We are working 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 will consist 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 will hold stormwater until it can be slowly released into the sewer system.
• The project will manage stormwater runoff from approximately seven acres of impervious area.
• These green stormwater infrastructure improvements will improve our sewer system capacity and reduce combined sewer overflows.

Construction Updates*

• Completed regrading of the site and installation of hardscaping and boulders for dry stream bed before a pause in construction over winter. 
• Construction restarted in May 2022. 
• Landscaping and site planting are expected in Spring/Summer 2022. 

*Schedule could change due to weather, unforeseen site conditions, etc.

Partnership

• Chatham University and PWSA are collaborating to design, construct, and maintain this project. 
• Project construction will be 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 will be performed through a cooperative agreement between Chatham University and PWSA.
• This project is partially funded by ALCOSAN’s GROW grant program.

Additional Information

• Project Poster