Bronx River Now Flows by Parks A River Recovering: The Bronx River was once among the most polluted waterways in America. Now a new generation is discovering and helping to save it. Michael Kimmelman, architecture critic, tours the river. PERHAPS the most unsung patch of heaven in New York City is a tiny sliver of riverfront parkland tucked between a metal-recycling yard and a giant wholesale produce market, on the far side of a six-lane highway and a pair of active freight train tracks. Hunts Point Riverside Park, a 1.4-acre speck in the South Bronx, opened a few years ago on what had been a filthy, weedy street end. A garden path now winds from the front gate past rose bushes and flowering butterfly bushes, beyond a sprinkling fountain and shaded benches under a flowered trellis, to a pier on the Bronx River. Save for a couple of brick apartment towers rising over the treetops, the view is green across the river. Herons and egrets silently roam the riverbank. The other afternoon teenagers from Rocking the Boat, a neighborhood organization that teaches boatbuilding, sailing and environmental restoration, were lugging rowboats to the muddy shore and launching themselves into the river. Jason Feldman, in tie and shirt sleeves, having trekked from his office at a heat exchange plant up the block, was on his way out of the park, after eating lunch at one of the wooden picnic tables. "I come here all the time," he said. It's incredible, no? For years one of the most blighted, abused waterways in the country, the southern end of the Bronx River has been slowly coming back and with it the shoreline that meanders through the South Bronx. Next year, barring further delays, what looks to be an innovative work of green architecture, by the Brooklyn firm Kiss & Cathcart, is slated to open in Starlight Park, a green stretch upriver from Hunts Point Riverside. This summer at the mouth of the river another street-end pocket park, Hunts Point Landing, is opening between a Sanitation Department depot and a food processing plant. The New York waterfront is changing perhaps more than any other part of the city. For centuries the interests of big money and industry shaped it. These days, notwithstanding dogged efforts by the Economic Development Corporation to kindle development business along the waterfronts of Sunset Park in Brooklyn and on Staten Island, the city's old industrial waterfront is in many places giving way to parks and luxury apartment towers where money still talks, like along the Hudson. But compared with headline-making projects in Manhattan and Brooklyn, the unexpected renaissance under way along the south end of the Bronx River flies largely below the radar. Park by park a patchwork of green spaces has been taking shape, the consequence of decades of grinding, grass-roots, community-driven efforts. For the environmentalists, educators, politicians, architects and landscape designers involved, the idea has not just been to revitalize a befouled waterway and create new public spaces. It has been to invest Bronx residents, for generations alienated from the water, in the beauty and upkeep of their local river. The transformation has involved an alphabet soup of public entities and local organizations like Rocking the Boat, Sustainable South Bronx, Youth Ministries for Peace and Justice, Partnership for Parks and the Bronx River Alliance. The Bloomberg administration has made the project a special priority. The South Bronx illustrates how government, although it can be obstructionist and infuriating, is also indispensable to urban improvement. Different federal administrations have mandated cooperation by often competing agencies. Dozens of community groups have subordinated their own pet interests to cleaning the river and creating parks. The results aren't complete or perfect, far from it. The new parks are still piecemeal and disconnected, plagued by good intentions, half-measures and bureaucratic foul-ups. Boat launches don't work; green spaces aren't always kept clean; sites are created without adequate programming. Progress is painfully slow. Still, what's happened, under the circumstances, is hardly short of miraculous.