Research Hints
See Update Below

I receive many requests, both from within the Philadelphia Water Department and (via the Internet) from people far and wide, for tips on how to research the historical topography of a particular neighborhood. People seem especially interested in discovering evidence of any streams that may have been piped underground in the vicinity of their property.

Often, hints can be gleaned from the existing topography. If a street enters what seems to be a valley, that can sometimes mean that a stream once flowed in that valley. Libraries, historical societies, county offices, etc. can be a good source for real copies of old maps that will help identify the original stream patterns before they were obliterated by development. In many urban and suburban areas, detailed atlases were done on a block-by-block basis, which locate not only streams but individual house lots, sewer lines, water pipes, etc. Generally, the earlier the map or atlas, the more of the original topography it will show.

For anyone interested in getting their hands on real (as opposed to digital) maps of the Philadelphia area, I recommend starting such research at the Free Library of Philadelphia Map Collection, located on the second floor of the main library at 1901 Vine Street. Besides the most complete and most accessible collection of Philadelphia atlases this side of the Library of Congress, many old atlases of adjacent suburban counties are available for perusal as well. A volume of particular interest to Philadelphia residents is a set of historic stream maps created by City engineers in the 1930s. The head of the collection, Richard Boardman, is friendly, helpful, and (most important) extremely knowledgeable. He and his staff can be reached at (215) 686-5397. Please tell them I sent you!

UPDATE 1-13-2013

The "Interactive Maps Viewer" at the Athenaeum of Philadelphia's Philadelphia Geohistory Network is the best online source of information for this type of research. While these map layers will give a good idea of the approximate location of the former routes of now-hidden streams, they should not be relied on for exact locations of such streams. Many of the maps from the Free Library Collection are on the Geohistory site. The Free Library has also created its own mirror site for old maps, which can also be consulted.

The History of Philadelphia's Watersheds and Sewers

Compiled by Adam Levine
Historical Consultant
Philadelphia Water Department
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