Changing Skyline: Attacking asphalt

No matter how many times we've heard Philadelphia described as William Penn's "greene countrie towne," we know the reality is rather different. Cities are cities because once-verdant land is relentlessly paved and covered over time. That's how we civilize our world.

It's also how we mess it up.

Every time the skies let forth a deluge, as they did with particular intensity this week, the city's asphalt-sealed streets and parking lots become churning torrents. The rain cascades to the nearest sewer outlet, picking up salts and oils along the way and overwhelming the underground system. As in many of America's older cities, Philadelphia's treatment facilities are incapable of handling the watery rush hour, so the overflow is released into the Delaware River, sewage and all.

The Philadelphia Water Department has been struggling for years to solve what it delicately calls "the overflow problem." One approach is to get people to consume less water, so less goes down the drain. No wonder the agency cheered a few years ago when Comcast announced it was bucking the powerful plumbers union and installing waterless urinals in its new skyscraper.

But reducing runoff from storms may be even trickier than negotiating with the well-connected plumbers. You can't simply unpave a city.

You can only try.

On June 26, the appropriately named Greenfield School will take a leap into a green new world when it begins ripping out its asphalt schoolyard as part of a Water Department pilot project. The hot, noisy, hard-surfaced schoolyard has been a staple of urban childhood, the scene of countless rounds of Double Dutch and tag. Now, the Water Department believes, it's time for the asphalt to go.

In its place, Greenfield, a public elementary school at 22d and Chestnut Streets, will plant a wide border around the perimeter of its schoolyard, nearly equal to half the playground's total surface. The green areas are designed to let rain percolate gently into the ground, cutting the schoolyard's contribution to the city's overflow problem by more than 80 percent.

Don't worry. Greenfield won't have to ban recess to help save the environment. The new schoolyard design - a joint effort by SMP Architects, Viridian Landscape Studio, and Meliora Environmental Design - reserves an island of asphalt in the center so kids can play basketball and other games. The remaining play areas will be resurfaced with a rubbery, porous material that absorbs runoff.

'Greening Greenfield'