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10.01.2013
Feature> The Nuanced Approach
Designers from coast to coast are breaking through the old distinction between grey and green infrastructure to establish strategies that apply a mix of the two.
SWA Group's Buffalo Bayou Promenade created recreational areas along the waterway and incorporated flood mitigation infrastructure.
Tom Fox / SWA Group

New York was still pumping Sandy’s surge-water out of its subway system when news headlines began to trumpet how best to ride out the next big storm—“NYC Sea Barrier: Its Time Has Come” or “Saving New York by Going Green”—leaving the impression that infrastructure could be neatly categorized into opposite kinds: grey vs. green or hard vs. soft. The thread that bound everything together was the promise of a more “resilient” New York. But the menacing irony here is that these kinds of easy dualisms have a lot to do with getting us to our present state of vulnerability in the first place. When the U.S. looks like a schoolroom map—blue for water, green for land, Mississippi River as a winding line, and barrier islands stretching out along the coast—it seems perfectly reasonable to build public housing on the Rockaways, industrial parks along the Gulf Coast, and cities in the Mississippi delta. In reality, though, coastlines are not lines at all, but zones of negotiation between land and sea, barrier islands are on the move (briskly so, on geological terms), and the delta is an impossible-to-distinguish mixture of water and land and everything in between. The climate-related risks we now face don’t hew to any dualisms. Floodwaters overwhelm dykes and dunes alike. Tornados and wildfires are blindly indiscriminate. And heat waves are just that: waves that lack clear boundary in space and time. It follows, then, that the strategies used to render our communities resilient from these risks must also emerge from this kind of nuance.

 
Buffalo Bayou Promenade.
Bill Tatham; Tom Fox
 

There are compelling guides in place. In On The Water: Palisade Bay, for example, pioneering research by structural engineer Guy Nordenson, with Catherine Seavitt, a landscape architect, and Adam Yarinsky, an architect, allowed the team to propose coastal planning strategies in the New York/New Jersey harbor that hybridized land and sea, hard and soft.

Leaving aside the question about whether it is caused by humans, there can be no doubt that sea levels are rising and that extreme climate events are happening more intensively and more regularly, so cities around the U.S. are planning for these events. For Houston, which trails only New Orleans as the city with the most repetitive flood claims in the U.S., developing a resilient urban design is of paramount concern. There, the SWA Group designed a 23-acre park along what had been the neglected banks of Buffalo Bayou, and, in the process, created a zone where green and grey become indistinguishable. Built to withstand flooding and engineered to mitigate the collateral damage incurred by those natural events, its planted slopes weave the waterway back into the urban experience as a strip of recreational space at the center of Houston.

 

Sasaki Associates’ plan for Cedar Rapids integrates flood protection infrastructure into the landscape.
Courtesy Sasaki Associates
 

Important though these measures are, rivers can’t be understood as isolated strips of water. As SWA Group CEO Kevin Shanley put it, “you don’t solve flooding issues by fixing the river.” Floods, after all, are the result of actions across entire watersheds. With this in mind, Shanley and SWA are working with regional agencies and municipalities to advocate for low-impact development as a way to increase permeability across the entire watershed. Since climate events don’t follow jurisdictional boundaries, resilience measures need to transcend those borders, too, knowing that cities in a region are linked to a similar set of risks. Urban design policies by each municipality in a watershed—even those that are politically and materially distinct—effect the others. “If a watershed is not yet urbanized, it could take days or weeks for water to reach the river,” explained Shanley. “But if you have a situation like Houston, where a lot of it is urbanized, that process takes hours or minutes.”

