The New York artist Mary Miss has proposed building a 1,500-foot bridge across a canal at a new 100-acre art and nature park for the Indianapolis Museum of Art. Miss is working with the New York structural engineer Guy Nordenson on developing the bridge as an innovative viewing device—a central platform for walking across, surrounded on either side with ha-ha’s, or walkways depressed 42 inches that form a sort of moat, which visitors can occupy along the bridge’s length. Imagine a “W” section through the bridge, with a wider center peak as the main path. The idea is to confront the viewer with nature, lessening the force of architecture by making such things as handrails effectively disappear.
“I’m trying to get people to notice what they take for granted in a landscape, to reveal multiple aspects of the site,” Miss says. “The bridge seems to be a platform with no edges—I want you to feel free to see this place as you’ve never seen it before.” In the 1970s, the art historian and critic Rosalind Krauss placed the work of artists like Miss in a new conceptual framework of practice, in an expanded field that included “site construction.” For Krauss, these artists did not work in the conventions of sculpture, but in a category that existed between traditional notions of landscape, architecture, and sculpture.
An increasing number of architects and designers embrace this notion of site development—spanning between the traditional roles of architect and landscape architect—embedding a variety of interpretations of site conditions into a new performance-based architecture of sustainable principles. But an architect must be interested enough in this new scope of opportunity, in areas such as groundwater-recharge and wastewater-treatment design, since it falls outside traditional practice.
The site of the Indianapolis project lies within an elbow of the White River, which runs from north to south, looping around the western edge of the park. A 35-acre lake, the legacy of a quarry mined to build a nearby highway, occupies the park. A canal dating to the 19th century slices the site off from the main museum building on a bluff to the east. The new park lies in a 100-year floodplain, though the park’s landscape architect, Ed Blake, wonders if the impact of global warming doesn’t make such considerations for a site as utterly dynamic as this one a little bit useless. Blake’s approach is not to keep water out, but to understand how it will travel.
“Because of flooding, you always have plants and soil coming into the site,” says Blake, the principal of Hattiesburg, Mississippi–based Landscape Studio. “It’s always in a perpetual state of disturbance.” The trick for Miss and Blake, as well as the architect for two buildings on the site, Marlon Blackwell, AIA, is to implement designs that flexibly correspond to a man-made site colonized by the forces of nature, be they water or plant.
Of an artificial nature
Each designer has incorporated the site’s inescapable presence of water into the proposed designs. Water sourced at the museum flows in a channel underneath Miss’s path and bridge down to Blackwell’s first structure, called the Experiential Center, which acts as a transitional boundary between architecture and the natural world with a rooftop pool around which visitors descend into a pavilion defined by a forest of columns. A rectangular aperturelike space 60 feet wide by 10 feet high meant for viewing the site’s expanse defines one wall of this space. The entire structure sits on what Blackwell calls the “mount,” a pile of vegetated debris left from previous construction; the mount will be more soundly reconstructed as the park develops.
A path leading north from the Experiential Center follows rain gardens planned by Blake, skirting along a constructed wetland that will recycle all water used by that building and the next, which Blackwell calls the Interpretive Center.
This gallery and classroom building, raised off the ground on pilotis, incorporates porous roofing and floor-decking systems to preserve groundwater recharge. “In some ways, the building is like a giant leaf,” Blackwell says. In some circles, this would be considered biomimicry, or the adaptation of natural structure and performance to the built world. Miss, Blake, and Blackwell each practice a form of this, but shy away from using trendy terminology, including such seemingly innocuous words as sustainability. “I think of landscape as a building,” Blake says. “I may put more water in or make it drier, or put pavement in to raise the temperature—all of those manipulations of nature-made materials are really human-made habitat.”
A growing body of literature supports the design approach epitomized by the Indianapolis project. Land and Natural Development (LAND) Code: Guidelines for Sustainable Land Development (John Wiley & Sons, 2007), written by landscape architect Diana Balmori and Gaboury Benoit, explores site design strategies based on the latest scientific studies and technical resources available, rating various options to help designers understand what would contribute most to a project. For example, the book argues for a site imperviousness of less than 10 percent—plainly documenting the damage of higher imperviousness on watersheds. It then recommends solutions like rain gardens or green roofs.
