By Jennie Farnsworth

Often the most eloquent and well thought out plans can encounter detours; however, obstacles can sometimes provide divine intervention to travel a different, more inspired, path. Such is the case with the U.S. National Park Service's (NPS) Twin Creeks Science and Education Center, designed by Lord, Aeck & Sargent of Atlanta, located within the Great Smoky Mountains National Park.

Scheduled for completion by year-end, Twin Creeks will allow interdisciplinary collaboration among researchers, including taxonomists, biologists, botanists and ecologists, as well as other government agencies, partner colleges, universities and museums. A "first of its kind" for NPS, this revolutionary, 15,000-square-foot research facility will also provide the necessary laboratory space for Discover Life in America's All Taxa Biodiversity Inventory (ATBI) project, an ecological effort to inventory and categorize the estimated 100,000 species within the half-million-acre park.

This rendering shows the integration of the Twin Creeks research facility, with its cobblestone base, within its surroundings of boulders and natural stone landscaping.
Illustration courtesy of Barbara Ratner

The Plan
From day one, NPS knew that the environment-friendly researchers needed an equally environment-friendly building and tapped the architectural firm Lord, Aeck & Sargent to make it happen. Leading Lord, Aeck & Sargent's sustainable design initiative, Jim Nicolow, AIA, LEED AP, stated that NPS wished to create an environmentally appropriate structure that also could be modeled for future facilities in the National Park System.

While departments are encouraged to evaluate the environmental impact of a project and consider green building strategies, NPS is not required to seek LEED certification, the U.S. Green Building Council's standard for high performance, sustainable design. However, during the initial three- or four-day collaboration, the two groups decided that not only would Twin Creeks include numerous sustainable design strategies, but they would also target LEED certification. Nicolow and the design team included a wide array of environmentally responsible design strategies, including daylight harvesting, natural storm water management, natural ventilation, high recycled content building materials, low-emitting finishes, an electric vehicle charging station and more.

	The Great Smoky Mountains National Park spans a half-million acres and contains more than 100,000 species of living organisms. Photo courtesy of the U.S. National Park Service

"Twin Creek's daylighting strategies, environmentally responsible design features, parametric thermal modeling and building envelope optimization have resulted in the design of a building that will consume considerably less energy than a traditional code-compliant building," Nicolow said. "At the same time, the National Park Service will gain a healthy, productive research environment for the building's users."

The Lemons
According to Meg Needle, project manager for Lord, Aeck & Sargent, the site of Twin Creeks was chosen due to its close proximity to an existing farmstead, which was converted into a makeshift research facility within the park. Upon further investigation of the site, they discovered the sloping area was the remnants of an enormous landslide that occurred thousands of years ago. Instead of finding some sort of solid surface to build upon, the team found a matrix of organic soils and loose cobble, approximately a hundred feet deep, where the building was to be constructed.

"There's no bedrock, but it's just this matrix all the way down," Nicolow said. "When we had the geo-technical test pits dug, they said what we were going to run into are stones ranging from the size of footballs to the size of Volkswagen Bugs."

An elevation map of the Great Smoky Mountains National Park. Photo courtesy of the U.S. National Park Service

Due to the widespread use of natural materials in the vicinity, including the dry-stacked natural stonewall leading up to the area and the prevalence of stone masonry buildings in the region, the collaborative team had already planned on integrating stone into the design. While the geological discovery made the use of stone that much more appealing, it certainly raised a few issues that required a reevaluation.

"We realized a couple of things with the geo-technical report," Nicolow said. "One was there were a lot of rocks; the other was that there were a lot of organic soils that wouldn't support a building very well."

The most cost-effective solution was to undercut and come back with an engineered fill — digging out not only to get a flat spot to build, but also to provide an engineered base. This undercutting for the building pad would yield many rocks and boulders in addition to soil.

"When we realized we had a whole lot of rocks, we just had to make lemonade out of lemons and make use of the rocks," Nicolow said.

Details of the Twin Creeks facility.
Illustration courtesy of Lord, Aeck & Sargent
Click here to view a larger version in a seperate window.

The Lemonade
Rather than trying to find a way to dispose of the boulders, the team and general contractor Hedges Construction decided to knock out two problems with one stone. First, the boulders were harvested and utilized as a gravity embankment to stabilize the site's slope — three feet high in the front and 10 feet at its highest point in the back. This not only assisted in supporting the structure, but also added to the environmentally friendly ideals that fueled the building's design; the team would not have to remove or dispose of the boulders, and the civil engineers could utilize materials already located on-site for some of the stabilization.

The design team also used the boulders to create a natural storm water treatment system.

"There's a cascading storm water system off the front of the building where the rainwater that falls off the roof comes down into a planter zone," Nicolow said. "It's created by a stone-clad retaining wall and has a series of scuppers, so once that is saturated, the water falls over into a swale created by the boulder embankment. That is then channeled into three cascading water quality ponds. There is a prized trout stream adjacent to the building, so [NPS] wanted to make sure that the storm water conditions were similar to predevelopment conditions following construction of the new facility."

Lord, Aeck & Sargent chose to harvest the boulders onsite to stabilize the embankment, as well as emphasize them in the surrounding landscaping.
Photo courtesy of Lord, Aeck & Sargent

The site's stones not only lend themselves to utilitarian purposes, but are also pivotal to the aesthetics of the Twin Creeks site. The boulders that were initially considered a potential source of problems have become a uniting tie throughout the landscape and exterior of the building. The visitor walking paths leading to the Twin Creeks facility flow around the existing features and topography, winding around the massive stones. While it's the flora and fauna that are the main focus within the building, the boulders create a feature attraction all their own in the surrounding landscape.

Needle stated that the design team specified a contractor's option to use smaller stones harvested from materials excavated for the building foundation in the cobble masonry veneer. However, the sorting of the site stone to identify material suitable for the veneer walls proved too labor-intensive. Instead, the mason contractor, Olen Ford Masonry of Knoxville, Tenn., chose to purchase a regional cobblestone that matches the site's natural palette from Smokey Mountain Stone, a local quarry, which will cover the lower half of the structure's veneer.

"The idea was to really have it feel indigenous to the place," Nicolow said.

A stonewall leading up to the Twin Creeks building site.
Photo courtesy of Lord, Aeck & Sargent

In the end, just as the researchers inside the building are learning new ways to understand and integrate humankind's existence within its precious natural ecosystem, thanks to the perseverance of the NPS and Lord, Aeck & Sargent collaborative team, the Twin Creeks facility and landscape will echo this sentiment outside as well.

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