14" TRANSMISSION MAIN - CLEANING AND LINING
ST. JOHNSBURY, VERMONT

Cleaning scapers are pulled through the water main to remove any mineral buildup that is present.

The summer of 2009 brought multiple Water Distribution Upgrades to the Town of St. Johnsbury, VT. One of these projects included the cleaning and cement lining of 6,700 LF of the 14-inch transmission water main designed by Dufresne Group (DG).

The 14-inch transmission main shared distribution with a 10-inch cast iron main which was abandoned at the end of the project and will become a process residual line for the Water Treatment Facility. Now, the 14-inch main is the only transmission line from the Water Treatment Facility to the central zone in Town, scheduling shut-downs to perform work was extremely crucial in this case. Multiple air release/vacuum valves were also installed along the main throughout the project.




KEY FEATURES

• This project required new pipe work at the old Treatment Plant, which re-configured an intersection of seven existing valves. Six of these valves were removed, reducing the 14-inch main to having only 1 valve. This was a crucial upgrade because the piping intersection included three opposite closing valves that were not discovered until this project began.
• Cleaning and lining was performed under the Moose River and up steep wooded slopes making accessibility to these access pits very tough.
• Special care and restoration had to be taken while work was conducted on rich farmland.