 
In addition to material infrastructure, Sasaki Associates’ plan for Cedar Rapids includes communication networks across the watershed region.
Courtesy Sasaki Associates
 

This was a lesson learned the hard way by Cedar Rapids, Iowa, when, in 2008, the Cedar River flooded, causing extensive damage across the city from floodwaters that crested over 30 feet. The Boston-based planning and design firm Sasaki developed a multi-phase redevelopment plan aimed not only at recovery, but also at preventing the kind of devastation seen in 2008. “Our focus was on understanding the relationship of the community with the natural environment,” explained Sasaki principal Jason Hellendrung, which meant treating the site not as a defined, physical entity, but rather as a diverse community of people within a watershed region. “By now, it’s pretty clearly understood that hard systems can fail,” said Hellendrung, so by calling for a 220-acre greenway along the river that incorporates infrastructure ranging from hard to soft, Sasaki designed the kind of overlapping systems that resilience demands. The project also highlights the need to consider interventions beyond the material. For months, Sasaki worked closely with community members and organizations to tailor its response to Cedar Rapids. And part of the redevelopment plan that ensued includes communication networks for flood warnings and plans to cooperate more closely with municipalities across the watershed region.

De Urbanisten’s Watersquare project in Rotterdam is a sunken urban plaza that doubles as a catchment system to manage stormwater.
Courtesy De Urbanisten
 

“Resiliency needs to be nuanced,” said Lisa Switkin, Managing Director of James Corner Field Operations. “On one hand, it is robust and persistent, and on the other, it’s yielding and adaptive. It’s all about finding the right balance for this mix.”

She is setting out to strike this balance in Brooklyn’s Greenpoint neighborhood, where the firm is currently at work on a 22-acre waterfront site. Though the park will serve as a front-line defense against storm surges, it is a task it will carry out covertly, as it functions primarily as a place for Greenpoint residents to do the things people do in a park. “After Sandy, ‘resilience’ has become a buzzword,” she warned. “But it’s completely embedded into the concept of landscape architecture, since we look at both soft systems and hard systems, and since we always take a long view in considering time.”

 
Watersquare in dry (left) and wet (right) conditions.
Courtesy De Urbanisten
 

The design includes plenty of grey. On the edge closest to the river, a concrete armor wall provides a hard barrier against pre-Sandy 100-year flood projections, while ribbons of precast concrete retaining walls offer second-, third-, and fourth-line defenses within the park itself, and concrete-paved walkways are fastened to the site. But the park’s section could double as a diagram for the so-called grey- and green-infrastructure integration. The broad promenade is divided into linear bands, a marbling of concrete walkways and planted strips. The retaining walls double as seating and also act to hem in raised planters. Not only do these bands allow the designers to hybridize green and grey into a cohesive system, they also make it possible to terrace the waterfront, leaving the edge along the adjacent community—and the vaults for the park’s electrical systems—well above the new 100-year flood levels.

“Rather than thinking of this as a singular bulkhead—as a strict edge where water and land meet—we are proposing a series of terraces that can be inundated and flooded,” said Switkin.

 

Rendering (top) and construction view (above) of De Urbanisten’s Watersquare project.
Courtesy De Urbanisten
 

For its Crane Cove Park design in San Francisco, AECOM faced a similar challenge, complicated by the fact that the site included historic buildings protected by preservation registers. This delicate arrangement highlights the fact that resiliency measures can’t be considered singularly and need to become integrated into the full range of design considerations—historic preservations, yes, but also livability, real estate, and environment. In this case, to raise the site would be to compromise the historicity of these structures, but to leave the grading in place would leave the entire site vulnerable to high waters. AECOM found a third way by modifying the topography through a series of cuts-and-fills. This way, the designers opened up areas in the site for floodwaters to fill. “We are embracing the fact that the park will flood during certain events,” said AECOM principal Alma du Solier. This will largely happen along the former ship-building slipways, where historic keel blocks will be repurposed as park amenities, but designed to be easily forklifted to higher ground as sea levels rise. “In essence,” said du Solier, “the project itself becomes a kind of levee for these historic buildings.”

 
AECOM’s Crane Cove Park in San Francisco is designed to flood, absorbing the brunt of a storm surge and protecting the populated area beyond.
Courtesy AECOM and Port of San Francisco
 

Even the Dutch, who are routinely touted as the “grey infrastructuralists” par excellence, are beginning to break down their own status quo. “Pumping out water and building higher dykes just isn’t feasible in the long run,” said Tracy Metz, author of Sweet & Salt: Water and the Dutch. Citing a regulation that mandates any new housing to set aside 10 percent of the site to water, she said “now, the priority is to incorporate water into already dense urban conditions.”

