For decades, planners and residents in Philadelphia—the East Coast’s second most populous city and a historic treasure—have been considering how to expand public access to waterfront parks now cut off by Interstate 95. But in fulfilling a master plan for redeveloping the Delaware River waterfront, the city must contend with the surprising challenge of tidal flooding.
Although Philadelphia is not directly on the coast, it is vulnerable to coastal flooding because tides affect the Delaware and Schuylkill Rivers, which surround the city. During the full moon in June 2012, for example, high tides caused widespread flooding along the Delaware.
By 2045, Philadelphia is projected to face more than 200 tidal floods a year—nearly 20 of them more extensive than the tidal flooding typically seen today. With officials aware of the threats of sea level rise and coastal flooding, the city’s master plan for the waterfront includes the creation of wetlands to help protect Philadelphia from the encroaching sea.