A green roof on Nationals Park. Photo by (afm)

There’s now more evidence that D.C. is becoming a green leader in the U.S.—according to Green Roofs for Healthy Cities, D.C. installed more green roofs than any other metropolitan area in 2011.

Last year, the city added 800,000 square feet of green roofs; Chicago took second place with under 600,000 square feet added. Still, Chicago remains the nation’s leader in green roofs, with over 3.5 million square feet installed between 2004 and 2011. D.C. comes in second with just over 2.5 million square feet for that same period, ahead of New York, Toronto, Vancouver, and Baltimore.

As part of Mayor Vince Gray’s recently released 20-year sustainability plan, D.C. will install another 1.5 million square feet of green roofs in the near future. According to the Post, a network of green roofs are being planned for new developments that will rise above a part of I-395 in Mt. Verson Square. Developers hope those green roofs can be used as urban farms.

The green roof industry says that they help with stormwater management, moderate the urban heat island effect, improve air quality, and increase biodiversity. D.C. has long sought to increase its proportion of permeable surface areas to better soak up rain and decrease runoff that often overwhelms storm drains and ends up in local rivers.

In January D.C. was cited as a national leader in green buildings.