NORMAN — The National Weather Center introduced the state’s first "green roof” Thursday to help celebrate Earth Day. The roof atop the University of Oklahoma research campus building has 160 trays measuring a combined 1,280 square feet that will hold plants and grasses planted in layers of clay, sand and organic material that have one-third the weight of regular soil. Reid Coffman, an OU landscape architecture assistant professor, said the green roof, also called a vegetative roof system, is designed to drastically reduce both storm water runoff and energy use and cost. "These have been shown, depending on conditions, to produce 25 to 75 percent in annual air conditioning savings,” said Coffman. Small sprouts can be seen in some trays while others are barren. Coffman said most trays will be filled with sedum plants, which have shallow roots that are ideal for the trays’ four-inch depth. Native grasses and perhaps wildflowers will be planted in the empty trays.
Second site plannedRainfall will absorb into the substrate of clay, sand and organic material instead of running off the roof, and the numerous plants that will cover the roof will interrupt solar radiation and keep the building cooler. The green roof trays are expected to stay three years atop the National Weather Center’s classroom deck for observation and research, Coffman said. They will be moved to a permanent location on campus after that. The system materials came from Weston Solutions, an Illinois-based company that specializes in green roofs. Michelle Brown, a Weston project leader, said OU has the state’s first green roof, though another is planned. The systems are more popular in northern states, and both Brown and Coffman said green roofs have been commonplace for years in Europe. OU’s green roof was produced by the School of Meteorology and College of Architecture and was sponsored by the Oklahoma Water Resource Board and Oklahoma Conservation Commission. "It will provide opportunities and benefits not only to the two colleges through research, but also to the entire state of Oklahoma by offering insights into energy efficiency and water quality,” said John Snow, dean of the College of Atmospheric and Geographic Sciences.