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Zoning as Design
by Jonathan Barnett, FAIA, FAICP
Can zoning keep up with climate change?

Many years ago, when I and my colleagues started the Urban Design Group at the New York City Planning Department, we were dismayed by proposals being brought to the Planning Commission for building designs which were certain to disrupt the areas around them. We were even more dismayed when we learned that, most of the time, the architects were simply trying to follow the requirements of the new zoning ordinance. The original 1916 New York City zoning code had been amended comprehensively in 1961. After a waiting period to permit pending projects to go ahead under the old rules, the new regulations were just taking effect when John Lindsay became the Mayor in 1966, and many of the new regulations’ unintended consequences were becoming visible.

​If the developers and their architects had to follow the rules, why weren’t the rules producing better results? And how could we change the rules so the results would actually be better? It was an interesting time, as developers, architects, and city officials were still trying to figure out what the new zoning prescriptions required. It was possible to make constructive changes; I described some of what we did to improve the way zoning shapes cities and buildings in a book, Urban Design as Public Policy, published back in 1974.

​Today, New York City’s development regulations are much more finely-tuned instruments than they were in the 1960s. Historic preservation is recognized, environmental issues are considered, there is much more attention to the public realm and to the context created by existing neighborhoods. In some notable parts of the city the interaction of private investment with government controls and incentives has produced very good results. Zoning has also been a force for conservation. The 1961 zoning, which – with many, many amendments – is still in effect, was a big down-zoning from the levels permitted under the 1916 rules. “40 Percent of the Buildings in Manhattan Could Not Be Built Today” was a headline in the New York Times of May 20, 2016. Not wanting to lose the advantages of older structures has made development much more respectful of existing buildings than it might otherwise have been. Changes in New York City neighborhoods are often driven by renovation and infill, not massive new construction.

​Superstorm Sandy in 2012 was a warning of the effects that climate change is beginning to have on vulnerable coastal cities like New York. One option is regional protections like those constructed across the Scheldt Delta in the Netherlands or the Thames Barrier downstream from central London. With comparable barriers in place for New York City, no additional measures should be needed to protect individual properties from flooding, so there would be no development regulation issue. For New York the regional protections would probably require a construction similar to the Scheldt Barrier from Sandy Hook to the Rockaway Peninsula and from Throgs Neck to Fort Totten. The costs would be very high. While the value of the properties protected would be very high also, there is not the kind of national consensus to do what is necessary that enabled the Dutch coast to be protected. A way to protect just the central part of New York city could be to build the equivalent of the Thames Barrier across the Verrazano Narrows with another protective barrier where Long Island Sound meets the East River. It is unlikely that there will be money to build anything like this either.

​What is now being called the Dry Line, which is intended to protect lower Manhattan from the kinds of flood surges that took place during Sandy, can have some local effectiveness; but relying on sea walls like these raises the question: where do you stop building the walls? What is to protect lower Manhattan if flood surges take place beyond the wall farther to the north and the water then flows south? In New Orleans in 2005 the flood surge breached the protective walls, backed up into large parts of the city, and then could not flow out. Much of New Orleans was inundated for weeks. The reason the Thames Barrier was constructed was to eliminate the need for a patchwork of floodwalls along the Thames in central London.

​In the absence of comprehensive flood protection, it looks as if development regulation will have to be a major instrument of public policy to manage the effects of sea level rise along the edges of New York City. There will be some special districts with their own physical protection, perhaps sea walls like the Dry Line for Lower Manhattan, but more likely raised streets and buildings like the HafenCity District in Hamburg. There will be some parts of the city where individual building owners will be required to raise the buildings on their properties above flood levels and to protect mechanical equipment by putting it on the top floor or the roof. And, unfortunately, there will be some coastal areas that will eventually be judged uninhabitable, and which will have to become buy-out zones, where new building will not be permitted, and where older buildings will eventually be demolished and city services discontinued.

​Not too long ago the consensus of climate scientists was that New York City would not have to face these kinds of decisions until the turn of the next century. But the polar ice caps are melting far faster than was expected, and a meter or more of sea-level rise is now considered possible by 2050, with effects visible long before then. Some coastal cities, like Norfolk and Miami Beach, are already seeing frequent, unprecedented flooding after high tides. When the next hurricane hits New York, the flood surges are likely to be higher, and more destructive than was experienced during Sandy.

​Some difficult zoning decisions will have to be made, which will end up redesigning much of New York City.

​Jonathan Barnett, FAIA, FAICP is an emeritus professor of City and Regional Planning at the University of Pennsylvania. With lawyer Brian Blaesser, he is the author of Reinventing Today’s Development Regulations, to be published by the Lincoln Institute of Land Policy.

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