The Sweetwater Creek State Park Visitor Center near Atlanta stands out not only for being an exceptional model of green building architecture, but also for the manner in which it was designed. Sweetwater Creek is one of only a few buildings worldwide and the first in the southeast U.S. to earn LEED Platinum certification, the highest level of eco-friendly building achievement from the U.S. Green Building Council. The building requires 77 percent less water and consumes 51 percent less energy than comparable buildings, to name just a couple of its virtues.

It’s also one of the first LEED Platinum buildings designed using 3D “virtual building” technology, otherwise known as “building information modeling” (BIM). With this BIM approach, architect Dan Gerding of Atlanta-based Gerding Collaborative was able to work with an integrated design team of engineers, environmentalists, interior designers, contractors, building staff and other stakeholders to blend the building naturally into its surroundings and capture maximum benefits from the environment.

When Gerding started his architectural firm in a spare room in 1993, his interest was in incorporating natural systems and resource conservation into his building designs. The emergence of virtual building technology at the same time dovetailed perfectly into his business model, allowing him and his team to interact with 3D design models as well as the BIM data used for predicting building systems’ performance for environmental sustainability.

Gerding Collaborative currently has nine full-time employees, comprised of technical staff, architects and interior designers. The firm has a diverse portfolio of public and private projects, but focuses primarily on institutional work like Sweetwater Creek. “I got on board with the concept of virtual modeling early on,” said Gerding. “It just seemed like the right direction — the way we used to do things, using two-dimensional drawings, was sort of archaic. We like to be at the forefront of technology, which is why we employed virtual building software.”

Getting Everyone On Board

Gerding’s client for the Sweetwater Creek was the Georgia Department of Natural Resources (DNR). Once he and the client agreed on a vision of a bold sustainable design, Gerding realized many other decision makers would need to be persuaded.

“We were working with a large design team that consisted of mechanical engineers, electrical engineers, plumbing engineers, the landscape architect, structural engineers, and the civil engineer,” he said.

But in addition to the design team, Gerding needed a way to showcase the ideas and gain consensus not only from the DNR staff, but also from a group of project fundraisers who held a significant portion of the purse strings. “This was a rather unusual building, both in concept and appearance. We needed to make sure that everyone had the same idea about the final structure,” he said.

Gerding’s architects and engineers were already skilled in ArchiCAD virtual building software, which gave them the 3D visual aids to display, communicate and enhance the project to the others. Gerding presented the group with a building design fully integrated into the landscape, blending in with the surrounding hillside and leaving a very minimal footprint on the environment.

While the initial design had more modest green building aspirations, the design team realized that this project had the potential to garner a higher level of LEED certification than any other project the members had worked on. “The project kick-off meeting was really a LEED kick-off meeting. We had all of the stakeholders and design team members in one room, and we identified the credits we thought we could achieve with this project,” said Gerding. “Given the budget and other parameters, we initially came up with a project at the Silver level.”

As the design ideas started flowing, Gerding’s team captured them fluidly in the virtual building environment. To approve the final design concept, the team was able to show 3D views of the building from all angles, displaying how the roof was going to be a natural extension of the hillside. According to Gerding, “Being able to model the building in that way, with that level of detail, got the stakeholders and our client really excited about the project. That excitement kept the design team’s momentum moving forward because we were all able to agree that this was a special opportunity.”

The technology not only provided a visual model of structure, but also demonstrated the sustainable design features to minimize the building’s effect on its surroundings and maximize the on-site environmental benefits, like tree shading and solar radiation. “We were able to conduct sun studies of the south face of the building to fine-tune the size and location of the shade devices and light shelves,” said Gerding.

This ability to experimentally optimize the building position allows the sun to provide heat to the building’s interior in the winter while almost completely eliminating the sun’s direct rays in the summer. The high-performance building also features composting toilets, vegetated roof, rainwater capture, bio-retention ponds and photovoltaic solar panels. The composting toilets and rainwater capture system eliminated the need for a leach field, saving both trees and money. The graywater system provides water for the low-maintenance gardens, eliminating the need for an irrigation system. The vegetated roof helps insulate the building while serving as an outdoor gathering plaza, further reducing the building’s environmental footprint. Taken together, these eco-friendly features helped reduce water waste by more than three-quarters, and energy consumption by more than half of comparable buildings, avoiding 27 tons of carbon emissions annually.

The technology allowed the architect to share 3D views of the interior with the design team and the client, giving them the ability to explain the concepts clearly. Decision-making was easier, better informed, and consensus-driven. The design team was able to continuously collaborate during the conceptual phase using a succession of 3D virtual models to create “what-if” scenarios. For example, mechanical engineers could easily understand how the building’s orientation minimized the amount of sunshine coming in and heating up the interior, downsizing the mechanical systems as a result. This downsizing provided big savings in electricity and equipment costs, resulting in cascading benefits that might otherwise have missed.

Tackling this project with only a conventional two-dimensional design would've extended the length of the project, added to the budget, and inhibited innovation and collaboration during the design project…ultimately resulting in a lesser certification.

Going for Platinum

Photo courtesy of Dan Gerding.

As the design progressed, the team realized that it was within reach of being able to exceed its own goal of LEED Silver certification and decided to push for more credits. “Being in a conservation park made the project a perfect opportunity to make a strong statement about resource conservation and respecting the natural environment,” Gerding said. “The mission of the park is to be a cultural and a natural resource. We feel we created a building that is really second in line to the environment — it sets a conservation example for the state of Georgia.”

The U.S. Green Building Council awarded the Visitor Center Platinum-level LEED certification. In the LEED-NC (new construction) category, Sweetwater Creek is only the 20th building in the world to be awarded the council’s highest distinction.

“Our firm has keen interest in sustainable design, and achieving LEED Platinum certification helped make us leaders in this movement,” said Gerding. “Virtual building technology gave us the platform to visualize the projects better and be more confident that when we put the designs in front of our clients. At each step of the process, we were generating various views of the model to discuss ways to better integrate with the surroundings.”

VISITOR CENTER SWEETWATER CREEK STATE CONSERVATION PARK

PROJECT OVERVIEW

The Visitors' Center is located in the historic Sweetwater Creek State Conservation Park, and serves as a gateway to the park trails and the historic New Manchester Manufacturing Company Mill ruins. Conceived as a site-integrated building, the design derives its form from program requirements, site topography, climate and solar orientation. The building’s design includes exhibit areas, retail, administrative offices, audio-visual / multi-purpose rooms, a water quality lab / classroom and restrooms.