Small could be beautiful under Mayor Nutter's plan announced Tuesday to add 500 acres of parks in Philadelphia neighborhoods by greening vacant lots and paved playgrounds around schools and recreation centers.

The worthy goal of the Green 2015 plan is to have at least a swatch of parkland - grass, trees, and a few park benches, perhaps - within a 10-minute walk anywhere in the city.

How can this be achieved amid tough economic times? Not with new tax dollars, it's good to hear city officials say.

Instead, the plan developed by the city's parks and recreation commissioner, Michael DiBerardinis, smartly envisions adding parkland by maximizing government funding that's already in the pipeline, by redirecting funds now spent on vacant land management, and by seeking foundation support and cooperation from private landowners.

Among the biggest potential partners in the effort would be the city Water Department, which will have access to funding to meet federal directives limiting stormwater runoff.

Replacing paving with planted and porous surfaces will be a key strategy for taming runoff, which will pay environmental dividends by keeping polluted water from rivers and streams as well as reducing stormwater backups that flood homeowners' basements.

With more than 9,000 acres in Fairmount Park, it may be hard to believe that any neighborhood is more than a short walk from the park's natural wonders.

But a report prepared for DiBerardinis by consultants at Penn Praxis identified five areas populated by more than 200,000 people where there's far more paving than parks. These areas will be targeted first.

The plan found that there are thousands of acres with green potential across the city. This land can be found alongside rivers, creeks, trails, and miles and miles of vacant rail beds - notably, the Reading Viaduct - and active rights of way.

Were these areas to be transformed into greenways, they could become signature settings that could spur economic development as well as enhance city residents' overall quality of life.

A central challenge for Nutter and his aides at every step of the way will be to assure that any new parkland will be maintained in the coming years.

While there's little regular maintenance needed for asphalt-paved playgrounds, every tract of grass, shrubs, and trees must be tended - as is all too evident in sometimes neglected parts of Fairmount Park.

Even in thinking small about adding parkland, making the plans to look after those new green spaces will be a big deal.