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Paradise under the expressway

How visionary landscaping and planning transformed highway underpasses into bucolic parks

As more rooftops start to double as farms and towers become artificial forests, it's clear that hybrid objects, those that are part manmade and part natural, are a hallmark of 21st century design. Engineered Nature, a five-part series by Karrie Jacobs, explores the emergence of this new hybrid world, from a sensor-packed hill in the New York Harbor to manmade rivers in East Texas.

Huge, shadowy, and magnificent, the man-made cavern known as the Cistern was built in 1926 as part of Houston’s water system. It’s an 87,500-square-foot sunken container, supported by a forest of 221 columns, each 25 feet tall. Now this long neglected hunk of infrastructure is the newest addition to Buffalo Bayou, a 2.3-mile-long park that follows the contours of its namesake bayou (Texan for "river") through the heart of Houston, and extends as a still-incomplete network of trails another ten miles into the city’s east side.

The Cistern, which opened to the public (but only for tours) in May, is one of the most stunning examples of industrial reuse I’ve seen. It hasn’t served as a reservoir since the 1970s when it sprang a leak, but there are a few inches of water at the bottom reflecting the columns, making them appear infinite. If you shout or whistle, the echo lingers in the murk, seemingly forever.

The park’s landscape architects from the SWA Group, a large firm founded in the 1950s by Hideo Sasaki and Peter Walker, discovered the Cistern when they were trying to gain access to the land that sits above it, a rare bit of high ground in low-lying Houston that offers a splendid view of downtown. SWA principal Kevin Shanley says that the site "was totally off limits post 9/11 as part of the water system of Houston."

Inside the Cistern, a 1926 underground reservoir rehabbed into an art and performance space.

This was despite the fact that it was no longer in use. Eventually he and his team caught wind of a plan to demolish the structure and got permission to take a look. "So we clambered down through this little hole with flashlights," Shanley recalls. "And opened up some air vents so we could get some natural light and it was just an amazing space."

During my visit, a Venezuelan artist named Magdalena Fernandez was testing a video work she hoped to install in the Cistern, projecting a glowing spray of white lines across the columns. The interior lighting was turned off for her test, and I walked around a perimeter pathway in the dark listening to the space, thinking how great it would be for a musical performance, one of those experimental compositions that’s all about the room acoustics.

This particular space is just one example of the fearless approach to adaptive reuse practiced by the Buffalo Bayou Partnership, the nonprofit that runs the park, under its president for the past 21 years, Anne Olson. The Cistern, however impressive, is not what I’m here for.

One man’s epiphany became another man’s political coup.

Instead I’m in Houston to explore an even more radical idea than turning a sunken reservoir into a kunsthalle. I’m here to experience the portion of the park that transforms the underside of Houston’s confluence of elevated highways into a space that’s as cool and tranquil as a forest glade.

One scorching July day, I visit the Sabine Promenade, a half-mile stretch of parkland where bike and pedestrian pathways snake beneath a thick maze of highways. Lovingly landscaped by SWA, with nighttime lighting that gradually changes from white to blue depending on the phases of the moon, this area beneath I-45 and its ramps is a seductive combination of bucolic and sculptural. Shanley calls it "a mélange of old infrastructure and new infrastructure," and the undersides of the highways with their rectilinear support structures look like they were made by Donald Judd.

In places, you can hear the thud of cars driving over a seam in the pavement directly over your head. But the proximity of the flowing water tempers the hard edges and dampens the roadway noise. As Shanley notes, "It’s a living space because the Bayou brings life with it." Because the highways overhead provide shade, it’s a shockingly pleasant spot to walk or ride a bike or simply linger.

Completed in 2006, the Sabine Promenade was radically ahead of its time. And it’s a touchstone for me because it’s the best example I know of a simple idea: the huge amount of property dominated by highways, including the two million acres used up by our Interstate system, is still viable land. Technically off-limits, the terrain under and around highways can be useful and habitable, and sometimes offers up grandeur at a scale that’s generally only seen in actual nature.

The underpinnings of I-45 and its ramps turn the pathways of Buffalo Bayou's Sabine Promenade into an unintentional sculpture park.

Enlightened planning practice says that to recoup the value of these seemingly inhospitable undersides and rights-of-way you have to tear down the highways. But maybe all you have to do is change your perspective.

We live at an extraordinary moment in which Americans have become passionate about their cities. Legions of urban crusaders are out discovering and reclaiming disused industrial and infrastructural leftovers (and not just for catching Pokemon). For a time, this phenomenon was thought of as the High Line Effect; every city wanted its own elevated linear park like the one that opened on Manhattan’s west side in 2009.

