Chew Avenue
Philadelphia, PA 19138

Rain Garden/Bioswale

The stormwater demonstration project at Cliveden Park captures runoff from adjacent streets and uses the park’s natural topography to detain stormwater before it flows into the combined sewer system. Small upland depressions provide water quality treatment and some infiltration of stormwater, and a modified outlet structure allows water to pond in the existing wetland before it is slowly released. The system provides stormwater volume removal through evapotranspiration and infiltration, and reduces the flow rate to the combined sewer system during the small, frequent storms that cause the majority of combined sewer overflows. The project meets stormwater management objectives, enhances the existing wetland in the park, and is also an amenity for the park community.

The design team worked closely with Friends of Cliveden Park to refine the design within the project constraints, which included budget limitations, permitting restrictions, community design considerations, historic and cultural landscape considerations and existing park conditions. In addition to design funds from PWD and implementation funds from the Pennsylvania DEP, Friends of Cliveden Park received a grant from Bank of America that was used to install a new pedestrian access and overlook to the project site.


  • Reduced combined sewer overflows through volume reduction and flow attenuation
  • Stormwater filtration and water quality treatment
  • Wetland and park enhancement