City Is Cultivating a Greener Future

Green roofs have numerous private benefits. They help to insulate the building, protect the roof from UV rays and extend its life by as many as 15 years, Murphy said. But a green roof's biggest impact is environmental: slowing the flow of storm water into area rivers.

"Storm-water runoff brings with it toxic pollution, such as oil and grease from cars," Connolly said. "The rain is literally like a broom that sweeps everything into the storm drain and into the river.

"If we do not control and capture and infiltrate storm water, we're not going to clean up the Anacostia," he said.

At the heart of the District's storm-water runoff problem, Connolly said, is its century-old sewer system, which dumps raw sewage and storm water runoff into the Anacostia whenever the city receives more than a half-inch of rain. The billions of gallons of polluted water have serious consequences for the Anacostia's plant and animal wildlife.

To help remedy the problem, the DC Water and Sewer Authority is working to repair all the broken pumps, clogged pipes and malfunctioning dams in its system, a project that Connolly said will reduce the combined sewer overflow into the Anacostia by about 40 percent. It should be completed in the fall.

But taking care of the remaining 60 percent requires the construction of $2 billion storage tanks that will hold storm-water overflow until it can be treated, Connolly said. So far, the project doesn't have the necessary funding.

Until it does, green roofs make a big difference.

In a report released in May 2007, local environmental advocacy group Casey Trees, working with environmental engineers from Limno-Tech, estimated that greening efforts could stop as much as 311 million to 1.2 billion gallons of storm water from entering area rivers.

"The idea with a watershed is that it's the land from where all the problems are coming," Connolly said. "We need to reestablish the cycle where the water sinks down into the soil. With roofs and pavements, we've taken away that step where it filters in, and instead it just rolls down a hill and into a stream."

"It's all about reducing what they call the 'footprint' of the building, or the impact it makes on the environment," Murphy said. "In Switzerland, when they're building a new building, they sometimes scoop up the dirt that was there and just put it on the roof. The U.S. is not quite at that stage," but it seems to be on its way.

Snyder said she thinks the District will continue to be on the forefront of the green efforts.

"I see D.C. becoming an environmental leader in the nation," she said. "We became a leader in the nation [when] we established mandatory green standards not only for our own buildings, but for private sector development. The point now is for us to follow through and to continue to push the edge."