consider is that New York City and its infrastructure managers have known for many years that New York City is vulnerable to flooding! Stormwater damage  and flooding are not concepts that have just been invented! This misreading of a tide table in the 30s led to the building of the FDR Drive below the East River’s high water mark, which led to the persistent flooding episodes that lasted through the mid-80s (until the road was rebuilt). In the postwar era the borough planners granted extensive grade waivers that allowed houses to be built below ‘ legal grade’--i.e., the grade that had been set in order to avoid flooding in most circumstances. The results of that policy are still observable in the City and in the annual tv footage displays of flooded houses and basements. The problems in southeast Queens, in Springfield Gardens, are still beling worked on to this day, six decades after development was inappropriately allowed. Coney Island was developed in ways that demand continuous pumping of both storm and sanitary flows, which was criticized well before any thought of global warming. The City is vulnerable  to flooding and has proved to be vulnerable many times in the past.

The 1968 hurricane that missed the city but flooded much of the south shore of Staten Island was a wake up call to what could happen. Fortunately there was little of the housing development that we see there now and so the damage was not as extensive as that we see today. But that event did trigger a Corps of Engineers study on what could be done and what should be done to protect Staten Island. Not unexpectedly, the Corps proposed a New Orleans-type barrier-and-pump system, one that would have cost billions to implement at that time. The City’s storm water management professionals rejected the proposal.

Why would the professionals reject the solution? They started with the certain knowledge that whatever you did would be relied on by others and encourage development in the areas behind the flood walls. Their second thought was that the City would be then left dependent on mechanical systems that had to function only during times of emergency.  If they failed--and there's no way to guarantee that they'll work until they're tested--they would leave  many to suffer and the City exposed to legal liability for the consequences. That's why New York City infrastrucure managers have been reluctant to recommend active systems where passive systems will do. Active systems can and do fail. Just look at the emergency power generation systems at both NYU and at Bellevue Hospital.

The City’s infrastructure is designed and panned wherever it can be around the laws of nature. The City’s water supply system is almost all managed with gravity ("it’s not just a good idea,it’s the law"). Drinking water is only extensively pumped in three limited  areas of the City. The sewer system runs on gravity as much as it can, with the major pumping done at the sewage treatment plants themselves. Reliance on active mechanical systems has proven hazardous, as storm damage to power supplies has left Coney Island (in the area where the drainage and sewer systems have to be continuously pumped to avoid backups) vulnerable on several occasions. Backup power solutions are only as useful as their ability to function, and few entities that rely on backup power perform the weekly operation-under-load routines that are recommended.  The longer you go without an emergency, the harder it is to get people to feel the proper sense of urgency about safety testing.

The third set of facts to keep in mind is that whatever you would like to do, the current environmental law framework means that the costlier the project, the longer the time for the design development and approval stage. Imagine that George Bush had made the protection of New Orleans his highest priority on the day he took office in 2001.  It is highly unlikely that any of the structures that he wanted to build would have even reached the construction stage by the time that Katrina struck. Reviews and approvals just take enormous amounts of time when you are using federal funds, and the grander the scale of the project, the grander the scale of the review. Trying to build large protective structures in the New York City area--structures that will have long term effects on the ecosystem of the harbor area--will require extensive data gathering and analysis and the resolution of many court cases. If we were to start today on the implementation of some of the major structural proposals that are envisioned, it is unlikely that construction would commence for more than a decade, at the very, very earliest.

All of these factoids have to be kept in mind as one reads about the dire warnings and the recommended major structural ‘ solutions’. For example, there is a recommendation that the City create three surge barriers to protect the inner harbor litoral, one at the Throgs Neck bridge between the Bronx and Queens, one at the Verranzano bridge between Brooklyn and Staten Island, and one at the mouth of the Arthur Kill between Staten Island and New Jersey. The barriers would be modeled on the Thames barrage that protects London.The barriers would rise during storm surge and protect the areas from flooding by holding back the weight of the ocean.

The problems of this proposal are cost and dependability.  How long will it take to get approvals to build such systems? Who will bear the many-multi-billion dollar cost for the system?  How will such systems be built in such an active harbor?The predictions of a $ 10 billion dollar cost are probably far under the mark; for comparison's sake, note that it will cost that amount just to replace one bridge over the Hudson. And, of course, like the construction of new subway routes, the benefits of the system will only be realized when the very last piece is finished and tested. You can’t just stop at the $10 billion dollar point, because there's no benefit unless the system is completed. My guess is that the creation of such moveable structures will cost at least ten times as much as is currently estimated and would have major impacts on the maritime economy during construction.

Then they have to be powered and tested periodically in an active harbor! Who will bear that cost? And who will be responsible when there is a failure that shuts down much of our maritime commerce? If one were a conspiracy theorist, one might believe that the proud sponsors of enabling federal legislation would be those Senators that represent the ports of Norfolk and Savannah! It is one thing to create such a system for the Thames in response to horrible storm surge, as the active port is now south of the barrier at Tilbury. But New York Harbor?

And, of course, it is not clear what happens to all of the water that doesn’t get into New York Harbor when the barriers are activated. It will go somewhere. And the adverse ecological impact will be huge as well, large enough to make the building of such a system a very long and drawn-out proposition.

 Keep in mind that we could do a lot with that $ 100 billion to protect what we have now. We could install more tunnel pumping capacity and pump to the ocean more easily. We could make sure that ConEd better protects its systems at 14th street and create alternatives to the excessive reliance on that one plant for both steam generation and electrical switchgear. There are so many things we could do with that money that would arguably much better serve New Yorkers. As we are seeing today, most of what is driving New Yorks crazy is relatively easily remedied. Can’t we find small engine units to power our gas pumps when the power is out? Or small generators? Shouldn’t the City has a well-tested plan to substitute an an adequate number of busses for the subways if ever they are out for any reason?

In my view, that’s what we should focus on. We need to be prudent; in an era of budget constraint, I think it will turn out that little fixes will have the greatest payoff. It is hard to see that the feds will have the amounts of money needed to fully protect New York City any time soon ,even if that were the right way to go. So in this case we should play small ball and really learn from what went right and what went wrong in this event-of-the-century.