Construction Update: March 2026

Out With the Old

Major construction activity in March focused on excavation to install new stormwater pipes to carry runoff away from the new West Parish Water Treatment Plant. The 24-inch stormwater pipe is the lowest and deepest utility in the area. Our new 60-inch and 72-inch large-diameter mains that convey raw water to the facility will be installed above the stormwater line.  

An estimated 3,000 to 4,000 cubic yards of material were excavated, and the trench reached approximately 27 feet below grade. Given the depth of the trench, the effort required significant excavation and material handling. 

After the excavation was completed, crews removed the existing vitrified clay pipe (VCP) and began installing new high-density polyethylene (HDPE) stormwater pipe in its place. The existing VCP dates to the 1950s and is susceptible to cracking and failure. HDPE pipe has an expected service life of approximately 50 to 100 years. 

Once the new pipes were installed, crews backfilled the site and lowered a remote-controlled vibratory trench compactor into the trench box to compact the backfill in place. 

Over by Regulator House 3, a 1925 structure that provides access and control for our four oldest remaining slow sand filters, crews used a hydraulic ramming hammer, or “hoe ram,” to break up and remove an old concrete vault. This is part of the underground infrastructure that supported the old slow sand filters. 

Sensitive Demolition

The planned alignment for the 60-inch raw water main crosses a brook and rock ledge with 15 to 20 evergreens that had to be removed from the excavation limits. Many of these trees were rooted in shallow soils over granite, and tree removal also helps prevent future conflicts between root systems and buried water mains. 

Because the future excavation will be within hard granite, rock removal will be performed by drilling pilot holes and breaking the rock using a hydraulic ramming hammer. No blasting or explosives will be used to protect the sensitive infrastructure at West Parish, including dams. Vibration and deflection monitoring will be conducted continuously to monitor any impact to existing facilities. 

Cutting and Capping Old Pipes

Crews cut and capped a century-old 42-inch raw water main to permanently isolate the legacy piping and support upcoming demolition activities. Originally installed in 1924, this legacy line has served us well and is being retired. Completion of the cut-and-cap work on these utilities enables forthcoming demolition of Regulator House 3 and slow sand filters 7 through 10, which date from 1925.