Randolph T. Hester’s thorough Design for Ecological Democracy (The MIT Press, 2006) artfully pleads for more of a total approach to city design based on a philosophy of community involvement and recognition of the interconnectedness of nature and urban infrastructure. Hester, a professor of landscape architecture at the University of California at Berkeley, is chiefly concerned with placemaking, long a design imperative of the landscape architect, but only rarely invoked in terms of sustainable design. As many architects will agree, sustainable design’s value depends in large part on how much a client appreciates it. Hester’s book calls to mind Ian L. McHarg’s 1967 Design With Nature (Wiley, reissued 1992), which focuses primarily on placing cities within the larger contexts of regional watersheds and geological development. Clearly, the newer books are written to be used almost as tools, more pragmatic than McHarg’s philosophical meditation on the big picture. Regardless, the literature all seeks to address what is perceived as the biggest challenge to the reclamation of site: rapid urbanization.
Sidwell Friends, a first for constructed wetlands
Philadelphia-based firm KieranTimberlake Associates is no stranger to site innovation, having developed the prefabricated Loblolly House for a sensitive coastal wetland site in Delaware. For the firm’s recent expansion of the Sidwell Friends School in Washington, D.C., the architects incorporated a constructed wetland into a courtyard of the building in order to process its wastewater for reuse in flushing toilets, among other uses for nonpotable water. The district’s health department hasn’t approved the wetland’s gray water for irrigation purposes, so a separate system collects storm-water runoff for irrigation.
The wetland, the first of its kind for D.C., occupies a series of terraces in the courtyard—premium space the architects argued should be used as much for teaching purposes as for lessening the building’s water use. Opened in fall 2006, the expansion uses 90 percent less water than comparable buildings, which helped it earn a LEED Platinum rating from the U.S. Green Building Council. “Primarily, it had to pump sewage,” says Stephen Kieran, FAIA, the project’s architect. “But it also had to be beautiful, since it’s right at the entrance to the building. It became an environmental aesthetic.”
Unlike Indianapolis, the Sidwell project is located in a dense urban site, where architects must reconcile land use with significant economic pressure and a city government less inclined to approve unconventional technology for use at a school. The urban location further obscures the effects of the project’s storm-water runoff, especially sensitive since Sidwell’s location in Northwest Washington places the campus in the watershed of Rock Creek Park to the east.
Sidwell’s wetland was instigated by the project’s environmental consultant, Bill Reed, but was designed with the guidance of Michael Ogden, a wetland expert and civil engineer with Natural Systems in Santa Fe, New Mexico. Ogden says Sidwell represents the first total reuse system—in that only negligible amounts of water leave the site via utility drainage systems—installed in an urban site in the country. “We don’t normally think of wastewater-treatment systems as architectural elements,” Ogden says, cognizant of the fact that generations of students passing through the school will now have first-hand experience with a process otherwise invisible in the urban landscape.
The six-and-a-half-day process, which treats nearly 8,000 gallons of water per day, begins with a primary treatment tank, where sewage from the 72,500-square-foot expansion/renovation project encounters anaerobic bacteria such as that found on the bottom of a pond. It is then pumped to a trickle filter, where it falls over rocks before moving on to the tiered wetland. Thus far, a typical gallon of water has been in the system roughly three days; the wetland itself requires another two days.
Sidwell’s wetland consists of microorganisms and microinvertebrate populations attached to the root hairs of plants, mostly stalked bulrush, a form of papyrus. Ogden says the thousands of bacteria types found on the roots of such plants ensure that most compounds in the sewage can be treated, noting that wetlands are better at removing prescription medicines from water than most utility wastewater-treatment plants. Sidwell’s wetland is of the subsurface-flow variety, where water lies beneath layers of pea gravel. Subsurface-flow wetlands, as opposed to the surface-flow type, are used when it would be likely for people to regularly come into contact with the water and when odors could pose problems. (A Living Machine, a proprietary tank-based constructed wetland, typically needs to be confined to a restricted room because of odors and health concerns.)
Finally, the water passes through a sand filter, where anything the wetland missed is removed prior to collecting the water in a storage tank where it can be used for flushing toilets. Color-coded purple pipe, required by the Uniform Plumbing Code, indicates gray-water systems in the building, which prevents plumbers working in the building in years to come from cross-connecting with potable systems. Further, Ogden says his company injects biodegradable blue dye into the water to prevent confusion.
