Philadelphia's Buried Streams

Much of Pennsylvania is webbed with creeks. This state is wet–it’s home to six major watersheds. Yet Philadelphia, despite being sandwiched between two major rivers, seems to be peculiarly dry. Historic city maps show intricate tributary networks, but in your neighborhood, can you name more than one or two smaller streams? Where is all that water coming from? Where is it going?

Map of Pennsylvanian tributaries.

The 19th and early 20th centuries were periods of growth for Philadelphia in every sense of the word. Industry had become crucial to the city’s economy. Textile and paper mills used the Schuylkill as a source of power and a fundamental step in the manufacturing process–industrial waste was dumped directly into its waters. Philadelphia’s population grew alongside its economy, and by 1900, the city was home to over one million people.

What public services were available (and there weren’t many) quickly became obsolete. Water resources were a huge part of the problem–sewer systems and drinking water stores simply could not keep up with the population boom.

It was then that hundreds of miles of urban streams were conscripted into Philadelphia’s wastewater network. These streams were buried underground in vast tunnel systems, still to this day carrying sewage and stormwater to treatment facilities and then discharged into the Schuylkill.

Mill Creek's collapse in 1952, on the 4300 block of Sansom St.

Mill Creek still runs partially above ground, originating at a spring in Merion Township. Next to the Overbrook Regional Rail station, you can see its waters disappear into a tunnel. Have you seen other disappearing creeks?

Map of buried streams in Philadelphia.