But the movement has gotten more diverse and more sophisticated. Olson, for example, has snapped up an abandoned 1920s sewage treatment plant on a piece of property along Buffalo Bayou’s far east end. We drive over to the less affluent side of town, park in a vacant lot, squeeze through a hole in a chain link fence, and gaze down at the facility’s rusted array of plumbing. Bravely—and somewhat perversely—she thinks the plant’s large, round settling basin (designed to allow solid human waste to sink to the bottom), unused since the 1970s, could be incorporated into a facility for a community group that wants to build a swimming hole along the Bayou.

Olson was, perhaps, still charged from a meeting she attended in June. High Line co-founder and executive director Robert Hammond convened a New York gathering with representatives of 15 North American urban reuse projects, including the Underline, a plan to use the land below Miami’s elevated Metrorail line to form a ten-mile-long park; the 606 in Chicago, a much less design-intensive version of the High Line; and, of course, Houston’s Buffalo Bayou. The idea was to coax a trend into a movement.

I had a conversation with Hammond recently to see if, in his discussions with like-minded project leaders from around the country, he had formed any conclusions about why people are now seeing the value in objects they once disregarded or reviled. "What was considered ugly, and what was considered the armpit of a city," he says, beginning a thought. He tries again, "As cities become more shiny, and glass filled towers…" Another pause. "It’s like a nostalgia."

Buffalo Bayou president Anne Olson is looking for a way to incorporate a decommisioned sewage treatment plant into the park.

Nostalgia, or something like it, is surely part of the equation. A few years ago, I took boat ride down the Passaic River in Newark, New Jersey. It was a scenic cruise on a pontoon boat along the industrial waterfront of New Jersey’s largest city. On this excursion, I began to see the familiar tableau of the New Jersey Meadowlands in a new way. We passed beneath the Pulaski Skyway, one of the world’s first elevated expressways, built in 1932, and under a soaring elevated portion of the New Jersey Turnpike circa 1951.

As a native of the Garden State, I’d grown up with these highways.

To me they were so familiar that they’re invisible, but from below on the Passaic, they took on an almost classical stature. The Turnpike’s underside in particular is a massive colonnade, a parade of concrete arches stretching to the horizon. Some of my newfound appreciation had to do with seeing the highway from a completely new angle. But I think something else is going on.

Highways like the Turnpike were mostly built in the 1950s and 1960s, meaning they’re now old enough to qualify for the National Register of Historic Places. Arguably, they can be seen as a form of midcentury modernism. As our romance with the automobile fades, it’s becoming possible to envision a future in which elevated highways are every bit as obsolete as Buffalo Bayou’s Cistern or the High Line’s freight railroad. So I am beginning to look at highways, still very much in use, as if they were artifacts from the past. I’m starting to have some regrets about their inevitable passing.

By this time next year, the Sabine Promenade will be outdone by a Canadian project that uses the underside of a major highway as highly programmed green space. Ken Greenberg, the respected former director of urban design and architecture for the city of Toronto (another attendee at Hammond’s gathering) is now leading something called Project: Under Gardiner (recently dubbed The Bentway for the "bents" that support the highway).

The area beneath expressway I-45 and its ramps is a seductive combination of bucolic and sculptural.

When the first phase of the plan is completed on July 1 of next year—the 150th anniversary of Canada’s confederation—the much loathed five-story-tall elevated expressway that separates downtown Toronto from Lake Ontario will begin to shelter a two-kilometer stretch of parkland, trails, and cultural spaces. Here’s what Greenberg said about the structure in an interview with the Toronto Globe and Mail: "People have not perceived its extreme beauty."

Its extreme beauty? The underside of a highway known colloquially as "the mistake by the lake"? Well, yes. In a recent conversation, Greenberg told me that this ambitious undertaking grew out of his insight that the land beneath the highway "could become a central park for seven very recent neighborhoods that have formed in the last 15 years, now housing 77,000 people."

Last spring, he brought Judy and Wil Matthews, philanthropists with an unusual passion for public space, to experience the highway’s underside. "They were as captivated by it as I had been," he recalls. They must have been, since they agreed to donate $25 million CAD, enough to fully fund the park’s construction.

