Author(s): Donald D. Carpenter; Preethi Kaluvakolanu; Biman Paudel; Rajesh Seth
Linked Author(s):
Keywords: Green roof; Green Infrastructure; Urban Stormwater Management
Abstract: Lawrence Technological University is a private university located on a 120-acre campus in highly urbanized Southfield, Michigan, U. S. (Detroit Metropolitan Area). The 40,000 square-foot A. Alfred Taubman Student Services Center (Center) was opened in 2005 as a showcase sustainable and energy efficient technologies. The Center features a 10,000 square foot green roof; geothermal heating and cooling; cistern water harvesting; a bioswale, and other energy efficient technologies. Of specific interest to stormwater management, the building features a 10,000 square foot Hydrotech Garden Roof? and gray water cistern that recycles roof water. The presence of the green roof provided an opportunity to evaluate the hydrologic performance of a full-scale green roof with other more traditional roofs on campus. This was accomplished by outfitting three separate roof drains (a traditional blacktop asphalt roof, a rock ballasted roof, and a hydrologically isolated 3500 sq ft section of the green roof) with automated water quantity and quality sensor. Measured variables that will be presented in this paper include the overall volume of precipitation retained and detained by the green roof compared with other roofs on campus, the attenuation and delay of peak discharge provided by the green roof, and the determination of run-off coefficients for various storm events. Measured performance data was also utilized to formulate and calibrate a simple run-off model for the green roof. The run-off model was than used to simulate green roof response to a number of Type II–24 hour design storms. Finally, the paper discusses how the simple run-off model, as well as measured hydrologic response variable such as run-off coefficient and volume retention, can be used as practical tools for judging the performance of a green roof with respect to stormwater management.
Year: 2010