The Water Next Time

How nature itself could become a city’s best defense against extreme weather

Renderings of green spaces designed to protect Hoboken from future flooding. Areas of the map that are shaded blue were inundated by Hurricane Sandy. (Haisam Hussein)

As we drove downhill along narrow Second Street in Hoboken, the compact New Jersey city separated from Manhattan by the Hudson River, the landscape and urban designer Diana Balmori remarked to me that after Hurricane Sandy, this part of town had basically been “a lake.” During Sandy’s storm surge, in October 2012, river water breached the town’s northern and southern tips and spilled into its low areas. On the west side of the city, still more water tumbled down the Palisades, the steep cliffs that run along the Hudson River. Only the highest part of Hoboken stayed dry, as if treading water in the lake that Balmori described. “It took a month to get rid of some of the water,” she said.

When the water was finally gone, so too were any doubts about the threat climate change might pose to the region. “Before, everybody thought, Well, who knows if this whole thing of global warming is happening?” she said. “There was such conviction after Sandy.”

In one measure of that conviction, the U.S. Department of Housing and Urban Development launched a giant, federally funded competition called Rebuild by Design, aimed at protecting areas battered by Sandy from future extreme weather. Which is how Balmori and her colleague Javier González-Campaña came to collaborate with the architecture firm (and project lead) OMA, the Dutch engineering consultancy Royal HaskoningDHV, and the economic strategists at HR&A Advisors on a plan to prepare Hoboken for future flooding. In June, when HUD parceled out nearly $1 billion among six winners, the Hoboken project received $230 million.

Hurricane Sandy “filled up Hoboken like a bathtub,” Mayor Dawn Zimmer says.

An island in the days of Henry Hudson, Hoboken put itself at odds with the river that bears the explorer’s name by filling in and building on the marshlands that once surrounded it. The city is the fifth-densest in the country, with some 50,000 residents stuffed into little more than a single square mile. Sandy flooded more than 1,700 Hoboken homes, knocked out the city’s power grid, and halted trains into New York; in total, the storm caused more than $100 million in damages. “It filled up Hoboken like a bathtub,” Mayor Dawn Zimmer told me when I visited her at city hall. Two years after the hurricane, Hoboken remains susceptible even to lesser storms; Zimmer explained that half a dozen significant floods have hit the city since Sandy. I asked her when Hoboken would ideally have a storm system in place. “Tomorrow,” she said, moments after an aide joked, “Yesterday.”

The team calls its plan “Resist, Delay, Store, Discharge,” and it intends to reduce local vulnerability to water in just the ways the name suggests. Flood walls strong enough to resist storm surges will protect high-risk sites along the riverfront. A system of parks, so-called green roofs, and terraced wetlands will hopefully act like sponges, soaking up water long enough to delay runoff and keep drains and sewers from being overwhelmed; another system of underground cisterns and retention basins will store excess water until high tides recede. Pumps will discharge floodwater back into the river once a storm has passed. Together, these parts should be capable of withstanding a once-in-500-years storm. What makes the plan so innovative, says Daniel Pittman, an architect and strategist at OMA and the overall lead for the design team, is that it doesn’t rely on one isolated tool for defense but instead weaves together “hard” infrastructure (like levees) with “soft” infrastructure (like parks).

This combination of tactics reflects a new approach to water management for coastal cities, one embraced most notably by the Dutch. Decades ago, the Netherlands—much of which is at or below sea level—built a vast system of dams, levees, and other hard barriers to protect against the North Sea. But as sea levels rose, and as major storms exposed the limitations of such structures, water experts realized the need for a change. Indeed, Mayor Zimmer told me that a recent visit to Rotterdam left her thinking that the Dutch had learned more than Americans had from storms like Katrina. Instead of continuing to bank on the idea of keeping water out, the Dutch have begun to create a sort of partnership with the sea, inviting a certain amount of flooding into trenches and urban parks.

A combined hard-and-soft approach seems well suited for Hoboken, which wants to maintain a close relationship with the river while still protecting residents from tides and storm surges. “The Hudson River is a danger for us, but most importantly, it’s a treasure to Hoboken,” Zimmer told me. “If you’re literally just blocking off the river, not only are you hurting the quality of life, you’re potentially impacting the economy of our city as well.”

