The Township is completing a stormwater project this week to repair an existing 134’ long corrugated metal pipe (CMP) that carries a stream under Knollwood Drive. The existing pipe is very large with an oblong diameter of 78” by 120”.
Knollwood Drive is a residential subdivision containing 30 single-family homes. Most importantly, the neighborhood has a single vehicle access point onto Phoenixville Pike.
Corrugated metal pipe has a life expectancy of between 25 and 30 years and this pipe had significant deterioration, so much so, that the Township Board of Supervisors deemed the repair an emergency.
Failure of the pipe would have led to half of the homes to be cut off to vehicular traffic until a repair was made.
In order to maintain vehicle access to the neighborhood at all times, the existing pipe was slip-lined. In the slip-lining process, the existing pipe is carefully measured and a slightly smaller new pipe is inserted into the existing pipe. The space between the existing pipe and the new pipe is then filled, using a liquid concrete product to provide even more strength. Finally, both ends of the new pipe will have concrete walls (head wall and end wall) in place to provide even more strength and act as a deterrent to future erosion.
The project cost is $408,000 and the work was performed by contractor J.A. Jurich of Aston, PA. Township funding for this project is from the Township Capital Reserve Fund.