As it turns out, there was a definite upside to the scorching drought of 2007-’08. It led to the birth of a high-performance landscape – a new, 6-acre pond, scooped out of 12 wooded acres on Duke University’s campus in Durham.
Its water will be pumped to a chilled water plant’s cooling tower that air-conditions a number of buildings on campus. But it’s also a pristine environmental gem, now inhabited by purple martins, scarlet tanagers and a single blue crane. And its looping pedestrian path meanders along water’s edge, offering an extensive and learned tutorial on plants native to the North Carolina Piedmont.
“Overall, our intent was to design a landscape as functional as it is beautiful – a working piece of civic and civil infrastructure,” says Evan Grimm, senior associate at Nelson Byrd Woltz Landscape Architecture (NBWLA) of Charlottesville, Va., and New York, N.Y. “It supplies water, it’s inhabitable, and it’s enjoyable to visitors, staff and students at the university.”
Duke Pond didn’t start out that way, not by any stretch of the imagination. It was initially envisioned as nothing more than a large hole in the ground, fed by a stream and surrounded by rip-rap – big, ugly rocks piled high to hold up the pond’s banks and halt soil erosion.
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A landscape design heritage
Then Mark Hough, university landscape architect, stepped in. “I spoke up and said it needed to be more than that, and from then on, I was involved in its design and construction,” Hough says. “It was originally designed to be a functional body of water to serve a specific purpose – but to my mind, it could achieve so much more than that one purpose.”
Hough reached back to a mid-1920s Duke landscape plan by the Olmsted Brothers, who also designed campuses at Vassar, Haverford, Harvard Law School and the University of Chicago. Their plan suggested two bodies of water for Duke, neither of which was ever developed. Hough colored them blue on a historic, birds-eye-view rendering, and presented it to senior university administrators – to show the pond as part of the original campus design.
Even as the budget for developing the pond more than doubled to $11.5 million, the project was greenlighted. Hough’s next step was to recommend hiring Warren Byrd of NBWLA, who had designed Duke Gardens’ Virtue Peace Pond, as well as an award-winning landscape project at the University of Virginia called The Dell. There, he unearthed a buried stream and created two ponds connected by a small dam to clean up stormwater before sending it downstream to the Rivanna River – and the Chesapeake Bay.
“We hired Warren Byrd, so it was the same team that did The Dell at the beginning,” Hough says. “He does designed landscapes, makes them look natural, and brings some element of formality to them.”
Engineering the solutions
For the pond’s functional aspects, Hough turned to James Caldwell, assistant director of water resources and infrastructure at The John R. McAdams Co. That firm is the keeper of Duke’s stormwater impact analysis, a study of how runoff travels across campus. They helped Duke identify eight potential pond sites, pared them down to four, then to two, and finally to one.
While NBWLA developed concept sketches, layouts and landscapes for the pond, Caldwell was working on models based on the weather during 1997, a fairly typical year for rainfall. The questions were: How much water could they pull out of the pond from a little stream that runs through campus, and how much could be sent to the chiller plant?
Right now, in the pond completed a year ago, there are 8 feet of water, or 9.1 million gallons – plus another 4 feet that flow in and out, adding 6.7 million more. That 4-foot water flux can rise up or down 2 feet day-to-day, as needed. The 8 feet of water below could be used for about two weeks during a drought like that of 2007-’08.
All told, that’s 15.8 million gallons for the chiller plant. Water will be pumped on a daily basis, depending on demand. On an overcast day demand will be low, but in mid-August the cooling tower might use as much as a million gallons daily. Annually, that could be 143 million gallons, based on the 1997 rainfall model, until Duke expands its chiller plant sometime before 2020. By then, the target could be 189 million gallons annually. “They’ll end up with about half of what they need,” Caldwell says. “The rest, they’ll buy from the city.”
Still, using the pond’s water translates into a potential savings of about $400,000 a year, in potable water no longer purchased from the city of Durham. So Duke Pond could pay for itself in about 25 years, and become an investment that keeps on giving indefinitely.
Designing the landscape
The pond’s design was informed and restrained by its boundaries. On its southern edge is Circuit Drive; to the north is Erwin Road, with Towerview Road to the west. The chiller plant, with parking lot and electrical substation lie to the east. An existing sanitary sewer line limited grading on the southern edge.
The 12-acre site is surrounded mostly by forest, a backdrop to the pond. “We wanted to retain as much existing landscape and plantings as possible,” says NBWLA’s Grimm, the pond’s project manager. “We worked with McAdams to minimize the amount of site disturbance and demolition.”
Still, 1,558 trees – mostly oaks and pines – were taken out and recycled into deck boards, hand rails, a pavilion, pump house cladding, and use elsewhere on campus. Other materials for structures on the site – decks, bridge, boardwalk and a promontory that descends from Circuit Drive down 36 steps to the pond’s edge – include poured-in-place concrete, as well as stone and aggregate already common to the campus.
Like The Dell at U.Va., a small pond precedes a larger body of water. Between them an underwater dam, or weir, slows the flow of water so its sediment drops down, while wetland plants around the perimeter feed on its hydrocarbons. Eventually, the pond’s clean overflow streams out through a stone-lined channel to a storm drain and then to Sandy Creek. From there it travels to New Hope Creek, Jordan Lake, the Haw River, and eventually, the Atlantic Ocean.
In a pattern that Grimm calls “rigor to rural,” his team planted stands of redbuds, river birch and bald cypress along the meandering loop, and added shrubs, seed mixes, tree seedlings, Stokes asters and water lilies, for a landscape that in time will appear wild and completely reforested. “You wouldn’t necessarily find them together in nature,” Grimm says. “It’s kind of a curated hydric landscape.”
If there’s a downside to the landscape design, it’s the hard right angles of man-made structures – the pavilion, the overlooks and the pump house – against the gentle curves of planted terraces. But that will be overcome by the softened edges of mature plantings. “The forest will return and become whole again, and that juxtaposition will be less obvious as the plant communities grow and everything gets bigger,” he says.
In the meantime, a leisurely ramble around the pond’s loop offers the opportunity to discover how smart landscape architecture – from sure and capable hands – can create a place as comforting as it is useful.
Note: This story has been corrected to show that the clean overflow from Duke Pond goes to the Haw River; not the Neuse.
J. Michael Welton writes about architecture, art and design for national and international publications, and edits a digital design magazine at www.architectsandartisans.com. He is the author of “Drawing From Practice: Architects and the Meaning of Freehand” (Routledge, 2015). He can be reached at firstname.lastname@example.org.
Visitors may access the pond from Circuit Drive or Towerview Road in Durham. A parking lot is off Circuit Drive, and a bike path runs through the site from Towerview Road to Circuit Drive.