As we continued our drive around town, Balmori and González-Campaña pointed out places where they imagined various landscape elements might delay or store storm water. Ribbons of parkland could flank the New Jersey Transit tracks below the Palisades. A verdant median might convert Washington Street into a “bioswale boulevard”—bioswales being slopes designed to capture runoff. Parks and parking lots designed to retain standing water could be added. “This is a green system that surrounds the whole city,” Balmori said. By preventing water from overwhelming city drains all at once, such a system would reduce flash flooding during heavy rains and stop the river from gaining destructive force during major storms.

What Balmori envisions would mark a major change for Hoboken, more than 90 percent of which is covered in pavement and other impermeable surfaces. “Hard infrastructure is needed in cities, and you cannot avoid that,” Balmori told me. “But I think we’ve discovered a tool, in soft infrastructure, that we’ve never been able to use before extensively.” (Not in major coastal cities, that is; in 1996, Balmori designed a 91-acre soft-infrastructure system in suburban Farmington, Minnesota, using a network of channels, swales, and ponds to improve drainage and avoid flooding.)

To see a site where the two strategies might work in harmony, we stopped at Weehawken Cove, a Hudson River inlet at the northern border of Hoboken. The cove is a pleasant public space, but it meets the city at a hard edge rimmed by narrow walkways. High water threatens the lower floors of adjacent buildings, which will need hard infrastructure to protect them. For the rest of the space, Balmori prefers a series of rising terraces that will serve as a park most days and as a buffer during storms, blocking the river from going too far inland and storing excess water. It’s civic amenity, economic stimulant, and climate adaptation in one. “We’re going to see it going up, going up,” she said, tracing the arc of the cove with her hand. “And the whole edge is green and soft.”

Balmori attributes her interest in landscapes to the time she spent camping in South America with her father, a linguist who studied indigenous tribes in remote terrains. “I was exposed to an incredible diversity of nature,” she recalled. After earning her doctorate in urban history at UCLA—studying Renaissance and 19th-century cities—then teaching at the State University of New York, she left full-time academia to practice landscape design, and in 1990 formed her firm, Balmori Associates.

Hoboken could be a model for other American cities.

Whereas traditional approaches to urban landscape design isolate nature from the city—the park as escape from urban bustle—Balmori says she wants to make green areas “visible” and “experiential.” She designed New York City’s first major green roof, a 35,000-square-foot installation completed in 2005 atop a television studio in Queens where The Sopranos was being filmed. More-recent projects include a continuous green roof that unifies 11 government buildings in Sejong City, South Korea; a terraced park near downtown Memphis that’s designed to handle the Mississippi’s high waters; and a riverfront overhaul that enhances pedestrian space near the Guggenheim Museum Bilbao, in Spain.

As for the Hoboken project, Balmori says it would be an “enormous achievement” to safeguard the whole city, but she knows a lot of work remains. Right now “Resist, Delay, Store, Discharge” is a loose collection of ideas. The next step is to transform those ideas into a master plan. The project has a dizzying number of stakeholders—from federal, state, and local officials to the mayors of neighboring Weehawken and Jersey City to public agencies such as New Jersey Transit—but Mayor Zimmer nonetheless hopes for an “aggressive” timeline. She’d like to finish the waterfront sections, including the hard barriers, in the next three to five years. In the meantime, as funding allows, the city will fill in the green-infrastructure network; a combined park/water-storage site, capable of holding 250,000 gallons, is already being planned.

If Balmori and her team exude a sense of urgency, it is not only because Hoboken remains so vulnerable to flooding. The Dutch planner Henk Ovink, who’s directing the Rebuild by Design effort for HUD, has said the proposed comprehensive system in Hoboken could be a model for other American cities.

As we approached the Holland Tunnel on our return to Manhattan, Balmori observed that even a city as big as New York might learn from this experiment. Protecting Hoboken—or a series of connected square-mile zones the size of Hoboken—may be more cost-effective and achievable than building one huge superstructure to save all of Manhattan. “We don’t know what’s coming,” she said as we headed under the river.

For more City Makers stories, go to: