STARTING tomorrow, children who attend or live near William Dick Elementary School, in North Philadelphia, will have a new playground, with more green space added to what used to be mostly asphalt.

The massive, 2-acre schoolyard, on Diamond Street near 24th, "has evolved from a totally empty, broken concrete slab" into an oasis, with new trees, new asphalt and a lush rain garden, said principal Amy L. Williams.

Two years ago, a group of sixth-, seventh- and eighth-graders at the school teamed up with designers and engineers, in a project organized by the Trust for Public Land, to plan the improvements.

The students helped to decide where a new playground structure would go, where maple trees should be planted and which plants would attract birds and butterflies to the new rain garden, installed against a back fence.

The rain garden eliminated 10,000 square feet of asphalt.

"I suggested we needed places to just sit and rest," said Aziza Pressley, 14, now an eighth-grader, who talked about his ideas for benches near the new trees.

"I thought of the spinning cups," said Keirra Richards, 13, pointing to red buckets in the new play area.

There are spaces for kickball and basketball, and a new turf field area that now has proper drainage after puddles had collected on the old one.

During the school year, the playground will provide outdoor classrooms where pupils can learn how the rain garden benefits the community by improving water quality. A map of the United States will be painted outside, Williams said.

The first playground improvements at William Dick came in 2007, when the Philadelphia Eagles added a playground structure and the Mural Arts Program painted murals on a back fence and around the school.

But the rest of the school was still barren, without trees or natural greenery. The broken asphalt was unpleasant to look at and posed a hazard.

"You could pick pieces up and throw it, so it was dangerous," said Danielle Denk, program manager for the Trust for Public Land, a national group that works to conserve land for parks, gardens and other natural places.

William Dick is the first of 10 playground or rec-center renovations planned to meet Mayor Nutter's goal of creating 500 new acres of public green space by 2015, said Deputy Mayor Michael DiBerardinis, head of the city's Parks and Recreation Department.

Nutter's goal, announced in his 2008 inaugural address, is to provide green space within a 10-minute walk of about 75 percent of the city's residents.

"The priority was to bring green space and high-quality recreation space to neighborhoods that didn't have access to it," DiBerardinis said.

The Trust for Public Land teamed with the city to help achieve that goal.

"The Trust for Public Land believes that parks help improve the environmental health of communities and the physical health of their citizens," said Jeff Danter, a vice president of the trust.

"People who live near a well-developed park are more likely to be healthy."

The changes also will help to keep storm water from flooding the city's drainage pipes, which can lead to sewer backups, polluted drinking water and flooded basements.

The William Dick playground will be open to the public in the evenings, on weekends and over the summer, and will function as a community park.

"It was a barren area that has really come to life with greenery that is not common in an inner-city playground," said Williams, the principal. "It's something for our entire community."