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Hastie Road Subsystem Rehabilitation and Canal Street Sanitary Sewer Improvement Projects
Community Involved: Borough of Castle Shannon
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Sanitary sewer trench backfill along Canal Street |
Project goal: To convert the existing sanitary sewer system to a storm sewer while constructing a new sanitary sewer system. A pump station was used to further separate this sewer from an overloaded trunk sewer. This has eliminated basement backups into residences.
Project Summary: This project included the construction of a new sanitary sewer parallel to the existing line and the conversion of the existing sanitary sewer to a neighborhood type underdrain system (Hastie Road); and the construction of a pump station and the installation of a collector sewer to serve 8 homes (Canal Street).
Total Cost: $283,491
3 Rivers Wet Weather Grant Award: $137,500
Start Date: October 2000
Completion Date: July 2002
Project Progress: This project is complete.
Final Project Report: The Hastie Road Sewer Replacement specifically addressed infiltration/inflow source removal. Most projects (locally and nationally) have focused on attempts to reduce the excess flows by sealing the sanitary sewers, and by searching and removing illegal storm connections. These methods have been generally unsuccessful in terms of reducing bypass and basement flooding, primarily because there was no proactive component designed to relieve the water that is always present under the ground surface, and inevitably, after rehabilitation was complete, found new points of entry into the system.
The parallel sewer system alternative for Hastie Road involved converting the existing system to a localized underdrain system. The existing sewer material was VCP that leaked and permitted groundwater infiltration and stormwater inflow to enter the sanitary sewer system. Once the new sanitary sewer line and new service laterals were constructed, the existing sewer was converted to an underdrain system to continue to collect I/I. Downspouts and other drains that were previously “illegal connections” in the sanitary sewer remained connected to the underdrain system. The underdrain system was disinfected and connected into the existing storm sewer. This provides the neighborhood residents a means to drain water without flooding neighbors or their own properties. In terms of inflow/infiltration removal effectiveness, this project was successful and cost-effective.
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