Local BP station sets good example with 'green' roofs

Environmental move lessens the runoff of storm water

Critical Eye

June 24, 2007|By Edward Gunts | Edward Gunts,Sun Architecture Critic

LIKE MUCH OF AMERICA, MARYLAND IS GOING "green," with green houses, green schools and green libraries. But a green gas station? Isn't that a contradiction in terms?

Even as customers fuel their gas guzzlers, a new BP station near downtown Baltimore aims, through its design, to be more friendly to nature.

From the road, the gas station looks deceptively conventional -- with six pumps, a convenience store and a car wash. What sets it apart is that the store and the car wash have "living roofs": soil and vegetation that keep rainwater from running into storm drains and ultimately into Baltimore's harbor, carrying the pollutants and toxins of the city with it.

The BP station opened this spring at 1465 Key Highway, the first business on the road's $13.8 million, quarter-mile extension deeper into Locust Point. Its owners say it's the first BP station in the United States to feature living roofs, and one of the first gas stations associated with any company to do so.

With more than 1,000 stations east of the Rockies and a slogan of "Beyond Petroleum," BP promotes itself as a leader in renewable and clean energy production. It's one of the largest producers of solar energy systems worldwide and an investor in wind farms in the U.S. and other countries.

But the idea of building a green gas station in Baltimore came from the local owner, Eastern Petroleum of Annapolis, and its chairman, J. Kent McNew.

Founded in 1969, Eastern sells motor fuels to more than 200 gas stations and marinas throughout the Baltimore-Washington area. McNew is a member of the Chesapeake Bay Foundation and the South River Federation, two organizations with a record of environmental activism.

McNew said he thought the Key Highway station, close to Baltimore's harbor and along a prominent approach to downtown, would be an ideal spot to set an example. "If we don't all do something for the environment," he says, "we're all in trouble."

The gas station occupies slightly more than an acre along Key Highway. The two green roofs cover 5,500 square feet of space, or about one-eighth of the total ground surface.

A simple system

The station was designed by Morris and Ritchie Associates of Abingdon, with masonry walls for the enclosed structures and BP's green and yellow graphics throughout. For the eco-friendly aspects of the project, McNew turned to Michael Furbish of Furbish Co., an expert in green roofs and other forms of "sustainable building."

Furbish devised a way to cover the two roofs with sedum plants and other materials that absorb rainwater, so less runs onto the pavement below than with non-living roofs.

Furbish spread 3 to 5 inches of "engineered soil," also called "growth media," over the conventional membrane roofs. He then seeded the soil with plants that become the living roofs, including Sedum album, Sedum kamtschaticum, Sedum reflexum, Sedum sexangulare and Sedum spurium 'Fuldaglut.'

The plants grow 4 to 8 inches tall and reach maturity after a year or so. Furbish said he has had to weed the roofs and water them during dry spells, as with a start-up lawn, but eventually they won't need much tending other than an occasional pruning. The living roofs cost about $42,000, out of a total budget of $3 million.

"It's a pretty simple system," Furbish said. "The irony of many environmentally-friendly design solutions is that they're low technology, not high technology. There's an elegant simplicity to so many aspects of green building."

According to city planners and others, the main benefit of this vegetated cover is that it provides "on-site storm water management." That means the roofs, once mature, will absorb about 65 percent of the rainwater that otherwise would run into storm drains. The water that is discharged from the roof does so slowly over an extended period, helping to cut down on storm drain surges that can harm marine life in the harbor.

Living roofs also help insulate buildings, reducing heating and cooling loads; extend the life of the roof membrane, which is not exposed to the weather; create habitats for birds; help improve air quality by giving off oxygen; and help break up the "heat island" effect in urban areas -- the retention of heat by manmade materials such as concrete and asphalt.

Saving 'offset fees'

But construction of the living roofs is not an entirely altruistic gesture. Baltimore and Maryland have regulations that encourage businesses to contain rainwater on their properties, rather than allowing it to run off-site. If they can't keep the water on their own land, owners must pay "offset fees" to the municipality that has to filter and treat what runs into storm drains. By creating living roofs that keep more water on site, Eastern Petroleum doesn't have to pay offset fees. The amount saved, in turn, helps pay to install the vegetated roofs.

City officials endorse the initiative as environmentally sound.

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