The High Line hoopla has overshadowed the protracted birth of Manhattan’s other new green strip: Hudson River Park. One block west of Chelsea’s new attraction, the park technically extends only from Battery Park City to 59th Street, but a just-opened section of greenway to the north connects to Riverside Park, which means that the linear idyll effectively runs clear up to the Little Red Lighthouse beneath the George Washington Bridge. Even during its decade-long gestation, the chain of parks and piers has gradually forged a new bond between New Yorkers and their waterfront. Benches have proliferated. Landscapers have created a series of linked ecosystems. In the wider sections, walkways split off from bike paths. Lounge-able lawns alternate with little patches of wetland, playgrounds, and arbors. It’s hard to remember when you’re pedaling alongside the embankment or jogging on freshly laid boardwalk that zags out over the water toward New Jersey, or reading a book with shades on because the sunlight glints off the waves, that not long ago most of the riverfront was grim or menacing or inaccessible. The park has brought a different class of dangers that stem from turf battles among speeding cyclists, doublewide strollers, and indecisive dogs. But those are tolerable frustrations, the wages of development driven not by profit but by that old-fashioned value, the public good.