Design for Disaster
Shortly after the terrorist attacks of Sept. 11, 2001, the pro-sprawl camp began painting high-density urban areas as little more than prime targets. In an undated, unattributed "Vanishing Automobile Update #19" posted on the Thoreau Institute Web site (www.ti.org), one writer proclaimed that the real lesson of the terrorist attacks was perfectly summarized by historian Stephen Ambrose's admonition, "Don't bunch up."
Lumping new urbanists such as James Howard Kunstler and Harriet Tregoning into a camp of "auto haters," the editorial waved off their support for low- to mid-rise mixed-use housing and a decreased reliance on mid-east oil, calling instead for a massive spreading out of American infrastructure; i.e., sprawl. No town centers, no public transit of any kind, no traditional neighborhoods. Smart growth measures "waste taxpayer dollars, reduce urban livability, and expose more people to terrorism," the article concluded.
That editorial's knee-jerk reaction wasn't the only one claiming that suburban sprawl is the antidote to terrorism's poison. In a Sept. 19, 2001 editorial posted on The Wall Street Journal's opinion Web site, Holman W. Jenkins Jr. urged that the Twin Towers not be rebuilt, claiming that other, less target-worthy uses would fill the void. "Condos, tennis courts and tourist havens reflect a natural evolution in the purposes to which cities are put," he wrote. Earlier in his piece, Jenkins told of the fear-driven decisions being made by company owners in the aftermath of 9/11, ranging from irrational building choices to all-out urban flight:
"Executives calculating where to house their employees are factoring in the need not to build something a suicide bomber might be tempted to knock down. The New York Times reported last week that dislocated firms were rushing to sign leases on nondescript properties outside the city, on terms suggesting no plans to come back."
The horror of 9/11 has saturated the psyche of American society, coloring our personal and political choices to the extent that we are beginning to damage the fabric of our urban centers. Jersey barriers and other measures defending against truck bombs have sprouted and surrounded our public buildings. New buildings are given astonishing setbacks. Underground parking is being deemed unsafe; instead, surface parking lots are gaining ground. Many government offices and private firms are already moving their facilities away from dense city centers. One design option for Manhattan's proposed Freedom Tower included a 200-foot-tall barrier to truck bombs.
Imagine what these measures look like on the ground. What kind of aesthetic are we creating as we illogically assume that the next terrorist attack -- whether it comes from Islamic militants or the next Timothy McVeigh -- might be just around the corner? Are we to live our lives in a brutal built environment because a terrorist might attack us in a beautiful one?
The "safety in sprawl" argument stands on weak legs for a number of reasons. First, it assumes that the motive of the 9/11 terrorists was to attack a dense urban center. Not true. The terrorists' motive was to bring down symbols of American wealth and political power. One of those symbols was the Pentagon, a four-story office building in an area far less dense than Manhattan. If we disperse our population, does it follow that national symbols of economic and political power will be eliminated? Of course not.
Second, the argument assumes that large numbers of people are found exclusively in urban centers. Will that prevent terrorists from attacking a sporting event such as NASCAR? What about multiplex theaters or megachurches? County fairs? Rodeos? "Terrorists would be just as happy to attack a suburban mall as they would to attack our cities, and the results would be just as unacceptable," wrote Sam Casella in a Nov. 26, 2001, editorial posted on Planetizen.com. "That is why attempting to protect ourselves by dispersing urban development will not work."
Third, documentation that terrorists gravitate toward urban areas is suspiciously hard to come by. In many African and South American nations, and parts of the Middle East, it is the rural areas that suffer the most from terror, paramilitaries, genocide, etc. Drug-growing regions that fund terrorists are rural. The mines, pipelines and refineries targeted by terrorists are not in cities.
The pundits' claims that citizens and companies are fleeing dense urban areas en masse are simply not true. In an article published in the fall 2002 issue of Transportation Quarterly, authors Hank Dittmar and Sarah C. Campbell wrote that exactly the opposite is true. Listing Houston, Atlanta, New York City and Washington, D.C., as examples of cities that were doing more than holding their own when it came to population retention -- in part because of a renewed commitment to public transit and infill housing options -- Dittmar and Campbell concluded that "while we don't expect a flood of new city dwellers, we do expect that a variety of conditions will balance the assets between cities and suburbs, producing a healthier relationship between the core of many regions and their suburban jurisdictions. And, we don't anticipate that the events of September 11 will change this direction."
Is new urban-style development indestructible? Of course not. But it is a proven development pattern that delivers comparable or better returns visually, economically and socially, while not posing measurably greater risk than conventional suburban development (CSD).