“People love water, so the challenge is to create these spaces that work as a safety measure, but also as places for people to enjoy,” she said, pointing to the de Urbanisten-designed Watersquare project, in Rotterdam, which creates a sunken urban plaza doubling as a catchment system to manage excess water in the event of flooding.

 
Crane Cove Park seen in low tide (left) and during high tide (right).
Courtesy AECOM and Port of San Francisco
 

Any design for resilience needs to carefully manage public perceptions of safety. Levees are often faulted for creating a false sense of security (and justifying risky real estate development) while the promises made by soft systems in urban contexts needs to be more fully studied. “This is a discussion that needs nuance—and a lot of rigorous scientific research,” said Shanley. “If you’re talking about adding dunes as surge protection, and you’re looking at a surge of 10, 15, 20 feet, plus the wave action on top of that, dunes are like seaweed. All of the energy in this water is in the upper zones, so it’s going to just flow right over,” he said, citing undergoing research at Houston’s Center for Severe Storm Prediction, Education, and Evacuation from Disasters. Rather than beating the drums for a seawall or promising to save New York by going green, designers with organizations like these ought to be doubling down, with justified urgency, to understand exactly what those systems mean across given regions.

 
 
James Corner Field Operations’ Greenpoint Waterfront Park acts as a frontline of defense against storm surge and as a public outdoor space.
Courtesy James Corner Field Operations
 

This kind of research-intensive design work is now being undertaken with Rebuild By Design, a competition sponsored by the U.S. Department of Housing and Urban Design (HUD), in collaboration with the Rockefeller Foundation, that aims, first, to undertake analyses of the entire Sandy-affected region, then to propose a range of design concepts on various scales that can be implemented by municipalities as needed. By organizing it in this way, HUD managed to cut across the types of partitions that would otherwise hamper resilience strategies. Teams, for example, include designers, planners, engineers, scientists, geographers, hydrologists, and policy experts. The scale of inquiry ranges from the building detail to entire ecosystems, sites can include dense urban areas and small communities, and, in an important step, it creates a jurisdictional venue that crosses state and city lines to treat the risk of storm surges as the regional issue that it is.

Courtesy James Corner Field Operations
 

It also brings world-class, site-specific research to vulnerable communities that might otherwise lack the resources to carry out that type of work. “You can never get 100 percent protection from every risk, but we can first understand the risks and tailor solutions to particular risks at specific locations,” said Dan Zarrilli, New York City’s Director of Resiliency. “There is a false dichotomy between hard and soft. Obviously, you wouldn’t build dunes off Lower Manhattan because of the geology and ecology of that place, but in the Rockaways, yes, absolutely.”

The big objective for resilience design, regardless of risk, is to short-circuit the entire list of false dichotomies, beginning with hard and soft, but including river and watershed, shore and sea, urban and rural, and natural and built. This will require a radical reorientation in the way projects are designed and carried out. Disciplines will need to collaborate in unprecedented ways—not by making vapid claims to “interdisciplinarity,” but by assembling committed teams of scientists, engineers, economists, planners and designers. And political borders need to be understood not as boundaries, but as sites of sharing and exchange.

There is a worrisome historical precedent to be found in the sustainability challenge popularized over the last decade. Though significant strides have been taken toward increasing energy efficiency in buildings and cities, many of the real possibilities for fundamental change have been hampered by the lure of a buzzword. Now is the time to imagine just what resilience can be, before it risks devolving into the kind prescribed solutions that can have such a stultifying effect on design. Before someone goes out to coin an acronym for resilience—LEED is taken, SEED, too, so REED seems a likely choice—let’s agree that the scope of resilience transcends any checklist, and it ought to be approached differently, in manner with the projects above.

John Gendall

John Gendall is a New York-based writer who teaches at Pratt Institute.