Tim Carter, a doctoral student at the UGA Institute of Ecology, developed a heightened sense of environmental awareness as a carpenter in Asheville, NC. Often, he stood on the roofs of grand custom homes he was working on to look out at the view. From this vantage point, he was struck by the stark contrast of beautiful mountains in the distance and the ugly dumpsters nearby.

The latter overflowed with pieces of two-by-fours and other discarded building material. Carter continued to notice large piles of waste resulting from every building he worked on, ready to be hauled off and dumped somewhere. He began questioning the human relationship with the earth and the ways in which we construct our buildings. "How can the surrounding environment be better protected from the way our buildings are designed, including the roofs?" This question gnawed at him.

At the same time, Carter observed growing pollution problems created by storm water runoff. This is water, not absorbed by any soil or marshes, that rushes off roads, roofs and parking lots, carrying sediment and foul materials into our streams and rivers. Since it is from all over, and not from just one location, it's known as, "non-point source pollution." The problem is due to widespread impervious surfaces typically associated with urban development, particularly our roofs and paved areas. For Carter, it was clearly time to question the "sacred urban cow."

Tim Carter

Carter understands how space is valuable in most urban settings. Yet, because roofs are usually "out of sight and out of mind," this is ignored space and rarely used to benefit anyone or the environment. Why not follow Germany's example and begin using these unused places in ways which protect the environment and add to the economic value to the building as well? Why not grow large numbers of low-growing plants in these empty spaces on roofs where they can absorb rain and benefit humans? In his view, the time has come for environmentalists to research ways to use vegetative roofs or "green roofs" in this country, too.

Carter's own research on the use of green roofs shows political awareness. He knows from his extensive review of the literature how valuable green roofs are in other places. Yet, he's the first to admit, "We don't know in specific terms how engineers can use the performance of green roofs in this region to help control the storm water runoff." Carter knows he must produce the hard data to show businesses, city planners, and engineers the information they need to support the addition of green roofs to buildings in a city like Athens.

Traditionally, our local engineers control storm water runoff with pipes and systems of pipes. As more of our land is built upon, the increased storm water runoff begins overwhelming the system and severely damages our urban stream ecosystems. So, typically, the response is to use bigger pipes and a larger system to handle the increase in storm water runoff. But Carter wants to encourage a much broader way of thinking. He asserts, "What if we were to manage it from the source? If there's less runoff to handle, then the pipes won't get overwhelmed, and flooding can be avoided, which lessens the environmental stresses on our streams. Other groups are considering ways to use porous pavements, build better retention pond systems and protect more green space in watershed areas to control storm water. Additionally, more roofs throughout the city including extensive areas of green plants to absorb rain would be a positive addition to the entire storm water approach. Such an approach would relieve the growing stress placed on the underground pipes and possibly permit ecosystems to function better as well."

Building owners and businesses may be easier to convince. The literature and earlier studies already reveal how green roofs extend the life of the roof for as much as twice as long as those roofs without plants. Constant radiation from the sun breaks down regular roofing material over time. Yet, when plants are available to absorb the sun's rays, the damage is lessened.

In addition, the cooling effect helps decrease the building's cooling costs during hot months. The entire building is no longer a major "heat sink" and contributes less heat to the overall urban setting. Even in cooler months, the green roofs act as an insulating layer. This insulating effect decreases the costs of heating for the building's occupants in the winter.

Carter is looking at all of these angles as his plants begin to take root in the soil area which he and other volunteers, including his major Professor Laurie Fowler, constructed on a flat roof just outside the Boyd Graduate Studies Research Center and the Science Library. It's right by Soule Street on the UGA campus. Fortunately, the employees of UGA's physical plant were open to his green roof experiment there, and the Georgia Forestry Commission was willing to fund this project. American Hydrotech, Saul Nurseries, Itsaul Natural and Carolina Stalite donated materials as did the local Home Depot store. However, Carter must also include what the costs would be for someone interested in creating a green roof in this area without access to these donated supplies. Is a green roof feasible for a building owner? What is the cost/benefit analysis of a green roof for a building owner in this region? These and many other questions must be answered in order for Carter's research to be complete. But his answers and final data may help Athens growing green roofs.

Liz Conroy