In April of 2015, Greenberg began working with the Toronto-based landscape design firm Public Work, developing a plan that includes a soaring pedestrian bridge suspended from the highway’s structure and an ice skating trail. In June, Toronto’s city council narrowly passed a controversial plan to repair and maintain most of the Gardiner, instead of tearing the thing down as many Toronto residents, including downtown’s elected representatives, would have preferred.

In July, Greenberg brought his already funded plan to redeem the Gardiner to the mayor and quickly got a green light. One man’s epiphany became another man’s political coup.

What I hope to learn from Greenberg is how he was able to see the underside of this mid-20th century artifact as parkland. To some extent, he says, insight was dictated by necessity: "We’re literally bringing hundreds of thousands of people to live in downtown Toronto and it’s really hard to buy public space once the land has a certain value."

Old gravel silos and other industrial artifacts line the Buffalo Bayou Park's eastern section.
The Sabine Promenade transforms the underside of Houston’s confluence of elevated highways into a space that’s as cool and tranquil as a forest glade

Then there’s the changing nature of public space. "It’s also thinking of public space not as discrete pieces but as interconnected networks," he says. "One of the things about our project is that 360 degrees all around us are trail systems that lead right to us, including those connecting to the waterfront and upland and in all directions."

Greenberg is utterly logical up to a point, but there’s an X factor, a thing that he can’t entirely explain: "We talk about a strange beauty," he acknowledges. "One of the slides I use when I show the project is the Roman colonnade in Palmyra which we hope that ISIS has spared. It has almost the same proportions as under the Gardiner."

Public Work partner Marc Ryan is also smitten with the found aesthetic of the expressway: "It is so powerful as it is," he told the Globe and Mail. "And we don’t want to destroy that. The design is less about aesthetics and more about curation and choreography." So essentially, Toronto is turning the underbelly of a highway into parkland because someone looked at something familiar in a new light.

Most people, however, don’t think elevated highways are magnificent, and structures like the Gardiner are disappearing one by one. These days, highways that traverse city centers are increasingly demolished or hidden.

Sometimes they’re relocated into a tunnel, as with Boston’s Big Dig, or covered over with a landscaped cap, as with Klyde Warren Park in Dallas, or replaced with slower moving surface roads, as with San Francisco’s Octavia Boulevard. Today’s conventional wisdom says that making downtown highways go away is the right thing to do. And it’s hard to argue. But the Sabine Promenade—and, maybe, the Bentway—suggests that peaceful coexistence is possible, even desirable.

In my conversation with Hammond, he brings up the Rose Fitzgerald Kennedy Greenway, the 1.5-mile stretch of parkland in downtown Boston created by the Big Dig. "The Rose Kennedy Greenway is just boring," Hammond complains. "They should have left some of the columns, they should have left part of the freeway. It’s a series of parks strung together, but it doesn’t have any soul or any connection to the city."

When Hammond made that point, I thought, Oh sure. Of course Mr. High Line would say that. Then I heard from Kinder Baumgardner, SWA’s Houston-based managing principal, about a project he’s currently working on: the demolition of I-45, the elevated highway that rings downtown.

Buffalo Bayou is now crossed by a series of pedestrian spans including the forked Rosemont Bridge.

"The entire downtown freeway system is moved to the east side, put below grade and covered with a cap park," Baumgardner informs me. This plan, of course, will do wonders for central Houston, which has emerged in recent years as a desirable urban place.

But it will also destroy the unique beauty of the Sabine Promenade: the maze of highways overhead that magically transforms this stretch of parkland into a sculpture garden will cease to exist. So should the highway, at least a portion of it, be preserved as we’ve more or less done the High Line? And if not, how is this extraordinary work of midcentury engineering different than the Cistern or the old sewage treatment plant?

When I put that question to Olson, she’s only just heard from the Texas Department of Transportation about the I-45 teardown. She assumes the changes "will make us have to think of new ways to travel through the green space," but what those new ways are, it’s too soon to tell.

The SWA designers who created the Sabine Promenade are surprisingly sanguine about this impending disfigurement: "More daylight and less noise will be better," reasons Shanley. Baumgardner largely concurs, but then directs me to the website of a High Line inspired movement to save the elevated portion of I-45 from demolition.

"What if we could turn a freeway into a park in the sky?" ask the advocates of something called the Pierce Sky Park. The site’s renderings, which recast I-45 as an elevated sliver of green snaking through downtown, confirm my suspicion that a shift, cultural or generational, is well underway. The Sky Park effort seems like a long shot, but I read it as an indication that people are beginning to see these hated highways as landmark structures, worthy of preservation and, potentially, as parkland that exists purely for pleasure.


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