Part of the reason high-density development is superior to its CSD counterpart is because it is more resilient. Manhattan is a good example. According to Dittmar and Campbell, replacement office space was found swiftly in midtown, and residents soon returned to the Battery Park area and TriBeCa. Jobs that left Manhattan relocated to another urban center, such as Newark or Jersey City, rather than move to southwestern states or to highly suburban locations. Less than two years after 9/11, the Urban Land Institute reported that commercial interest in the borough of Queens had increased. About the same time, The Associated Press reported an increase in apartment rentals in Battery Park buildings located adjacent to the World Trade Center site. And real estate sales in Washington, D.C., and nearby Virginia are still booming.
Dittmar and Campbell also found no evidence that transit use was affected by terrorism beyond the immediate period following September 11. To the contrary, "the Washington region's Metro-rail has enjoyed record ridership levels [in 2002], including three of the five highest days in its 25-year history."
In summary, Dittmar and Campbell wrote that "all indications are that people are seeking community after the terrorist attacks, not running to hide," citing a Brookings report, an ABC News/Washington Post poll, and a Public Agenda Online poll that found evidence of increasing attachment to New York and Washington, and little change in citizens' day-to-day lives.
The transit component should be addressed, too. Immediately following the terrorist attack on the Pentagon, D.C. went into a state of gridlock that took hours to clear. In addition to the government releasing its workers, all the schools shut down, meaning that parents had to pick up their children. The street network was at a standstill downtown; even in the suburbs there were mile-long backups.
Meanwhile, tens or hundreds of thousands of people simply walked out of downtown (it's relatively easy to do that in D.C., unlike many cities in the United States, and unlike most suburbs). After an initial crush of users, the Metro subway system functioned well and played a large role in evacuation and coordination. Try that in a sprawl environment.
If the proper response to terrorism is development sprawl and social isolation, someone in that camp needs to do a better job of getting the word out.
When Hurricane Katrina roared ashore on Aug. 29, 2005, no development pattern could have withstood the furious 145-mph winds and 30-foot storm surge. Along the Mississippi and Louisiana Gulf Coast, roads caved in, trees rocked and fell over, entire houses were ripped from their foundations, sill plates and all.
The question for Gulf Coast cities is how they will rebuild. Will their environments take on the Anyplace, U.S.A., look of CSD or will they reclaim the scale and character they had before the disaster?
Most of the towns' citizens have stated a desire for the latter, and Step One toward that goal is adoption of a SmartCode calibrated for each town. Flying in the face of conventional zoning codes, the SmartCode is intended to be a legal and substantive framework for planning and for creating zoning that achieves the plans desired by the citizens.
Step Two? The buildings. Architectural style has little to do with storm resistance; those buildings' density comes into greater play, says Terry Anderson, P.E., an engineer with Anderson Engineers in Santa Rosa Beach, Fla., who touts the current Florida Building Code as the best in the country for dealing with the effects of hurricanes. It's so good, he says, that following the devastation of Hurricane Katrina, building codes in Mississippi, Louisiana, and other coastal states are being revised to incorporate successful elements of the Florida Codes.
Let's start with the buildings themselves.
"Under current design codes, each structure in a hurricane-prone region . is completely 'wrapped' on the exterior with a minimum half-inch-thick sheathing, and every structural member is secured by fasteners or connectors adequate to carry the loads imposed on that member," says Anderson.
For Anderson, architectural details need to respect the need to incorporate sound structural elements in a home design. "The necessity of properly located shear walls, hold-down systems, and component and cladding protection definitely affects the architectural features of the structure," he says. "The main thing the designer needs to keep in mind is the phrase 'continuous load path'; that is, a load exerted at any point on a structure has to eventually find its way down into the foundation system without hitting a 'weak link.'"
As for density as a weapon against wind, Anderson sees it as a two-edged sword. "The density of development, as well as topographic considerations, play a big role in the calculation of wind effects. Buildings in some densely developed areas may have the effect of shielding other structures from the wind, while in other situations the density of development might cause a 'tunneling' effect that actually increases the wind forces. Each development has to be considered on a case-by-case basis, taking into account the height of the buildings, distance from the coastline, type of construction and topographic considerations.
As new urban architects and designers work to generate suitable buildings for the Gulf Coast rebuilding effort, they're needing to address not only the wind velocity challenge, but also the new advisory flood insurance rate maps released by FEMA. The reassessed maps "give local governments a more accurate assessment of the vulnerabilities they face," says Gavin Smith, a FEMA consultant now heading the Mississippi Governor's Office for Recovery and Renewal. "This is a good thing, because timing is so important in disaster recovery. This gives local governments tools to use to make a decision, and they have the tools -- in this case the maps -- right now, instead of years from now, after rebuilding has begun or has been completed."
