City Hall Celebrates Greenroof Installation

December 23, 2003 – Mayor Shirley Franklin recently joined representatives of the City’s departments of Watershed Management and General Services to unveil the newest jewel in the City Hall crown: a 3,000-square-foot garden on the building’s fifth-floor roof. The project, sponsored by Watershed Management with the Mayor’s enthusiastic support, offers benefits both aesthetic and functional for City Hall and Atlanta.

"Greenroof technology is a viable tool for mitigating the ‘urban heat island’ effect and for dealing with stormwater problems," Watershed Management Commissioner Jack Ravan said, as he joined Mayor Franklin in an informal walk around the garden. Ravan’s department provided $42,000 of the project’s $60,000 price tag. A grant from the Georgia Environmental Facilities Authority made up the difference.

The City Hall greenroof is the first municipal project of its kind in the South; similar projects have been completed in Chicago; Portland, Ore.; and Seattle. When designed and implemented as part of the overall infrastructure, greenroofs are a cost-effective strategy for dealing with numerous urban ills, including:

• Air quality. The natural processes of photosynthesis and evapotranspiration can serve to ameliorate the urban heat island effect, lowering air temperatures, absorbing carbon dioxide and other pollutants, filtering air, binding dust particles and reducing glare;

• Water quality. Greenroofs absorb pollutants from rainwater, ensuring cleaner and cooler runoff, and provide erosion and sedimentation control, thus protecting watersheds and sewer systems;

• Stormwater management. Greenroofs alleviate the burden on stormwater infrastructure systems through vegetation/root and soil systems and evapotranspiration, which reduces the amount of total runoff and lowers runoff flow rates;

• Energy consumption. The added insulation layers, including soil and plant layers, in a greenroof can help reduce consumption rates and lower energy bills;

• Added economic benefits. The greenroof system helps protect the structural elements of the roof; guards against ultraviolet rays, wind extremes and temperature fluctuations; provides acoustical insulation to suppress noise; and can help extend the life of the roof;

• Habitat provision. Although not a substitute for forested areas, greenroofs can supply habitat corridors for displaced birds and other small wildlife;

• Aesthetic and psychological benefits. Urban areas are enhanced by the natural beauty and soothing aesthetics offered by plant life.

Bill Brigham, landscape architect for the City, and Ben Taube, the City’s environmental manager, served as project managers for the greenroof installation. They will contine to assess the roof’s effects and report their findings to the public. Both see the project as a model that can demonstrate for developers the benefits of a functioning greenroof system.

Also contributing to the project were: Kemper (waterproofing), Excel Electrical (electrical conduit), Saul Nurseries (plants), Itsaul Natural (soil), JDR Enterprises (drainage system), Unique Environmental (landscaping services), Flintstone Pavers (labor for paver installation), Sims Stones (pavers) and the City’s Department of General Services (labor).

Photo ID: (left to right) Commissioner Jack Ravan, Sharon Owen, Procurement Officer for the Department of Watershed Management; Mayor Shirley Franklin; Ben Taube, City of Atlanta Environmental Manager; and Bill Brigham, City of Atlanta Landscape Architect.