Tredyffrin Township Green Streets/Sidewalks


Tredyffrin Township’s Green Streets/Sidewalks incorporated several innovative stormwater management measures, also known as Best Management Practices (BMPs), which are designed to manage stormwater runoff produced by the installation of sidewalks, as well as manage some additional roadway runoff currently affecting the area. The Stormwater BMPs consist of shallow infiltration trenches underneath the proposed sidewalk and in several vegetated curbed bump-out areas along the proposed sidewalk route. Additional storm sewer inlets were placed along the roadway shoulder in coordination with underground piping throughout the infiltration trenches, which will direct remaining stormwater to the existing storm sewer system.

The project included a variety of measures that will allow for safer pedestrian travel, as well as aid in further control of vehicular traffic. Along the sidewalk route, pedestrian crosswalks were provided at each roadway crossing. Additional pedestrian crossing signage will be provided at crosswalk locations. In addition, two (2) raised pedestrian crosswalks were installed on Old Lancaster Road. On Conestoga Road between Irish Road and Old Lancaster Road shoulders, signage, and lane striping were provided to control and calm traffic flow through the curve. The Township and Consultant Team also invested revisions to the existing PennDOT school zone permits to further define and clarify the school zone limits. PennDOT did not allow the Township to make any changes to the school zones.

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Lessons Learned
Keep plant palette relatively simple when homeowners are responsible for maintenance. Ensure that curb cuts into vegetated curb extensions are located at the right locations and that there are enough of them to “feed” the curb extensions in a distributed manner. Ensure that curb cuts into vegetated curb extensions are stabilized; consider a stone channel along the likely flow path(s). Consider filter inserts as pretreatment for inlets draining into infiltration trenches. Consider sediment forebays in vegetated curb extensions.


County: Chester County
Watershed: Darby-Cobbs Creek


Tredyffrin Township
Jacobs Engineering Group
Campbell Thomas & Co.
Brenton Associates




Daniel Wible
CH2M HILL, Water Resources Engineer
1717 Arch Street
Suite 4400
Philadelphia, PA 19103
Phone: 215-640-9110

Stephen Burgo
Township Engineer, Tredyffrin Township

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