The new maps carry one particular challenge for building designers and architects, though: the height at which people will have to rebuild if their home was more than 50 percent damaged or if they're building a new home. "Generally, the homes will need to be elevated 3 to 8 feet higher than the height at which they were built before Katrina," says Smith. "The height fluctuates according to topography and hydrologic factors."
How does that elevation stipulation play out in the real world? Ask architect Allison Anderson, co-principal of Unabridged Architects in Bay St. Louis, Miss. "There is no magic bullet," she says, while working on a series of elevated homes that accommodate the FEMA regulations and maintain coastal appeal.
Anderson did her homework before beginning her post-Katrina design work and doesn't sugarcoat the realities of bad weather. "I went out and looked at why buildings I had designed had failed, and found that water was to blame in most cases. Water pressure is so much more significant than wind pressure. We can design for 140-mph winds -- and are being required to do so. That's what's outlined in the International Building Code. But water pressure is 2,000 pounds per square foot, as opposed to a few hundred. It's foolish to think that you can resist it."
Anderson also toured structures that did not fail and made one particularly interesting discovery. Her own home, a modernist structure that ended up holding 8 feet of water inside, was still standing, still structurally sound. Why? Anderson chalks it up to 2-by-6 construction, shear walls that stiffened a wall parallel to the beach, and giant timbers that strengthened a grass roof over a portion of the house. "That weight at the end of the structure really anchored the house; we had two friends down the street who floated out and took shelter under our grass roof, because it was the only thing in the neighborhood that wasn't moving," says Anderson.
As architects and planners continue to design for the Gulf Coast renewal, many are taking their cues from old and new urban towns and cities that have already weathered hurricanes far better than their CSD counterparts.
When Hurricane Dennis hit the Florida panhandle in 2005, Seaside demonstrated why it's a shining example of how to build a hurricane-ready town near the beach. Seaside's houses are built to standards that have become the model for construction after Hurricane Andrew hit South Florida in 1992. With special windows, doors and concrete walls, they are also immediately adjacent to one another on zero lot lines, with many houses tethered together by steel cables. And instead of resting on traditional concrete slabs, the homes are on wooden pilings that are drilled 40 feet deep into the ground for more stability. Power lines and phone cables also are buried. The roofs of the homes are polished corrugated metal rather than the tiles that adorn most North Florida homes.
Siting also plays a role: The majority of the community sits north of a busy beachside road. With most residents living a bit back from the water, the community avoided the wind and wave action that demolished dozens of homes, hotels and other businesses only a few miles to the west. Seaside businesses and eateries, built to the same high standards as the houses, weathered the storm without worries. "Not even a screen door ripped," says Charles Modica, owner of Modica Market.
Walton County, Fla., officials have said the layout of the community and the hardy manner in which the homes are built make it one of the safest places on the Gulf of Mexico.
Charleston, S.C., played host to Hurricane Hugo in 1989, which packed sustained winds of 100 mph, with gusts to 140 mph and a 20-ft. storm surge -- the largest major hurricane to hit the Carolinas in decades.
How did Charleston fare? According to The New York Times, Charleston's compactness actually kept the wind from doing nearly as much damage as it could have, even though it ripped off several roofs in the historic district. Several churches were damaged, but all were restored rather than demolished. In total, only 30 structures were damaged to the point of being irretrievable.
On the west coast, where earthquakes are almost as commonplace as hurricanes are in the southeast, the form of development plays less of a role, at least during the initial event, says Daniel Parolek, principal with Opticos Design Inc. in Berkeley, Calif.
"With the current standards for retrofitting and engineering standards for new buildings, I don't see much of a difference in the initial impact from an earthquake in high-density vs. low-density areas. It's the secondary stuff, such as fires from severed gas lines, that's a concern. Once a fire starts in an urban area, it's harder to contain.
"What's interesting, though, is how a community can respond and assist each other after an earthquake. The Berkeley neighborhood I live in has neighborhood organizations that meet on a regular basis to talk about earthquake preparedness and how to respond. That puts me at ease, knowing there's this informal network in place to assist one another after an earthquake. At some point, in a less dense area, you're kind of on your own. In more suburban locations, are people doing this? I don't know," says Parolek.
The earthquake equation informs more than just building design. In Seattle, Wash., a brouhaha is raging over what to do with the Alaskan Way Viaduct, a stacked freeway that separates downtown from the waterfront district along Elliott Bay. The 2001 Nisqually earthquake severely damaged the viaduct; with the possibility of the next earthquake flattening it like a pancake, every politician in the state agrees it must be removed.
But what should replace it? Seattle Mayor Greg Nickels and most of its City Council want a tunnel. Gov. Chris Gregoire and many state lawmakers say a tunnel is too expensive (at least $3.4 billion); better to go with a bigger, modern rebuild of the viaduct ($2.8 billion).
