Cathedral Run Constructed Wetland


The Philadelphia Water Department and the Fairmount Park Commission are working together to design a stormwater treatment wetland at the headwaters of Cathedral Run. Cathedral Run is a small first order tributary to the Wissahickon Creek. The stream originates from springs downstream of Courtesy Stables and then travels approximately 2,500 feet through a wooded section of Fairmount Park before entering Wissahickon Creek. The stream is relatively steep with an average gradient of 8.5%; however, the downstream half of the tributary is visibly steeper than the upstream reach. It is therefore more at risk of erosion.

The project features a diversion structure from the adjacent storm sewer system. The diverter will redirect some stormwater runoff from the storm sewer system into the wetland, which can store 94,445 cubic feet of water. The collected runoff will enhance wetland conditions and create valuable meadow habitat. In addition to capturing sediment from the horse stables nearby, the wetland’s vegetation will also filter pollutants from the runoff, preventing nutrients and other contaminants from entering Cathedral Run and the Wissahickon Creek.

Construction is scheduled to begin in Spring 2010, and the project is expected to be completed in August 2010.


County: Philadelphia
Watershed: Wissahickon Creek


Fairmount Park Commission
Philadelphia Water Department


Total: $440,000 (90,000 for design/$350,000 for construction)


Philadelphia Water Department
1101 Market Street, 4th Floor
Philadelphia PA 19107

Aerial View of Restoration Site

Site Plan 

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