Distillations: Science + Culture + History

Philadelphia just had the wettest decade on record, and all that precipitation has wreaked havoc on the city’s waterways. Like most old cities, Philadelphia has a combined sewer system—that is, one pipe is used to carry both sewage and stormwater. When it rains a lot, the system gets overwhelmed, forcing the water department to send raw sewage into rivers and creeks. City officials and engineers knew this was going to be a problem when they built the sewer system in the 1800s. The reason why they used a combined system anyway can be best explained by two forces: knowledge ceilings and path dependency. In this episode we’re going to explore how the city got to this point and how, in an interesting twist, it led to Philadelphia having one of the most innovative water systems in the country.    Philadelphia is home of the Distillations podcast. For this episode we are going to break down three centuries of water-pollution history in our backyard. It is a special collaboration with the Philadelphia Inquirer as pa