These two choices were recently put to Seattle voters, who on March 14 turned in a not entirely surprising verdict, one that was predicted by weekly newspaper editor Dan Savage as he filled out his ballot onstage during a live taping of This American Life on March 7: "No to the tunnel. And hell no to the rebuild."
This may create inroads for a third option to gain traction: Tear down the viaduct and replace it with a new surface street and more public transit in the form of buses.
With a proven track record of freeway removal and the regenerative effect that can have on a city, former Milwaukee mayor and Congress for the New Urbanism (CNU) President John Norquist has gone on record to support that third option, saying the surface-streets-and-transit option may prove very beneficial.
A review by engineers Norman Marshall and Lucinda Gibson, PE, with Smart Mobility, of the Washington State Department of Transportation's analysis of the "no-replacement option" for the damaged Alaskan Way Viaduct found significant flaws in that analysis, including the use of exaggerated estimates of future downtown street traffic and misleading conclusions about the amount of truck traffic on the viaduct.
"This transportation review shows that the experience of San Francisco, Portland and Milwaukee deserves serious consideration in Seattle. Given how traffic has redistributed and how neighborhoods have come back to life, it's hard to find anyone in these cities who would consider rebuilding the elevated freeway or digging a big tunnel."
Protection Project, the planning effort is meant to guide the investment of public and private resources in the downtown area during the next 20 years, while protecting the area from flood damage up to and including the 100-year flood of the Skagit River. Mount Vernon's future is uncertain, but its need is immediate: Unless flood protection measures are implemented, the area will continue to suffer from damaging floods and the local economy will continue to experience depressing effects due to the potential harm and uncertainties associated with future floods.
Farther upriver, the small town of Hamilton (pop. 309) is considering a strategy that has been discussed as an option for Mount Vernon: physically moving the entire town out of harm's way, using federal, state and county funds. Strapped for cash and facing disincorporation, Hamilton sees the relocation as one strategy to save itself and remain self-sustaining. A recent town meeting included visual preference images to help residents imagine the new and improved Hamilton; the majority vote went to a traditional pattern.
And as the clock ticks, the Skagit floodwaters inundate the town almost every other year.
With low incomes the norm in Hamilton (59 percent of its citizens live under the poverty level), residents have few options when it comes to building design. Many simply watch the floodwaters swirl and recede, then spend weeks cleaning out their crawlspaces and replacing insulation and drywall. Some homes are built atop 5-foot-tall, poured-in-place concrete crawlspaces that you can almost stand up in; during the summer months, a tour of these spaces reveals powdery gray river silt dusting the inside walls.
Skagit County, city officials and agencies such as the U.S. Army Corps of Engineers are working on a plan to bring some relief to the cities and towns along the Skagit River. For this region, design for disaster begins with attempts to control or redirect the cause of the disaster: the river. Measures under consideration include a series of bypasses, designed to redirect the river during flood events; a system of dikes and gates that could trap water before it reaches a narrow channel between Burlington and Mount Vernon; and strategic use of dams far upriver to regulate the amount of water allowed downstream.
History has taught us that cities are crucial to civilization, says Sam Casella. "That is why London, Berlin, Tokyo and many other cities were rebuilt after World War II," he writes.
And whether the threatening disaster is man-made or natural, a panicky retreat from a proven development pattern would, in the long term, damage our society far more than a terrorist's bomb or a 100-year storm. "Civilized people treasure the historic buildings, culture, creativity and entrepreneurial drive found in cities," writes Casella.
We owe it to ourselves to preserve and protect them.
New Towns Web editor Laurence Aurbach contributed to this article.
Designing our cities, towns and neighborhoods based on the worst-case scenario of a terrorist attack is a little like creating an oceanic parking lot that will be used to capacity only one or two days each year.
What are the odds that you'll meet your maker at the hands of a terrorist? One in 88,000, says Foreign Policy magazine. According to their 2005 study, you're more likely to die from a fall off a ladder (one chance in 10,010).
Let's look at the numbers before we go out of our way to abandon time-tested approaches to good urban design. Of the myriad ways to shuffle off this mortal coil, falling prey to a terrorist is, well, a less-than-terrifying probability. Perhaps we should all just ride the bus more -- or, better yet, the streetcar.
|Odds that this will happen to you:
||1 in 7
||1 in 121
||1 in 218
|Hit by car while walking
||1 in 626
||1 in 9,097
|Fall from ladder
||1 in 10,010
|Contact with hornets, wasps and bees
||1 in 56,789
||1 in 83,930
||1 in 88,000
|Vehicular accident while riding a bus
||1 in 104,113
||1 in 340,733
|Vehicular accident while riding a streetcar
||1 in 1,874,034
Sources: Foreign Policy, National Safety Council, LiveScience.com.