We worked with Chatham University to coordinate this project as a priority to improve the performance of our combined sewer system in the A-22 sewershed. 

During periods of intense rainfall, this sewershed has experienced sewer system surcharging and frequent basement sewage backups. Green infrastructure has been prioritized as a cost-effective strategy to increase existing system capacity and reduce the risk of flooding.

This project is located near the headwaters of a historic stream named Two Mile Run, which was routed underground into sewer pipes to flow to the Allegheny River. 

Project Details

• The dry stream bed consists of a channel lined with stones, engineered soil, and plants, all designed to mimic a natural stream’s headwaters and manage stormwater.
• Modular underground storage tanks hold stormwater until it can be slowly released into the sewer system.
• The project manages stormwater runoff from approximately seven acres of impervious area.
• These green stormwater infrastructure improvements help improve our sewer system capacity and reduce combined sewer overflows.

Partnership

• Chatham University and PWSA are collaborating to design, construct, and maintain this project. 
• Project construction was funded as a cost-share, with PWSA funding construction costs related to stormwater management and Chatham University funding construction costs not related to stormwater management, such as additional landscaping and surface amenities.
• Maintenance is performed through a cooperative agreement between Chatham University and PWSA. Chatham University will maintain the surface components (storm inlets, landscape maintenance, litter removal). PWSA will inspect and maintain the piping and underground stormwater storage systems.
• This project is partially funded by ALCOSAN’s GROW grant program.

Additional Information

• Stormwater Series Video: Chatham University Stormwater Project
• Project Poster