Battery Park City — One in ten.

That's the proportion of children in central Harlem who have been put in foster care, living in someone else's house because the courts have decided that their own parents are unfit to care for them. In 1997, it amounted to more than 3,000 children in that one neighborhood alone.

It's an appalling statistic, but not an isolated one. In other parts of the city--all of them poor, and overwhelmingly African-American and Latino--a sizeable number of children have been removed from their homes by the city's Administration for Children's Services. In Morrisania, it's one in 12. In Mott Haven and Hunts Point, Bed-Stuy and Brownsville, about 6 percent of all the neighborhood's kids have been uprooted and sent to a new home, which could be anywhere in the city or even outside of it. Just 12 percent of children citywide are in foster care in the neighborhood they came from.

These children have literally been taken away, not just removed from their parents but ripped out of a neighborhood, an entire world. What they get is a new routine that often requires weekly visits to a foster care agency's headquarters, an alien place that may be downtown, in another borough or outside city lines. Doctors and therapists, usually part of this new regime, call for other trips to other strange places. When foster children do see their parents again, it's for short supervised visits in an office-turned-playroom at the child welfare agency.

That's all about to change. Starting in June, New York's 33,000 foster children are supposed to be able to leave their families without leaving home. In this ambitious overhaul of the child welfare system, ACS has asked about 60 private, nonprofit child welfare agencies to transform themselves from centralized bureaucracies into institutions that are a deep and integral part of neighborhood life, as much a part of the local fabric as schools, firehouses and police precincts.

Under the new system, distressed families will be able to turn to child welfare centers within walking or bus distance from their homes, where they will get help coping, through counseling, classes and a place for the kids to go when their parents need a break. If ACS decides children must be put in foster care for their own safety, those same centers become their one-stop shops for counseling, medical care and visits with their parents. Parents, too, will have local access to services like drug treatment and parenting classes that they must attend in order to get their kids back, making it more likely they'll actually go.

And in the vision of ACS Commissioner Nicholas Scoppetta, the glue holding everything together is the neighborhood itself: the neighbors, teachers, clergy and shopkeepers who know a family, are familiar with its problems and can help ACS cook up a remedy. No longer will protecting children be a mere government service; now, it's a community's obligation to itself.

This radical plan is that rare thing in the child welfare world: something almost everyone, from parents' rights advocates to Mayor Giuliani, agrees is a good idea. Its principles were devised not by bureaucrats but child welfare experts from the Annie E. Casey Foundation. Los Angeles, Cleveland and other cities have already made these ideas work.

But for child welfare to succeed as a neighborhood business in New York, children are going to have to find foster homes nearby. As ACS officials are fond of saying, kids from Mott Haven will no longer end up in Woodhaven. That also means that child welfare workers in Mott Haven will have to find many new foster parents willing and able to do the job.