While a school may not pose significant challenges to a wetland, since even conventional cleaning products are generally easily filtered, Ogden has used wetlands in tough cases like landfills, refineries, food-processing facilities, and slaughterhouses, all in a variety of extreme climates. “They are much better than industrial technology, since machines break,” Ogden says. “We need to rely on self-organizing, self-regulating systems that connect to the natural environment.”
Government Canyon, gateway to an endangered aquifer
Establishing a connection to the natural environment impressed itself immediately on Lake/Flato Architects when the San Antonio–based firm undertook design on the Government Canyon Visitor Center in Helotes, Texas. The project, completed in October 2005 as a gateway to an 8,000-acre groundwater recharge conservation district, straddles the threshold of a watershed feeding the Edwards Aquifer—San Antonio’s main source of water.
The center’s south side faces a parking lot, while the north side overlooks the periphery of the environmentally sensitive recharge zone.
Lake/Flato designed three structures—classroom, gallery, and combination administrative/gift shop buildings—all oriented around a courtyard storm-water-collection system. The sloped, corrugated-metal roofs of each building siphon rainwater into gutters and onto rain chains descending into two underground concrete cisterns (roughly 8,600 gallons each), mimicking the naturally sloped land and percolation process of the aquifer’s catchment basin. A solar-powered system pumps water to a third cistern, perched atop a tower, which creates pressure for flushing toilets and what little irrigation the center’s plants need. State officials rejected the use of a constructed wetland for treating sewage, arguing it could threaten public health (a common argument in many jurisdictions), so it flows into a conventional septic tank system.
“We wanted to demarcate the edge of the recharge zone with our buildings,” says Robert Harris, AIA, project architect on the Lake/Flato team. “The long wings stretching out across the landscape with dry-stacked stone walls indicate where the aquifer’s preservation begins.” Harris says design began with establishing the average expected annual rainfall amounts (32 inches) and then calculating how much water the roof area would collect. Once designers subtracted the amount of water needed to flush toilets, the remaining water volume determined the area of irrigated landscape the project could support. A backup valve connection to the utility water source ensures toilets will always flush. Harris notes that some rural districts view stormwater collection as robbing a watershed, but in Texas, where rapid runoff and flooding pose serious soil-erosion problems, slowing the water down helps immensely.
While visitors can’t miss the stormwater-reuse system, the subtlety of the architectural moves undertaken by Lake/Flato—like the site itself—require more careful observation. For example, the architects raised the central gallery building 18 inches above grade, supporting the wood-deck floor with rusted steel pipes high enough off the ground to allow the natural flow of water underneath. A topographical survey, commissioned by the Texas Department of Parks and Wildlife, helped the architects determine how to orient the project with minimal disturbance to the watershed. “In urban watersheds, that work has been done for you, but in rural ones, you often don’t discover what’s happening until it’s changed,” Harris says. “Regional planning for watersheds is just not an institutionalized part of our development process.”
From impervious to pervious at Philadelphia’s Navy Yard
The idea of the pristine site in America is most likely a thing of the past. Even Government Canyon, as lush and bucolic as it appears, experiences the aftereffects of nearby suburban sprawl development. While Sidwell exposes the constructed nature of landscape most apparently, the Indianapolis park development cannot escape its industrial legacy, where the site’s topography represents layers of decisions made for various economic reasons decades ago. These embedded narrative threads—landscape histories made evident through the ingredients of nature—form the working methodology of Charlottesville, Virginia–based D.I.R.T. Studio. The studio’s two landscape architects, Julie Bargmann and Christopher Fannin, approach each site design as an investigation of existing conditions, with the goal of reconfiguring those into an emergent, new condition. “These postindustrial places have these echoes and we have to find in them the transformative agent that makes them relevant today,” Fannin says. “We also work with the premise that nothing leaves the site.”
D.I.R.T.’s design for the Navy Yard in Philadelphia, which included a courtyard for the Urban Outfitter’s retail group, incorporated artfully demolished concrete chunks from an existing impervious parking lot that were reinstalled in a layer of porous gravel around newly planted trees—water can now flow freely into the ground. Bargmann notes of the project, completed in early 2006, “This is not high technology, just a new way of building.” As American developers return to the city as the new territory of expansion, such innovative ways of designing for and building on a site—of understanding the baseline of what constitutes the inhabited natural world in a technological age—will certainly figure greatly in the success or failure of any venture. The real question is whether architects will help people see this, or construct another barrier.