- The Washington Times - Thursday, December 5, 2002

Culture critic Frederick Turner, asked to submit a design for the memorial on the grounds where the World Trade Center once stood, had a vision of green.
"Put the garden on top of the building," he said. "Memorialize the dead where they died, a thousand feet above the street."
His design of two trumpet-shaped towers included rooftop gardens to provide peaceful oases for people to remember and pray.
"The place will be windy and cleaner, the temperature three degrees lower than the streets below," Mr. Turner wrote, "preserving a hundred years from now the climate of New York as it was and reminding them of what New York was like two hundred years ago."
That is partly the concept behind green roofs, also called eco-roofs or living roofs, in which the tops of buildings are covered with dense mats of live plants.
To grow plants on a rooftop, a waterproof membrane is covered with about 4 inches of soil. In between the membrane and the low-growing plants is a drainage layer.
Proponents say mini-ecosystems can help cool a city full of heat-trapping concrete buildings. They also grab pollution out of the air and break it down in the soil, and filter dirty rainfall into cleaner runoff.
Green rooftops retain 50 percent to 70 percent of the storm water they capture, the Environmental News Network reports, easing the strain on underground drainage pipes.
This is one concept that is likely to please both green groups and economists: It is a healthy, attractive solution to urban ecology problems and creates jobs in the process.
But critics say the projects belong at the grass roots.
"It might be a perfectly nice thing," says Mike Hardiman, lobbyist for the American Land Rights Association, which advocates for private-property rights and multiple use of federal lands. "The controversial part is when you start talking about government money" and building codes.
"Then you have the feds saying, 'We're not going to mandate anything, but if you don't do it, your building permit is going to cost 10 times more.'"
Free-market economists, he says, will be supportive so long as the money stays private: "If it's already happening, that's great. Why mess it up with a government program?"
Until conflicts arise, proponents are happy to learn how a healthy garden grows.
"A green roof can be an excellent living laboratory," says Dawn Gifford, program director of D.C. Greenworks/Community Resources, a nonprofit with a contracting arm for developing green roofs.
The movement to promote this technology is "starting to snowball," she says, but a typical first reaction is: "Plants on the roof? What?"
She and others are working create an understanding of what eco-roofs are and what they do. The so-called green-roof movement is supported by a network of organizations that fall under the umbrella group Green Roofs for Healthy Cities.
"Rooftops The last urban frontier," the group proclaims in its press materials. The mission of Green Roofs for Healthy Cities is to develop a multimillion-dollar market "for green roof infrastructure products and services in cities across North America."
They say cities can benefit from savings related to reduced energy consumption and greenhouse gases, as well as from air-quality improvement.
The First North American Green Roof Infrastructure Conference, Awards, and Trade Show will be held May 29-30 in Chicago. The annual meeting will focus on the concept's move from underground project to nationwide trend.
Miss Gifford illustrates how green roofs can alleviate some of the District's problems by introducing two key concepts: the "urban heat island effect" and the "combined sewer overflow problem."
The former affects concrete-jungle cities like New York, Philadelphia and Washington and the latter is common anywhere that has plentiful rainfall.
"Blacktop and asphalt hold the summer heat," Miss Gifford says, noting that scorching rooftops can raise the overall ground temperature. The ecosystem created by a green roof cools and cleans the air.
Regarding water overflow, the District in particular has the combined sewer problem.
"The rain will fall. It will wash down the gutter where it's concentrated into a stream, which will run across the land, taking sediment and pollution down to the sewers," she says, recalling how a major storm last year left many D.C. residents "knee-deep in raw sewage" in their homes.
Contrary to some of what has been published on the subject, the East Coast might just be the area most in need of green roofs, said David J. Beattie, associate professor of ornamental horticulture at Pennsylvania State University's Green Roof Research Center.
"People say Portland [Ore.] is the hub of green-roof activity I think the mid-Atlantic region is more," Mr. Beattie says.
"We get a lot of thunderstorms and our rainfall is more evenly distributed; [the Pacific Northwest has] nine months of drizzle and 3 months of no rain."
The Penn State program's goal is to "offer hard numbers to architects and engineers," which will be valuable in promoting the green-roof concept.
The folks at D.C. Greenworks are optimistic, but must overcome "clear impediments to citywide acceptance" in the District. They say city officials are reluctant to change rigid building codes and have raised questions about incentive and cost.
"It's budgetary but also educational. They're not savvy to what this is," Miss Gifford says. "They might be a bit costly up front, but [an eco-roof] protects the life of the roof by at least twofold, so it pays for itself."
Miss Gifford cites the District's first example, viewable by appointment: Matthew Henson Earth Conservation Center, an old pump house at 2000 Half St. SW and V Street just shy of Buzzards Point. This "little blighted piece of land" soon will hold part of the Anacostia Riverwalk.
Proponents of this emerging technology continue to study the unique challenges of urban areas nationwide.
"Each bio-region is going to have certain plants that do better than others: Grasses in prairie countries do really well; in California, you want more cacti green roofs," says Miss Gifford. "We're trying to figure out what works best here and have a living example of that."

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