Green on top-‘Ecoroofs’ cleanse water, cool homes and save money

When Chris Moehling wants to show off the new garden at the youth hostel he manages, he steps out a second-story bedroom window onto a roof blooming with plants.

By GILLIAN FLACCUS Associated Press

The 650-square-foot garden of scrubby succulents and yellow marigolds grows right out of the roof, above the busy street and is visible to the hundreds of shoppers and motorists who pass below.

"We get people walking in from the street asking all kinds of questions," said Moehling. "This is one of the more visible streets in town. People really get a kick out of it."

The hostel’s plantings are the latest in a string of green spaces flourishing on Portland’s roofs in place of traditional shingles and tar – and the trend is no coincidence.

The city has emerged as an international leader in the budding "ecoroof" movement. Portland has boosted its reputation by enacting recent city regulations that offer breaks to developers who install green roofs and by officials who aggressively promote rooftop planting.

Living roofs, long common in Germany, Holland and Switzerland, can reduce runoff after rainstorms by up to 90 percent, slash a building’s energy costs by 10 percent and reduce summer temperatures on scorching city rooftops by about 70 degrees, experts say.

They also delay the runoff after a major storm by several hours, preventing flooding and sewage problems that occur when a city’s stormwater system overflows.

And the gardens filter pollutants and heavy metals from rainwater and cool the excess water before it enters streams and threatens sensitive aquatic species, such as salmon in the Pacific Northwest.

"Once a person sees all the things that an ecoroof can do, it’s almost dumb not to plant them," said Tom Liptan, an environmental specialist for the city. "I expect we’ll see a lot more."

Portland isn’t the only city to plant gardens on its skyline.

A handful of other cities, including Chicago, Toronto and Seattle, have grown gardens on their city halls and courthouses and Atlanta plans to follow suit. Ford Motor Co. will finish a 10.6-acre living roof on its Dearborn Truck Plant in Dearborn, Mich., next year and county buildings in Anne Arundel County, Md. have recently sprouted grassy tops.

What sets Portland apart, experts say, is the city’s financial commitment to ecoroofs in the form of tax breaks, grants and building codes and the range of buildings – both public and private – that sport rooftop gardens.

"If you look at it on the surface, offering economic incentives makes a lot of sense," said David Beattie, director of the Center for Green Roof Research at Pennsylvania State University.

"We have to drag people to the table, so having economic incentives such as you have in Portland is the way to do it."

Portland took the lead in the tiny, but growing, green roof movement nearly two years ago, when it approved a regulation that allows developers to expand their building plans if those plans include an ecoroof. Experts say Portland is the only city in North America to offer such an incentive; it also waives certain code requirements for those with green roofs.

In the future, Portland may create zoning that encourages ecoroofs or offer significant discounts on stormwater fees for people who cultivate their rooftops, said Dean Marriott, Portland’s director of environmental services.

"I’ve just been talking this up to anyone who will listen," he said. "We’re trying to get public and private examples of ecoroofs in the community and we’re trying to use all the incentives that we can think of."

Portland hopes green roofs will help end the severe and recurring sewage overflows that pour into the Columbia and Willamette rivers after nearly every heavy rainstorm by reducing the amount of water runoff. The runoff floods the system, forcing raw sewage into nearby rivers.

Under federal mandate, the city must correct the problem by 2011.

Portland has made government incentives for green roofs a priority because of the technology’s cost. Green roofs cost about two times more than regular roofs to install – between $10 to $15 per square foot – and require extensive research and planning.

Financial support from the government is key to convincing companies and individuals to install ecoroofs, said Ireen Wieditz, director of the Toronto-based Green Roofs for Healthy Cities.

"There’s always a lot of interest, but I think it’s still new to a lot of people," she said. "People seem to love the idea and are really embracing it, but we just need the government to support it."

Faced with crowding, runoff and pollution problems, some German cities require new flat roofs to be green roofs while others require residents to pay taxes based on the percentage of paved surface they own.

As a result, one out of seven German roofs are green; in some cities, one-quarter of buildings have ecoroofs, said Beattie, the Penn State professor.

"Man has an amazing capacity to dirty his own nest and the Germans have done it before we did," he said. "They simply faced the problem before we did."

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