D.C.

Researchers install environmentally-friendly 'green roofs' in D.C.

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(WJLA) - Here at D.C.’s Engine Company 7, researchers at American University are more concerned about what’s sitting on top of its roof.

Through a grant that started with the National Fish and Wildlife Foundation, they were able to install these green roofs at its fire stations to study the ecological impact and energy savings they could provide.

A fire station can be an ideal place to observe this, because it’s a two-story building with a ground story that’s a garage, and a second story that’s a dormitory which is heavily cooled in a building that is otherwise not so well-insulated.

So how exactly does this work?

Well, the pans underneath collect rain water – in both planted and unplanted roof panels – using a new type of foam technology instead of soil to help absorb the water, which later becomes a backup reservoir for the plants. When the water evaporates from these panels, it drops the temperature on the floor beneath it up to 40 degrees.

Results at another fire station have already showed that green roofs have helped save 5-percent in electric usage over the course of a year. But so far, that foam technology has also provided that it can take up to 50 to 60-percent of dirt from entering the river.

Researchers say the plants use about 80-percent of the nitrogen that comes in runoff, which ends up killing fish and oysters.

“Nitrogen causes algae blooms in the bay and the rivers around here, which end up sucking the oxygen out of the water, so anything that needs oxygen is in real trouble,” explains American University Professor Stephen MacAvoy.

The hope is that by going green, D.C. will not only save money in the future, but also help save the city’s waterways at the same time.

D.C. eventually wants to make the Anacostia River fishable and swimmable in the next 18 years – it’s one of the 10 most polluted rivers in the country, so retaining nutrients and suspending solids before they get in the river will be the way to do it.

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