New canopy for the asphalt jungle

Part of the solution to pollution and flooding from D.C. storm-water runoff is up on the roof, according to a new report.

As much as 10 percent of the water that now gets funneled into sewers and rivers around the District could be absorbed on roofs of buildings if more owners plant vegetation on them, according to the study released yesterday by the American Society of Landscape Architects (ASLA) in conjunction with Howard University.

"Both green roofs and trees decrease the volume of runoff, reduce rates of runoff and improve water quality," ASLA said in its report.

Green roofs refer to buildings with plants on top of them to provide insulation and capture rainwater.

Washington is running a close second to Chicago as the city with the largest amount of green roof space.

The District had at least 301,751 square feet covered by green roofs in 2006, according to the environmental group Green Roofs for Healthy Cities. Chicago had at least 358,774 square feet of green roofs last year.

"They were the innovators," said Jim Lapides, ASLA spokesman.

Chicago urban planners started promoting green roofs after a July 1995 heat wave that filled city morgues with the bodies of 525 mostly elderly persons who succumbed to triple-digit temperatures.

more from the Washington (DC) Times