RESIDUAL RISK
I like men who have known the best and the worst, whose life has been anything but a smooth trip. Storms have battered them, they have lain, sometimes for months on end, becalmed. There is a residue even if they fail.
—James Salter, Burning the Days: Recollection (1997)
THE FAILURE OF THE LEVEES during Hurricane Katrina in 2005 highlighted a tragic inconsistency in the prevailing perceptions of risk. Ironically, improvements in urban infrastructure, which had actually lowered the risk associated with frequent but minor flooding, had increased the risk associated with less frequent but major events, by making the city’s population feel safer—expanding development to areas that should not have been inhabited. This trend, which geographer Robert W. Kates termed “the safe development paradox,”¹ reveals that the management of risk requires difficult choices, particularly the need to balance long- and short-term threats. Yet there is also a balkanization of our efforts to mitigate natural hazards, exacerbated by the fact that all politics are local. For example, in New Orleans (along with the rest of the Gulf Coast region and the Eastern Seaboard), the flood design standard is typically based on the one-hundred-year storm return period, meaning that structures need to be designed to withstand a flood with a 1 percent chance of occurring in any given year. In the western US, the 2004 Indian Ocean and 2011 Tōhoku earthquakes and the tsunamis they caused have spurred decisions to adhere to the radically longer return period of 2,475 years, commonly used for earthquake hazard mitigation. Adding to the confusion, design guidelines for wind pressures are based on yet other return periods. These wildly varying ranges mean that risk is apportioned unevenly. Worse, residual risk—that of the assumed hazards being greatly exceeded, of climate change, or of levees or other flood control structures unexpectedly failing—is unaccounted for. Given the rapidly evolving dangers of climate change and rising sea levels, the hundred-year flood of yesterday may well be the decadal or even annual event of tomorrow.
These inconsistencies in our assessment of risk are problems of science and policy, but also— given the different ways risk is understood and the often unequal ways in which the consequences of residual risks are meted out—of philosophy and social justice. Today, they are problems for art and design as well. As much a cultural construction as a scientific one, risk is all too easily manipulated. Post-9/11, we have been subject both to manufactured fear and to the careless production of residual financial risks. But art and design can mediate between the statistical abstractions of risk and its material and cultural effects; they can also reimagine risk’s influence on how we build and inhabit our cities or go about our daily lives. We need an art and design of risk to bring the science of risk back to reality.
EXTREME MAPPING
AFTER SUPERSTORM SANDY, we have witnessed a scramble for new and more detailed information about the New York coastline, perhaps guided by the fantasy that we could control our environment completely if only we collected as much data as possible. The result is a surge in what was already an upward trend in precision mapping: Various agencies have produced digital elevation models at a 1/9-arc-second resolution (a three-meter grid with the elevation of each intersection precisely located) or gathered high-resolution lidar (Light Detection and Ranging) data (provided by airborne laser sweeps of urban landforms with accuracies of within ten centimeters). Have these digital models finally achieved the infinitesimal detail of Jorge Luis Borges’s fabled one-to-one map of the kingdom? FEMA has just issued more detailed maps of high-risk coastal zones, and New York City has recently created meticulous new risk projections for flood-evacuation areas, subdividing its three previous zones into six while also expanding the range of its projections. Simultaneously, the New York City Panel on Climate Change (NPCC2)² has released new sea-level-rise projections for 2020 and 2050. All this data, collected from high above the ground, will ostensibly fit right into the abundant adaptation reports and shorefront community handbooks being developed all along the East Coast. Amid this precision mania, we would do well to remember the philosopher and scientist Alfred Korzybski’s famous statement “The map is not the territory.”
The most helpful maps may be those that seek not to reproduce a territory’s physical terrain but rather to engage its culture. One of the most poignant realizations in the tragic aftermath of the 2011 Tōhoku earthquake and tsunami along Japan’s northern coast was the wisdom of the “tsunami stones”—individual stone markers that appear along the coastline of Japan, some almost six hundred years old. A typical inscription reads: “High dwellings are the peace and harmony of our descendants. Remember the calamity of the great tsunamis. Do not build any homes below this point.” More than an ancient version of FEMA’s flood-insurance maps or New York City’s increasingly detailed evacuation-zone maps, these stones mark the high-water point in a way that memorializes past disasters while informing future generations of risk. Like the horoi of the ancient Athens agora, the markers are a simple and effective speech act, a way of folding risk into public discourse.³
SOFT EDGES
THIS SUMMER, New York City steadfastly refused to abandon its waterfront with the issuance of the Special Initiative for Rebuilding and Resiliency (SIRR) report generated by Mayor Michael Bloomberg’s office. But does this refusal simply justify the administration’s continuing redevelopment and gentrification of the shoreline territories once occupied by maritime and industrial programs? Throughout the post-Sandy debates in New York and New Jersey, any suggestion of “retreat”—as the depopulation of the waterfront edge has been described—is often vilified. It appears that, at least within some political jurisdictions, we can only expect more of the kind of wrestling with nature we have long seen in the Sisyphean struggles of the Army Corps of Engineers at the juncture of the Atchafalaya and Mississippi Rivers.
But what does holding the front line versus beating a retreat to high ground really mean? Neither option radically transforms our relationship with water in the urban realm: Holding the front line generally means keeping the Anthropocene footprint dry, or elevating it high above the wet ground. Recent research, including our own, has attempted to muddy and extend this front line—the shoreline—recognizing it as a dynamic ecological entity.4 Much of the work in the Museum of Modern Art’s 2010 exhibition “Rising Currents: Projects for New York’s Waterfront,” for example, offered a gradient in lieu of a hard edge. Softer infrastructure might accept water within the urban realm, with waterproof “flood control” giving way to a wetter “controlled flooding.” More resilient and adaptable plans for coastal flood protection could provide defense both horizontally—through abating layers of barrier islands, reefs, beaches, dunes, revetments, levees, and gates—and vertically, through the plants, habitats, and ecologies that will give these barriers resilience and malleability. Ultimately, the future of such initiatives lies in local will. Can we develop a strategy of wetness for a city that prefers to be dry?
A recent séjour in Venice, that exemplar of amphibious urbanism, reminded us that architectural historian Manfredo Tafuri had deemed it the first modern metropolis in part because it was the first city to be built without medieval walls. Venice’s watery environs actually functioned as military protection: Those without knowledge of the lagoon’s secret channels and passages, which were easily obscured by the quick removal of the wooden posts that marked their locations, could not safely approach. The city’s welfare was dependent on keeping things wet, and so letting in the sea was an act of security—high walls, by contrast, were considered antimodern; dry land represented nothing but risk.
Guy Nordenson is a professor of engineering and architecture at Princeton University and a partner of Guy Nordenson and Associates Structural Engineers. Catherine Seavitt is an associate professor of landscape architecture at the City College of New York and principal of Catherine Seavitt Studio.
NOTES
1. R.W. Kates, C. E. Colten, S. Laska, and S. P. Leatherman, “Reconstruction of New Orleans After Hurricane Katrina: A Research Perspective,” Proceedings of the National Academy of Sciences 103, no. 40 (2006): 14653–14660.
2. Nordenson serves on NPCC2.
3. Josiah Ober, “Greek Horoi: Artifactual Texts and the Contingency of Meaning,” in Methods in the Mediterranean: Historical and Archaeological Views on Texts and Archaeology, ed. David B. Small (Leiden, the Netherlands: E. J. Brill, 1995), 91–123.
4. Guy Nordenson, Catherine Seavitt, and Adam Yarinsky, On the Water: Palisade Bay (Stuttgart, Germany: Hatje Cantz Verlag, 2010).