(PHILADELPHIA – Sept. 29, 2010) – Federal and local officials celebrated today the completion of the third largest green roof in the District, a $1.1 million project funded in part by the U.S. Environmental Protection Agency through the American Recovery and Reinvestment Act. Sitting atop the World Wildlife Fund headquarters in Northwest D.C., the 27,750 square feet of green roof will help reduce stormwater runoff to nearby Rock Creek and bring additional benefits to the urban environment.