Washington, DC wants $10 million from the EPA to place grass on rooftops to reduce stormwater runoff.
The Washington Post reports,
DC Water’s general manager, George Hawkins, asked the EPA’s permission to spend $10 million to place grass on rooftops, put flower gardens at curbsides, and lay sidewalks made of porous stone along the Potomac River leading into Georgetown and neighborhoods in the Piney Branch area.
Several cities moved forward with major green projects some time ago. An aerial view of a neighborhood in Philadelphia, for example, shows carpets of green across building tops, and in Portland, water authority officials claim that street planters, rain gardens and permeable pavement soaked up 60 percent of storm-water runoff.
Count us as skeptical. You generally want water off rooftops, not on them. Trying to capture water sounds like a great way to have more standing water and, possibly disease-bearing mosquitoes. Then there’s the initial cost and maintenance. Goofy green ideas are not a substitute for competent civil engineering.
It’s actually not a bad idea if you can get something out of it. The enjoyment that can come from a rooftop vista or rose garden can be worth the cost.
As for stormwater, those numbers are ridiculous. Open ground doesn’t absorb that much, much less shallow flower boxes or cracked concrete. Besides, runoff isn’t a problem. The only problem is if you don’t maintain your sanitary sewer, but the permeable concrete will make that problem worse.
In the City of Vancouver, there is an entire industry devoted to the maintenance of rooftop landscapes, including mowing.
One of the NORAHG contributors lives right across from John Travolta’s two-storey summit apartment with a landscaped garden and forty-foot shade tree.
Who provides the labor for keeping these rooftop lawns “cut?” We all know Yard Work is one of those jobs “Americans won’t do!” 😉