Pittsburgh exists for three reasons: the Allegheny, Monongahela and Ohio. In the 20th century, the banks of those rivers were controlled by industrial behemoths. They largely lost that identity after the waning of the steel industry in the 1980s. Over the last two decades, however, the city’s progress in clearing and cleaning its waterfront has created 12 miles of recreational trails, three professional sports stadiums, several boat landings and an influx of nearly 2,000 new downtown residents. The city has managed to leverage a $124 million investment in publicly accessible riverfront into $4 billion in corporate, public, nonprofit and entertainment development downtown. That success has renewed a debate that would have been unthinkable in Pittsburgh’s polluted industrial heyday: how best to expand public access to the shorelines of the three rivers. Projects proposed for two of the largest tracts left to be developed on the downtown fringe illustrate the opportunities and limits of public-private partnerships.