Water, Sewer, Storm Improvements

Combined sewers were designed to collect rainwater runoff, sewage, and industrial wastewater in the same system.  Much of the time all of this is transported to a wastewater treatment facility where it is treated and discharged as normal.  However, heavy rainfall and/or snowmelt can result in a combined sewer overflow (CSO), discharging untreated human and industrial waste into nearby waterbodies.

The Pleasant Street and Gilman Avenue drainage areas were identified in an overall wastewater system evaluation as a priority for combined sewer separation to reduce overflows during heavy rain events.

This area of the St. Johnsbury sewer system is served by a combination of vitrified clay tile, asbestos cement, and PVC pipes, which will be replaced with PVC pipe.  The project will also replace 21 catch basins that are currently contributing to the flows at CSO 016.

A key part of the project is the new sewer siphons at the Moose River crossing near Concord Avenue.  The existing siphon lacked redundancy and has contributed to surcharging in the upstream mains, leading to overflows at CSO 016.  The two new siphons will ensure a redundancy to support maintenance activities.

Also included in this project are upgrades to the water system on most of the streets in the project area.  As a result, many sections of the project area will have all new sewer, stormwater, and water infrastructure after construction is completed.

Dufresne Group is currently providing construction services.  Construction started in the summer of 2021 and is expected to continue through the summer of 2023.