During the course of Philadelphia’s development in the 19th
and 20th centuries, the majority of the city’s streams were diverted into pipes--their
valleys leveled with millions of yards of fill and overlaid with a grid of streets.
These pipes were designed as combined sewers, carrying the stream flow, raw sewage
and stormwater runoff.
Wingohocking Creek Combined Sewer under construction, 1909
At the time, the use of streams for sewage disposal was standard practice. Stream
pollution and its deleterious effect on the public’s health, however, triggered
the piping of these streams. Furthermore, the piping, filling, and development on
top of the streams created a more convenient terrain for developers to build. Fundamentally,
the city decided that by diverting the streams into pipes they were taking a positive
step towards the protection of the public’s health.
Out of the 265 stream miles
that once existed in Philadelphia, only 71 (27%) miles remain. 194 (73%) of our
“historic” streams have been piped to date. It was not until the early 20th century
that city planners realized the negative impacts of piping streams and the benefits
of creating parks in stream valleys. Historical Progression of the piping of streams
and the benefits of creating parks in stream valleys.
Historical Progression of the piping of streams (click on image to view larger version)