National Weather Center Green Roof Project

OCC’s Water Quality division is working with the University of Oklahoma’s College of Architecture and its Landscape Architecture Division on a Green Roof Project for the  top of the National Weather Center (NWC) building at the OU campus in Norman. Roof greening, the growth of plants on rooftops, is becoming a popular technique in North American cities to reduce stormwater runoff quantity, improve discharge quality and reduce warm season energy demand.

In this aerial photo of the NWC building in Norman, green squares are used to indicate the areas where the Green Roof Project will be installed.

Two-foot square plant containers with four to six inches of growing media will be placed together in paddocks to create contiguous areas of green roof. Sedum plants will be used, overseeded with native grasses and perennials including blue grama and purple coneflower. The project is split between two areas on the multi-roof building — the service roof and the classroom roof, using two different manufacturers’ systems for comparison. The smaller classroom roof will be used for study, teaching of students and officials and as an exhibit for visitors. The larger service roof will be used for long-term examination and study.

Recent studies show green roofs reduce annual stormwater runoff by 50-75 percent while preventing atmospheric pollutants from entering the stormwater system. Simultaneously, these vegetative roof systems intercept solar radiation and act to cool the building during summer, reducing the air conditioning costs by between 25-75 percent. The project can demonstrate broader economic benefits for the public as well. For example, covering 90 percent of the rooftops of Chicago with green roofs could save the city 750 megawatts of peak flow electric consumption annually. Rising temperatures created by the urban heat effect can be reduced three to four degrees.

Despite its growth in popularity elsewhere, Green Roof is largely unknown in Oklahoma. One goal of the OCC/NWC Green Roof Project is to serve as a model and increase awareness of the concept. Its location on the University Campus will lend itself to research, examination and visitation by numerous scholars, students and officials.

The cost for the one-year project is $86,000. Funding is through the U.S Environmental Protection Agency under the Green Reserve Program. Green Reserve is a portion of the water infrastructure funds in the American Recovery and Reinvstment Act stimulus plan that is intended for communities to spend on green infrastructure, water and energy efficiency and environmental innovation. Planning and design began in July 2009 and was completed in December. Installation is now underway and is scheduled to be complete in May 2010.